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6  * Licensed to the Apache Software Foundation (ASF) under one or more
7  * contributor license agreements.  See the NOTICE file distributed with
8  * this work for additional information regarding copyright ownership.
9  * The ASF licenses this file to You under the Apache License, Version 2.0
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11  * the License.  You may obtain a copy of the License at
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21 
22 package com.sun.org.apache.xalan.internal.xsltc.compiler;
23 
24 import com.sun.org.apache.bcel.internal.classfile.Field;
25 import com.sun.org.apache.bcel.internal.generic.BranchHandle;
26 import com.sun.org.apache.bcel.internal.generic.CHECKCAST;
27 import com.sun.org.apache.bcel.internal.generic.IFNONNULL;
28 import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
29 import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
30 import com.sun.org.apache.bcel.internal.generic.Instruction;
31 import com.sun.org.apache.bcel.internal.generic.InstructionList;
32 import com.sun.org.apache.bcel.internal.generic.PUSH;
33 import com.sun.org.apache.bcel.internal.generic.PUTFIELD;
34 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
35 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
36 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
37 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
38 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
39 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ObjectType;
40 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
41 import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;
42 
43 /**
44  * @author Jacek Ambroziak
45  * @author Santiago Pericas-Geertsen
46  * @author Morten Jorgensen
47  * @author Erwin Bolwidt <ejb@klomp.org>
48  * @author John Howard <JohnH@schemasoft.com>
49  */
50 final class Param extends VariableBase {
51 
52     /**
53      * True if this Param is declared in a simple named template.
54      * This is used to optimize codegen for parameter passing
55      * in named templates.
56      */
57     private boolean _isInSimpleNamedTemplate = false;
58 
59     /**
60      * Display variable as single string
61      */
toString()62     public String toString() {
63         return "param(" + _name + ")";
64     }
65 
66     /**
67      * Set the instruction for loading the value of this variable onto the
68      * JVM stack and returns the old instruction.
69      */
setLoadInstruction(Instruction instruction)70     public Instruction setLoadInstruction(Instruction instruction) {
71         Instruction tmp = _loadInstruction;
72         _loadInstruction = instruction;
73         return tmp;
74     }
75 
76     /**
77      * Set the instruction for storing a value from the stack into this
78      * variable and returns the old instruction.
79      */
setStoreInstruction(Instruction instruction)80     public Instruction setStoreInstruction(Instruction instruction) {
81         Instruction tmp = _storeInstruction;
82         _storeInstruction = instruction;
83         return tmp;
84     }
85 
86     /**
87      * Display variable in a full AST dump
88      */
display(int indent)89     public void display(int indent) {
90         indent(indent);
91         System.out.println("param " + _name);
92         if (_select != null) {
93             indent(indent + IndentIncrement);
94             System.out.println("select " + _select.toString());
95         }
96         displayContents(indent + IndentIncrement);
97     }
98 
99     /**
100      * Parse the contents of the <xsl:param> element. This method must read
101      * the 'name' (required) and 'select' (optional) attributes.
102      */
parseContents(Parser parser)103     public void parseContents(Parser parser) {
104 
105         // Parse 'name' and 'select' attributes plus parameter contents
106         super.parseContents(parser);
107 
108         // Add a ref to this param to its enclosing construct
109         final SyntaxTreeNode parent = getParent();
110         if (parent instanceof Stylesheet) {
111             // Mark this as a global parameter
112             _isLocal = false;
113             // Check if a global variable with this name already exists...
114             Param param = parser.getSymbolTable().lookupParam(_name);
115             // ...and if it does we need to check import precedence
116             if (param != null) {
117                 final int us = this.getImportPrecedence();
118                 final int them = param.getImportPrecedence();
119                 // It is an error if the two have the same import precedence
120                 if (us == them) {
121                     final String name = _name.toString();
122                     reportError(this, parser, ErrorMsg.VARIABLE_REDEF_ERR,name);
123                 }
124                 // Ignore this if previous definition has higher precedence
125                 else if (them > us) {
126                     _ignore = true;
127                     copyReferences(param);
128                     return;
129                 }
130                 else {
131                     param.copyReferences(this);
132                     param.disable();
133                 }
134             }
135             // Add this variable if we have higher precedence
136             ((Stylesheet)parent).addParam(this);
137             parser.getSymbolTable().addParam(this);
138         }
139         else if (parent instanceof Template) {
140             Template template = (Template) parent;
141             _isLocal = true;
142             template.addParameter(this);
143             if (template.isSimpleNamedTemplate()) {
144                 _isInSimpleNamedTemplate = true;
145             }
146         }
147     }
148 
149     /**
150      * Type-checks the parameter. The parameter type is determined by the
151      * 'select' expression (if present) or is a result tree if the parameter
152      * element has a body and no 'select' expression.
153      */
typeCheck(SymbolTable stable)154     public Type typeCheck(SymbolTable stable) throws TypeCheckError {
155         if (_select != null) {
156             _type = _select.typeCheck(stable);
157             if (_type instanceof ReferenceType == false && !(_type instanceof ObjectType)) {
158                 _select = new CastExpr(_select, Type.Reference);
159             }
160         }
161         else if (hasContents()) {
162             typeCheckContents(stable);
163         }
164         _type = Type.Reference;
165 
166         // This element has no type (the parameter does, but the parameter
167         // element itself does not).
168         return Type.Void;
169     }
170 
translate(ClassGenerator classGen, MethodGenerator methodGen)171     public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
172         final ConstantPoolGen cpg = classGen.getConstantPool();
173         final InstructionList il = methodGen.getInstructionList();
174 
175         if (_ignore) return;
176         _ignore = true;
177 
178         /*
179          * To fix bug 24518 related to setting parameters of the form
180          * {namespaceuri}localName which will get mapped to an instance
181          * variable in the class.
182          */
183         final String name = BasisLibrary.mapQNameToJavaName(_name.toString());
184         final String signature = _type.toSignature();
185         final String className = _type.getClassName();
186 
187         if (isLocal()) {
188             /*
189               * If simple named template then generate a conditional init of the
190               * param using its default value:
191               *       if (param == null) param = <default-value>
192               */
193             if (_isInSimpleNamedTemplate) {
194                 il.append(loadInstruction());
195                 BranchHandle ifBlock = il.append(new IFNONNULL(null));
196                 translateValue(classGen, methodGen);
197                 il.append(storeInstruction());
198                 ifBlock.setTarget(il.append(NOP));
199                 return;
200             }
201 
202             il.append(classGen.loadTranslet());
203             il.append(new PUSH(cpg, name));
204             translateValue(classGen, methodGen);
205             il.append(new PUSH(cpg, true));
206 
207             // Call addParameter() from this class
208             il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
209                                                          ADD_PARAMETER,
210                                                          ADD_PARAMETER_SIG)));
211             if (className != EMPTYSTRING) {
212                 il.append(new CHECKCAST(cpg.addClass(className)));
213             }
214 
215             _type.translateUnBox(classGen, methodGen);
216 
217             if (_refs.isEmpty()) { // nobody uses the value
218                 il.append(_type.POP());
219                 _local = null;
220             }
221             else {              // normal case
222                 _local = methodGen.addLocalVariable2(name,
223                                                      _type.toJCType(),
224                                                      il.getEnd());
225                 // Cache the result of addParameter() in a local variable
226                 il.append(_type.STORE(_local.getIndex()));
227             }
228         }
229         else {
230             if (classGen.containsField(name) == null) {
231                 classGen.addField(new Field(ACC_PUBLIC, cpg.addUtf8(name),
232                                             cpg.addUtf8(signature),
233                                             null, cpg.getConstantPool()));
234                 il.append(classGen.loadTranslet());
235                 il.append(DUP);
236                 il.append(new PUSH(cpg, name));
237                 translateValue(classGen, methodGen);
238                 il.append(new PUSH(cpg, true));
239 
240                 // Call addParameter() from this class
241                 il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
242                                                      ADD_PARAMETER,
243                                                      ADD_PARAMETER_SIG)));
244 
245                 _type.translateUnBox(classGen, methodGen);
246 
247                 // Cache the result of addParameter() in a field
248                 if (className != EMPTYSTRING) {
249                     il.append(new CHECKCAST(cpg.addClass(className)));
250                 }
251                 il.append(new PUTFIELD(cpg.addFieldref(classGen.getClassName(),
252                                                        name, signature)));
253             }
254         }
255     }
256 }
257