1 /* 2 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package com.sun.tools.javac.code; 27 28 import java.lang.ref.SoftReference; 29 import java.util.HashSet; 30 import java.util.HashMap; 31 import java.util.Locale; 32 import java.util.Map; 33 import java.util.Set; 34 import java.util.WeakHashMap; 35 36 import javax.tools.JavaFileObject; 37 38 import com.sun.tools.javac.code.Attribute.RetentionPolicy; 39 import com.sun.tools.javac.code.Lint.LintCategory; 40 import com.sun.tools.javac.code.Type.UndetVar.InferenceBound; 41 import com.sun.tools.javac.comp.AttrContext; 42 import com.sun.tools.javac.comp.Check; 43 import com.sun.tools.javac.comp.Enter; 44 import com.sun.tools.javac.comp.Env; 45 import com.sun.tools.javac.jvm.ClassReader; 46 import com.sun.tools.javac.tree.JCTree; 47 import com.sun.tools.javac.util.*; 48 import static com.sun.tools.javac.code.BoundKind.*; 49 import static com.sun.tools.javac.code.Flags.*; 50 import static com.sun.tools.javac.code.Kinds.MTH; 51 import static com.sun.tools.javac.code.Scope.*; 52 import static com.sun.tools.javac.code.Symbol.*; 53 import static com.sun.tools.javac.code.Type.*; 54 import static com.sun.tools.javac.code.TypeTag.*; 55 import static com.sun.tools.javac.jvm.ClassFile.externalize; 56 57 /** 58 * Utility class containing various operations on types. 59 * 60 * <p>Unless other names are more illustrative, the following naming 61 * conventions should be observed in this file: 62 * 63 * <dl> 64 * <dt>t</dt> 65 * <dd>If the first argument to an operation is a type, it should be named t.</dd> 66 * <dt>s</dt> 67 * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd> 68 * <dt>ts</dt> 69 * <dd>If an operations takes a list of types, the first should be named ts.</dd> 70 * <dt>ss</dt> 71 * <dd>A second list of types should be named ss.</dd> 72 * </dl> 73 * 74 * <p><b>This is NOT part of any supported API. 75 * If you write code that depends on this, you do so at your own risk. 76 * This code and its internal interfaces are subject to change or 77 * deletion without notice.</b> 78 */ 79 public class Types { 80 protected static final Context.Key<Types> typesKey = 81 new Context.Key<Types>(); 82 83 final Symtab syms; 84 final JavacMessages messages; 85 final Names names; 86 final boolean allowBoxing; 87 final boolean allowCovariantReturns; 88 final boolean allowObjectToPrimitiveCast; 89 final boolean allowDefaultMethods; 90 final ClassReader reader; 91 final Check chk; 92 final Enter enter; 93 JCDiagnostic.Factory diags; 94 List<Warner> warnStack = List.nil(); 95 final Name capturedName; 96 private final FunctionDescriptorLookupError functionDescriptorLookupError; 97 98 public final Warner noWarnings; 99 100 // <editor-fold defaultstate="collapsed" desc="Instantiating"> instance(Context context)101 public static Types instance(Context context) { 102 Types instance = context.get(typesKey); 103 if (instance == null) 104 instance = new Types(context); 105 return instance; 106 } 107 Types(Context context)108 protected Types(Context context) { 109 context.put(typesKey, this); 110 syms = Symtab.instance(context); 111 names = Names.instance(context); 112 Source source = Source.instance(context); 113 allowBoxing = source.allowBoxing(); 114 allowCovariantReturns = source.allowCovariantReturns(); 115 allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast(); 116 allowDefaultMethods = source.allowDefaultMethods(); 117 reader = ClassReader.instance(context); 118 chk = Check.instance(context); 119 enter = Enter.instance(context); 120 capturedName = names.fromString("<captured wildcard>"); 121 messages = JavacMessages.instance(context); 122 diags = JCDiagnostic.Factory.instance(context); 123 functionDescriptorLookupError = new FunctionDescriptorLookupError(); 124 noWarnings = new Warner(null); 125 } 126 // </editor-fold> 127 128 // <editor-fold defaultstate="collapsed" desc="bounds"> 129 /** 130 * Get a wildcard's upper bound, returning non-wildcards unchanged. 131 * @param t a type argument, either a wildcard or a type 132 */ wildUpperBound(Type t)133 public Type wildUpperBound(Type t) { 134 if (t.hasTag(WILDCARD)) { 135 WildcardType w = (WildcardType) t.unannotatedType(); 136 if (w.isSuperBound()) 137 return w.bound == null ? syms.objectType : w.bound.bound; 138 else 139 return wildUpperBound(w.type); 140 } 141 else return t.unannotatedType(); 142 } 143 144 /** 145 * Get a capture variable's upper bound, returning other types unchanged. 146 * @param t a type 147 */ cvarUpperBound(Type t)148 public Type cvarUpperBound(Type t) { 149 if (t.hasTag(TYPEVAR)) { 150 TypeVar v = (TypeVar) t.unannotatedType(); 151 return v.isCaptured() ? cvarUpperBound(v.bound) : v; 152 } 153 else return t.unannotatedType(); 154 } 155 156 /** 157 * Get a wildcard's lower bound, returning non-wildcards unchanged. 158 * @param t a type argument, either a wildcard or a type 159 */ wildLowerBound(Type t)160 public Type wildLowerBound(Type t) { 161 if (t.hasTag(WILDCARD)) { 162 WildcardType w = (WildcardType) t.unannotatedType(); 163 return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type); 164 } 165 else return t.unannotatedType(); 166 } 167 168 /** 169 * Get a capture variable's lower bound, returning other types unchanged. 170 * @param t a type 171 */ cvarLowerBound(Type t)172 public Type cvarLowerBound(Type t) { 173 if (t.hasTag(TYPEVAR)) { 174 TypeVar v = (TypeVar) t.unannotatedType(); 175 return v.isCaptured() ? cvarLowerBound(v.getLowerBound()) : v; 176 } 177 else return t.unannotatedType(); 178 } 179 // </editor-fold> 180 181 // <editor-fold defaultstate="collapsed" desc="isUnbounded"> 182 /** 183 * Checks that all the arguments to a class are unbounded 184 * wildcards or something else that doesn't make any restrictions 185 * on the arguments. If a class isUnbounded, a raw super- or 186 * subclass can be cast to it without a warning. 187 * @param t a type 188 * @return true iff the given type is unbounded or raw 189 */ isUnbounded(Type t)190 public boolean isUnbounded(Type t) { 191 return isUnbounded.visit(t); 192 } 193 // where 194 private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() { 195 196 public Boolean visitType(Type t, Void ignored) { 197 return true; 198 } 199 200 @Override 201 public Boolean visitClassType(ClassType t, Void ignored) { 202 List<Type> parms = t.tsym.type.allparams(); 203 List<Type> args = t.allparams(); 204 while (parms.nonEmpty()) { 205 WildcardType unb = new WildcardType(syms.objectType, 206 BoundKind.UNBOUND, 207 syms.boundClass, 208 (TypeVar)parms.head.unannotatedType()); 209 if (!containsType(args.head, unb)) 210 return false; 211 parms = parms.tail; 212 args = args.tail; 213 } 214 return true; 215 } 216 }; 217 // </editor-fold> 218 219 // <editor-fold defaultstate="collapsed" desc="asSub"> 220 /** 221 * Return the least specific subtype of t that starts with symbol 222 * sym. If none exists, return null. The least specific subtype 223 * is determined as follows: 224 * 225 * <p>If there is exactly one parameterized instance of sym that is a 226 * subtype of t, that parameterized instance is returned.<br> 227 * Otherwise, if the plain type or raw type `sym' is a subtype of 228 * type t, the type `sym' itself is returned. Otherwise, null is 229 * returned. 230 */ asSub(Type t, Symbol sym)231 public Type asSub(Type t, Symbol sym) { 232 return asSub.visit(t, sym); 233 } 234 // where 235 private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() { 236 237 public Type visitType(Type t, Symbol sym) { 238 return null; 239 } 240 241 @Override 242 public Type visitClassType(ClassType t, Symbol sym) { 243 if (t.tsym == sym) 244 return t; 245 Type base = asSuper(sym.type, t.tsym); 246 if (base == null) 247 return null; 248 ListBuffer<Type> from = new ListBuffer<Type>(); 249 ListBuffer<Type> to = new ListBuffer<Type>(); 250 try { 251 adapt(base, t, from, to); 252 } catch (AdaptFailure ex) { 253 return null; 254 } 255 Type res = subst(sym.type, from.toList(), to.toList()); 256 if (!isSubtype(res, t)) 257 return null; 258 ListBuffer<Type> openVars = new ListBuffer<Type>(); 259 for (List<Type> l = sym.type.allparams(); 260 l.nonEmpty(); l = l.tail) 261 if (res.contains(l.head) && !t.contains(l.head)) 262 openVars.append(l.head); 263 if (openVars.nonEmpty()) { 264 if (t.isRaw()) { 265 // The subtype of a raw type is raw 266 res = erasure(res); 267 } else { 268 // Unbound type arguments default to ? 269 List<Type> opens = openVars.toList(); 270 ListBuffer<Type> qs = new ListBuffer<Type>(); 271 for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) { 272 qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head.unannotatedType())); 273 } 274 res = subst(res, opens, qs.toList()); 275 } 276 } 277 return res; 278 } 279 280 @Override 281 public Type visitErrorType(ErrorType t, Symbol sym) { 282 return t; 283 } 284 }; 285 // </editor-fold> 286 287 // <editor-fold defaultstate="collapsed" desc="isConvertible"> 288 /** 289 * Is t a subtype of or convertible via boxing/unboxing 290 * conversion to s? 291 */ isConvertible(Type t, Type s, Warner warn)292 public boolean isConvertible(Type t, Type s, Warner warn) { 293 if (t.hasTag(ERROR)) { 294 return true; 295 } 296 boolean tPrimitive = t.isPrimitive(); 297 boolean sPrimitive = s.isPrimitive(); 298 if (tPrimitive == sPrimitive) { 299 return isSubtypeUnchecked(t, s, warn); 300 } 301 if (!allowBoxing) return false; 302 return tPrimitive 303 ? isSubtype(boxedClass(t).type, s) 304 : isSubtype(unboxedType(t), s); 305 } 306 307 /** 308 * Is t a subtype of or convertible via boxing/unboxing 309 * conversions to s? 310 */ isConvertible(Type t, Type s)311 public boolean isConvertible(Type t, Type s) { 312 return isConvertible(t, s, noWarnings); 313 } 314 // </editor-fold> 315 316 // <editor-fold defaultstate="collapsed" desc="findSam"> 317 318 /** 319 * Exception used to report a function descriptor lookup failure. The exception 320 * wraps a diagnostic that can be used to generate more details error 321 * messages. 322 */ 323 public static class FunctionDescriptorLookupError extends RuntimeException { 324 private static final long serialVersionUID = 0; 325 326 JCDiagnostic diagnostic; 327 FunctionDescriptorLookupError()328 FunctionDescriptorLookupError() { 329 this.diagnostic = null; 330 } 331 setMessage(JCDiagnostic diag)332 FunctionDescriptorLookupError setMessage(JCDiagnostic diag) { 333 this.diagnostic = diag; 334 return this; 335 } 336 getDiagnostic()337 public JCDiagnostic getDiagnostic() { 338 return diagnostic; 339 } 340 } 341 342 /** 343 * A cache that keeps track of function descriptors associated with given 344 * functional interfaces. 345 */ 346 class DescriptorCache { 347 348 private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<TypeSymbol, Entry>(); 349 350 class FunctionDescriptor { 351 Symbol descSym; 352 FunctionDescriptor(Symbol descSym)353 FunctionDescriptor(Symbol descSym) { 354 this.descSym = descSym; 355 } 356 getSymbol()357 public Symbol getSymbol() { 358 return descSym; 359 } 360 getType(Type site)361 public Type getType(Type site) { 362 site = removeWildcards(site); 363 if (!chk.checkValidGenericType(site)) { 364 //if the inferred functional interface type is not well-formed, 365 //or if it's not a subtype of the original target, issue an error 366 throw failure(diags.fragment("no.suitable.functional.intf.inst", site)); 367 } 368 return memberType(site, descSym); 369 } 370 } 371 372 class Entry { 373 final FunctionDescriptor cachedDescRes; 374 final int prevMark; 375 Entry(FunctionDescriptor cachedDescRes, int prevMark)376 public Entry(FunctionDescriptor cachedDescRes, 377 int prevMark) { 378 this.cachedDescRes = cachedDescRes; 379 this.prevMark = prevMark; 380 } 381 matches(int mark)382 boolean matches(int mark) { 383 return this.prevMark == mark; 384 } 385 } 386 get(TypeSymbol origin)387 FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError { 388 Entry e = _map.get(origin); 389 CompoundScope members = membersClosure(origin.type, false); 390 if (e == null || 391 !e.matches(members.getMark())) { 392 FunctionDescriptor descRes = findDescriptorInternal(origin, members); 393 _map.put(origin, new Entry(descRes, members.getMark())); 394 return descRes; 395 } 396 else { 397 return e.cachedDescRes; 398 } 399 } 400 401 /** 402 * Compute the function descriptor associated with a given functional interface 403 */ findDescriptorInternal(TypeSymbol origin, CompoundScope membersCache)404 public FunctionDescriptor findDescriptorInternal(TypeSymbol origin, 405 CompoundScope membersCache) throws FunctionDescriptorLookupError { 406 if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) { 407 //t must be an interface 408 throw failure("not.a.functional.intf", origin); 409 } 410 411 final ListBuffer<Symbol> abstracts = new ListBuffer<>(); 412 for (Symbol sym : membersCache.getElements(new DescriptorFilter(origin))) { 413 Type mtype = memberType(origin.type, sym); 414 if (abstracts.isEmpty() || 415 (sym.name == abstracts.first().name && 416 overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) { 417 abstracts.append(sym); 418 } else { 419 //the target method(s) should be the only abstract members of t 420 throw failure("not.a.functional.intf.1", origin, 421 diags.fragment("incompatible.abstracts", Kinds.kindName(origin), origin)); 422 } 423 } 424 if (abstracts.isEmpty()) { 425 //t must define a suitable non-generic method 426 throw failure("not.a.functional.intf.1", origin, 427 diags.fragment("no.abstracts", Kinds.kindName(origin), origin)); 428 } else if (abstracts.size() == 1) { 429 return new FunctionDescriptor(abstracts.first()); 430 } else { // size > 1 431 FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList()); 432 if (descRes == null) { 433 //we can get here if the functional interface is ill-formed 434 ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>(); 435 for (Symbol desc : abstracts) { 436 String key = desc.type.getThrownTypes().nonEmpty() ? 437 "descriptor.throws" : "descriptor"; 438 descriptors.append(diags.fragment(key, desc.name, 439 desc.type.getParameterTypes(), 440 desc.type.getReturnType(), 441 desc.type.getThrownTypes())); 442 } 443 JCDiagnostic.MultilineDiagnostic incompatibleDescriptors = 444 new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf", 445 Kinds.kindName(origin), origin), descriptors.toList()); 446 throw failure(incompatibleDescriptors); 447 } 448 return descRes; 449 } 450 } 451 452 /** 453 * Compute a synthetic type for the target descriptor given a list 454 * of override-equivalent methods in the functional interface type. 455 * The resulting method type is a method type that is override-equivalent 456 * and return-type substitutable with each method in the original list. 457 */ mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms)458 private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) { 459 //pick argument types - simply take the signature that is a 460 //subsignature of all other signatures in the list (as per JLS 8.4.2) 461 List<Symbol> mostSpecific = List.nil(); 462 outer: for (Symbol msym1 : methodSyms) { 463 Type mt1 = memberType(origin.type, msym1); 464 for (Symbol msym2 : methodSyms) { 465 Type mt2 = memberType(origin.type, msym2); 466 if (!isSubSignature(mt1, mt2)) { 467 continue outer; 468 } 469 } 470 mostSpecific = mostSpecific.prepend(msym1); 471 } 472 if (mostSpecific.isEmpty()) { 473 return null; 474 } 475 476 477 //pick return types - this is done in two phases: (i) first, the most 478 //specific return type is chosen using strict subtyping; if this fails, 479 //a second attempt is made using return type substitutability (see JLS 8.4.5) 480 boolean phase2 = false; 481 Symbol bestSoFar = null; 482 while (bestSoFar == null) { 483 outer: for (Symbol msym1 : mostSpecific) { 484 Type mt1 = memberType(origin.type, msym1); 485 for (Symbol msym2 : methodSyms) { 486 Type mt2 = memberType(origin.type, msym2); 487 if (phase2 ? 488 !returnTypeSubstitutable(mt1, mt2) : 489 !isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) { 490 continue outer; 491 } 492 } 493 bestSoFar = msym1; 494 } 495 if (phase2) { 496 break; 497 } else { 498 phase2 = true; 499 } 500 } 501 if (bestSoFar == null) return null; 502 503 //merge thrown types - form the intersection of all the thrown types in 504 //all the signatures in the list 505 boolean toErase = !bestSoFar.type.hasTag(FORALL); 506 List<Type> thrown = null; 507 Type mt1 = memberType(origin.type, bestSoFar); 508 for (Symbol msym2 : methodSyms) { 509 Type mt2 = memberType(origin.type, msym2); 510 List<Type> thrown_mt2 = mt2.getThrownTypes(); 511 if (toErase) { 512 thrown_mt2 = erasure(thrown_mt2); 513 } else { 514 /* If bestSoFar is generic then all the methods are generic. 515 * The opposite is not true: a non generic method can override 516 * a generic method (raw override) so it's safe to cast mt1 and 517 * mt2 to ForAll. 518 */ 519 ForAll fa1 = (ForAll)mt1; 520 ForAll fa2 = (ForAll)mt2; 521 thrown_mt2 = subst(thrown_mt2, fa2.tvars, fa1.tvars); 522 } 523 thrown = (thrown == null) ? 524 thrown_mt2 : 525 chk.intersect(thrown_mt2, thrown); 526 } 527 528 final List<Type> thrown1 = thrown; 529 return new FunctionDescriptor(bestSoFar) { 530 @Override 531 public Type getType(Type origin) { 532 Type mt = memberType(origin, getSymbol()); 533 return createMethodTypeWithThrown(mt, thrown1); 534 } 535 }; 536 } 537 isSubtypeInternal(Type s, Type t)538 boolean isSubtypeInternal(Type s, Type t) { 539 return (s.isPrimitive() && t.isPrimitive()) ? 540 isSameType(t, s) : 541 isSubtype(s, t); 542 } 543 failure(String msg, Object... args)544 FunctionDescriptorLookupError failure(String msg, Object... args) { 545 return failure(diags.fragment(msg, args)); 546 } 547 failure(JCDiagnostic diag)548 FunctionDescriptorLookupError failure(JCDiagnostic diag) { 549 return functionDescriptorLookupError.setMessage(diag); 550 } 551 } 552 553 private DescriptorCache descCache = new DescriptorCache(); 554 555 /** 556 * Find the method descriptor associated to this class symbol - if the 557 * symbol 'origin' is not a functional interface, an exception is thrown. 558 */ 559 public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError { 560 return descCache.get(origin).getSymbol(); 561 } 562 563 /** 564 * Find the type of the method descriptor associated to this class symbol - 565 * if the symbol 'origin' is not a functional interface, an exception is thrown. 566 */ 567 public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError { 568 return descCache.get(origin.tsym).getType(origin); 569 } 570 571 /** 572 * Is given type a functional interface? 573 */ 574 public boolean isFunctionalInterface(TypeSymbol tsym) { 575 try { 576 findDescriptorSymbol(tsym); 577 return true; 578 } catch (FunctionDescriptorLookupError ex) { 579 return false; 580 } 581 } 582 583 public boolean isFunctionalInterface(Type site) { 584 try { 585 findDescriptorType(site); 586 return true; 587 } catch (FunctionDescriptorLookupError ex) { 588 return false; 589 } 590 } 591 592 public Type removeWildcards(Type site) { 593 Type capturedSite = capture(site); 594 if (capturedSite != site) { 595 Type formalInterface = site.tsym.type; 596 ListBuffer<Type> typeargs = new ListBuffer<>(); 597 List<Type> actualTypeargs = site.getTypeArguments(); 598 List<Type> capturedTypeargs = capturedSite.getTypeArguments(); 599 //simply replace the wildcards with its bound 600 for (Type t : formalInterface.getTypeArguments()) { 601 if (actualTypeargs.head.hasTag(WILDCARD)) { 602 WildcardType wt = (WildcardType)actualTypeargs.head.unannotatedType(); 603 Type bound; 604 switch (wt.kind) { 605 case EXTENDS: 606 case UNBOUND: 607 CapturedType capVar = (CapturedType)capturedTypeargs.head.unannotatedType(); 608 //use declared bound if it doesn't depend on formal type-args 609 bound = capVar.bound.containsAny(capturedSite.getTypeArguments()) ? 610 wt.type : capVar.bound; 611 break; 612 default: 613 bound = wt.type; 614 } 615 typeargs.append(bound); 616 } else { 617 typeargs.append(actualTypeargs.head); 618 } 619 actualTypeargs = actualTypeargs.tail; 620 capturedTypeargs = capturedTypeargs.tail; 621 } 622 return subst(formalInterface, formalInterface.getTypeArguments(), typeargs.toList()); 623 } else { 624 return site; 625 } 626 } 627 628 /** 629 * Create a symbol for a class that implements a given functional interface 630 * and overrides its functional descriptor. This routine is used for two 631 * main purposes: (i) checking well-formedness of a functional interface; 632 * (ii) perform functional interface bridge calculation. 633 */ 634 public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, List<Type> targets, long cflags) { 635 if (targets.isEmpty()) { 636 return null; 637 } 638 Symbol descSym = findDescriptorSymbol(targets.head.tsym); 639 Type descType = findDescriptorType(targets.head); 640 ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass()); 641 csym.completer = null; 642 csym.members_field = new Scope(csym); 643 MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym); 644 csym.members_field.enter(instDescSym); 645 Type.ClassType ctype = new Type.ClassType(Type.noType, List.<Type>nil(), csym); 646 ctype.supertype_field = syms.objectType; 647 ctype.interfaces_field = targets; 648 csym.type = ctype; 649 csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile; 650 return csym; 651 } 652 653 /** 654 * Find the minimal set of methods that are overridden by the functional 655 * descriptor in 'origin'. All returned methods are assumed to have different 656 * erased signatures. 657 */ 658 public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) { 659 Assert.check(isFunctionalInterface(origin)); 660 Symbol descSym = findDescriptorSymbol(origin); 661 CompoundScope members = membersClosure(origin.type, false); 662 ListBuffer<Symbol> overridden = new ListBuffer<>(); 663 outer: for (Symbol m2 : members.getElementsByName(descSym.name, bridgeFilter)) { 664 if (m2 == descSym) continue; 665 else if (descSym.overrides(m2, origin, Types.this, false)) { 666 for (Symbol m3 : overridden) { 667 if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) || 668 (m3.overrides(m2, origin, Types.this, false) && 669 (pendingBridges((ClassSymbol)origin, m3.enclClass()) || 670 (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) { 671 continue outer; 672 } 673 } 674 overridden.add(m2); 675 } 676 } 677 return overridden.toList(); 678 } 679 //where 680 private Filter<Symbol> bridgeFilter = new Filter<Symbol>() { 681 public boolean accepts(Symbol t) { 682 return t.kind == Kinds.MTH && 683 t.name != names.init && 684 t.name != names.clinit && 685 (t.flags() & SYNTHETIC) == 0; 686 } 687 }; 688 private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) { 689 //a symbol will be completed from a classfile if (a) symbol has 690 //an associated file object with CLASS kind and (b) the symbol has 691 //not been entered 692 if (origin.classfile != null && 693 origin.classfile.getKind() == JavaFileObject.Kind.CLASS && 694 enter.getEnv(origin) == null) { 695 return false; 696 } 697 if (origin == s) { 698 return true; 699 } 700 for (Type t : interfaces(origin.type)) { 701 if (pendingBridges((ClassSymbol)t.tsym, s)) { 702 return true; 703 } 704 } 705 return false; 706 } 707 // </editor-fold> 708 709 /** 710 * Scope filter used to skip methods that should be ignored (such as methods 711 * overridden by j.l.Object) during function interface conversion interface check 712 */ 713 class DescriptorFilter implements Filter<Symbol> { 714 715 TypeSymbol origin; 716 717 DescriptorFilter(TypeSymbol origin) { 718 this.origin = origin; 719 } 720 721 @Override 722 public boolean accepts(Symbol sym) { 723 return sym.kind == Kinds.MTH && 724 (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT && 725 !overridesObjectMethod(origin, sym) && 726 (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0; 727 } 728 }; 729 730 // <editor-fold defaultstate="collapsed" desc="isSubtype"> 731 /** 732 * Is t an unchecked subtype of s? 733 */ 734 public boolean isSubtypeUnchecked(Type t, Type s) { 735 return isSubtypeUnchecked(t, s, noWarnings); 736 } 737 /** 738 * Is t an unchecked subtype of s? 739 */ 740 public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) { 741 boolean result = isSubtypeUncheckedInternal(t, s, warn); 742 if (result) { 743 checkUnsafeVarargsConversion(t, s, warn); 744 } 745 return result; 746 } 747 //where 748 private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) { 749 if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) { 750 t = t.unannotatedType(); 751 s = s.unannotatedType(); 752 if (((ArrayType)t).elemtype.isPrimitive()) { 753 return isSameType(elemtype(t), elemtype(s)); 754 } else { 755 return isSubtypeUnchecked(elemtype(t), elemtype(s), warn); 756 } 757 } else if (isSubtype(t, s)) { 758 return true; 759 } else if (t.hasTag(TYPEVAR)) { 760 return isSubtypeUnchecked(t.getUpperBound(), s, warn); 761 } else if (!s.isRaw()) { 762 Type t2 = asSuper(t, s.tsym); 763 if (t2 != null && t2.isRaw()) { 764 if (isReifiable(s)) { 765 warn.silentWarn(LintCategory.UNCHECKED); 766 } else { 767 warn.warn(LintCategory.UNCHECKED); 768 } 769 return true; 770 } 771 } 772 return false; 773 } 774 775 private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) { 776 if (!t.hasTag(ARRAY) || isReifiable(t)) { 777 return; 778 } 779 t = t.unannotatedType(); 780 s = s.unannotatedType(); 781 ArrayType from = (ArrayType)t; 782 boolean shouldWarn = false; 783 switch (s.getTag()) { 784 case ARRAY: 785 ArrayType to = (ArrayType)s; 786 shouldWarn = from.isVarargs() && 787 !to.isVarargs() && 788 !isReifiable(from); 789 break; 790 case CLASS: 791 shouldWarn = from.isVarargs(); 792 break; 793 } 794 if (shouldWarn) { 795 warn.warn(LintCategory.VARARGS); 796 } 797 } 798 799 /** 800 * Is t a subtype of s?<br> 801 * (not defined for Method and ForAll types) 802 */ 803 final public boolean isSubtype(Type t, Type s) { 804 return isSubtype(t, s, true); 805 } 806 final public boolean isSubtypeNoCapture(Type t, Type s) { 807 return isSubtype(t, s, false); 808 } 809 public boolean isSubtype(Type t, Type s, boolean capture) { 810 if (t == s) 811 return true; 812 813 t = t.unannotatedType(); 814 s = s.unannotatedType(); 815 816 if (t == s) 817 return true; 818 819 if (s.isPartial()) 820 return isSuperType(s, t); 821 822 if (s.isCompound()) { 823 for (Type s2 : interfaces(s).prepend(supertype(s))) { 824 if (!isSubtype(t, s2, capture)) 825 return false; 826 } 827 return true; 828 } 829 830 // Generally, if 's' is a type variable, recur on lower bound; but 831 // for inference variables and intersections, we need to keep 's' 832 // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars) 833 if (!t.hasTag(UNDETVAR) && !t.isCompound()) { 834 // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s 835 Type lower = cvarLowerBound(wildLowerBound(s)); 836 if (s != lower) 837 return isSubtype(capture ? capture(t) : t, lower, false); 838 } 839 840 return isSubtype.visit(capture ? capture(t) : t, s); 841 } 842 // where 843 private TypeRelation isSubtype = new TypeRelation() 844 { 845 @Override 846 public Boolean visitType(Type t, Type s) { 847 switch (t.getTag()) { 848 case BYTE: 849 return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag())); 850 case CHAR: 851 return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag())); 852 case SHORT: case INT: case LONG: 853 case FLOAT: case DOUBLE: 854 return t.getTag().isSubRangeOf(s.getTag()); 855 case BOOLEAN: case VOID: 856 return t.hasTag(s.getTag()); 857 case TYPEVAR: 858 return isSubtypeNoCapture(t.getUpperBound(), s); 859 case BOT: 860 return 861 s.hasTag(BOT) || s.hasTag(CLASS) || 862 s.hasTag(ARRAY) || s.hasTag(TYPEVAR); 863 case WILDCARD: //we shouldn't be here - avoids crash (see 7034495) 864 case NONE: 865 return false; 866 default: 867 throw new AssertionError("isSubtype " + t.getTag()); 868 } 869 } 870 871 private Set<TypePair> cache = new HashSet<TypePair>(); 872 873 private boolean containsTypeRecursive(Type t, Type s) { 874 TypePair pair = new TypePair(t, s); 875 if (cache.add(pair)) { 876 try { 877 return containsType(t.getTypeArguments(), 878 s.getTypeArguments()); 879 } finally { 880 cache.remove(pair); 881 } 882 } else { 883 return containsType(t.getTypeArguments(), 884 rewriteSupers(s).getTypeArguments()); 885 } 886 } 887 888 private Type rewriteSupers(Type t) { 889 if (!t.isParameterized()) 890 return t; 891 ListBuffer<Type> from = new ListBuffer<>(); 892 ListBuffer<Type> to = new ListBuffer<>(); 893 adaptSelf(t, from, to); 894 if (from.isEmpty()) 895 return t; 896 ListBuffer<Type> rewrite = new ListBuffer<>(); 897 boolean changed = false; 898 for (Type orig : to.toList()) { 899 Type s = rewriteSupers(orig); 900 if (s.isSuperBound() && !s.isExtendsBound()) { 901 s = new WildcardType(syms.objectType, 902 BoundKind.UNBOUND, 903 syms.boundClass); 904 changed = true; 905 } else if (s != orig) { 906 s = new WildcardType(wildUpperBound(s), 907 BoundKind.EXTENDS, 908 syms.boundClass); 909 changed = true; 910 } 911 rewrite.append(s); 912 } 913 if (changed) 914 return subst(t.tsym.type, from.toList(), rewrite.toList()); 915 else 916 return t; 917 } 918 919 @Override 920 public Boolean visitClassType(ClassType t, Type s) { 921 Type sup = asSuper(t, s.tsym); 922 if (sup == null) return false; 923 // If t is an intersection, sup might not be a class type 924 if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s); 925 return sup.tsym == s.tsym 926 // Check type variable containment 927 && (!s.isParameterized() || containsTypeRecursive(s, sup)) 928 && isSubtypeNoCapture(sup.getEnclosingType(), 929 s.getEnclosingType()); 930 } 931 932 @Override 933 public Boolean visitArrayType(ArrayType t, Type s) { 934 if (s.hasTag(ARRAY)) { 935 if (t.elemtype.isPrimitive()) 936 return isSameType(t.elemtype, elemtype(s)); 937 else 938 return isSubtypeNoCapture(t.elemtype, elemtype(s)); 939 } 940 941 if (s.hasTag(CLASS)) { 942 Name sname = s.tsym.getQualifiedName(); 943 return sname == names.java_lang_Object 944 || sname == names.java_lang_Cloneable 945 || sname == names.java_io_Serializable; 946 } 947 948 return false; 949 } 950 951 @Override 952 public Boolean visitUndetVar(UndetVar t, Type s) { 953 //todo: test against origin needed? or replace with substitution? 954 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) { 955 return true; 956 } else if (s.hasTag(BOT)) { 957 //if 's' is 'null' there's no instantiated type U for which 958 //U <: s (but 'null' itself, which is not a valid type) 959 return false; 960 } 961 962 t.addBound(InferenceBound.UPPER, s, Types.this); 963 return true; 964 } 965 966 @Override 967 public Boolean visitErrorType(ErrorType t, Type s) { 968 return true; 969 } 970 }; 971 972 /** 973 * Is t a subtype of every type in given list `ts'?<br> 974 * (not defined for Method and ForAll types)<br> 975 * Allows unchecked conversions. 976 */ 977 public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) { 978 for (List<Type> l = ts; l.nonEmpty(); l = l.tail) 979 if (!isSubtypeUnchecked(t, l.head, warn)) 980 return false; 981 return true; 982 } 983 984 /** 985 * Are corresponding elements of ts subtypes of ss? If lists are 986 * of different length, return false. 987 */ 988 public boolean isSubtypes(List<Type> ts, List<Type> ss) { 989 while (ts.tail != null && ss.tail != null 990 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 991 isSubtype(ts.head, ss.head)) { 992 ts = ts.tail; 993 ss = ss.tail; 994 } 995 return ts.tail == null && ss.tail == null; 996 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 997 } 998 999 /** 1000 * Are corresponding elements of ts subtypes of ss, allowing 1001 * unchecked conversions? If lists are of different length, 1002 * return false. 1003 **/ 1004 public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) { 1005 while (ts.tail != null && ss.tail != null 1006 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 1007 isSubtypeUnchecked(ts.head, ss.head, warn)) { 1008 ts = ts.tail; 1009 ss = ss.tail; 1010 } 1011 return ts.tail == null && ss.tail == null; 1012 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 1013 } 1014 // </editor-fold> 1015 1016 // <editor-fold defaultstate="collapsed" desc="isSuperType"> 1017 /** 1018 * Is t a supertype of s? 1019 */ 1020 public boolean isSuperType(Type t, Type s) { 1021 switch (t.getTag()) { 1022 case ERROR: 1023 return true; 1024 case UNDETVAR: { 1025 UndetVar undet = (UndetVar)t; 1026 if (t == s || 1027 undet.qtype == s || 1028 s.hasTag(ERROR) || 1029 s.hasTag(BOT)) { 1030 return true; 1031 } 1032 undet.addBound(InferenceBound.LOWER, s, this); 1033 return true; 1034 } 1035 default: 1036 return isSubtype(s, t); 1037 } 1038 } 1039 // </editor-fold> 1040 1041 // <editor-fold defaultstate="collapsed" desc="isSameType"> 1042 /** 1043 * Are corresponding elements of the lists the same type? If 1044 * lists are of different length, return false. 1045 */ 1046 public boolean isSameTypes(List<Type> ts, List<Type> ss) { 1047 return isSameTypes(ts, ss, false); 1048 } 1049 public boolean isSameTypes(List<Type> ts, List<Type> ss, boolean strict) { 1050 while (ts.tail != null && ss.tail != null 1051 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ && 1052 isSameType(ts.head, ss.head, strict)) { 1053 ts = ts.tail; 1054 ss = ss.tail; 1055 } 1056 return ts.tail == null && ss.tail == null; 1057 /*inlined: ts.isEmpty() && ss.isEmpty();*/ 1058 } 1059 1060 /** 1061 * A polymorphic signature method (JLS SE 7, 8.4.1) is a method that 1062 * (i) is declared in the java.lang.invoke.MethodHandle class, (ii) takes 1063 * a single variable arity parameter (iii) whose declared type is Object[], 1064 * (iv) has a return type of Object and (v) is native. 1065 */ 1066 public boolean isSignaturePolymorphic(MethodSymbol msym) { 1067 List<Type> argtypes = msym.type.getParameterTypes(); 1068 return (msym.flags_field & NATIVE) != 0 && 1069 msym.owner == syms.methodHandleType.tsym && 1070 argtypes.length() == 1 && 1071 argtypes.head.hasTag(TypeTag.ARRAY) && 1072 msym.type.getReturnType().tsym == syms.objectType.tsym && 1073 ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym; 1074 } 1075 1076 /** 1077 * Is t the same type as s? 1078 */ 1079 public boolean isSameType(Type t, Type s) { 1080 return isSameType(t, s, false); 1081 } 1082 public boolean isSameType(Type t, Type s, boolean strict) { 1083 return strict ? 1084 isSameTypeStrict.visit(t, s) : 1085 isSameTypeLoose.visit(t, s); 1086 } 1087 public boolean isSameAnnotatedType(Type t, Type s) { 1088 return isSameAnnotatedType.visit(t, s); 1089 } 1090 // where 1091 abstract class SameTypeVisitor extends TypeRelation { 1092 1093 public Boolean visitType(Type t, Type s) { 1094 if (t == s) 1095 return true; 1096 1097 if (s.isPartial()) 1098 return visit(s, t); 1099 1100 switch (t.getTag()) { 1101 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: 1102 case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE: 1103 return t.hasTag(s.getTag()); 1104 case TYPEVAR: { 1105 if (s.hasTag(TYPEVAR)) { 1106 //type-substitution does not preserve type-var types 1107 //check that type var symbols and bounds are indeed the same 1108 return sameTypeVars((TypeVar)t.unannotatedType(), (TypeVar)s.unannotatedType()); 1109 } 1110 else { 1111 //special case for s == ? super X, where upper(s) = u 1112 //check that u == t, where u has been set by Type.withTypeVar 1113 return s.isSuperBound() && 1114 !s.isExtendsBound() && 1115 visit(t, wildUpperBound(s)); 1116 } 1117 } 1118 default: 1119 throw new AssertionError("isSameType " + t.getTag()); 1120 } 1121 } 1122 1123 abstract boolean sameTypeVars(TypeVar tv1, TypeVar tv2); 1124 1125 @Override 1126 public Boolean visitWildcardType(WildcardType t, Type s) { 1127 if (s.isPartial()) 1128 return visit(s, t); 1129 else 1130 return false; 1131 } 1132 1133 @Override 1134 public Boolean visitClassType(ClassType t, Type s) { 1135 if (t == s) 1136 return true; 1137 1138 if (s.isPartial()) 1139 return visit(s, t); 1140 1141 if (s.isSuperBound() && !s.isExtendsBound()) 1142 return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s)); 1143 1144 if (t.isCompound() && s.isCompound()) { 1145 if (!visit(supertype(t), supertype(s))) 1146 return false; 1147 1148 HashSet<UniqueType> set = new HashSet<UniqueType>(); 1149 for (Type x : interfaces(t)) 1150 set.add(new UniqueType(x.unannotatedType(), Types.this)); 1151 for (Type x : interfaces(s)) { 1152 if (!set.remove(new UniqueType(x.unannotatedType(), Types.this))) 1153 return false; 1154 } 1155 return (set.isEmpty()); 1156 } 1157 return t.tsym == s.tsym 1158 && visit(t.getEnclosingType(), s.getEnclosingType()) 1159 && containsTypes(t.getTypeArguments(), s.getTypeArguments()); 1160 } 1161 1162 abstract protected boolean containsTypes(List<Type> ts1, List<Type> ts2); 1163 1164 @Override 1165 public Boolean visitArrayType(ArrayType t, Type s) { 1166 if (t == s) 1167 return true; 1168 1169 if (s.isPartial()) 1170 return visit(s, t); 1171 1172 return s.hasTag(ARRAY) 1173 && containsTypeEquivalent(t.elemtype, elemtype(s)); 1174 } 1175 1176 @Override 1177 public Boolean visitMethodType(MethodType t, Type s) { 1178 // isSameType for methods does not take thrown 1179 // exceptions into account! 1180 return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType()); 1181 } 1182 1183 @Override 1184 public Boolean visitPackageType(PackageType t, Type s) { 1185 return t == s; 1186 } 1187 1188 @Override 1189 public Boolean visitForAll(ForAll t, Type s) { 1190 if (!s.hasTag(FORALL)) { 1191 return false; 1192 } 1193 1194 ForAll forAll = (ForAll)s; 1195 return hasSameBounds(t, forAll) 1196 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); 1197 } 1198 1199 @Override 1200 public Boolean visitUndetVar(UndetVar t, Type s) { 1201 if (s.hasTag(WILDCARD)) { 1202 // FIXME, this might be leftovers from before capture conversion 1203 return false; 1204 } 1205 1206 if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) { 1207 return true; 1208 } 1209 1210 t.addBound(InferenceBound.EQ, s, Types.this); 1211 1212 return true; 1213 } 1214 1215 @Override 1216 public Boolean visitErrorType(ErrorType t, Type s) { 1217 return true; 1218 } 1219 } 1220 1221 /** 1222 * Standard type-equality relation - type variables are considered 1223 * equals if they share the same type symbol. 1224 */ 1225 TypeRelation isSameTypeLoose = new LooseSameTypeVisitor(); 1226 1227 private class LooseSameTypeVisitor extends SameTypeVisitor { 1228 1229 /** cache of the type-variable pairs being (recursively) tested. */ 1230 private Set<TypePair> cache = new HashSet<>(); 1231 1232 @Override 1233 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) { 1234 return tv1.tsym == tv2.tsym && checkSameBounds(tv1, tv2); 1235 } 1236 @Override 1237 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) { 1238 return containsTypeEquivalent(ts1, ts2); 1239 } 1240 1241 /** 1242 * Since type-variable bounds can be recursive, we need to protect against 1243 * infinite loops - where the same bounds are checked over and over recursively. 1244 */ 1245 private boolean checkSameBounds(TypeVar tv1, TypeVar tv2) { 1246 TypePair p = new TypePair(tv1, tv2, true); 1247 if (cache.add(p)) { 1248 try { 1249 return visit(tv1.getUpperBound(), tv2.getUpperBound()); 1250 } finally { 1251 cache.remove(p); 1252 } 1253 } else { 1254 return false; 1255 } 1256 } 1257 }; 1258 1259 /** 1260 * Strict type-equality relation - type variables are considered 1261 * equals if they share the same object identity. 1262 */ 1263 TypeRelation isSameTypeStrict = new SameTypeVisitor() { 1264 @Override 1265 boolean sameTypeVars(TypeVar tv1, TypeVar tv2) { 1266 return tv1 == tv2; 1267 } 1268 @Override 1269 protected boolean containsTypes(List<Type> ts1, List<Type> ts2) { 1270 return isSameTypes(ts1, ts2, true); 1271 } 1272 1273 @Override 1274 public Boolean visitWildcardType(WildcardType t, Type s) { 1275 if (!s.hasTag(WILDCARD)) { 1276 return false; 1277 } else { 1278 WildcardType t2 = (WildcardType)s.unannotatedType(); 1279 return t.kind == t2.kind && 1280 isSameType(t.type, t2.type, true); 1281 } 1282 } 1283 }; 1284 1285 /** 1286 * A version of LooseSameTypeVisitor that takes AnnotatedTypes 1287 * into account. 1288 */ 1289 TypeRelation isSameAnnotatedType = new LooseSameTypeVisitor() { 1290 @Override 1291 public Boolean visitAnnotatedType(AnnotatedType t, Type s) { 1292 if (!s.isAnnotated()) 1293 return false; 1294 if (!t.getAnnotationMirrors().containsAll(s.getAnnotationMirrors())) 1295 return false; 1296 if (!s.getAnnotationMirrors().containsAll(t.getAnnotationMirrors())) 1297 return false; 1298 return visit(t.unannotatedType(), s); 1299 } 1300 }; 1301 // </editor-fold> 1302 1303 // <editor-fold defaultstate="collapsed" desc="Contains Type"> 1304 public boolean containedBy(Type t, Type s) { 1305 switch (t.getTag()) { 1306 case UNDETVAR: 1307 if (s.hasTag(WILDCARD)) { 1308 UndetVar undetvar = (UndetVar)t; 1309 WildcardType wt = (WildcardType)s.unannotatedType(); 1310 switch(wt.kind) { 1311 case UNBOUND: 1312 break; 1313 case EXTENDS: { 1314 Type bound = wildUpperBound(s); 1315 undetvar.addBound(InferenceBound.UPPER, bound, this); 1316 break; 1317 } 1318 case SUPER: { 1319 Type bound = wildLowerBound(s); 1320 undetvar.addBound(InferenceBound.LOWER, bound, this); 1321 break; 1322 } 1323 } 1324 return true; 1325 } else { 1326 return isSameType(t, s); 1327 } 1328 case ERROR: 1329 return true; 1330 default: 1331 return containsType(s, t); 1332 } 1333 } 1334 1335 boolean containsType(List<Type> ts, List<Type> ss) { 1336 while (ts.nonEmpty() && ss.nonEmpty() 1337 && containsType(ts.head, ss.head)) { 1338 ts = ts.tail; 1339 ss = ss.tail; 1340 } 1341 return ts.isEmpty() && ss.isEmpty(); 1342 } 1343 1344 /** 1345 * Check if t contains s. 1346 * 1347 * <p>T contains S if: 1348 * 1349 * <p>{@code L(T) <: L(S) && U(S) <: U(T)} 1350 * 1351 * <p>This relation is only used by ClassType.isSubtype(), that 1352 * is, 1353 * 1354 * <p>{@code C<S> <: C<T> if T contains S.} 1355 * 1356 * <p>Because of F-bounds, this relation can lead to infinite 1357 * recursion. Thus we must somehow break that recursion. Notice 1358 * that containsType() is only called from ClassType.isSubtype(). 1359 * Since the arguments have already been checked against their 1360 * bounds, we know: 1361 * 1362 * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)} 1363 * 1364 * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)} 1365 * 1366 * @param t a type 1367 * @param s a type 1368 */ 1369 public boolean containsType(Type t, Type s) { 1370 return containsType.visit(t, s); 1371 } 1372 // where 1373 private TypeRelation containsType = new TypeRelation() { 1374 1375 public Boolean visitType(Type t, Type s) { 1376 if (s.isPartial()) 1377 return containedBy(s, t); 1378 else 1379 return isSameType(t, s); 1380 } 1381 1382 // void debugContainsType(WildcardType t, Type s) { 1383 // System.err.println(); 1384 // System.err.format(" does %s contain %s?%n", t, s); 1385 // System.err.format(" %s U(%s) <: U(%s) %s = %s%n", 1386 // wildUpperBound(s), s, t, wildUpperBound(t), 1387 // t.isSuperBound() 1388 // || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))); 1389 // System.err.format(" %s L(%s) <: L(%s) %s = %s%n", 1390 // wildLowerBound(t), t, s, wildLowerBound(s), 1391 // t.isExtendsBound() 1392 // || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))); 1393 // System.err.println(); 1394 // } 1395 1396 @Override 1397 public Boolean visitWildcardType(WildcardType t, Type s) { 1398 if (s.isPartial()) 1399 return containedBy(s, t); 1400 else { 1401 // debugContainsType(t, s); 1402 return isSameWildcard(t, s) 1403 || t.type == s 1404 || isCaptureOf(s, t) 1405 || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), cvarLowerBound(wildLowerBound(s)))) && 1406 // TODO: JDK-8039214, cvarUpperBound call here is incorrect 1407 (t.isSuperBound() || isSubtypeNoCapture(cvarUpperBound(wildUpperBound(s)), wildUpperBound(t)))); 1408 } 1409 } 1410 1411 @Override 1412 public Boolean visitUndetVar(UndetVar t, Type s) { 1413 if (!s.hasTag(WILDCARD)) { 1414 return isSameType(t, s); 1415 } else { 1416 return false; 1417 } 1418 } 1419 1420 @Override 1421 public Boolean visitErrorType(ErrorType t, Type s) { 1422 return true; 1423 } 1424 }; 1425 1426 public boolean isCaptureOf(Type s, WildcardType t) { 1427 if (!s.hasTag(TYPEVAR) || !((TypeVar)s.unannotatedType()).isCaptured()) 1428 return false; 1429 return isSameWildcard(t, ((CapturedType)s.unannotatedType()).wildcard); 1430 } 1431 1432 public boolean isSameWildcard(WildcardType t, Type s) { 1433 if (!s.hasTag(WILDCARD)) 1434 return false; 1435 WildcardType w = (WildcardType)s.unannotatedType(); 1436 return w.kind == t.kind && w.type == t.type; 1437 } 1438 1439 public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) { 1440 while (ts.nonEmpty() && ss.nonEmpty() 1441 && containsTypeEquivalent(ts.head, ss.head)) { 1442 ts = ts.tail; 1443 ss = ss.tail; 1444 } 1445 return ts.isEmpty() && ss.isEmpty(); 1446 } 1447 // </editor-fold> 1448 1449 /** 1450 * Can t and s be compared for equality? Any primitive == 1451 * primitive or primitive == object comparisons here are an error. 1452 * Unboxing and correct primitive == primitive comparisons are 1453 * already dealt with in Attr.visitBinary. 1454 * 1455 */ 1456 public boolean isEqualityComparable(Type s, Type t, Warner warn) { 1457 if (t.isNumeric() && s.isNumeric()) 1458 return true; 1459 1460 boolean tPrimitive = t.isPrimitive(); 1461 boolean sPrimitive = s.isPrimitive(); 1462 if (!tPrimitive && !sPrimitive) { 1463 return isCastable(s, t, warn) || isCastable(t, s, warn); 1464 } else { 1465 return false; 1466 } 1467 } 1468 1469 // <editor-fold defaultstate="collapsed" desc="isCastable"> 1470 public boolean isCastable(Type t, Type s) { 1471 return isCastable(t, s, noWarnings); 1472 } 1473 1474 /** 1475 * Is t is castable to s?<br> 1476 * s is assumed to be an erased type.<br> 1477 * (not defined for Method and ForAll types). 1478 */ 1479 public boolean isCastable(Type t, Type s, Warner warn) { 1480 if (t == s) 1481 return true; 1482 1483 if (t.isPrimitive() != s.isPrimitive()) 1484 return allowBoxing && ( 1485 isConvertible(t, s, warn) 1486 || (allowObjectToPrimitiveCast && 1487 s.isPrimitive() && 1488 isSubtype(boxedClass(s).type, t))); 1489 if (warn != warnStack.head) { 1490 try { 1491 warnStack = warnStack.prepend(warn); 1492 checkUnsafeVarargsConversion(t, s, warn); 1493 return isCastable.visit(t,s); 1494 } finally { 1495 warnStack = warnStack.tail; 1496 } 1497 } else { 1498 return isCastable.visit(t,s); 1499 } 1500 } 1501 // where 1502 private TypeRelation isCastable = new TypeRelation() { 1503 1504 public Boolean visitType(Type t, Type s) { 1505 if (s.hasTag(ERROR)) 1506 return true; 1507 1508 switch (t.getTag()) { 1509 case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT: 1510 case DOUBLE: 1511 return s.isNumeric(); 1512 case BOOLEAN: 1513 return s.hasTag(BOOLEAN); 1514 case VOID: 1515 return false; 1516 case BOT: 1517 return isSubtype(t, s); 1518 default: 1519 throw new AssertionError(); 1520 } 1521 } 1522 1523 @Override 1524 public Boolean visitWildcardType(WildcardType t, Type s) { 1525 return isCastable(wildUpperBound(t), s, warnStack.head); 1526 } 1527 1528 @Override 1529 public Boolean visitClassType(ClassType t, Type s) { 1530 if (s.hasTag(ERROR) || s.hasTag(BOT)) 1531 return true; 1532 1533 if (s.hasTag(TYPEVAR)) { 1534 if (isCastable(t, s.getUpperBound(), noWarnings)) { 1535 warnStack.head.warn(LintCategory.UNCHECKED); 1536 return true; 1537 } else { 1538 return false; 1539 } 1540 } 1541 1542 if (t.isIntersection() || s.isIntersection()) { 1543 return !t.isIntersection() ? 1544 visitIntersectionType((IntersectionClassType)s.unannotatedType(), t, true) : 1545 visitIntersectionType((IntersectionClassType)t.unannotatedType(), s, false); 1546 } 1547 1548 if (s.hasTag(CLASS) || s.hasTag(ARRAY)) { 1549 boolean upcast; 1550 if ((upcast = isSubtype(erasure(t), erasure(s))) 1551 || isSubtype(erasure(s), erasure(t))) { 1552 if (!upcast && s.hasTag(ARRAY)) { 1553 if (!isReifiable(s)) 1554 warnStack.head.warn(LintCategory.UNCHECKED); 1555 return true; 1556 } else if (s.isRaw()) { 1557 return true; 1558 } else if (t.isRaw()) { 1559 if (!isUnbounded(s)) 1560 warnStack.head.warn(LintCategory.UNCHECKED); 1561 return true; 1562 } 1563 // Assume |a| <: |b| 1564 final Type a = upcast ? t : s; 1565 final Type b = upcast ? s : t; 1566 final boolean HIGH = true; 1567 final boolean LOW = false; 1568 final boolean DONT_REWRITE_TYPEVARS = false; 1569 Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS); 1570 Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS); 1571 Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS); 1572 Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS); 1573 Type lowSub = asSub(bLow, aLow.tsym); 1574 Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); 1575 if (highSub == null) { 1576 final boolean REWRITE_TYPEVARS = true; 1577 aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS); 1578 aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS); 1579 bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS); 1580 bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS); 1581 lowSub = asSub(bLow, aLow.tsym); 1582 highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym); 1583 } 1584 if (highSub != null) { 1585 if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) { 1586 Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym); 1587 } 1588 if (!disjointTypes(aHigh.allparams(), highSub.allparams()) 1589 && !disjointTypes(aHigh.allparams(), lowSub.allparams()) 1590 && !disjointTypes(aLow.allparams(), highSub.allparams()) 1591 && !disjointTypes(aLow.allparams(), lowSub.allparams())) { 1592 if (upcast ? giveWarning(a, b) : 1593 giveWarning(b, a)) 1594 warnStack.head.warn(LintCategory.UNCHECKED); 1595 return true; 1596 } 1597 } 1598 if (isReifiable(s)) 1599 return isSubtypeUnchecked(a, b); 1600 else 1601 return isSubtypeUnchecked(a, b, warnStack.head); 1602 } 1603 1604 // Sidecast 1605 if (s.hasTag(CLASS)) { 1606 if ((s.tsym.flags() & INTERFACE) != 0) { 1607 return ((t.tsym.flags() & FINAL) == 0) 1608 ? sideCast(t, s, warnStack.head) 1609 : sideCastFinal(t, s, warnStack.head); 1610 } else if ((t.tsym.flags() & INTERFACE) != 0) { 1611 return ((s.tsym.flags() & FINAL) == 0) 1612 ? sideCast(t, s, warnStack.head) 1613 : sideCastFinal(t, s, warnStack.head); 1614 } else { 1615 // unrelated class types 1616 return false; 1617 } 1618 } 1619 } 1620 return false; 1621 } 1622 1623 boolean visitIntersectionType(IntersectionClassType ict, Type s, boolean reverse) { 1624 Warner warn = noWarnings; 1625 for (Type c : ict.getComponents()) { 1626 warn.clear(); 1627 if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn)) 1628 return false; 1629 } 1630 if (warn.hasLint(LintCategory.UNCHECKED)) 1631 warnStack.head.warn(LintCategory.UNCHECKED); 1632 return true; 1633 } 1634 1635 @Override 1636 public Boolean visitArrayType(ArrayType t, Type s) { 1637 switch (s.getTag()) { 1638 case ERROR: 1639 case BOT: 1640 return true; 1641 case TYPEVAR: 1642 if (isCastable(s, t, noWarnings)) { 1643 warnStack.head.warn(LintCategory.UNCHECKED); 1644 return true; 1645 } else { 1646 return false; 1647 } 1648 case CLASS: 1649 return isSubtype(t, s); 1650 case ARRAY: 1651 if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) { 1652 return elemtype(t).hasTag(elemtype(s).getTag()); 1653 } else { 1654 return visit(elemtype(t), elemtype(s)); 1655 } 1656 default: 1657 return false; 1658 } 1659 } 1660 1661 @Override 1662 public Boolean visitTypeVar(TypeVar t, Type s) { 1663 switch (s.getTag()) { 1664 case ERROR: 1665 case BOT: 1666 return true; 1667 case TYPEVAR: 1668 if (isSubtype(t, s)) { 1669 return true; 1670 } else if (isCastable(t.bound, s, noWarnings)) { 1671 warnStack.head.warn(LintCategory.UNCHECKED); 1672 return true; 1673 } else { 1674 return false; 1675 } 1676 default: 1677 return isCastable(t.bound, s, warnStack.head); 1678 } 1679 } 1680 1681 @Override 1682 public Boolean visitErrorType(ErrorType t, Type s) { 1683 return true; 1684 } 1685 }; 1686 // </editor-fold> 1687 1688 // <editor-fold defaultstate="collapsed" desc="disjointTypes"> 1689 public boolean disjointTypes(List<Type> ts, List<Type> ss) { 1690 while (ts.tail != null && ss.tail != null) { 1691 if (disjointType(ts.head, ss.head)) return true; 1692 ts = ts.tail; 1693 ss = ss.tail; 1694 } 1695 return false; 1696 } 1697 1698 /** 1699 * Two types or wildcards are considered disjoint if it can be 1700 * proven that no type can be contained in both. It is 1701 * conservative in that it is allowed to say that two types are 1702 * not disjoint, even though they actually are. 1703 * 1704 * The type {@code C<X>} is castable to {@code C<Y>} exactly if 1705 * {@code X} and {@code Y} are not disjoint. 1706 */ 1707 public boolean disjointType(Type t, Type s) { 1708 return disjointType.visit(t, s); 1709 } 1710 // where 1711 private TypeRelation disjointType = new TypeRelation() { 1712 1713 private Set<TypePair> cache = new HashSet<TypePair>(); 1714 1715 @Override 1716 public Boolean visitType(Type t, Type s) { 1717 if (s.hasTag(WILDCARD)) 1718 return visit(s, t); 1719 else 1720 return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t); 1721 } 1722 1723 private boolean isCastableRecursive(Type t, Type s) { 1724 TypePair pair = new TypePair(t, s); 1725 if (cache.add(pair)) { 1726 try { 1727 return Types.this.isCastable(t, s); 1728 } finally { 1729 cache.remove(pair); 1730 } 1731 } else { 1732 return true; 1733 } 1734 } 1735 1736 private boolean notSoftSubtypeRecursive(Type t, Type s) { 1737 TypePair pair = new TypePair(t, s); 1738 if (cache.add(pair)) { 1739 try { 1740 return Types.this.notSoftSubtype(t, s); 1741 } finally { 1742 cache.remove(pair); 1743 } 1744 } else { 1745 return false; 1746 } 1747 } 1748 1749 @Override 1750 public Boolean visitWildcardType(WildcardType t, Type s) { 1751 if (t.isUnbound()) 1752 return false; 1753 1754 if (!s.hasTag(WILDCARD)) { 1755 if (t.isExtendsBound()) 1756 return notSoftSubtypeRecursive(s, t.type); 1757 else 1758 return notSoftSubtypeRecursive(t.type, s); 1759 } 1760 1761 if (s.isUnbound()) 1762 return false; 1763 1764 if (t.isExtendsBound()) { 1765 if (s.isExtendsBound()) 1766 return !isCastableRecursive(t.type, wildUpperBound(s)); 1767 else if (s.isSuperBound()) 1768 return notSoftSubtypeRecursive(wildLowerBound(s), t.type); 1769 } else if (t.isSuperBound()) { 1770 if (s.isExtendsBound()) 1771 return notSoftSubtypeRecursive(t.type, wildUpperBound(s)); 1772 } 1773 return false; 1774 } 1775 }; 1776 // </editor-fold> 1777 1778 // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds"> 1779 public List<Type> cvarLowerBounds(List<Type> ts) { 1780 return map(ts, cvarLowerBoundMapping); 1781 } 1782 private final Mapping cvarLowerBoundMapping = new Mapping("cvarLowerBound") { 1783 public Type apply(Type t) { 1784 return cvarLowerBound(t); 1785 } 1786 }; 1787 // </editor-fold> 1788 1789 // <editor-fold defaultstate="collapsed" desc="notSoftSubtype"> 1790 /** 1791 * This relation answers the question: is impossible that 1792 * something of type `t' can be a subtype of `s'? This is 1793 * different from the question "is `t' not a subtype of `s'?" 1794 * when type variables are involved: Integer is not a subtype of T 1795 * where {@code <T extends Number>} but it is not true that Integer cannot 1796 * possibly be a subtype of T. 1797 */ 1798 public boolean notSoftSubtype(Type t, Type s) { 1799 if (t == s) return false; 1800 if (t.hasTag(TYPEVAR)) { 1801 TypeVar tv = (TypeVar) t; 1802 return !isCastable(tv.bound, 1803 relaxBound(s), 1804 noWarnings); 1805 } 1806 if (!s.hasTag(WILDCARD)) 1807 s = cvarUpperBound(s); 1808 1809 return !isSubtype(t, relaxBound(s)); 1810 } 1811 1812 private Type relaxBound(Type t) { 1813 if (t.hasTag(TYPEVAR)) { 1814 while (t.hasTag(TYPEVAR)) 1815 t = t.getUpperBound(); 1816 t = rewriteQuantifiers(t, true, true); 1817 } 1818 return t; 1819 } 1820 // </editor-fold> 1821 1822 // <editor-fold defaultstate="collapsed" desc="isReifiable"> 1823 public boolean isReifiable(Type t) { 1824 return isReifiable.visit(t); 1825 } 1826 // where 1827 private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() { 1828 1829 public Boolean visitType(Type t, Void ignored) { 1830 return true; 1831 } 1832 1833 @Override 1834 public Boolean visitClassType(ClassType t, Void ignored) { 1835 if (t.isCompound()) 1836 return false; 1837 else { 1838 if (!t.isParameterized()) 1839 return true; 1840 1841 for (Type param : t.allparams()) { 1842 if (!param.isUnbound()) 1843 return false; 1844 } 1845 return true; 1846 } 1847 } 1848 1849 @Override 1850 public Boolean visitArrayType(ArrayType t, Void ignored) { 1851 return visit(t.elemtype); 1852 } 1853 1854 @Override 1855 public Boolean visitTypeVar(TypeVar t, Void ignored) { 1856 return false; 1857 } 1858 }; 1859 // </editor-fold> 1860 1861 // <editor-fold defaultstate="collapsed" desc="Array Utils"> 1862 public boolean isArray(Type t) { 1863 while (t.hasTag(WILDCARD)) 1864 t = wildUpperBound(t); 1865 return t.hasTag(ARRAY); 1866 } 1867 1868 /** 1869 * The element type of an array. 1870 */ 1871 public Type elemtype(Type t) { 1872 switch (t.getTag()) { 1873 case WILDCARD: 1874 return elemtype(wildUpperBound(t)); 1875 case ARRAY: 1876 t = t.unannotatedType(); 1877 return ((ArrayType)t).elemtype; 1878 case FORALL: 1879 return elemtype(((ForAll)t).qtype); 1880 case ERROR: 1881 return t; 1882 default: 1883 return null; 1884 } 1885 } 1886 1887 public Type elemtypeOrType(Type t) { 1888 Type elemtype = elemtype(t); 1889 return elemtype != null ? 1890 elemtype : 1891 t; 1892 } 1893 1894 /** 1895 * Mapping to take element type of an arraytype 1896 */ 1897 private Mapping elemTypeFun = new Mapping ("elemTypeFun") { 1898 public Type apply(Type t) { 1899 while (t.hasTag(TYPEVAR)) { 1900 t = t.getUpperBound(); 1901 } 1902 return elemtype(t); 1903 } 1904 }; 1905 1906 /** 1907 * The number of dimensions of an array type. 1908 */ 1909 public int dimensions(Type t) { 1910 int result = 0; 1911 while (t.hasTag(ARRAY)) { 1912 result++; 1913 t = elemtype(t); 1914 } 1915 return result; 1916 } 1917 1918 /** 1919 * Returns an ArrayType with the component type t 1920 * 1921 * @param t The component type of the ArrayType 1922 * @return the ArrayType for the given component 1923 */ 1924 public ArrayType makeArrayType(Type t) { 1925 if (t.hasTag(VOID) || t.hasTag(PACKAGE)) { 1926 Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString()); 1927 } 1928 return new ArrayType(t, syms.arrayClass); 1929 } 1930 // </editor-fold> 1931 1932 // <editor-fold defaultstate="collapsed" desc="asSuper"> 1933 /** 1934 * Return the (most specific) base type of t that starts with the 1935 * given symbol. If none exists, return null. 1936 * 1937 * @param t a type 1938 * @param sym a symbol 1939 */ 1940 public Type asSuper(Type t, Symbol sym) { 1941 /* Some examples: 1942 * 1943 * (Enum<E>, Comparable) => Comparable<E> 1944 * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind> 1945 * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree 1946 * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) => 1947 * Iterable<capture#160 of ? extends c.s.s.d.DocTree> 1948 */ 1949 if (sym.type == syms.objectType) { //optimization 1950 return syms.objectType; 1951 } 1952 return asSuper.visit(t, sym); 1953 } 1954 // where 1955 private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() { 1956 1957 public Type visitType(Type t, Symbol sym) { 1958 return null; 1959 } 1960 1961 @Override 1962 public Type visitClassType(ClassType t, Symbol sym) { 1963 if (t.tsym == sym) 1964 return t; 1965 1966 Type st = supertype(t); 1967 if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) { 1968 Type x = asSuper(st, sym); 1969 if (x != null) 1970 return x; 1971 } 1972 if ((sym.flags() & INTERFACE) != 0) { 1973 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { 1974 if (!l.head.hasTag(ERROR)) { 1975 Type x = asSuper(l.head, sym); 1976 if (x != null) 1977 return x; 1978 } 1979 } 1980 } 1981 return null; 1982 } 1983 1984 @Override 1985 public Type visitArrayType(ArrayType t, Symbol sym) { 1986 return isSubtype(t, sym.type) ? sym.type : null; 1987 } 1988 1989 @Override 1990 public Type visitTypeVar(TypeVar t, Symbol sym) { 1991 if (t.tsym == sym) 1992 return t; 1993 else 1994 return asSuper(t.bound, sym); 1995 } 1996 1997 @Override 1998 public Type visitErrorType(ErrorType t, Symbol sym) { 1999 return t; 2000 } 2001 }; 2002 2003 /** 2004 * Return the base type of t or any of its outer types that starts 2005 * with the given symbol. If none exists, return null. 2006 * 2007 * @param t a type 2008 * @param sym a symbol 2009 */ 2010 public Type asOuterSuper(Type t, Symbol sym) { 2011 switch (t.getTag()) { 2012 case CLASS: 2013 do { 2014 Type s = asSuper(t, sym); 2015 if (s != null) return s; 2016 t = t.getEnclosingType(); 2017 } while (t.hasTag(CLASS)); 2018 return null; 2019 case ARRAY: 2020 return isSubtype(t, sym.type) ? sym.type : null; 2021 case TYPEVAR: 2022 return asSuper(t, sym); 2023 case ERROR: 2024 return t; 2025 default: 2026 return null; 2027 } 2028 } 2029 2030 /** 2031 * Return the base type of t or any of its enclosing types that 2032 * starts with the given symbol. If none exists, return null. 2033 * 2034 * @param t a type 2035 * @param sym a symbol 2036 */ 2037 public Type asEnclosingSuper(Type t, Symbol sym) { 2038 switch (t.getTag()) { 2039 case CLASS: 2040 do { 2041 Type s = asSuper(t, sym); 2042 if (s != null) return s; 2043 Type outer = t.getEnclosingType(); 2044 t = (outer.hasTag(CLASS)) ? outer : 2045 (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type : 2046 Type.noType; 2047 } while (t.hasTag(CLASS)); 2048 return null; 2049 case ARRAY: 2050 return isSubtype(t, sym.type) ? sym.type : null; 2051 case TYPEVAR: 2052 return asSuper(t, sym); 2053 case ERROR: 2054 return t; 2055 default: 2056 return null; 2057 } 2058 } 2059 // </editor-fold> 2060 2061 // <editor-fold defaultstate="collapsed" desc="memberType"> 2062 /** 2063 * The type of given symbol, seen as a member of t. 2064 * 2065 * @param t a type 2066 * @param sym a symbol 2067 */ 2068 public Type memberType(Type t, Symbol sym) { 2069 return (sym.flags() & STATIC) != 0 2070 ? sym.type 2071 : memberType.visit(t, sym); 2072 } 2073 // where 2074 private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() { 2075 2076 public Type visitType(Type t, Symbol sym) { 2077 return sym.type; 2078 } 2079 2080 @Override 2081 public Type visitWildcardType(WildcardType t, Symbol sym) { 2082 return memberType(wildUpperBound(t), sym); 2083 } 2084 2085 @Override 2086 public Type visitClassType(ClassType t, Symbol sym) { 2087 Symbol owner = sym.owner; 2088 long flags = sym.flags(); 2089 if (((flags & STATIC) == 0) && owner.type.isParameterized()) { 2090 Type base = asOuterSuper(t, owner); 2091 //if t is an intersection type T = CT & I1 & I2 ... & In 2092 //its supertypes CT, I1, ... In might contain wildcards 2093 //so we need to go through capture conversion 2094 base = t.isCompound() ? capture(base) : base; 2095 if (base != null) { 2096 List<Type> ownerParams = owner.type.allparams(); 2097 List<Type> baseParams = base.allparams(); 2098 if (ownerParams.nonEmpty()) { 2099 if (baseParams.isEmpty()) { 2100 // then base is a raw type 2101 return erasure(sym.type); 2102 } else { 2103 return subst(sym.type, ownerParams, baseParams); 2104 } 2105 } 2106 } 2107 } 2108 return sym.type; 2109 } 2110 2111 @Override 2112 public Type visitTypeVar(TypeVar t, Symbol sym) { 2113 return memberType(t.bound, sym); 2114 } 2115 2116 @Override 2117 public Type visitErrorType(ErrorType t, Symbol sym) { 2118 return t; 2119 } 2120 }; 2121 // </editor-fold> 2122 2123 // <editor-fold defaultstate="collapsed" desc="isAssignable"> 2124 public boolean isAssignable(Type t, Type s) { 2125 return isAssignable(t, s, noWarnings); 2126 } 2127 2128 /** 2129 * Is t assignable to s?<br> 2130 * Equivalent to subtype except for constant values and raw 2131 * types.<br> 2132 * (not defined for Method and ForAll types) 2133 */ 2134 public boolean isAssignable(Type t, Type s, Warner warn) { 2135 if (t.hasTag(ERROR)) 2136 return true; 2137 if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) { 2138 int value = ((Number)t.constValue()).intValue(); 2139 switch (s.getTag()) { 2140 case BYTE: 2141 if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE) 2142 return true; 2143 break; 2144 case CHAR: 2145 if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE) 2146 return true; 2147 break; 2148 case SHORT: 2149 if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE) 2150 return true; 2151 break; 2152 case INT: 2153 return true; 2154 case CLASS: 2155 switch (unboxedType(s).getTag()) { 2156 case BYTE: 2157 case CHAR: 2158 case SHORT: 2159 return isAssignable(t, unboxedType(s), warn); 2160 } 2161 break; 2162 } 2163 } 2164 return isConvertible(t, s, warn); 2165 } 2166 // </editor-fold> 2167 2168 // <editor-fold defaultstate="collapsed" desc="erasure"> 2169 /** 2170 * The erasure of t {@code |t|} -- the type that results when all 2171 * type parameters in t are deleted. 2172 */ 2173 public Type erasure(Type t) { 2174 return eraseNotNeeded(t)? t : erasure(t, false); 2175 } 2176 //where 2177 private boolean eraseNotNeeded(Type t) { 2178 // We don't want to erase primitive types and String type as that 2179 // operation is idempotent. Also, erasing these could result in loss 2180 // of information such as constant values attached to such types. 2181 return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym); 2182 } 2183 2184 private Type erasure(Type t, boolean recurse) { 2185 if (t.isPrimitive()) 2186 return t; /* fast special case */ 2187 else 2188 return erasure.visit(t, recurse); 2189 } 2190 // where 2191 private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() { 2192 public Type visitType(Type t, Boolean recurse) { 2193 if (t.isPrimitive()) 2194 return t; /*fast special case*/ 2195 else 2196 return t.map(recurse ? erasureRecFun : erasureFun); 2197 } 2198 2199 @Override 2200 public Type visitWildcardType(WildcardType t, Boolean recurse) { 2201 return erasure(wildUpperBound(t), recurse); 2202 } 2203 2204 @Override 2205 public Type visitClassType(ClassType t, Boolean recurse) { 2206 Type erased = t.tsym.erasure(Types.this); 2207 if (recurse) { 2208 erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym); 2209 } 2210 return erased; 2211 } 2212 2213 @Override 2214 public Type visitTypeVar(TypeVar t, Boolean recurse) { 2215 return erasure(t.bound, recurse); 2216 } 2217 2218 @Override 2219 public Type visitErrorType(ErrorType t, Boolean recurse) { 2220 return t; 2221 } 2222 2223 @Override 2224 public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) { 2225 Type erased = erasure(t.unannotatedType(), recurse); 2226 if (erased.isAnnotated()) { 2227 // This can only happen when the underlying type is a 2228 // type variable and the upper bound of it is annotated. 2229 // The annotation on the type variable overrides the one 2230 // on the bound. 2231 erased = ((AnnotatedType)erased).unannotatedType(); 2232 } 2233 return erased.annotatedType(t.getAnnotationMirrors()); 2234 } 2235 }; 2236 2237 private Mapping erasureFun = new Mapping ("erasure") { 2238 public Type apply(Type t) { return erasure(t); } 2239 }; 2240 2241 private Mapping erasureRecFun = new Mapping ("erasureRecursive") { 2242 public Type apply(Type t) { return erasureRecursive(t); } 2243 }; 2244 2245 public List<Type> erasure(List<Type> ts) { 2246 return Type.map(ts, erasureFun); 2247 } 2248 2249 public Type erasureRecursive(Type t) { 2250 return erasure(t, true); 2251 } 2252 2253 public List<Type> erasureRecursive(List<Type> ts) { 2254 return Type.map(ts, erasureRecFun); 2255 } 2256 // </editor-fold> 2257 2258 // <editor-fold defaultstate="collapsed" desc="makeIntersectionType"> 2259 /** 2260 * Make an intersection type from non-empty list of types. The list should be ordered according to 2261 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion. 2262 * Hence, this version of makeIntersectionType may not be called during a classfile read. 2263 * 2264 * @param bounds the types from which the intersection type is formed 2265 */ 2266 public IntersectionClassType makeIntersectionType(List<Type> bounds) { 2267 return makeIntersectionType(bounds, bounds.head.tsym.isInterface()); 2268 } 2269 2270 /** 2271 * Make an intersection type from non-empty list of types. The list should be ordered according to 2272 * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as 2273 * an extra parameter indicates as to whether all bounds are interfaces - in which case the 2274 * supertype is implicitly assumed to be 'Object'. 2275 * 2276 * @param bounds the types from which the intersection type is formed 2277 * @param allInterfaces are all bounds interface types? 2278 */ 2279 public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) { 2280 Assert.check(bounds.nonEmpty()); 2281 Type firstExplicitBound = bounds.head; 2282 if (allInterfaces) { 2283 bounds = bounds.prepend(syms.objectType); 2284 } 2285 ClassSymbol bc = 2286 new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC, 2287 Type.moreInfo 2288 ? names.fromString(bounds.toString()) 2289 : names.empty, 2290 null, 2291 syms.noSymbol); 2292 IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces); 2293 bc.type = intersectionType; 2294 bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ? 2295 syms.objectType : // error condition, recover 2296 erasure(firstExplicitBound); 2297 bc.members_field = new Scope(bc); 2298 return intersectionType; 2299 } 2300 2301 /** 2302 * A convenience wrapper for {@link #makeIntersectionType(List)}; the 2303 * arguments are converted to a list and passed to the other 2304 * method. Note that this might cause a symbol completion. 2305 * Hence, this version of makeIntersectionType may not be called 2306 * during a classfile read. 2307 */ 2308 public Type makeIntersectionType(Type bound1, Type bound2) { 2309 return makeIntersectionType(List.of(bound1, bound2)); 2310 } 2311 // </editor-fold> 2312 2313 // <editor-fold defaultstate="collapsed" desc="supertype"> 2314 public Type supertype(Type t) { 2315 return supertype.visit(t); 2316 } 2317 // where 2318 private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() { 2319 2320 public Type visitType(Type t, Void ignored) { 2321 // A note on wildcards: there is no good way to 2322 // determine a supertype for a super bounded wildcard. 2323 return Type.noType; 2324 } 2325 2326 @Override 2327 public Type visitClassType(ClassType t, Void ignored) { 2328 if (t.supertype_field == null) { 2329 Type supertype = ((ClassSymbol)t.tsym).getSuperclass(); 2330 // An interface has no superclass; its supertype is Object. 2331 if (t.isInterface()) 2332 supertype = ((ClassType)t.tsym.type).supertype_field; 2333 if (t.supertype_field == null) { 2334 List<Type> actuals = classBound(t).allparams(); 2335 List<Type> formals = t.tsym.type.allparams(); 2336 if (t.hasErasedSupertypes()) { 2337 t.supertype_field = erasureRecursive(supertype); 2338 } else if (formals.nonEmpty()) { 2339 t.supertype_field = subst(supertype, formals, actuals); 2340 } 2341 else { 2342 t.supertype_field = supertype; 2343 } 2344 } 2345 } 2346 return t.supertype_field; 2347 } 2348 2349 /** 2350 * The supertype is always a class type. If the type 2351 * variable's bounds start with a class type, this is also 2352 * the supertype. Otherwise, the supertype is 2353 * java.lang.Object. 2354 */ 2355 @Override 2356 public Type visitTypeVar(TypeVar t, Void ignored) { 2357 if (t.bound.hasTag(TYPEVAR) || 2358 (!t.bound.isCompound() && !t.bound.isInterface())) { 2359 return t.bound; 2360 } else { 2361 return supertype(t.bound); 2362 } 2363 } 2364 2365 @Override 2366 public Type visitArrayType(ArrayType t, Void ignored) { 2367 if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType)) 2368 return arraySuperType(); 2369 else 2370 return new ArrayType(supertype(t.elemtype), t.tsym); 2371 } 2372 2373 @Override 2374 public Type visitErrorType(ErrorType t, Void ignored) { 2375 return Type.noType; 2376 } 2377 }; 2378 // </editor-fold> 2379 2380 // <editor-fold defaultstate="collapsed" desc="interfaces"> 2381 /** 2382 * Return the interfaces implemented by this class. 2383 */ 2384 public List<Type> interfaces(Type t) { 2385 return interfaces.visit(t); 2386 } 2387 // where 2388 private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() { 2389 2390 public List<Type> visitType(Type t, Void ignored) { 2391 return List.nil(); 2392 } 2393 2394 @Override 2395 public List<Type> visitClassType(ClassType t, Void ignored) { 2396 if (t.interfaces_field == null) { 2397 List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces(); 2398 if (t.interfaces_field == null) { 2399 // If t.interfaces_field is null, then t must 2400 // be a parameterized type (not to be confused 2401 // with a generic type declaration). 2402 // Terminology: 2403 // Parameterized type: List<String> 2404 // Generic type declaration: class List<E> { ... } 2405 // So t corresponds to List<String> and 2406 // t.tsym.type corresponds to List<E>. 2407 // The reason t must be parameterized type is 2408 // that completion will happen as a side 2409 // effect of calling 2410 // ClassSymbol.getInterfaces. Since 2411 // t.interfaces_field is null after 2412 // completion, we can assume that t is not the 2413 // type of a class/interface declaration. 2414 Assert.check(t != t.tsym.type, t); 2415 List<Type> actuals = t.allparams(); 2416 List<Type> formals = t.tsym.type.allparams(); 2417 if (t.hasErasedSupertypes()) { 2418 t.interfaces_field = erasureRecursive(interfaces); 2419 } else if (formals.nonEmpty()) { 2420 t.interfaces_field = subst(interfaces, formals, actuals); 2421 } 2422 else { 2423 t.interfaces_field = interfaces; 2424 } 2425 } 2426 } 2427 return t.interfaces_field; 2428 } 2429 2430 @Override 2431 public List<Type> visitTypeVar(TypeVar t, Void ignored) { 2432 if (t.bound.isCompound()) 2433 return interfaces(t.bound); 2434 2435 if (t.bound.isInterface()) 2436 return List.of(t.bound); 2437 2438 return List.nil(); 2439 } 2440 }; 2441 2442 public List<Type> directSupertypes(Type t) { 2443 return directSupertypes.visit(t); 2444 } 2445 // where 2446 private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() { 2447 2448 public List<Type> visitType(final Type type, final Void ignored) { 2449 if (!type.isIntersection()) { 2450 final Type sup = supertype(type); 2451 return (sup == Type.noType || sup == type || sup == null) 2452 ? interfaces(type) 2453 : interfaces(type).prepend(sup); 2454 } else { 2455 return visitIntersectionType((IntersectionClassType) type); 2456 } 2457 } 2458 2459 private List<Type> visitIntersectionType(final IntersectionClassType it) { 2460 return it.getExplicitComponents(); 2461 } 2462 2463 }; 2464 2465 public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) { 2466 for (Type i2 : interfaces(origin.type)) { 2467 if (isym == i2.tsym) return true; 2468 } 2469 return false; 2470 } 2471 // </editor-fold> 2472 2473 // <editor-fold defaultstate="collapsed" desc="isDerivedRaw"> 2474 Map<Type,Boolean> isDerivedRawCache = new HashMap<Type,Boolean>(); 2475 2476 public boolean isDerivedRaw(Type t) { 2477 Boolean result = isDerivedRawCache.get(t); 2478 if (result == null) { 2479 result = isDerivedRawInternal(t); 2480 isDerivedRawCache.put(t, result); 2481 } 2482 return result; 2483 } 2484 2485 public boolean isDerivedRawInternal(Type t) { 2486 if (t.isErroneous()) 2487 return false; 2488 return 2489 t.isRaw() || 2490 supertype(t) != Type.noType && isDerivedRaw(supertype(t)) || 2491 isDerivedRaw(interfaces(t)); 2492 } 2493 2494 public boolean isDerivedRaw(List<Type> ts) { 2495 List<Type> l = ts; 2496 while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail; 2497 return l.nonEmpty(); 2498 } 2499 // </editor-fold> 2500 2501 // <editor-fold defaultstate="collapsed" desc="setBounds"> 2502 /** 2503 * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly, 2504 * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise 2505 * the supertype is simply left null (in this case, the supertype is assumed to be the head of 2506 * the bound list passed as second argument). Note that this check might cause a symbol completion. 2507 * Hence, this version of setBounds may not be called during a classfile read. 2508 * 2509 * @param t a type variable 2510 * @param bounds the bounds, must be nonempty 2511 */ 2512 public void setBounds(TypeVar t, List<Type> bounds) { 2513 setBounds(t, bounds, bounds.head.tsym.isInterface()); 2514 } 2515 2516 /** 2517 * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds. 2518 * This does not cause symbol completion as an extra parameter indicates as to whether all bounds 2519 * are interfaces - in which case the supertype is implicitly assumed to be 'Object'. 2520 * 2521 * @param t a type variable 2522 * @param bounds the bounds, must be nonempty 2523 * @param allInterfaces are all bounds interface types? 2524 */ 2525 public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) { 2526 t.bound = bounds.tail.isEmpty() ? 2527 bounds.head : 2528 makeIntersectionType(bounds, allInterfaces); 2529 t.rank_field = -1; 2530 } 2531 // </editor-fold> 2532 2533 // <editor-fold defaultstate="collapsed" desc="getBounds"> 2534 /** 2535 * Return list of bounds of the given type variable. 2536 */ 2537 public List<Type> getBounds(TypeVar t) { 2538 if (t.bound.hasTag(NONE)) 2539 return List.nil(); 2540 else if (t.bound.isErroneous() || !t.bound.isCompound()) 2541 return List.of(t.bound); 2542 else if ((erasure(t).tsym.flags() & INTERFACE) == 0) 2543 return interfaces(t).prepend(supertype(t)); 2544 else 2545 // No superclass was given in bounds. 2546 // In this case, supertype is Object, erasure is first interface. 2547 return interfaces(t); 2548 } 2549 // </editor-fold> 2550 2551 // <editor-fold defaultstate="collapsed" desc="classBound"> 2552 /** 2553 * If the given type is a (possibly selected) type variable, 2554 * return the bounding class of this type, otherwise return the 2555 * type itself. 2556 */ 2557 public Type classBound(Type t) { 2558 return classBound.visit(t); 2559 } 2560 // where 2561 private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() { 2562 2563 public Type visitType(Type t, Void ignored) { 2564 return t; 2565 } 2566 2567 @Override 2568 public Type visitClassType(ClassType t, Void ignored) { 2569 Type outer1 = classBound(t.getEnclosingType()); 2570 if (outer1 != t.getEnclosingType()) 2571 return new ClassType(outer1, t.getTypeArguments(), t.tsym); 2572 else 2573 return t; 2574 } 2575 2576 @Override 2577 public Type visitTypeVar(TypeVar t, Void ignored) { 2578 return classBound(supertype(t)); 2579 } 2580 2581 @Override 2582 public Type visitErrorType(ErrorType t, Void ignored) { 2583 return t; 2584 } 2585 }; 2586 // </editor-fold> 2587 2588 // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence"> 2589 /** 2590 * Returns true iff the first signature is a <em>sub 2591 * signature</em> of the other. This is <b>not</b> an equivalence 2592 * relation. 2593 * 2594 * @jls section 8.4.2. 2595 * @see #overrideEquivalent(Type t, Type s) 2596 * @param t first signature (possibly raw). 2597 * @param s second signature (could be subjected to erasure). 2598 * @return true if t is a sub signature of s. 2599 */ 2600 public boolean isSubSignature(Type t, Type s) { 2601 return isSubSignature(t, s, true); 2602 } 2603 2604 public boolean isSubSignature(Type t, Type s, boolean strict) { 2605 return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict); 2606 } 2607 2608 /** 2609 * Returns true iff these signatures are related by <em>override 2610 * equivalence</em>. This is the natural extension of 2611 * isSubSignature to an equivalence relation. 2612 * 2613 * @jls section 8.4.2. 2614 * @see #isSubSignature(Type t, Type s) 2615 * @param t a signature (possible raw, could be subjected to 2616 * erasure). 2617 * @param s a signature (possible raw, could be subjected to 2618 * erasure). 2619 * @return true if either argument is a sub signature of the other. 2620 */ 2621 public boolean overrideEquivalent(Type t, Type s) { 2622 return hasSameArgs(t, s) || 2623 hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s); 2624 } 2625 2626 public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) { 2627 for (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) { 2628 if (msym.overrides(e.sym, origin, Types.this, true)) { 2629 return true; 2630 } 2631 } 2632 return false; 2633 } 2634 2635 // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site"> 2636 class ImplementationCache { 2637 2638 private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = 2639 new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>(); 2640 2641 class Entry { 2642 final MethodSymbol cachedImpl; 2643 final Filter<Symbol> implFilter; 2644 final boolean checkResult; 2645 final int prevMark; 2646 2647 public Entry(MethodSymbol cachedImpl, 2648 Filter<Symbol> scopeFilter, 2649 boolean checkResult, 2650 int prevMark) { 2651 this.cachedImpl = cachedImpl; 2652 this.implFilter = scopeFilter; 2653 this.checkResult = checkResult; 2654 this.prevMark = prevMark; 2655 } 2656 2657 boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) { 2658 return this.implFilter == scopeFilter && 2659 this.checkResult == checkResult && 2660 this.prevMark == mark; 2661 } 2662 } 2663 2664 MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) { 2665 SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms); 2666 Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null; 2667 if (cache == null) { 2668 cache = new HashMap<TypeSymbol, Entry>(); 2669 _map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(cache)); 2670 } 2671 Entry e = cache.get(origin); 2672 CompoundScope members = membersClosure(origin.type, true); 2673 if (e == null || 2674 !e.matches(implFilter, checkResult, members.getMark())) { 2675 MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter); 2676 cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark())); 2677 return impl; 2678 } 2679 else { 2680 return e.cachedImpl; 2681 } 2682 } 2683 2684 private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) { 2685 for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) { 2686 while (t.hasTag(TYPEVAR)) 2687 t = t.getUpperBound(); 2688 TypeSymbol c = t.tsym; 2689 for (Scope.Entry e = c.members().lookup(ms.name, implFilter); 2690 e.scope != null; 2691 e = e.next(implFilter)) { 2692 if (e.sym != null && 2693 e.sym.overrides(ms, origin, Types.this, checkResult)) 2694 return (MethodSymbol)e.sym; 2695 } 2696 } 2697 return null; 2698 } 2699 } 2700 2701 private ImplementationCache implCache = new ImplementationCache(); 2702 2703 public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) { 2704 return implCache.get(ms, origin, checkResult, implFilter); 2705 } 2706 // </editor-fold> 2707 2708 // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site"> 2709 class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> { 2710 2711 private Map<TypeSymbol, CompoundScope> _map = new HashMap<>(); 2712 2713 Set<TypeSymbol> seenTypes = new HashSet<>(); 2714 2715 class MembersScope extends CompoundScope { 2716 2717 CompoundScope scope; 2718 2719 public MembersScope(CompoundScope scope) { 2720 super(scope.owner); 2721 this.scope = scope; 2722 } 2723 2724 Filter<Symbol> combine(final Filter<Symbol> sf) { 2725 return new Filter<Symbol>() { 2726 @Override 2727 public boolean accepts(Symbol s) { 2728 return !s.owner.isInterface() && (sf == null || sf.accepts(s)); 2729 } 2730 }; 2731 } 2732 2733 @Override 2734 public Iterable<Symbol> getElements(Filter<Symbol> sf) { 2735 return scope.getElements(combine(sf)); 2736 } 2737 2738 @Override 2739 public Iterable<Symbol> getElementsByName(Name name, Filter<Symbol> sf) { 2740 return scope.getElementsByName(name, combine(sf)); 2741 } 2742 2743 @Override 2744 public int getMark() { 2745 return scope.getMark(); 2746 } 2747 } 2748 2749 CompoundScope nilScope; 2750 2751 /** members closure visitor methods **/ 2752 2753 public CompoundScope visitType(Type t, Void _unused) { 2754 if (nilScope == null) { 2755 nilScope = new CompoundScope(syms.noSymbol); 2756 } 2757 return nilScope; 2758 } 2759 2760 @Override 2761 public CompoundScope visitClassType(ClassType t, Void _unused) { 2762 if (!seenTypes.add(t.tsym)) { 2763 //this is possible when an interface is implemented in multiple 2764 //superclasses, or when a class hierarchy is circular - in such 2765 //cases we don't need to recurse (empty scope is returned) 2766 return new CompoundScope(t.tsym); 2767 } 2768 try { 2769 seenTypes.add(t.tsym); 2770 ClassSymbol csym = (ClassSymbol)t.tsym; 2771 CompoundScope membersClosure = _map.get(csym); 2772 if (membersClosure == null) { 2773 membersClosure = new CompoundScope(csym); 2774 for (Type i : interfaces(t)) { 2775 membersClosure.addSubScope(visit(i, null)); 2776 } 2777 membersClosure.addSubScope(visit(supertype(t), null)); 2778 membersClosure.addSubScope(csym.members()); 2779 _map.put(csym, membersClosure); 2780 } 2781 return membersClosure; 2782 } 2783 finally { 2784 seenTypes.remove(t.tsym); 2785 } 2786 } 2787 2788 @Override 2789 public CompoundScope visitTypeVar(TypeVar t, Void _unused) { 2790 return visit(t.getUpperBound(), null); 2791 } 2792 } 2793 2794 private MembersClosureCache membersCache = new MembersClosureCache(); 2795 2796 public CompoundScope membersClosure(Type site, boolean skipInterface) { 2797 CompoundScope cs = membersCache.visit(site, null); 2798 if (cs == null) 2799 Assert.error("type " + site); 2800 return skipInterface ? membersCache.new MembersScope(cs) : cs; 2801 } 2802 // </editor-fold> 2803 2804 2805 /** Return first abstract member of class `sym'. 2806 */ 2807 public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) { 2808 try { 2809 return firstUnimplementedAbstractImpl(sym, sym); 2810 } catch (CompletionFailure ex) { 2811 chk.completionError(enter.getEnv(sym).tree.pos(), ex); 2812 return null; 2813 } 2814 } 2815 //where: 2816 private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) { 2817 MethodSymbol undef = null; 2818 // Do not bother to search in classes that are not abstract, 2819 // since they cannot have abstract members. 2820 if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) { 2821 Scope s = c.members(); 2822 for (Scope.Entry e = s.elems; 2823 undef == null && e != null; 2824 e = e.sibling) { 2825 if (e.sym.kind == MTH && 2826 (e.sym.flags() & (ABSTRACT|IPROXY|DEFAULT)) == ABSTRACT) { 2827 MethodSymbol absmeth = (MethodSymbol)e.sym; 2828 MethodSymbol implmeth = absmeth.implementation(impl, this, true); 2829 if (implmeth == null || implmeth == absmeth) { 2830 //look for default implementations 2831 if (allowDefaultMethods) { 2832 MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head; 2833 if (prov != null && prov.overrides(absmeth, impl, this, true)) { 2834 implmeth = prov; 2835 } 2836 } 2837 } 2838 if (implmeth == null || implmeth == absmeth) { 2839 undef = absmeth; 2840 } 2841 } 2842 } 2843 if (undef == null) { 2844 Type st = supertype(c.type); 2845 if (st.hasTag(CLASS)) 2846 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym); 2847 } 2848 for (List<Type> l = interfaces(c.type); 2849 undef == null && l.nonEmpty(); 2850 l = l.tail) { 2851 undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym); 2852 } 2853 } 2854 return undef; 2855 } 2856 2857 2858 //where 2859 public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) { 2860 Filter<Symbol> filter = new MethodFilter(ms, site); 2861 List<MethodSymbol> candidates = List.nil(); 2862 for (Symbol s : membersClosure(site, false).getElements(filter)) { 2863 if (!site.tsym.isInterface() && !s.owner.isInterface()) { 2864 return List.of((MethodSymbol)s); 2865 } else if (!candidates.contains(s)) { 2866 candidates = candidates.prepend((MethodSymbol)s); 2867 } 2868 } 2869 return prune(candidates); 2870 } 2871 2872 public List<MethodSymbol> prune(List<MethodSymbol> methods) { 2873 ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>(); 2874 for (MethodSymbol m1 : methods) { 2875 boolean isMin_m1 = true; 2876 for (MethodSymbol m2 : methods) { 2877 if (m1 == m2) continue; 2878 if (m2.owner != m1.owner && 2879 asSuper(m2.owner.type, m1.owner) != null) { 2880 isMin_m1 = false; 2881 break; 2882 } 2883 } 2884 if (isMin_m1) 2885 methodsMin.append(m1); 2886 } 2887 return methodsMin.toList(); 2888 } 2889 // where 2890 private class MethodFilter implements Filter<Symbol> { 2891 2892 Symbol msym; 2893 Type site; 2894 2895 MethodFilter(Symbol msym, Type site) { 2896 this.msym = msym; 2897 this.site = site; 2898 } 2899 2900 public boolean accepts(Symbol s) { 2901 return s.kind == Kinds.MTH && 2902 s.name == msym.name && 2903 (s.flags() & SYNTHETIC) == 0 && 2904 s.isInheritedIn(site.tsym, Types.this) && 2905 overrideEquivalent(memberType(site, s), memberType(site, msym)); 2906 } 2907 }; 2908 // </editor-fold> 2909 2910 /** 2911 * Does t have the same arguments as s? It is assumed that both 2912 * types are (possibly polymorphic) method types. Monomorphic 2913 * method types "have the same arguments", if their argument lists 2914 * are equal. Polymorphic method types "have the same arguments", 2915 * if they have the same arguments after renaming all type 2916 * variables of one to corresponding type variables in the other, 2917 * where correspondence is by position in the type parameter list. 2918 */ 2919 public boolean hasSameArgs(Type t, Type s) { 2920 return hasSameArgs(t, s, true); 2921 } 2922 2923 public boolean hasSameArgs(Type t, Type s, boolean strict) { 2924 return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict); 2925 } 2926 2927 private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) { 2928 return hasSameArgs.visit(t, s); 2929 } 2930 // where 2931 private class HasSameArgs extends TypeRelation { 2932 2933 boolean strict; 2934 2935 public HasSameArgs(boolean strict) { 2936 this.strict = strict; 2937 } 2938 2939 public Boolean visitType(Type t, Type s) { 2940 throw new AssertionError(); 2941 } 2942 2943 @Override 2944 public Boolean visitMethodType(MethodType t, Type s) { 2945 return s.hasTag(METHOD) 2946 && containsTypeEquivalent(t.argtypes, s.getParameterTypes()); 2947 } 2948 2949 @Override 2950 public Boolean visitForAll(ForAll t, Type s) { 2951 if (!s.hasTag(FORALL)) 2952 return strict ? false : visitMethodType(t.asMethodType(), s); 2953 2954 ForAll forAll = (ForAll)s; 2955 return hasSameBounds(t, forAll) 2956 && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars)); 2957 } 2958 2959 @Override 2960 public Boolean visitErrorType(ErrorType t, Type s) { 2961 return false; 2962 } 2963 }; 2964 2965 TypeRelation hasSameArgs_strict = new HasSameArgs(true); 2966 TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false); 2967 2968 // </editor-fold> 2969 2970 // <editor-fold defaultstate="collapsed" desc="subst"> 2971 public List<Type> subst(List<Type> ts, 2972 List<Type> from, 2973 List<Type> to) { 2974 return new Subst(from, to).subst(ts); 2975 } 2976 2977 /** 2978 * Substitute all occurrences of a type in `from' with the 2979 * corresponding type in `to' in 't'. Match lists `from' and `to' 2980 * from the right: If lists have different length, discard leading 2981 * elements of the longer list. 2982 */ 2983 public Type subst(Type t, List<Type> from, List<Type> to) { 2984 return new Subst(from, to).subst(t); 2985 } 2986 2987 private class Subst extends UnaryVisitor<Type> { 2988 List<Type> from; 2989 List<Type> to; 2990 2991 public Subst(List<Type> from, List<Type> to) { 2992 int fromLength = from.length(); 2993 int toLength = to.length(); 2994 while (fromLength > toLength) { 2995 fromLength--; 2996 from = from.tail; 2997 } 2998 while (fromLength < toLength) { 2999 toLength--; 3000 to = to.tail; 3001 } 3002 this.from = from; 3003 this.to = to; 3004 } 3005 3006 Type subst(Type t) { 3007 if (from.tail == null) 3008 return t; 3009 else 3010 return visit(t); 3011 } 3012 3013 List<Type> subst(List<Type> ts) { 3014 if (from.tail == null) 3015 return ts; 3016 boolean wild = false; 3017 if (ts.nonEmpty() && from.nonEmpty()) { 3018 Type head1 = subst(ts.head); 3019 List<Type> tail1 = subst(ts.tail); 3020 if (head1 != ts.head || tail1 != ts.tail) 3021 return tail1.prepend(head1); 3022 } 3023 return ts; 3024 } 3025 3026 public Type visitType(Type t, Void ignored) { 3027 return t; 3028 } 3029 3030 @Override 3031 public Type visitMethodType(MethodType t, Void ignored) { 3032 List<Type> argtypes = subst(t.argtypes); 3033 Type restype = subst(t.restype); 3034 List<Type> thrown = subst(t.thrown); 3035 if (argtypes == t.argtypes && 3036 restype == t.restype && 3037 thrown == t.thrown) 3038 return t; 3039 else 3040 return new MethodType(argtypes, restype, thrown, t.tsym); 3041 } 3042 3043 @Override 3044 public Type visitTypeVar(TypeVar t, Void ignored) { 3045 for (List<Type> from = this.from, to = this.to; 3046 from.nonEmpty(); 3047 from = from.tail, to = to.tail) { 3048 if (t == from.head) { 3049 return to.head.withTypeVar(t); 3050 } 3051 } 3052 return t; 3053 } 3054 3055 @Override 3056 public Type visitUndetVar(UndetVar t, Void ignored) { 3057 //do nothing - we should not replace inside undet variables 3058 return t; 3059 } 3060 3061 @Override 3062 public Type visitClassType(ClassType t, Void ignored) { 3063 if (!t.isCompound()) { 3064 List<Type> typarams = t.getTypeArguments(); 3065 List<Type> typarams1 = subst(typarams); 3066 Type outer = t.getEnclosingType(); 3067 Type outer1 = subst(outer); 3068 if (typarams1 == typarams && outer1 == outer) 3069 return t; 3070 else 3071 return new ClassType(outer1, typarams1, t.tsym); 3072 } else { 3073 Type st = subst(supertype(t)); 3074 List<Type> is = subst(interfaces(t)); 3075 if (st == supertype(t) && is == interfaces(t)) 3076 return t; 3077 else 3078 return makeIntersectionType(is.prepend(st)); 3079 } 3080 } 3081 3082 @Override 3083 public Type visitWildcardType(WildcardType t, Void ignored) { 3084 Type bound = t.type; 3085 if (t.kind != BoundKind.UNBOUND) 3086 bound = subst(bound); 3087 if (bound == t.type) { 3088 return t; 3089 } else { 3090 if (t.isExtendsBound() && bound.isExtendsBound()) 3091 bound = wildUpperBound(bound); 3092 return new WildcardType(bound, t.kind, syms.boundClass, t.bound); 3093 } 3094 } 3095 3096 @Override 3097 public Type visitArrayType(ArrayType t, Void ignored) { 3098 Type elemtype = subst(t.elemtype); 3099 if (elemtype == t.elemtype) 3100 return t; 3101 else 3102 return new ArrayType(elemtype, t.tsym); 3103 } 3104 3105 @Override 3106 public Type visitForAll(ForAll t, Void ignored) { 3107 if (Type.containsAny(to, t.tvars)) { 3108 //perform alpha-renaming of free-variables in 't' 3109 //if 'to' types contain variables that are free in 't' 3110 List<Type> freevars = newInstances(t.tvars); 3111 t = new ForAll(freevars, 3112 Types.this.subst(t.qtype, t.tvars, freevars)); 3113 } 3114 List<Type> tvars1 = substBounds(t.tvars, from, to); 3115 Type qtype1 = subst(t.qtype); 3116 if (tvars1 == t.tvars && qtype1 == t.qtype) { 3117 return t; 3118 } else if (tvars1 == t.tvars) { 3119 return new ForAll(tvars1, qtype1); 3120 } else { 3121 return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)); 3122 } 3123 } 3124 3125 @Override 3126 public Type visitErrorType(ErrorType t, Void ignored) { 3127 return t; 3128 } 3129 } 3130 3131 public List<Type> substBounds(List<Type> tvars, 3132 List<Type> from, 3133 List<Type> to) { 3134 if (tvars.isEmpty()) 3135 return tvars; 3136 ListBuffer<Type> newBoundsBuf = new ListBuffer<>(); 3137 boolean changed = false; 3138 // calculate new bounds 3139 for (Type t : tvars) { 3140 TypeVar tv = (TypeVar) t; 3141 Type bound = subst(tv.bound, from, to); 3142 if (bound != tv.bound) 3143 changed = true; 3144 newBoundsBuf.append(bound); 3145 } 3146 if (!changed) 3147 return tvars; 3148 ListBuffer<Type> newTvars = new ListBuffer<>(); 3149 // create new type variables without bounds 3150 for (Type t : tvars) { 3151 newTvars.append(new TypeVar(t.tsym, null, syms.botType)); 3152 } 3153 // the new bounds should use the new type variables in place 3154 // of the old 3155 List<Type> newBounds = newBoundsBuf.toList(); 3156 from = tvars; 3157 to = newTvars.toList(); 3158 for (; !newBounds.isEmpty(); newBounds = newBounds.tail) { 3159 newBounds.head = subst(newBounds.head, from, to); 3160 } 3161 newBounds = newBoundsBuf.toList(); 3162 // set the bounds of new type variables to the new bounds 3163 for (Type t : newTvars.toList()) { 3164 TypeVar tv = (TypeVar) t; 3165 tv.bound = newBounds.head; 3166 newBounds = newBounds.tail; 3167 } 3168 return newTvars.toList(); 3169 } 3170 3171 public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) { 3172 Type bound1 = subst(t.bound, from, to); 3173 if (bound1 == t.bound) 3174 return t; 3175 else { 3176 // create new type variable without bounds 3177 TypeVar tv = new TypeVar(t.tsym, null, syms.botType); 3178 // the new bound should use the new type variable in place 3179 // of the old 3180 tv.bound = subst(bound1, List.<Type>of(t), List.<Type>of(tv)); 3181 return tv; 3182 } 3183 } 3184 // </editor-fold> 3185 3186 // <editor-fold defaultstate="collapsed" desc="hasSameBounds"> 3187 /** 3188 * Does t have the same bounds for quantified variables as s? 3189 */ 3190 public boolean hasSameBounds(ForAll t, ForAll s) { 3191 List<Type> l1 = t.tvars; 3192 List<Type> l2 = s.tvars; 3193 while (l1.nonEmpty() && l2.nonEmpty() && 3194 isSameType(l1.head.getUpperBound(), 3195 subst(l2.head.getUpperBound(), 3196 s.tvars, 3197 t.tvars))) { 3198 l1 = l1.tail; 3199 l2 = l2.tail; 3200 } 3201 return l1.isEmpty() && l2.isEmpty(); 3202 } 3203 // </editor-fold> 3204 3205 // <editor-fold defaultstate="collapsed" desc="newInstances"> 3206 /** Create new vector of type variables from list of variables 3207 * changing all recursive bounds from old to new list. 3208 */ 3209 public List<Type> newInstances(List<Type> tvars) { 3210 List<Type> tvars1 = Type.map(tvars, newInstanceFun); 3211 for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) { 3212 TypeVar tv = (TypeVar) l.head; 3213 tv.bound = subst(tv.bound, tvars, tvars1); 3214 } 3215 return tvars1; 3216 } 3217 private static final Mapping newInstanceFun = new Mapping("newInstanceFun") { 3218 public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); } 3219 }; 3220 // </editor-fold> 3221 3222 public Type createMethodTypeWithParameters(Type original, List<Type> newParams) { 3223 return original.accept(methodWithParameters, newParams); 3224 } 3225 // where 3226 private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() { 3227 public Type visitType(Type t, List<Type> newParams) { 3228 throw new IllegalArgumentException("Not a method type: " + t); 3229 } 3230 public Type visitMethodType(MethodType t, List<Type> newParams) { 3231 return new MethodType(newParams, t.restype, t.thrown, t.tsym); 3232 } 3233 public Type visitForAll(ForAll t, List<Type> newParams) { 3234 return new ForAll(t.tvars, t.qtype.accept(this, newParams)); 3235 } 3236 }; 3237 3238 public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) { 3239 return original.accept(methodWithThrown, newThrown); 3240 } 3241 // where 3242 private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() { 3243 public Type visitType(Type t, List<Type> newThrown) { 3244 throw new IllegalArgumentException("Not a method type: " + t); 3245 } 3246 public Type visitMethodType(MethodType t, List<Type> newThrown) { 3247 return new MethodType(t.argtypes, t.restype, newThrown, t.tsym); 3248 } 3249 public Type visitForAll(ForAll t, List<Type> newThrown) { 3250 return new ForAll(t.tvars, t.qtype.accept(this, newThrown)); 3251 } 3252 }; 3253 3254 public Type createMethodTypeWithReturn(Type original, Type newReturn) { 3255 return original.accept(methodWithReturn, newReturn); 3256 } 3257 // where 3258 private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() { 3259 public Type visitType(Type t, Type newReturn) { 3260 throw new IllegalArgumentException("Not a method type: " + t); 3261 } 3262 public Type visitMethodType(MethodType t, Type newReturn) { 3263 return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym); 3264 } 3265 public Type visitForAll(ForAll t, Type newReturn) { 3266 return new ForAll(t.tvars, t.qtype.accept(this, newReturn)); 3267 } 3268 }; 3269 3270 // <editor-fold defaultstate="collapsed" desc="createErrorType"> 3271 public Type createErrorType(Type originalType) { 3272 return new ErrorType(originalType, syms.errSymbol); 3273 } 3274 3275 public Type createErrorType(ClassSymbol c, Type originalType) { 3276 return new ErrorType(c, originalType); 3277 } 3278 3279 public Type createErrorType(Name name, TypeSymbol container, Type originalType) { 3280 return new ErrorType(name, container, originalType); 3281 } 3282 // </editor-fold> 3283 3284 // <editor-fold defaultstate="collapsed" desc="rank"> 3285 /** 3286 * The rank of a class is the length of the longest path between 3287 * the class and java.lang.Object in the class inheritance 3288 * graph. Undefined for all but reference types. 3289 */ 3290 public int rank(Type t) { 3291 t = t.unannotatedType(); 3292 switch(t.getTag()) { 3293 case CLASS: { 3294 ClassType cls = (ClassType)t; 3295 if (cls.rank_field < 0) { 3296 Name fullname = cls.tsym.getQualifiedName(); 3297 if (fullname == names.java_lang_Object) 3298 cls.rank_field = 0; 3299 else { 3300 int r = rank(supertype(cls)); 3301 for (List<Type> l = interfaces(cls); 3302 l.nonEmpty(); 3303 l = l.tail) { 3304 if (rank(l.head) > r) 3305 r = rank(l.head); 3306 } 3307 cls.rank_field = r + 1; 3308 } 3309 } 3310 return cls.rank_field; 3311 } 3312 case TYPEVAR: { 3313 TypeVar tvar = (TypeVar)t; 3314 if (tvar.rank_field < 0) { 3315 int r = rank(supertype(tvar)); 3316 for (List<Type> l = interfaces(tvar); 3317 l.nonEmpty(); 3318 l = l.tail) { 3319 if (rank(l.head) > r) r = rank(l.head); 3320 } 3321 tvar.rank_field = r + 1; 3322 } 3323 return tvar.rank_field; 3324 } 3325 case ERROR: 3326 case NONE: 3327 return 0; 3328 default: 3329 throw new AssertionError(); 3330 } 3331 } 3332 // </editor-fold> 3333 3334 /** 3335 * Helper method for generating a string representation of a given type 3336 * accordingly to a given locale 3337 */ 3338 public String toString(Type t, Locale locale) { 3339 return Printer.createStandardPrinter(messages).visit(t, locale); 3340 } 3341 3342 /** 3343 * Helper method for generating a string representation of a given type 3344 * accordingly to a given locale 3345 */ 3346 public String toString(Symbol t, Locale locale) { 3347 return Printer.createStandardPrinter(messages).visit(t, locale); 3348 } 3349 3350 // <editor-fold defaultstate="collapsed" desc="toString"> 3351 /** 3352 * This toString is slightly more descriptive than the one on Type. 3353 * 3354 * @deprecated Types.toString(Type t, Locale l) provides better support 3355 * for localization 3356 */ 3357 @Deprecated 3358 public String toString(Type t) { 3359 if (t.hasTag(FORALL)) { 3360 ForAll forAll = (ForAll)t; 3361 return typaramsString(forAll.tvars) + forAll.qtype; 3362 } 3363 return "" + t; 3364 } 3365 // where 3366 private String typaramsString(List<Type> tvars) { 3367 StringBuilder s = new StringBuilder(); 3368 s.append('<'); 3369 boolean first = true; 3370 for (Type t : tvars) { 3371 if (!first) s.append(", "); 3372 first = false; 3373 appendTyparamString(((TypeVar)t.unannotatedType()), s); 3374 } 3375 s.append('>'); 3376 return s.toString(); 3377 } 3378 private void appendTyparamString(TypeVar t, StringBuilder buf) { 3379 buf.append(t); 3380 if (t.bound == null || 3381 t.bound.tsym.getQualifiedName() == names.java_lang_Object) 3382 return; 3383 buf.append(" extends "); // Java syntax; no need for i18n 3384 Type bound = t.bound; 3385 if (!bound.isCompound()) { 3386 buf.append(bound); 3387 } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) { 3388 buf.append(supertype(t)); 3389 for (Type intf : interfaces(t)) { 3390 buf.append('&'); 3391 buf.append(intf); 3392 } 3393 } else { 3394 // No superclass was given in bounds. 3395 // In this case, supertype is Object, erasure is first interface. 3396 boolean first = true; 3397 for (Type intf : interfaces(t)) { 3398 if (!first) buf.append('&'); 3399 first = false; 3400 buf.append(intf); 3401 } 3402 } 3403 } 3404 // </editor-fold> 3405 3406 // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types"> 3407 /** 3408 * A cache for closures. 3409 * 3410 * <p>A closure is a list of all the supertypes and interfaces of 3411 * a class or interface type, ordered by ClassSymbol.precedes 3412 * (that is, subclasses come first, arbitrary but fixed 3413 * otherwise). 3414 */ 3415 private Map<Type,List<Type>> closureCache = new HashMap<Type,List<Type>>(); 3416 3417 /** 3418 * Returns the closure of a class or interface type. 3419 */ 3420 public List<Type> closure(Type t) { 3421 List<Type> cl = closureCache.get(t); 3422 if (cl == null) { 3423 Type st = supertype(t); 3424 if (!t.isCompound()) { 3425 if (st.hasTag(CLASS)) { 3426 cl = insert(closure(st), t); 3427 } else if (st.hasTag(TYPEVAR)) { 3428 cl = closure(st).prepend(t); 3429 } else { 3430 cl = List.of(t); 3431 } 3432 } else { 3433 cl = closure(supertype(t)); 3434 } 3435 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) 3436 cl = union(cl, closure(l.head)); 3437 closureCache.put(t, cl); 3438 } 3439 return cl; 3440 } 3441 3442 /** 3443 * Insert a type in a closure 3444 */ 3445 public List<Type> insert(List<Type> cl, Type t) { 3446 if (cl.isEmpty()) { 3447 return cl.prepend(t); 3448 } else if (t.tsym == cl.head.tsym) { 3449 return cl; 3450 } else if (t.tsym.precedes(cl.head.tsym, this)) { 3451 return cl.prepend(t); 3452 } else { 3453 // t comes after head, or the two are unrelated 3454 return insert(cl.tail, t).prepend(cl.head); 3455 } 3456 } 3457 3458 /** 3459 * Form the union of two closures 3460 */ 3461 public List<Type> union(List<Type> cl1, List<Type> cl2) { 3462 if (cl1.isEmpty()) { 3463 return cl2; 3464 } else if (cl2.isEmpty()) { 3465 return cl1; 3466 } else if (cl1.head.tsym == cl2.head.tsym) { 3467 return union(cl1.tail, cl2.tail).prepend(cl1.head); 3468 } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) { 3469 return union(cl1.tail, cl2).prepend(cl1.head); 3470 } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) { 3471 return union(cl1, cl2.tail).prepend(cl2.head); 3472 } else { 3473 // unrelated types 3474 return union(cl1.tail, cl2).prepend(cl1.head); 3475 } 3476 } 3477 3478 /** 3479 * Intersect two closures 3480 */ 3481 public List<Type> intersect(List<Type> cl1, List<Type> cl2) { 3482 if (cl1 == cl2) 3483 return cl1; 3484 if (cl1.isEmpty() || cl2.isEmpty()) 3485 return List.nil(); 3486 if (cl1.head.tsym.precedes(cl2.head.tsym, this)) 3487 return intersect(cl1.tail, cl2); 3488 if (cl2.head.tsym.precedes(cl1.head.tsym, this)) 3489 return intersect(cl1, cl2.tail); 3490 if (isSameType(cl1.head, cl2.head)) 3491 return intersect(cl1.tail, cl2.tail).prepend(cl1.head); 3492 if (cl1.head.tsym == cl2.head.tsym && 3493 cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) { 3494 if (cl1.head.isParameterized() && cl2.head.isParameterized()) { 3495 Type merge = merge(cl1.head,cl2.head); 3496 return intersect(cl1.tail, cl2.tail).prepend(merge); 3497 } 3498 if (cl1.head.isRaw() || cl2.head.isRaw()) 3499 return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head)); 3500 } 3501 return intersect(cl1.tail, cl2.tail); 3502 } 3503 // where 3504 class TypePair { 3505 final Type t1; 3506 final Type t2; 3507 boolean strict; 3508 3509 TypePair(Type t1, Type t2) { 3510 this(t1, t2, false); 3511 } 3512 3513 TypePair(Type t1, Type t2, boolean strict) { 3514 this.t1 = t1; 3515 this.t2 = t2; 3516 this.strict = strict; 3517 } 3518 @Override 3519 public int hashCode() { 3520 return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2); 3521 } 3522 @Override 3523 public boolean equals(Object obj) { 3524 if (!(obj instanceof TypePair)) 3525 return false; 3526 TypePair typePair = (TypePair)obj; 3527 return isSameType(t1, typePair.t1, strict) 3528 && isSameType(t2, typePair.t2, strict); 3529 } 3530 } 3531 Set<TypePair> mergeCache = new HashSet<TypePair>(); 3532 private Type merge(Type c1, Type c2) { 3533 ClassType class1 = (ClassType) c1; 3534 List<Type> act1 = class1.getTypeArguments(); 3535 ClassType class2 = (ClassType) c2; 3536 List<Type> act2 = class2.getTypeArguments(); 3537 ListBuffer<Type> merged = new ListBuffer<Type>(); 3538 List<Type> typarams = class1.tsym.type.getTypeArguments(); 3539 3540 while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) { 3541 if (containsType(act1.head, act2.head)) { 3542 merged.append(act1.head); 3543 } else if (containsType(act2.head, act1.head)) { 3544 merged.append(act2.head); 3545 } else { 3546 TypePair pair = new TypePair(c1, c2); 3547 Type m; 3548 if (mergeCache.add(pair)) { 3549 m = new WildcardType(lub(wildUpperBound(act1.head), 3550 wildUpperBound(act2.head)), 3551 BoundKind.EXTENDS, 3552 syms.boundClass); 3553 mergeCache.remove(pair); 3554 } else { 3555 m = new WildcardType(syms.objectType, 3556 BoundKind.UNBOUND, 3557 syms.boundClass); 3558 } 3559 merged.append(m.withTypeVar(typarams.head)); 3560 } 3561 act1 = act1.tail; 3562 act2 = act2.tail; 3563 typarams = typarams.tail; 3564 } 3565 Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty()); 3566 return new ClassType(class1.getEnclosingType(), merged.toList(), class1.tsym); 3567 } 3568 3569 /** 3570 * Return the minimum type of a closure, a compound type if no 3571 * unique minimum exists. 3572 */ 3573 private Type compoundMin(List<Type> cl) { 3574 if (cl.isEmpty()) return syms.objectType; 3575 List<Type> compound = closureMin(cl); 3576 if (compound.isEmpty()) 3577 return null; 3578 else if (compound.tail.isEmpty()) 3579 return compound.head; 3580 else 3581 return makeIntersectionType(compound); 3582 } 3583 3584 /** 3585 * Return the minimum types of a closure, suitable for computing 3586 * compoundMin or glb. 3587 */ 3588 private List<Type> closureMin(List<Type> cl) { 3589 ListBuffer<Type> classes = new ListBuffer<>(); 3590 ListBuffer<Type> interfaces = new ListBuffer<>(); 3591 Set<Type> toSkip = new HashSet<>(); 3592 while (!cl.isEmpty()) { 3593 Type current = cl.head; 3594 boolean keep = !toSkip.contains(current); 3595 if (keep && current.hasTag(TYPEVAR)) { 3596 // skip lower-bounded variables with a subtype in cl.tail 3597 for (Type t : cl.tail) { 3598 if (isSubtypeNoCapture(t, current)) { 3599 keep = false; 3600 break; 3601 } 3602 } 3603 } 3604 if (keep) { 3605 if (current.isInterface()) 3606 interfaces.append(current); 3607 else 3608 classes.append(current); 3609 for (Type t : cl.tail) { 3610 // skip supertypes of 'current' in cl.tail 3611 if (isSubtypeNoCapture(current, t)) 3612 toSkip.add(t); 3613 } 3614 } 3615 cl = cl.tail; 3616 } 3617 return classes.appendList(interfaces).toList(); 3618 } 3619 3620 /** 3621 * Return the least upper bound of list of types. if the lub does 3622 * not exist return null. 3623 */ 3624 public Type lub(List<Type> ts) { 3625 return lub(ts.toArray(new Type[ts.length()])); 3626 } 3627 3628 /** 3629 * Return the least upper bound (lub) of set of types. If the lub 3630 * does not exist return the type of null (bottom). 3631 */ 3632 public Type lub(Type... ts) { 3633 final int UNKNOWN_BOUND = 0; 3634 final int ARRAY_BOUND = 1; 3635 final int CLASS_BOUND = 2; 3636 3637 int[] kinds = new int[ts.length]; 3638 3639 int boundkind = UNKNOWN_BOUND; 3640 for (int i = 0 ; i < ts.length ; i++) { 3641 Type t = ts[i]; 3642 switch (t.getTag()) { 3643 case CLASS: 3644 boundkind |= kinds[i] = CLASS_BOUND; 3645 break; 3646 case ARRAY: 3647 boundkind |= kinds[i] = ARRAY_BOUND; 3648 break; 3649 case TYPEVAR: 3650 do { 3651 t = t.getUpperBound(); 3652 } while (t.hasTag(TYPEVAR)); 3653 if (t.hasTag(ARRAY)) { 3654 boundkind |= kinds[i] = ARRAY_BOUND; 3655 } else { 3656 boundkind |= kinds[i] = CLASS_BOUND; 3657 } 3658 break; 3659 default: 3660 kinds[i] = UNKNOWN_BOUND; 3661 if (t.isPrimitive()) 3662 return syms.errType; 3663 } 3664 } 3665 switch (boundkind) { 3666 case 0: 3667 return syms.botType; 3668 3669 case ARRAY_BOUND: 3670 // calculate lub(A[], B[]) 3671 Type[] elements = new Type[ts.length]; 3672 for (int i = 0 ; i < ts.length ; i++) { 3673 Type elem = elements[i] = elemTypeFun.apply(ts[i]); 3674 if (elem.isPrimitive()) { 3675 // if a primitive type is found, then return 3676 // arraySuperType unless all the types are the 3677 // same 3678 Type first = ts[0]; 3679 for (int j = 1 ; j < ts.length ; j++) { 3680 if (!isSameType(first, ts[j])) { 3681 // lub(int[], B[]) is Cloneable & Serializable 3682 return arraySuperType(); 3683 } 3684 } 3685 // all the array types are the same, return one 3686 // lub(int[], int[]) is int[] 3687 return first; 3688 } 3689 } 3690 // lub(A[], B[]) is lub(A, B)[] 3691 return new ArrayType(lub(elements), syms.arrayClass); 3692 3693 case CLASS_BOUND: 3694 // calculate lub(A, B) 3695 int startIdx = 0; 3696 for (int i = 0; i < ts.length ; i++) { 3697 Type t = ts[i]; 3698 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) { 3699 break; 3700 } else { 3701 startIdx++; 3702 } 3703 } 3704 Assert.check(startIdx < ts.length); 3705 //step 1 - compute erased candidate set (EC) 3706 List<Type> cl = erasedSupertypes(ts[startIdx]); 3707 for (int i = startIdx + 1 ; i < ts.length ; i++) { 3708 Type t = ts[i]; 3709 if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) 3710 cl = intersect(cl, erasedSupertypes(t)); 3711 } 3712 //step 2 - compute minimal erased candidate set (MEC) 3713 List<Type> mec = closureMin(cl); 3714 //step 3 - for each element G in MEC, compute lci(Inv(G)) 3715 List<Type> candidates = List.nil(); 3716 for (Type erasedSupertype : mec) { 3717 List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym)); 3718 for (int i = startIdx + 1 ; i < ts.length ; i++) { 3719 Type superType = asSuper(ts[i], erasedSupertype.tsym); 3720 lci = intersect(lci, superType != null ? List.of(superType) : List.<Type>nil()); 3721 } 3722 candidates = candidates.appendList(lci); 3723 } 3724 //step 4 - let MEC be { G1, G2 ... Gn }, then we have that 3725 //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn)) 3726 return compoundMin(candidates); 3727 3728 default: 3729 // calculate lub(A, B[]) 3730 List<Type> classes = List.of(arraySuperType()); 3731 for (int i = 0 ; i < ts.length ; i++) { 3732 if (kinds[i] != ARRAY_BOUND) // Filter out any arrays 3733 classes = classes.prepend(ts[i]); 3734 } 3735 // lub(A, B[]) is lub(A, arraySuperType) 3736 return lub(classes); 3737 } 3738 } 3739 // where 3740 List<Type> erasedSupertypes(Type t) { 3741 ListBuffer<Type> buf = new ListBuffer<>(); 3742 for (Type sup : closure(t)) { 3743 if (sup.hasTag(TYPEVAR)) { 3744 buf.append(sup); 3745 } else { 3746 buf.append(erasure(sup)); 3747 } 3748 } 3749 return buf.toList(); 3750 } 3751 3752 private Type arraySuperType = null; 3753 private Type arraySuperType() { 3754 // initialized lazily to avoid problems during compiler startup 3755 if (arraySuperType == null) { 3756 synchronized (this) { 3757 if (arraySuperType == null) { 3758 // JLS 10.8: all arrays implement Cloneable and Serializable. 3759 arraySuperType = makeIntersectionType(List.of(syms.serializableType, 3760 syms.cloneableType), true); 3761 } 3762 } 3763 } 3764 return arraySuperType; 3765 } 3766 // </editor-fold> 3767 3768 // <editor-fold defaultstate="collapsed" desc="Greatest lower bound"> 3769 public Type glb(List<Type> ts) { 3770 Type t1 = ts.head; 3771 for (Type t2 : ts.tail) { 3772 if (t1.isErroneous()) 3773 return t1; 3774 t1 = glb(t1, t2); 3775 } 3776 return t1; 3777 } 3778 //where 3779 public Type glb(Type t, Type s) { 3780 if (s == null) 3781 return t; 3782 else if (t.isPrimitive() || s.isPrimitive()) 3783 return syms.errType; 3784 else if (isSubtypeNoCapture(t, s)) 3785 return t; 3786 else if (isSubtypeNoCapture(s, t)) 3787 return s; 3788 3789 List<Type> closure = union(closure(t), closure(s)); 3790 return glbFlattened(closure, t); 3791 } 3792 //where 3793 /** 3794 * Perform glb for a list of non-primitive, non-error, non-compound types; 3795 * redundant elements are removed. Bounds should be ordered according to 3796 * {@link Symbol#precedes(TypeSymbol,Types)}. 3797 * 3798 * @param flatBounds List of type to glb 3799 * @param errT Original type to use if the result is an error type 3800 */ 3801 private Type glbFlattened(List<Type> flatBounds, Type errT) { 3802 List<Type> bounds = closureMin(flatBounds); 3803 3804 if (bounds.isEmpty()) { // length == 0 3805 return syms.objectType; 3806 } else if (bounds.tail.isEmpty()) { // length == 1 3807 return bounds.head; 3808 } else { // length > 1 3809 int classCount = 0; 3810 List<Type> lowers = List.nil(); 3811 for (Type bound : bounds) { 3812 if (!bound.isInterface()) { 3813 classCount++; 3814 Type lower = cvarLowerBound(bound); 3815 if (bound != lower && !lower.hasTag(BOT)) 3816 lowers = insert(lowers, lower); 3817 } 3818 } 3819 if (classCount > 1) { 3820 if (lowers.isEmpty()) 3821 return createErrorType(errT); 3822 else 3823 return glbFlattened(union(bounds, lowers), errT); 3824 } 3825 } 3826 return makeIntersectionType(bounds); 3827 } 3828 // </editor-fold> 3829 3830 // <editor-fold defaultstate="collapsed" desc="hashCode"> 3831 /** 3832 * Compute a hash code on a type. 3833 */ 3834 public int hashCode(Type t) { 3835 return hashCode.visit(t); 3836 } 3837 // where 3838 private static final UnaryVisitor<Integer> hashCode = new UnaryVisitor<Integer>() { 3839 3840 public Integer visitType(Type t, Void ignored) { 3841 return t.getTag().ordinal(); 3842 } 3843 3844 @Override 3845 public Integer visitClassType(ClassType t, Void ignored) { 3846 int result = visit(t.getEnclosingType()); 3847 result *= 127; 3848 result += t.tsym.flatName().hashCode(); 3849 for (Type s : t.getTypeArguments()) { 3850 result *= 127; 3851 result += visit(s); 3852 } 3853 return result; 3854 } 3855 3856 @Override 3857 public Integer visitMethodType(MethodType t, Void ignored) { 3858 int h = METHOD.ordinal(); 3859 for (List<Type> thisargs = t.argtypes; 3860 thisargs.tail != null; 3861 thisargs = thisargs.tail) 3862 h = (h << 5) + visit(thisargs.head); 3863 return (h << 5) + visit(t.restype); 3864 } 3865 3866 @Override 3867 public Integer visitWildcardType(WildcardType t, Void ignored) { 3868 int result = t.kind.hashCode(); 3869 if (t.type != null) { 3870 result *= 127; 3871 result += visit(t.type); 3872 } 3873 return result; 3874 } 3875 3876 @Override 3877 public Integer visitArrayType(ArrayType t, Void ignored) { 3878 return visit(t.elemtype) + 12; 3879 } 3880 3881 @Override 3882 public Integer visitTypeVar(TypeVar t, Void ignored) { 3883 return System.identityHashCode(t.tsym); 3884 } 3885 3886 @Override 3887 public Integer visitUndetVar(UndetVar t, Void ignored) { 3888 return System.identityHashCode(t); 3889 } 3890 3891 @Override 3892 public Integer visitErrorType(ErrorType t, Void ignored) { 3893 return 0; 3894 } 3895 }; 3896 // </editor-fold> 3897 3898 // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable"> 3899 /** 3900 * Does t have a result that is a subtype of the result type of s, 3901 * suitable for covariant returns? It is assumed that both types 3902 * are (possibly polymorphic) method types. Monomorphic method 3903 * types are handled in the obvious way. Polymorphic method types 3904 * require renaming all type variables of one to corresponding 3905 * type variables in the other, where correspondence is by 3906 * position in the type parameter list. */ 3907 public boolean resultSubtype(Type t, Type s, Warner warner) { 3908 List<Type> tvars = t.getTypeArguments(); 3909 List<Type> svars = s.getTypeArguments(); 3910 Type tres = t.getReturnType(); 3911 Type sres = subst(s.getReturnType(), svars, tvars); 3912 return covariantReturnType(tres, sres, warner); 3913 } 3914 3915 /** 3916 * Return-Type-Substitutable. 3917 * @jls section 8.4.5 3918 */ 3919 public boolean returnTypeSubstitutable(Type r1, Type r2) { 3920 if (hasSameArgs(r1, r2)) 3921 return resultSubtype(r1, r2, noWarnings); 3922 else 3923 return covariantReturnType(r1.getReturnType(), 3924 erasure(r2.getReturnType()), 3925 noWarnings); 3926 } 3927 3928 public boolean returnTypeSubstitutable(Type r1, 3929 Type r2, Type r2res, 3930 Warner warner) { 3931 if (isSameType(r1.getReturnType(), r2res)) 3932 return true; 3933 if (r1.getReturnType().isPrimitive() || r2res.isPrimitive()) 3934 return false; 3935 3936 if (hasSameArgs(r1, r2)) 3937 return covariantReturnType(r1.getReturnType(), r2res, warner); 3938 if (!allowCovariantReturns) 3939 return false; 3940 if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner)) 3941 return true; 3942 if (!isSubtype(r1.getReturnType(), erasure(r2res))) 3943 return false; 3944 warner.warn(LintCategory.UNCHECKED); 3945 return true; 3946 } 3947 3948 /** 3949 * Is t an appropriate return type in an overrider for a 3950 * method that returns s? 3951 */ 3952 public boolean covariantReturnType(Type t, Type s, Warner warner) { 3953 return 3954 isSameType(t, s) || 3955 allowCovariantReturns && 3956 !t.isPrimitive() && 3957 !s.isPrimitive() && 3958 isAssignable(t, s, warner); 3959 } 3960 // </editor-fold> 3961 3962 // <editor-fold defaultstate="collapsed" desc="Box/unbox support"> 3963 /** 3964 * Return the class that boxes the given primitive. 3965 */ 3966 public ClassSymbol boxedClass(Type t) { 3967 return reader.enterClass(syms.boxedName[t.getTag().ordinal()]); 3968 } 3969 3970 /** 3971 * Return the boxed type if 't' is primitive, otherwise return 't' itself. 3972 */ 3973 public Type boxedTypeOrType(Type t) { 3974 return t.isPrimitive() ? 3975 boxedClass(t).type : 3976 t; 3977 } 3978 3979 /** 3980 * Return the primitive type corresponding to a boxed type. 3981 */ 3982 public Type unboxedType(Type t) { 3983 if (allowBoxing) { 3984 for (int i=0; i<syms.boxedName.length; i++) { 3985 Name box = syms.boxedName[i]; 3986 if (box != null && 3987 asSuper(t, reader.enterClass(box)) != null) 3988 return syms.typeOfTag[i]; 3989 } 3990 } 3991 return Type.noType; 3992 } 3993 3994 /** 3995 * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself. 3996 */ 3997 public Type unboxedTypeOrType(Type t) { 3998 Type unboxedType = unboxedType(t); 3999 return unboxedType.hasTag(NONE) ? t : unboxedType; 4000 } 4001 // </editor-fold> 4002 4003 // <editor-fold defaultstate="collapsed" desc="Capture conversion"> 4004 /* 4005 * JLS 5.1.10 Capture Conversion: 4006 * 4007 * Let G name a generic type declaration with n formal type 4008 * parameters A1 ... An with corresponding bounds U1 ... Un. There 4009 * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>, 4010 * where, for 1 <= i <= n: 4011 * 4012 * + If Ti is a wildcard type argument (4.5.1) of the form ? then 4013 * Si is a fresh type variable whose upper bound is 4014 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null 4015 * type. 4016 * 4017 * + If Ti is a wildcard type argument of the form ? extends Bi, 4018 * then Si is a fresh type variable whose upper bound is 4019 * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is 4020 * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is 4021 * a compile-time error if for any two classes (not interfaces) 4022 * Vi and Vj,Vi is not a subclass of Vj or vice versa. 4023 * 4024 * + If Ti is a wildcard type argument of the form ? super Bi, 4025 * then Si is a fresh type variable whose upper bound is 4026 * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi. 4027 * 4028 * + Otherwise, Si = Ti. 4029 * 4030 * Capture conversion on any type other than a parameterized type 4031 * (4.5) acts as an identity conversion (5.1.1). Capture 4032 * conversions never require a special action at run time and 4033 * therefore never throw an exception at run time. 4034 * 4035 * Capture conversion is not applied recursively. 4036 */ 4037 /** 4038 * Capture conversion as specified by the JLS. 4039 */ 4040 4041 public List<Type> capture(List<Type> ts) { 4042 List<Type> buf = List.nil(); 4043 for (Type t : ts) { 4044 buf = buf.prepend(capture(t)); 4045 } 4046 return buf.reverse(); 4047 } 4048 4049 public Type capture(Type t) { 4050 if (!t.hasTag(CLASS)) { 4051 return t; 4052 } 4053 if (t.getEnclosingType() != Type.noType) { 4054 Type capturedEncl = capture(t.getEnclosingType()); 4055 if (capturedEncl != t.getEnclosingType()) { 4056 Type type1 = memberType(capturedEncl, t.tsym); 4057 t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments()); 4058 } 4059 } 4060 t = t.unannotatedType(); 4061 ClassType cls = (ClassType)t; 4062 if (cls.isRaw() || !cls.isParameterized()) 4063 return cls; 4064 4065 ClassType G = (ClassType)cls.asElement().asType(); 4066 List<Type> A = G.getTypeArguments(); 4067 List<Type> T = cls.getTypeArguments(); 4068 List<Type> S = freshTypeVariables(T); 4069 4070 List<Type> currentA = A; 4071 List<Type> currentT = T; 4072 List<Type> currentS = S; 4073 boolean captured = false; 4074 while (!currentA.isEmpty() && 4075 !currentT.isEmpty() && 4076 !currentS.isEmpty()) { 4077 if (currentS.head != currentT.head) { 4078 captured = true; 4079 WildcardType Ti = (WildcardType)currentT.head.unannotatedType(); 4080 Type Ui = currentA.head.getUpperBound(); 4081 CapturedType Si = (CapturedType)currentS.head.unannotatedType(); 4082 if (Ui == null) 4083 Ui = syms.objectType; 4084 switch (Ti.kind) { 4085 case UNBOUND: 4086 Si.bound = subst(Ui, A, S); 4087 Si.lower = syms.botType; 4088 break; 4089 case EXTENDS: 4090 Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S)); 4091 Si.lower = syms.botType; 4092 break; 4093 case SUPER: 4094 Si.bound = subst(Ui, A, S); 4095 Si.lower = Ti.getSuperBound(); 4096 break; 4097 } 4098 Type tmpBound = Si.bound.hasTag(UNDETVAR) ? ((UndetVar)Si.bound).qtype : Si.bound; 4099 Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower; 4100 if (!Si.bound.hasTag(ERROR) && 4101 !Si.lower.hasTag(ERROR) && 4102 isSameType(tmpBound, tmpLower, false)) { 4103 currentS.head = Si.bound; 4104 } 4105 } 4106 currentA = currentA.tail; 4107 currentT = currentT.tail; 4108 currentS = currentS.tail; 4109 } 4110 if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty()) 4111 return erasure(t); // some "rare" type involved 4112 4113 if (captured) 4114 return new ClassType(cls.getEnclosingType(), S, cls.tsym); 4115 else 4116 return t; 4117 } 4118 // where 4119 public List<Type> freshTypeVariables(List<Type> types) { 4120 ListBuffer<Type> result = new ListBuffer<>(); 4121 for (Type t : types) { 4122 if (t.hasTag(WILDCARD)) { 4123 t = t.unannotatedType(); 4124 Type bound = ((WildcardType)t).getExtendsBound(); 4125 if (bound == null) 4126 bound = syms.objectType; 4127 result.append(new CapturedType(capturedName, 4128 syms.noSymbol, 4129 bound, 4130 syms.botType, 4131 (WildcardType)t)); 4132 } else { 4133 result.append(t); 4134 } 4135 } 4136 return result.toList(); 4137 } 4138 // </editor-fold> 4139 4140 // <editor-fold defaultstate="collapsed" desc="Internal utility methods"> 4141 private boolean sideCast(Type from, Type to, Warner warn) { 4142 // We are casting from type $from$ to type $to$, which are 4143 // non-final unrelated types. This method 4144 // tries to reject a cast by transferring type parameters 4145 // from $to$ to $from$ by common superinterfaces. 4146 boolean reverse = false; 4147 Type target = to; 4148 if ((to.tsym.flags() & INTERFACE) == 0) { 4149 Assert.check((from.tsym.flags() & INTERFACE) != 0); 4150 reverse = true; 4151 to = from; 4152 from = target; 4153 } 4154 List<Type> commonSupers = superClosure(to, erasure(from)); 4155 boolean giveWarning = commonSupers.isEmpty(); 4156 // The arguments to the supers could be unified here to 4157 // get a more accurate analysis 4158 while (commonSupers.nonEmpty()) { 4159 Type t1 = asSuper(from, commonSupers.head.tsym); 4160 Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym); 4161 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) 4162 return false; 4163 giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)); 4164 commonSupers = commonSupers.tail; 4165 } 4166 if (giveWarning && !isReifiable(reverse ? from : to)) 4167 warn.warn(LintCategory.UNCHECKED); 4168 if (!allowCovariantReturns) 4169 // reject if there is a common method signature with 4170 // incompatible return types. 4171 chk.checkCompatibleAbstracts(warn.pos(), from, to); 4172 return true; 4173 } 4174 4175 private boolean sideCastFinal(Type from, Type to, Warner warn) { 4176 // We are casting from type $from$ to type $to$, which are 4177 // unrelated types one of which is final and the other of 4178 // which is an interface. This method 4179 // tries to reject a cast by transferring type parameters 4180 // from the final class to the interface. 4181 boolean reverse = false; 4182 Type target = to; 4183 if ((to.tsym.flags() & INTERFACE) == 0) { 4184 Assert.check((from.tsym.flags() & INTERFACE) != 0); 4185 reverse = true; 4186 to = from; 4187 from = target; 4188 } 4189 Assert.check((from.tsym.flags() & FINAL) != 0); 4190 Type t1 = asSuper(from, to.tsym); 4191 if (t1 == null) return false; 4192 Type t2 = to; 4193 if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments())) 4194 return false; 4195 if (!allowCovariantReturns) 4196 // reject if there is a common method signature with 4197 // incompatible return types. 4198 chk.checkCompatibleAbstracts(warn.pos(), from, to); 4199 if (!isReifiable(target) && 4200 (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2))) 4201 warn.warn(LintCategory.UNCHECKED); 4202 return true; 4203 } 4204 4205 private boolean giveWarning(Type from, Type to) { 4206 List<Type> bounds = to.isCompound() ? 4207 ((IntersectionClassType)to.unannotatedType()).getComponents() : List.of(to); 4208 for (Type b : bounds) { 4209 Type subFrom = asSub(from, b.tsym); 4210 if (b.isParameterized() && 4211 (!(isUnbounded(b) || 4212 isSubtype(from, b) || 4213 ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) { 4214 return true; 4215 } 4216 } 4217 return false; 4218 } 4219 4220 private List<Type> superClosure(Type t, Type s) { 4221 List<Type> cl = List.nil(); 4222 for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) { 4223 if (isSubtype(s, erasure(l.head))) { 4224 cl = insert(cl, l.head); 4225 } else { 4226 cl = union(cl, superClosure(l.head, s)); 4227 } 4228 } 4229 return cl; 4230 } 4231 4232 private boolean containsTypeEquivalent(Type t, Type s) { 4233 return 4234 isSameType(t, s) || // shortcut 4235 containsType(t, s) && containsType(s, t); 4236 } 4237 4238 // <editor-fold defaultstate="collapsed" desc="adapt"> 4239 /** 4240 * Adapt a type by computing a substitution which maps a source 4241 * type to a target type. 4242 * 4243 * @param source the source type 4244 * @param target the target type 4245 * @param from the type variables of the computed substitution 4246 * @param to the types of the computed substitution. 4247 */ 4248 public void adapt(Type source, 4249 Type target, 4250 ListBuffer<Type> from, 4251 ListBuffer<Type> to) throws AdaptFailure { 4252 new Adapter(from, to).adapt(source, target); 4253 } 4254 4255 class Adapter extends SimpleVisitor<Void, Type> { 4256 4257 ListBuffer<Type> from; 4258 ListBuffer<Type> to; 4259 Map<Symbol,Type> mapping; 4260 4261 Adapter(ListBuffer<Type> from, ListBuffer<Type> to) { 4262 this.from = from; 4263 this.to = to; 4264 mapping = new HashMap<Symbol,Type>(); 4265 } 4266 4267 public void adapt(Type source, Type target) throws AdaptFailure { 4268 visit(source, target); 4269 List<Type> fromList = from.toList(); 4270 List<Type> toList = to.toList(); 4271 while (!fromList.isEmpty()) { 4272 Type val = mapping.get(fromList.head.tsym); 4273 if (toList.head != val) 4274 toList.head = val; 4275 fromList = fromList.tail; 4276 toList = toList.tail; 4277 } 4278 } 4279 4280 @Override 4281 public Void visitClassType(ClassType source, Type target) throws AdaptFailure { 4282 if (target.hasTag(CLASS)) 4283 adaptRecursive(source.allparams(), target.allparams()); 4284 return null; 4285 } 4286 4287 @Override 4288 public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure { 4289 if (target.hasTag(ARRAY)) 4290 adaptRecursive(elemtype(source), elemtype(target)); 4291 return null; 4292 } 4293 4294 @Override 4295 public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure { 4296 if (source.isExtendsBound()) 4297 adaptRecursive(wildUpperBound(source), wildUpperBound(target)); 4298 else if (source.isSuperBound()) 4299 adaptRecursive(wildLowerBound(source), wildLowerBound(target)); 4300 return null; 4301 } 4302 4303 @Override 4304 public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure { 4305 // Check to see if there is 4306 // already a mapping for $source$, in which case 4307 // the old mapping will be merged with the new 4308 Type val = mapping.get(source.tsym); 4309 if (val != null) { 4310 if (val.isSuperBound() && target.isSuperBound()) { 4311 val = isSubtype(wildLowerBound(val), wildLowerBound(target)) 4312 ? target : val; 4313 } else if (val.isExtendsBound() && target.isExtendsBound()) { 4314 val = isSubtype(wildUpperBound(val), wildUpperBound(target)) 4315 ? val : target; 4316 } else if (!isSameType(val, target)) { 4317 throw new AdaptFailure(); 4318 } 4319 } else { 4320 val = target; 4321 from.append(source); 4322 to.append(target); 4323 } 4324 mapping.put(source.tsym, val); 4325 return null; 4326 } 4327 4328 @Override 4329 public Void visitType(Type source, Type target) { 4330 return null; 4331 } 4332 4333 private Set<TypePair> cache = new HashSet<TypePair>(); 4334 4335 private void adaptRecursive(Type source, Type target) { 4336 TypePair pair = new TypePair(source, target); 4337 if (cache.add(pair)) { 4338 try { 4339 visit(source, target); 4340 } finally { 4341 cache.remove(pair); 4342 } 4343 } 4344 } 4345 4346 private void adaptRecursive(List<Type> source, List<Type> target) { 4347 if (source.length() == target.length()) { 4348 while (source.nonEmpty()) { 4349 adaptRecursive(source.head, target.head); 4350 source = source.tail; 4351 target = target.tail; 4352 } 4353 } 4354 } 4355 } 4356 4357 public static class AdaptFailure extends RuntimeException { 4358 static final long serialVersionUID = -7490231548272701566L; 4359 } 4360 4361 private void adaptSelf(Type t, 4362 ListBuffer<Type> from, 4363 ListBuffer<Type> to) { 4364 try { 4365 //if (t.tsym.type != t) 4366 adapt(t.tsym.type, t, from, to); 4367 } catch (AdaptFailure ex) { 4368 // Adapt should never fail calculating a mapping from 4369 // t.tsym.type to t as there can be no merge problem. 4370 throw new AssertionError(ex); 4371 } 4372 } 4373 // </editor-fold> 4374 4375 /** 4376 * Rewrite all type variables (universal quantifiers) in the given 4377 * type to wildcards (existential quantifiers). This is used to 4378 * determine if a cast is allowed. For example, if high is true 4379 * and {@code T <: Number}, then {@code List<T>} is rewritten to 4380 * {@code List<? extends Number>}. Since {@code List<Integer> <: 4381 * List<? extends Number>} a {@code List<T>} can be cast to {@code 4382 * List<Integer>} with a warning. 4383 * @param t a type 4384 * @param high if true return an upper bound; otherwise a lower 4385 * bound 4386 * @param rewriteTypeVars only rewrite captured wildcards if false; 4387 * otherwise rewrite all type variables 4388 * @return the type rewritten with wildcards (existential 4389 * quantifiers) only 4390 */ 4391 private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) { 4392 return new Rewriter(high, rewriteTypeVars).visit(t); 4393 } 4394 4395 class Rewriter extends UnaryVisitor<Type> { 4396 4397 boolean high; 4398 boolean rewriteTypeVars; 4399 4400 Rewriter(boolean high, boolean rewriteTypeVars) { 4401 this.high = high; 4402 this.rewriteTypeVars = rewriteTypeVars; 4403 } 4404 4405 @Override 4406 public Type visitClassType(ClassType t, Void s) { 4407 ListBuffer<Type> rewritten = new ListBuffer<Type>(); 4408 boolean changed = false; 4409 for (Type arg : t.allparams()) { 4410 Type bound = visit(arg); 4411 if (arg != bound) { 4412 changed = true; 4413 } 4414 rewritten.append(bound); 4415 } 4416 if (changed) 4417 return subst(t.tsym.type, 4418 t.tsym.type.allparams(), 4419 rewritten.toList()); 4420 else 4421 return t; 4422 } 4423 4424 public Type visitType(Type t, Void s) { 4425 return t; 4426 } 4427 4428 @Override 4429 public Type visitCapturedType(CapturedType t, Void s) { 4430 Type w_bound = t.wildcard.type; 4431 Type bound = w_bound.contains(t) ? 4432 erasure(w_bound) : 4433 visit(w_bound); 4434 return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind); 4435 } 4436 4437 @Override 4438 public Type visitTypeVar(TypeVar t, Void s) { 4439 if (rewriteTypeVars) { 4440 Type bound = t.bound.contains(t) ? 4441 erasure(t.bound) : 4442 visit(t.bound); 4443 return rewriteAsWildcardType(bound, t, EXTENDS); 4444 } else { 4445 return t; 4446 } 4447 } 4448 4449 @Override 4450 public Type visitWildcardType(WildcardType t, Void s) { 4451 Type bound2 = visit(t.type); 4452 return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind); 4453 } 4454 4455 private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) { 4456 switch (bk) { 4457 case EXTENDS: return high ? 4458 makeExtendsWildcard(B(bound), formal) : 4459 makeExtendsWildcard(syms.objectType, formal); 4460 case SUPER: return high ? 4461 makeSuperWildcard(syms.botType, formal) : 4462 makeSuperWildcard(B(bound), formal); 4463 case UNBOUND: return makeExtendsWildcard(syms.objectType, formal); 4464 default: 4465 Assert.error("Invalid bound kind " + bk); 4466 return null; 4467 } 4468 } 4469 4470 Type B(Type t) { 4471 while (t.hasTag(WILDCARD)) { 4472 WildcardType w = (WildcardType)t.unannotatedType(); 4473 t = high ? 4474 w.getExtendsBound() : 4475 w.getSuperBound(); 4476 if (t == null) { 4477 t = high ? syms.objectType : syms.botType; 4478 } 4479 } 4480 return t; 4481 } 4482 } 4483 4484 4485 /** 4486 * Create a wildcard with the given upper (extends) bound; create 4487 * an unbounded wildcard if bound is Object. 4488 * 4489 * @param bound the upper bound 4490 * @param formal the formal type parameter that will be 4491 * substituted by the wildcard 4492 */ 4493 private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) { 4494 if (bound == syms.objectType) { 4495 return new WildcardType(syms.objectType, 4496 BoundKind.UNBOUND, 4497 syms.boundClass, 4498 formal); 4499 } else { 4500 return new WildcardType(bound, 4501 BoundKind.EXTENDS, 4502 syms.boundClass, 4503 formal); 4504 } 4505 } 4506 4507 /** 4508 * Create a wildcard with the given lower (super) bound; create an 4509 * unbounded wildcard if bound is bottom (type of {@code null}). 4510 * 4511 * @param bound the lower bound 4512 * @param formal the formal type parameter that will be 4513 * substituted by the wildcard 4514 */ 4515 private WildcardType makeSuperWildcard(Type bound, TypeVar formal) { 4516 if (bound.hasTag(BOT)) { 4517 return new WildcardType(syms.objectType, 4518 BoundKind.UNBOUND, 4519 syms.boundClass, 4520 formal); 4521 } else { 4522 return new WildcardType(bound, 4523 BoundKind.SUPER, 4524 syms.boundClass, 4525 formal); 4526 } 4527 } 4528 4529 /** 4530 * A wrapper for a type that allows use in sets. 4531 */ 4532 public static class UniqueType { 4533 public final Type type; 4534 final Types types; 4535 4536 public UniqueType(Type type, Types types) { 4537 this.type = type; 4538 this.types = types; 4539 } 4540 4541 public int hashCode() { 4542 return types.hashCode(type); 4543 } 4544 4545 public boolean equals(Object obj) { 4546 return (obj instanceof UniqueType) && 4547 types.isSameAnnotatedType(type, ((UniqueType)obj).type); 4548 } 4549 4550 public String toString() { 4551 return type.toString(); 4552 } 4553 4554 } 4555 // </editor-fold> 4556 4557 // <editor-fold defaultstate="collapsed" desc="Visitors"> 4558 /** 4559 * A default visitor for types. All visitor methods except 4560 * visitType are implemented by delegating to visitType. Concrete 4561 * subclasses must provide an implementation of visitType and can 4562 * override other methods as needed. 4563 * 4564 * @param <R> the return type of the operation implemented by this 4565 * visitor; use Void if no return type is needed. 4566 * @param <S> the type of the second argument (the first being the 4567 * type itself) of the operation implemented by this visitor; use 4568 * Void if a second argument is not needed. 4569 */ 4570 public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> { 4571 final public R visit(Type t, S s) { return t.accept(this, s); } 4572 public R visitClassType(ClassType t, S s) { return visitType(t, s); } 4573 public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); } 4574 public R visitArrayType(ArrayType t, S s) { return visitType(t, s); } 4575 public R visitMethodType(MethodType t, S s) { return visitType(t, s); } 4576 public R visitPackageType(PackageType t, S s) { return visitType(t, s); } 4577 public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); } 4578 public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); } 4579 public R visitForAll(ForAll t, S s) { return visitType(t, s); } 4580 public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); } 4581 public R visitErrorType(ErrorType t, S s) { return visitType(t, s); } 4582 // Pretend annotations don't exist 4583 public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.unannotatedType(), s); } 4584 } 4585 4586 /** 4587 * A default visitor for symbols. All visitor methods except 4588 * visitSymbol are implemented by delegating to visitSymbol. Concrete 4589 * subclasses must provide an implementation of visitSymbol and can 4590 * override other methods as needed. 4591 * 4592 * @param <R> the return type of the operation implemented by this 4593 * visitor; use Void if no return type is needed. 4594 * @param <S> the type of the second argument (the first being the 4595 * symbol itself) of the operation implemented by this visitor; use 4596 * Void if a second argument is not needed. 4597 */ 4598 public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> { 4599 final public R visit(Symbol s, S arg) { return s.accept(this, arg); } 4600 public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); } 4601 public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); } 4602 public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); } 4603 public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); } 4604 public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); } 4605 public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); } 4606 } 4607 4608 /** 4609 * A <em>simple</em> visitor for types. This visitor is simple as 4610 * captured wildcards, for-all types (generic methods), and 4611 * undetermined type variables (part of inference) are hidden. 4612 * Captured wildcards are hidden by treating them as type 4613 * variables and the rest are hidden by visiting their qtypes. 4614 * 4615 * @param <R> the return type of the operation implemented by this 4616 * visitor; use Void if no return type is needed. 4617 * @param <S> the type of the second argument (the first being the 4618 * type itself) of the operation implemented by this visitor; use 4619 * Void if a second argument is not needed. 4620 */ 4621 public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> { 4622 @Override 4623 public R visitCapturedType(CapturedType t, S s) { 4624 return visitTypeVar(t, s); 4625 } 4626 @Override 4627 public R visitForAll(ForAll t, S s) { 4628 return visit(t.qtype, s); 4629 } 4630 @Override 4631 public R visitUndetVar(UndetVar t, S s) { 4632 return visit(t.qtype, s); 4633 } 4634 } 4635 4636 /** 4637 * A plain relation on types. That is a 2-ary function on the 4638 * form Type × Type → Boolean. 4639 * <!-- In plain text: Type x Type -> Boolean --> 4640 */ 4641 public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {} 4642 4643 /** 4644 * A convenience visitor for implementing operations that only 4645 * require one argument (the type itself), that is, unary 4646 * operations. 4647 * 4648 * @param <R> the return type of the operation implemented by this 4649 * visitor; use Void if no return type is needed. 4650 */ 4651 public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> { 4652 final public R visit(Type t) { return t.accept(this, null); } 4653 } 4654 4655 /** 4656 * A visitor for implementing a mapping from types to types. The 4657 * default behavior of this class is to implement the identity 4658 * mapping (mapping a type to itself). This can be overridden in 4659 * subclasses. 4660 * 4661 * @param <S> the type of the second argument (the first being the 4662 * type itself) of this mapping; use Void if a second argument is 4663 * not needed. 4664 */ 4665 public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> { 4666 final public Type visit(Type t) { return t.accept(this, null); } 4667 public Type visitType(Type t, S s) { return t; } 4668 } 4669 // </editor-fold> 4670 4671 4672 // <editor-fold defaultstate="collapsed" desc="Annotation support"> 4673 4674 public RetentionPolicy getRetention(Attribute.Compound a) { 4675 return getRetention(a.type.tsym); 4676 } 4677 4678 public RetentionPolicy getRetention(Symbol sym) { 4679 RetentionPolicy vis = RetentionPolicy.CLASS; // the default 4680 Attribute.Compound c = sym.attribute(syms.retentionType.tsym); 4681 if (c != null) { 4682 Attribute value = c.member(names.value); 4683 if (value != null && value instanceof Attribute.Enum) { 4684 Name levelName = ((Attribute.Enum)value).value.name; 4685 if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE; 4686 else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS; 4687 else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME; 4688 else ;// /* fail soft */ throw new AssertionError(levelName); 4689 } 4690 } 4691 return vis; 4692 } 4693 // </editor-fold> 4694 4695 // <editor-fold defaultstate="collapsed" desc="Signature Generation"> 4696 4697 public static abstract class SignatureGenerator { 4698 4699 private final Types types; 4700 4701 protected abstract void append(char ch); 4702 protected abstract void append(byte[] ba); 4703 protected abstract void append(Name name); 4704 protected void classReference(ClassSymbol c) { /* by default: no-op */ } 4705 4706 protected SignatureGenerator(Types types) { 4707 this.types = types; 4708 } 4709 4710 /** 4711 * Assemble signature of given type in string buffer. 4712 */ 4713 public void assembleSig(Type type) { 4714 type = type.unannotatedType(); 4715 switch (type.getTag()) { 4716 case BYTE: 4717 append('B'); 4718 break; 4719 case SHORT: 4720 append('S'); 4721 break; 4722 case CHAR: 4723 append('C'); 4724 break; 4725 case INT: 4726 append('I'); 4727 break; 4728 case LONG: 4729 append('J'); 4730 break; 4731 case FLOAT: 4732 append('F'); 4733 break; 4734 case DOUBLE: 4735 append('D'); 4736 break; 4737 case BOOLEAN: 4738 append('Z'); 4739 break; 4740 case VOID: 4741 append('V'); 4742 break; 4743 case CLASS: 4744 append('L'); 4745 assembleClassSig(type); 4746 append(';'); 4747 break; 4748 case ARRAY: 4749 ArrayType at = (ArrayType) type; 4750 append('['); 4751 assembleSig(at.elemtype); 4752 break; 4753 case METHOD: 4754 MethodType mt = (MethodType) type; 4755 append('('); 4756 assembleSig(mt.argtypes); 4757 append(')'); 4758 assembleSig(mt.restype); 4759 if (hasTypeVar(mt.thrown)) { 4760 for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) { 4761 append('^'); 4762 assembleSig(l.head); 4763 } 4764 } 4765 break; 4766 case WILDCARD: { 4767 Type.WildcardType ta = (Type.WildcardType) type; 4768 switch (ta.kind) { 4769 case SUPER: 4770 append('-'); 4771 assembleSig(ta.type); 4772 break; 4773 case EXTENDS: 4774 append('+'); 4775 assembleSig(ta.type); 4776 break; 4777 case UNBOUND: 4778 append('*'); 4779 break; 4780 default: 4781 throw new AssertionError(ta.kind); 4782 } 4783 break; 4784 } 4785 case TYPEVAR: 4786 append('T'); 4787 append(type.tsym.name); 4788 append(';'); 4789 break; 4790 case FORALL: 4791 Type.ForAll ft = (Type.ForAll) type; 4792 assembleParamsSig(ft.tvars); 4793 assembleSig(ft.qtype); 4794 break; 4795 default: 4796 throw new AssertionError("typeSig " + type.getTag()); 4797 } 4798 } 4799 4800 public boolean hasTypeVar(List<Type> l) { 4801 while (l.nonEmpty()) { 4802 if (l.head.hasTag(TypeTag.TYPEVAR)) { 4803 return true; 4804 } 4805 l = l.tail; 4806 } 4807 return false; 4808 } 4809 4810 public void assembleClassSig(Type type) { 4811 type = type.unannotatedType(); 4812 ClassType ct = (ClassType) type; 4813 ClassSymbol c = (ClassSymbol) ct.tsym; 4814 classReference(c); 4815 Type outer = ct.getEnclosingType(); 4816 if (outer.allparams().nonEmpty()) { 4817 boolean rawOuter = 4818 c.owner.kind == Kinds.MTH || // either a local class 4819 c.name == types.names.empty; // or anonymous 4820 assembleClassSig(rawOuter 4821 ? types.erasure(outer) 4822 : outer); 4823 append(rawOuter ? '$' : '.'); 4824 Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname)); 4825 append(rawOuter 4826 ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength()) 4827 : c.name); 4828 } else { 4829 append(externalize(c.flatname)); 4830 } 4831 if (ct.getTypeArguments().nonEmpty()) { 4832 append('<'); 4833 assembleSig(ct.getTypeArguments()); 4834 append('>'); 4835 } 4836 } 4837 4838 public void assembleParamsSig(List<Type> typarams) { 4839 append('<'); 4840 for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) { 4841 Type.TypeVar tvar = (Type.TypeVar) ts.head; 4842 append(tvar.tsym.name); 4843 List<Type> bounds = types.getBounds(tvar); 4844 if ((bounds.head.tsym.flags() & INTERFACE) != 0) { 4845 append(':'); 4846 } 4847 for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) { 4848 append(':'); 4849 assembleSig(l.head); 4850 } 4851 } 4852 append('>'); 4853 } 4854 4855 private void assembleSig(List<Type> types) { 4856 for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) { 4857 assembleSig(ts.head); 4858 } 4859 } 4860 } 4861 // </editor-fold> 4862 } 4863