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: VariableRefBase.java,v 1.5 2005/09/28 13:48:18 pvedula Exp $
  22  */
  23 
  24 package com.sun.org.apache.xalan.internal.xsltc.compiler;
  25 
  26 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
  27 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
  28 import java.util.Objects;
  29 
  30 /**
  31  * @author Morten Jorgensen
  32  * @author Santiago Pericas-Geertsen
  33  */
  34 class VariableRefBase extends Expression {
  35 
  36     /**
  37      * A reference to the associated variable.
  38      */
  39     protected VariableBase _variable;
  40 
  41     /**
  42      * A reference to the enclosing expression/instruction for which a
  43      * closure is needed (Predicate, Number or Sort).
  44      */
  45     protected Closure _closure = null;
  46 
  47     public VariableRefBase(VariableBase variable) {
  48         _variable = variable;
  49         variable.addReference(this);
  50     }
  51 
  52     public VariableRefBase() {
  53         _variable = null;
  54     }
  55 
  56     /**
  57      * Returns a reference to the associated variable
  58      */
  59     public VariableBase getVariable() {
  60         return _variable;
  61     }
  62 
  63     /**
  64      * If this variable reference is in a top-level element like
  65      * another variable, param or key, add a dependency between
  66      * that top-level element and the referenced variable. For
  67      * example,
  68      *
  69      *   <xsl:variable name="x" .../>
  70      *   <xsl:variable name="y" select="$x + 1"/>
  71      *
  72      * and assuming this class represents "$x", add a reference
  73      * between variable y and variable x.
  74      */
  75     public void addParentDependency() {
  76         SyntaxTreeNode node = this;
  77         while (node != null && node instanceof TopLevelElement == false) {
  78             node = node.getParent();
  79         }
  80 
  81         TopLevelElement parent = (TopLevelElement) node;
  82         if (parent != null) {
  83             VariableBase var = _variable;
  84             if (_variable._ignore) {
  85                 if (_variable instanceof Variable) {
  86                     var = parent.getSymbolTable()
  87                                 .lookupVariable(_variable._name);
  88                 } else if (_variable instanceof Param) {
  89                     var = parent.getSymbolTable().lookupParam(_variable._name);
  90                 }
  91             }
  92 
  93             parent.addDependency(var);
  94         }
  95     }
  96 
  97     /**
  98      * Two variable references are deemed equal if they refer to the
  99      * same variable.
 100      */
 101     @Override
 102     public boolean equals(Object obj) {
 103         return obj == this || (obj instanceof VariableRefBase)
 104             && (_variable == ((VariableRefBase) obj)._variable);
 105     }
 106 
 107     @Override
 108     public int hashCode() {
 109         return Objects.hashCode(this._variable);
 110     }
 111 
 112     /**
 113      * Returns a string representation of this variable reference on the
 114      * format 'variable-ref(<var-name>)'.
 115      * @return Variable reference description
 116      */
 117     @Override
 118     public String toString() {
 119         return "variable-ref("+_variable.getName()+'/'+_variable.getType()+')';
 120     }
 121 
 122     @Override
 123     public Type typeCheck(SymbolTable stable)
 124         throws TypeCheckError
 125     {
 126         // Returned cached type if available
 127         if (_type != null) return _type;
 128 
 129         // Find nearest closure to add a variable reference
 130         if (_variable.isLocal()) {
 131             SyntaxTreeNode node = getParent();
 132             do {
 133                 if (node instanceof Closure) {
 134                     _closure = (Closure) node;
 135                     break;
 136                 }
 137                 if (node instanceof TopLevelElement) {
 138                     break;      // way up in the tree
 139                 }
 140                 node = node.getParent();
 141             } while (node != null);
 142 
 143             if (_closure != null) {
 144                 _closure.addVariable(this);
 145             }
 146         }
 147 
 148         // Attempt to get the cached variable type
 149         _type = _variable.getType();
 150 
 151         // If that does not work we must force a type-check (this is normally
 152         // only needed for globals in included/imported stylesheets
 153         if (_type == null) {
 154             _variable.typeCheck(stable);
 155             _type = _variable.getType();
 156         }
 157 
 158         // If in a top-level element, create dependency to the referenced var
 159         addParentDependency();
 160 
 161         // Return the type of the referenced variable
 162         return _type;
 163     }
 164 
 165 }