View Javadoc
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: AbsolutePathPattern.java,v 1.2.4.1 2005/09/01 09:17:09 pvedula Exp $
22   */
23  
24  package com.sun.org.apache.xalan.internal.xsltc.compiler;
25  
26  import com.sun.org.apache.bcel.internal.generic.BranchHandle;
27  import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
28  import com.sun.org.apache.bcel.internal.generic.GOTO_W;
29  import com.sun.org.apache.bcel.internal.generic.IF_ICMPEQ;
30  import com.sun.org.apache.bcel.internal.generic.ILOAD;
31  import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
32  import com.sun.org.apache.bcel.internal.generic.ISTORE;
33  import com.sun.org.apache.bcel.internal.generic.InstructionHandle;
34  import com.sun.org.apache.bcel.internal.generic.InstructionList;
35  import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
36  import com.sun.org.apache.bcel.internal.generic.PUSH;
37  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
38  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
39  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
40  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
41  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;
42  import com.sun.org.apache.xml.internal.dtm.DTM;
43  
44  /**
45   * @author Jacek Ambroziak
46   * @author Santiago Pericas-Geertsen
47   */
48  final class AbsolutePathPattern extends LocationPathPattern {
49      private final RelativePathPattern _left; // may be null
50  
51      public AbsolutePathPattern(RelativePathPattern left) {
52          _left = left;
53          if (left != null) {
54              left.setParent(this);
55          }
56      }
57  
58      public void setParser(Parser parser) {
59          super.setParser(parser);
60          if (_left != null)
61              _left.setParser(parser);
62      }
63  
64      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
65          return _left == null ? Type.Root : _left.typeCheck(stable);
66      }
67  
68      public boolean isWildcard() {
69          return false;
70      }
71  
72      public StepPattern getKernelPattern() {
73          return _left != null ? _left.getKernelPattern() : null;
74      }
75  
76      public void reduceKernelPattern() {
77          _left.reduceKernelPattern();
78      }
79  
80      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
81          final ConstantPoolGen cpg = classGen.getConstantPool();
82          final InstructionList il = methodGen.getInstructionList();
83  
84          if (_left != null) {
85              if (_left instanceof StepPattern) {
86                  final LocalVariableGen local =
87                      // absolute path pattern temporary
88                      methodGen.addLocalVariable2("apptmp",
89                                                  Util.getJCRefType(NODE_SIG),
90                                                  null);
91                  il.append(DUP);
92                  local.setStart(il.append(new ISTORE(local.getIndex())));
93                  _left.translate(classGen, methodGen);
94                  il.append(methodGen.loadDOM());
95                  local.setEnd(il.append(new ILOAD(local.getIndex())));
96                  methodGen.removeLocalVariable(local);
97              }
98              else {
99                  _left.translate(classGen, methodGen);
100             }
101         }
102 
103         final int getParent = cpg.addInterfaceMethodref(DOM_INTF,
104                                                         GET_PARENT,
105                                                         GET_PARENT_SIG);
106         final int getType = cpg.addInterfaceMethodref(DOM_INTF,
107                                                       "getExpandedTypeID",
108                                                       "(I)I");
109 
110         InstructionHandle begin = il.append(methodGen.loadDOM());
111         il.append(SWAP);
112         il.append(new INVOKEINTERFACE(getParent, 2));
113         if (_left instanceof AncestorPattern) {
114             il.append(methodGen.loadDOM());
115             il.append(SWAP);
116         }
117         il.append(new INVOKEINTERFACE(getType, 2));
118         il.append(new PUSH(cpg, DTM.DOCUMENT_NODE));
119 
120         final BranchHandle skip = il.append(new IF_ICMPEQ(null));
121         _falseList.add(il.append(new GOTO_W(null)));
122         skip.setTarget(il.append(NOP));
123 
124         if (_left != null) {
125             _left.backPatchTrueList(begin);
126 
127             /*
128              * If _left is an ancestor pattern, backpatch this pattern's false
129              * list to the loop that searches for more ancestors.
130              */
131             if (_left instanceof AncestorPattern) {
132                 final AncestorPattern ancestor = (AncestorPattern) _left;
133                 _falseList.backPatch(ancestor.getLoopHandle());         // clears list
134             }
135             _falseList.append(_left._falseList);
136         }
137     }
138 
139     public String toString() {
140         return "absolutePathPattern(" + (_left != null ? _left.toString() : ")");
141     }
142 }