1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /*
6 * Copyright 2001-2004 The Apache Software Foundation.
7 *
8 * Licensed under the Apache License, Version 2.0 (the "License");
9 * you may not use this file except in compliance with the License.
10 * You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
19 */
20 /*
21 * $Id: Param.java,v 1.2.4.1 2005/09/02 11:03:42 pvedula Exp $
22 */
23
24 package com.sun.org.apache.xalan.internal.xsltc.compiler;
25
26 import com.sun.org.apache.bcel.internal.classfile.Field;
27 import com.sun.org.apache.bcel.internal.generic.BranchHandle;
28 import com.sun.org.apache.bcel.internal.generic.CHECKCAST;
29 import com.sun.org.apache.bcel.internal.generic.IFNONNULL;
30 import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
31 import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
32 import com.sun.org.apache.bcel.internal.generic.Instruction;
33 import com.sun.org.apache.bcel.internal.generic.InstructionList;
34 import com.sun.org.apache.bcel.internal.generic.PUSH;
35 import com.sun.org.apache.bcel.internal.generic.PUTFIELD;
36 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
37 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
38 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
39 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
40 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
41 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ObjectType;
42 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
43 import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;
44
45 /**
46 * @author Jacek Ambroziak
47 * @author Santiago Pericas-Geertsen
48 * @author Morten Jorgensen
49 * @author Erwin Bolwidt <ejb@klomp.org>
50 * @author John Howard <JohnH@schemasoft.com>
51 */
52 final class Param extends VariableBase {
53
54 /**
55 * True if this Param is declared in a simple named template.
56 * This is used to optimize codegen for parameter passing
57 * in named templates.
58 */
59 private boolean _isInSimpleNamedTemplate = false;
60
61 /**
62 * Display variable as single string
63 */
64 public String toString() {
65 return "param(" + _name + ")";
66 }
67
68 /**
69 * Set the instruction for loading the value of this variable onto the
70 * JVM stack and returns the old instruction.
71 */
72 public Instruction setLoadInstruction(Instruction instruction) {
73 Instruction tmp = _loadInstruction;
74 _loadInstruction = instruction;
75 return tmp;
76 }
77
78 /**
79 * Set the instruction for storing a value from the stack into this
80 * variable and returns the old instruction.
81 */
82 public Instruction setStoreInstruction(Instruction instruction) {
83 Instruction tmp = _storeInstruction;
84 _storeInstruction = instruction;
85 return tmp;
86 }
87
88 /**
89 * Display variable in a full AST dump
90 */
91 public void display(int indent) {
92 indent(indent);
93 System.out.println("param " + _name);
94 if (_select != null) {
95 indent(indent + IndentIncrement);
96 System.out.println("select " + _select.toString());
97 }
98 displayContents(indent + IndentIncrement);
99 }
100
101 /**
102 * Parse the contents of the <xsl:param> element. This method must read
103 * the 'name' (required) and 'select' (optional) attributes.
104 */
105 public void parseContents(Parser parser) {
106
107 // Parse 'name' and 'select' attributes plus parameter contents
108 super.parseContents(parser);
109
110 // Add a ref to this param to its enclosing construct
111 final SyntaxTreeNode parent = getParent();
112 if (parent instanceof Stylesheet) {
113 // Mark this as a global parameter
114 _isLocal = false;
115 // Check if a global variable with this name already exists...
116 Param param = parser.getSymbolTable().lookupParam(_name);
117 // ...and if it does we need to check import precedence
118 if (param != null) {
119 final int us = this.getImportPrecedence();
120 final int them = param.getImportPrecedence();
121 // It is an error if the two have the same import precedence
122 if (us == them) {
123 final String name = _name.toString();
124 reportError(this, parser, ErrorMsg.VARIABLE_REDEF_ERR,name);
125 }
126 // Ignore this if previous definition has higher precedence
127 else if (them > us) {
128 _ignore = true;
129 copyReferences(param);
130 return;
131 }
132 else {
133 param.copyReferences(this);
134 param.disable();
135 }
136 }
137 // Add this variable if we have higher precedence
138 ((Stylesheet)parent).addParam(this);
139 parser.getSymbolTable().addParam(this);
140 }
141 else if (parent instanceof Template) {
142 Template template = (Template) parent;
143 _isLocal = true;
144 template.addParameter(this);
145 if (template.isSimpleNamedTemplate()) {
146 _isInSimpleNamedTemplate = true;
147 }
148 }
149 }
150
151 /**
152 * Type-checks the parameter. The parameter type is determined by the
153 * 'select' expression (if present) or is a result tree if the parameter
154 * element has a body and no 'select' expression.
155 */
156 public Type typeCheck(SymbolTable stable) throws TypeCheckError {
157 if (_select != null) {
158 _type = _select.typeCheck(stable);
159 if (_type instanceof ReferenceType == false && !(_type instanceof ObjectType)) {
160 _select = new CastExpr(_select, Type.Reference);
161 }
162 }
163 else if (hasContents()) {
164 typeCheckContents(stable);
165 }
166 _type = Type.Reference;
167
168 // This element has no type (the parameter does, but the parameter
169 // element itself does not).
170 return Type.Void;
171 }
172
173 public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
174 final ConstantPoolGen cpg = classGen.getConstantPool();
175 final InstructionList il = methodGen.getInstructionList();
176
177 if (_ignore) return;
178 _ignore = true;
179
180 /*
181 * To fix bug 24518 related to setting parameters of the form
182 * {namespaceuri}localName which will get mapped to an instance
183 * variable in the class.
184 */
185 final String name = BasisLibrary.mapQNameToJavaName(_name.toString());
186 final String signature = _type.toSignature();
187 final String className = _type.getClassName();
188
189 if (isLocal()) {
190 /*
191 * If simple named template then generate a conditional init of the
192 * param using its default value:
193 * if (param == null) param = <default-value>
194 */
195 if (_isInSimpleNamedTemplate) {
196 il.append(loadInstruction());
197 BranchHandle ifBlock = il.append(new IFNONNULL(null));
198 translateValue(classGen, methodGen);
199 il.append(storeInstruction());
200 ifBlock.setTarget(il.append(NOP));
201 return;
202 }
203
204 il.append(classGen.loadTranslet());
205 il.append(new PUSH(cpg, name));
206 translateValue(classGen, methodGen);
207 il.append(new PUSH(cpg, true));
208
209 // Call addParameter() from this class
210 il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
211 ADD_PARAMETER,
212 ADD_PARAMETER_SIG)));
213 if (className != EMPTYSTRING) {
214 il.append(new CHECKCAST(cpg.addClass(className)));
215 }
216
217 _type.translateUnBox(classGen, methodGen);
218
219 if (_refs.isEmpty()) { // nobody uses the value
220 il.append(_type.POP());
221 _local = null;
222 }
223 else { // normal case
224 _local = methodGen.addLocalVariable2(name,
225 _type.toJCType(),
226 il.getEnd());
227 // Cache the result of addParameter() in a local variable
228 il.append(_type.STORE(_local.getIndex()));
229 }
230 }
231 else {
232 if (classGen.containsField(name) == null) {
233 classGen.addField(new Field(ACC_PUBLIC, cpg.addUtf8(name),
234 cpg.addUtf8(signature),
235 null, cpg.getConstantPool()));
236 il.append(classGen.loadTranslet());
237 il.append(DUP);
238 il.append(new PUSH(cpg, name));
239 translateValue(classGen, methodGen);
240 il.append(new PUSH(cpg, true));
241
242 // Call addParameter() from this class
243 il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
244 ADD_PARAMETER,
245 ADD_PARAMETER_SIG)));
246
247 _type.translateUnBox(classGen, methodGen);
248
249 // Cache the result of addParameter() in a field
250 if (className != EMPTYSTRING) {
251 il.append(new CHECKCAST(cpg.addClass(className)));
252 }
253 il.append(new PUTFIELD(cpg.addFieldref(classGen.getClassName(),
254 name, signature)));
255 }
256 }
257 }
258 }