1 // Copyright 2021 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef INCLUDE_V8_VALUE_H_ 6 #define INCLUDE_V8_VALUE_H_ 7 8 #include "v8-data.h" // NOLINT(build/include_directory) 9 #include "v8-internal.h" // NOLINT(build/include_directory) 10 #include "v8-local-handle.h" // NOLINT(build/include_directory) 11 #include "v8-maybe.h" // NOLINT(build/include_directory) 12 #include "v8config.h" // NOLINT(build/include_directory) 13 14 /** 15 * The v8 JavaScript engine. 16 */ 17 namespace v8 { 18 19 class BigInt; 20 class Int32; 21 class Integer; 22 class Number; 23 class Object; 24 class String; 25 class Uint32; 26 27 /** 28 * The superclass of all JavaScript values and objects. 29 */ 30 class V8_EXPORT Value : public Data { 31 public: 32 /** 33 * Returns true if this value is the undefined value. See ECMA-262 34 * 4.3.10. 35 * 36 * This is equivalent to `value === undefined` in JS. 37 */ 38 V8_INLINE bool IsUndefined() const; 39 40 /** 41 * Returns true if this value is the null value. See ECMA-262 42 * 4.3.11. 43 * 44 * This is equivalent to `value === null` in JS. 45 */ 46 V8_INLINE bool IsNull() const; 47 48 /** 49 * Returns true if this value is either the null or the undefined value. 50 * See ECMA-262 51 * 4.3.11. and 4.3.12 52 * 53 * This is equivalent to `value == null` in JS. 54 */ 55 V8_INLINE bool IsNullOrUndefined() const; 56 57 /** 58 * Returns true if this value is true. 59 * 60 * This is not the same as `BooleanValue()`. The latter performs a 61 * conversion to boolean, i.e. the result of `Boolean(value)` in JS, whereas 62 * this checks `value === true`. 63 */ 64 bool IsTrue() const; 65 66 /** 67 * Returns true if this value is false. 68 * 69 * This is not the same as `!BooleanValue()`. The latter performs a 70 * conversion to boolean, i.e. the result of `!Boolean(value)` in JS, whereas 71 * this checks `value === false`. 72 */ 73 bool IsFalse() const; 74 75 /** 76 * Returns true if this value is a symbol or a string. 77 * 78 * This is equivalent to 79 * `typeof value === 'string' || typeof value === 'symbol'` in JS. 80 */ 81 bool IsName() const; 82 83 /** 84 * Returns true if this value is an instance of the String type. 85 * See ECMA-262 8.4. 86 * 87 * This is equivalent to `typeof value === 'string'` in JS. 88 */ 89 V8_INLINE bool IsString() const; 90 91 /** 92 * Returns true if this value is a symbol. 93 * 94 * This is equivalent to `typeof value === 'symbol'` in JS. 95 */ 96 bool IsSymbol() const; 97 98 /** 99 * Returns true if this value is a function. 100 * 101 * This is equivalent to `typeof value === 'function'` in JS. 102 */ 103 bool IsFunction() const; 104 105 /** 106 * Returns true if this value is an array. Note that it will return false for 107 * an Proxy for an array. 108 */ 109 bool IsArray() const; 110 111 /** 112 * Returns true if this value is an object. 113 */ 114 bool IsObject() const; 115 116 /** 117 * Returns true if this value is a bigint. 118 * 119 * This is equivalent to `typeof value === 'bigint'` in JS. 120 */ 121 bool IsBigInt() const; 122 123 /** 124 * Returns true if this value is boolean. 125 * 126 * This is equivalent to `typeof value === 'boolean'` in JS. 127 */ 128 bool IsBoolean() const; 129 130 /** 131 * Returns true if this value is a number. 132 * 133 * This is equivalent to `typeof value === 'number'` in JS. 134 */ 135 bool IsNumber() const; 136 137 /** 138 * Returns true if this value is an `External` object. 139 */ 140 bool IsExternal() const; 141 142 /** 143 * Returns true if this value is a 32-bit signed integer. 144 */ 145 bool IsInt32() const; 146 147 /** 148 * Returns true if this value is a 32-bit unsigned integer. 149 */ 150 bool IsUint32() const; 151 152 /** 153 * Returns true if this value is a Date. 154 */ 155 bool IsDate() const; 156 157 /** 158 * Returns true if this value is an Arguments object. 159 */ 160 bool IsArgumentsObject() const; 161 162 /** 163 * Returns true if this value is a BigInt object. 164 */ 165 bool IsBigIntObject() const; 166 167 /** 168 * Returns true if this value is a Boolean object. 169 */ 170 bool IsBooleanObject() const; 171 172 /** 173 * Returns true if this value is a Number object. 174 */ 175 bool IsNumberObject() const; 176 177 /** 178 * Returns true if this value is a String object. 179 */ 180 bool IsStringObject() const; 181 182 /** 183 * Returns true if this value is a Symbol object. 184 */ 185 bool IsSymbolObject() const; 186 187 /** 188 * Returns true if this value is a NativeError. 189 */ 190 bool IsNativeError() const; 191 192 /** 193 * Returns true if this value is a RegExp. 194 */ 195 bool IsRegExp() const; 196 197 /** 198 * Returns true if this value is an async function. 199 */ 200 bool IsAsyncFunction() const; 201 202 /** 203 * Returns true if this value is a Generator function. 204 */ 205 bool IsGeneratorFunction() const; 206 207 /** 208 * Returns true if this value is a Generator object (iterator). 209 */ 210 bool IsGeneratorObject() const; 211 212 /** 213 * Returns true if this value is a Promise. 214 */ 215 bool IsPromise() const; 216 217 /** 218 * Returns true if this value is a Map. 219 */ 220 bool IsMap() const; 221 222 /** 223 * Returns true if this value is a Set. 224 */ 225 bool IsSet() const; 226 227 /** 228 * Returns true if this value is a Map Iterator. 229 */ 230 bool IsMapIterator() const; 231 232 /** 233 * Returns true if this value is a Set Iterator. 234 */ 235 bool IsSetIterator() const; 236 237 /** 238 * Returns true if this value is a WeakMap. 239 */ 240 bool IsWeakMap() const; 241 242 /** 243 * Returns true if this value is a WeakSet. 244 */ 245 bool IsWeakSet() const; 246 247 /** 248 * Returns true if this value is an ArrayBuffer. 249 */ 250 bool IsArrayBuffer() const; 251 252 /** 253 * Returns true if this value is an ArrayBufferView. 254 */ 255 bool IsArrayBufferView() const; 256 257 /** 258 * Returns true if this value is one of TypedArrays. 259 */ 260 bool IsTypedArray() const; 261 262 /** 263 * Returns true if this value is an Uint8Array. 264 */ 265 bool IsUint8Array() const; 266 267 /** 268 * Returns true if this value is an Uint8ClampedArray. 269 */ 270 bool IsUint8ClampedArray() const; 271 272 /** 273 * Returns true if this value is an Int8Array. 274 */ 275 bool IsInt8Array() const; 276 277 /** 278 * Returns true if this value is an Uint16Array. 279 */ 280 bool IsUint16Array() const; 281 282 /** 283 * Returns true if this value is an Int16Array. 284 */ 285 bool IsInt16Array() const; 286 287 /** 288 * Returns true if this value is an Uint32Array. 289 */ 290 bool IsUint32Array() const; 291 292 /** 293 * Returns true if this value is an Int32Array. 294 */ 295 bool IsInt32Array() const; 296 297 /** 298 * Returns true if this value is a Float32Array. 299 */ 300 bool IsFloat32Array() const; 301 302 /** 303 * Returns true if this value is a Float64Array. 304 */ 305 bool IsFloat64Array() const; 306 307 /** 308 * Returns true if this value is a BigInt64Array. 309 */ 310 bool IsBigInt64Array() const; 311 312 /** 313 * Returns true if this value is a BigUint64Array. 314 */ 315 bool IsBigUint64Array() const; 316 317 /** 318 * Returns true if this value is a DataView. 319 */ 320 bool IsDataView() const; 321 322 /** 323 * Returns true if this value is a SharedArrayBuffer. 324 */ 325 bool IsSharedArrayBuffer() const; 326 327 /** 328 * Returns true if this value is a JavaScript Proxy. 329 */ 330 bool IsProxy() const; 331 332 /** 333 * Returns true if this value is a WasmMemoryObject. 334 */ 335 bool IsWasmMemoryObject() const; 336 337 /** 338 * Returns true if this value is a WasmModuleObject. 339 */ 340 bool IsWasmModuleObject() const; 341 342 /** 343 * Returns true if the value is a Module Namespace Object. 344 */ 345 bool IsModuleNamespaceObject() const; 346 347 /** 348 * Perform the equivalent of `BigInt(value)` in JS. 349 */ 350 V8_WARN_UNUSED_RESULT MaybeLocal<BigInt> ToBigInt( 351 Local<Context> context) const; 352 /** 353 * Perform the equivalent of `Number(value)` in JS. 354 */ 355 V8_WARN_UNUSED_RESULT MaybeLocal<Number> ToNumber( 356 Local<Context> context) const; 357 /** 358 * Perform the equivalent of `String(value)` in JS. 359 */ 360 V8_WARN_UNUSED_RESULT MaybeLocal<String> ToString( 361 Local<Context> context) const; 362 /** 363 * Provide a string representation of this value usable for debugging. 364 * This operation has no observable side effects and will succeed 365 * unless e.g. execution is being terminated. 366 */ 367 V8_WARN_UNUSED_RESULT MaybeLocal<String> ToDetailString( 368 Local<Context> context) const; 369 /** 370 * Perform the equivalent of `Object(value)` in JS. 371 */ 372 V8_WARN_UNUSED_RESULT MaybeLocal<Object> ToObject( 373 Local<Context> context) const; 374 /** 375 * Perform the equivalent of `Number(value)` in JS and convert the result 376 * to an integer. Negative values are rounded up, positive values are rounded 377 * down. NaN is converted to 0. Infinite values yield undefined results. 378 */ 379 V8_WARN_UNUSED_RESULT MaybeLocal<Integer> ToInteger( 380 Local<Context> context) const; 381 /** 382 * Perform the equivalent of `Number(value)` in JS and convert the result 383 * to an unsigned 32-bit integer by performing the steps in 384 * https://tc39.es/ecma262/#sec-touint32. 385 */ 386 V8_WARN_UNUSED_RESULT MaybeLocal<Uint32> ToUint32( 387 Local<Context> context) const; 388 /** 389 * Perform the equivalent of `Number(value)` in JS and convert the result 390 * to a signed 32-bit integer by performing the steps in 391 * https://tc39.es/ecma262/#sec-toint32. 392 */ 393 V8_WARN_UNUSED_RESULT MaybeLocal<Int32> ToInt32(Local<Context> context) const; 394 395 /** 396 * Perform the equivalent of `Boolean(value)` in JS. This can never fail. 397 */ 398 Local<Boolean> ToBoolean(Isolate* isolate) const; 399 400 /** 401 * Attempts to convert a string to an array index. 402 * Returns an empty handle if the conversion fails. 403 */ 404 V8_WARN_UNUSED_RESULT MaybeLocal<Uint32> ToArrayIndex( 405 Local<Context> context) const; 406 407 /** Returns the equivalent of `ToBoolean()->Value()`. */ 408 bool BooleanValue(Isolate* isolate) const; 409 410 /** Returns the equivalent of `ToNumber()->Value()`. */ 411 V8_WARN_UNUSED_RESULT Maybe<double> NumberValue(Local<Context> context) const; 412 /** Returns the equivalent of `ToInteger()->Value()`. */ 413 V8_WARN_UNUSED_RESULT Maybe<int64_t> IntegerValue( 414 Local<Context> context) const; 415 /** Returns the equivalent of `ToUint32()->Value()`. */ 416 V8_WARN_UNUSED_RESULT Maybe<uint32_t> Uint32Value( 417 Local<Context> context) const; 418 /** Returns the equivalent of `ToInt32()->Value()`. */ 419 V8_WARN_UNUSED_RESULT Maybe<int32_t> Int32Value(Local<Context> context) const; 420 421 /** JS == */ 422 V8_WARN_UNUSED_RESULT Maybe<bool> Equals(Local<Context> context, 423 Local<Value> that) const; 424 bool StrictEquals(Local<Value> that) const; 425 bool SameValue(Local<Value> that) const; 426 427 template <class T> Cast(T * value)428 V8_INLINE static Value* Cast(T* value) { 429 return static_cast<Value*>(value); 430 } 431 432 Local<String> TypeOf(Isolate*); 433 434 Maybe<bool> InstanceOf(Local<Context> context, Local<Object> object); 435 436 private: 437 V8_INLINE bool QuickIsUndefined() const; 438 V8_INLINE bool QuickIsNull() const; 439 V8_INLINE bool QuickIsNullOrUndefined() const; 440 V8_INLINE bool QuickIsString() const; 441 bool FullIsUndefined() const; 442 bool FullIsNull() const; 443 bool FullIsString() const; 444 445 static void CheckCast(Data* that); 446 }; 447 448 template <> Cast(Data * value)449V8_INLINE Value* Value::Cast(Data* value) { 450 #ifdef V8_ENABLE_CHECKS 451 CheckCast(value); 452 #endif 453 return static_cast<Value*>(value); 454 } 455 IsUndefined()456bool Value::IsUndefined() const { 457 #ifdef V8_ENABLE_CHECKS 458 return FullIsUndefined(); 459 #else 460 return QuickIsUndefined(); 461 #endif 462 } 463 QuickIsUndefined()464bool Value::QuickIsUndefined() const { 465 using A = internal::Address; 466 using I = internal::Internals; 467 A obj = *reinterpret_cast<const A*>(this); 468 if (!I::HasHeapObjectTag(obj)) return false; 469 if (I::GetInstanceType(obj) != I::kOddballType) return false; 470 return (I::GetOddballKind(obj) == I::kUndefinedOddballKind); 471 } 472 IsNull()473bool Value::IsNull() const { 474 #ifdef V8_ENABLE_CHECKS 475 return FullIsNull(); 476 #else 477 return QuickIsNull(); 478 #endif 479 } 480 QuickIsNull()481bool Value::QuickIsNull() const { 482 using A = internal::Address; 483 using I = internal::Internals; 484 A obj = *reinterpret_cast<const A*>(this); 485 if (!I::HasHeapObjectTag(obj)) return false; 486 if (I::GetInstanceType(obj) != I::kOddballType) return false; 487 return (I::GetOddballKind(obj) == I::kNullOddballKind); 488 } 489 IsNullOrUndefined()490bool Value::IsNullOrUndefined() const { 491 #ifdef V8_ENABLE_CHECKS 492 return FullIsNull() || FullIsUndefined(); 493 #else 494 return QuickIsNullOrUndefined(); 495 #endif 496 } 497 QuickIsNullOrUndefined()498bool Value::QuickIsNullOrUndefined() const { 499 using A = internal::Address; 500 using I = internal::Internals; 501 A obj = *reinterpret_cast<const A*>(this); 502 if (!I::HasHeapObjectTag(obj)) return false; 503 if (I::GetInstanceType(obj) != I::kOddballType) return false; 504 int kind = I::GetOddballKind(obj); 505 return kind == I::kNullOddballKind || kind == I::kUndefinedOddballKind; 506 } 507 IsString()508bool Value::IsString() const { 509 #ifdef V8_ENABLE_CHECKS 510 return FullIsString(); 511 #else 512 return QuickIsString(); 513 #endif 514 } 515 QuickIsString()516bool Value::QuickIsString() const { 517 using A = internal::Address; 518 using I = internal::Internals; 519 A obj = *reinterpret_cast<const A*>(this); 520 if (!I::HasHeapObjectTag(obj)) return false; 521 return (I::GetInstanceType(obj) < I::kFirstNonstringType); 522 } 523 524 } // namespace v8 525 526 #endif // INCLUDE_V8_VALUE_H_ 527