1. /*

  2.  * Copyright 2001-2004 The Apache Software Foundation.

  3.  *

  4.  * Licensed under the Apache License, Version 2.0 (the "License");

  5.  * you may not use this file except in compliance with the License.

  6.  * You may obtain a copy of the License at

  7.  *

  8.  *     http://www.apache.org/licenses/LICENSE-2.0

  9.  *

  10.  * Unless required by applicable law or agreed to in writing, software

  11.  * distributed under the License is distributed on an "AS IS" BASIS,

  12.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  13.  * See the License for the specific language governing permissions and

  14.  * limitations under the License.

  15.  */

  16. /*

  17.  * $Id: CastExpr.java,v 1.21 2004/02/16 22:24:29 minchau Exp $

  18.  */

  19. 

  20. package com.sun.org.apache.xalan.internal.xsltc.compiler;

  21. 

  22. import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;

  23. import com.sun.org.apache.bcel.internal.generic.IF_ICMPNE;

  24. import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;

  25. import com.sun.org.apache.bcel.internal.generic.InstructionList;

  26. import com.sun.org.apache.bcel.internal.generic.SIPUSH;

  27. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.BooleanType;

  28. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;

  29. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;

  30. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;

  31. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MultiHashtable;

  32. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeType;

  33. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ResultTreeType;

  34. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;

  35. import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;

  36. import com.sun.org.apache.xalan.internal.xsltc.dom.Axis;

  37. 

  38. /**

  39.  * @author Jacek Ambroziak

  40.  * @author Santiago Pericas-Geertsen

  41.  * @author Morten Jorgensen

  42.  * @author Erwin Bolwidt <ejb@klomp.org>

  43.  */

  44. final class CastExpr extends Expression {

  45.     private final Expression _left;

  46. 

  47.     /**

  48.      * Legal conversions between internal types.

  49.      */

  50.     static private MultiHashtable InternalTypeMap = new MultiHashtable();

  51. 

  52.     static {

  53. 	// Possible type conversions between internal types

  54. 	InternalTypeMap.put(Type.Boolean, Type.Boolean);

  55. 	InternalTypeMap.put(Type.Boolean, Type.Real);

  56. 	InternalTypeMap.put(Type.Boolean, Type.String);

  57. 	InternalTypeMap.put(Type.Boolean, Type.Reference);

  58.         InternalTypeMap.put(Type.Boolean, Type.Object);

  59. 

  60. 	InternalTypeMap.put(Type.Real, Type.Real);

  61. 	InternalTypeMap.put(Type.Real, Type.Int);

  62. 	InternalTypeMap.put(Type.Real, Type.Boolean);

  63. 	InternalTypeMap.put(Type.Real, Type.String);

  64. 	InternalTypeMap.put(Type.Real, Type.Reference);

  65.         InternalTypeMap.put(Type.Real, Type.Object);

  66. 

  67. 	InternalTypeMap.put(Type.Int, Type.Int);

  68. 	InternalTypeMap.put(Type.Int, Type.Real);

  69. 	InternalTypeMap.put(Type.Int, Type.Boolean);

  70. 	InternalTypeMap.put(Type.Int, Type.String);

  71. 	InternalTypeMap.put(Type.Int, Type.Reference);

  72.         InternalTypeMap.put(Type.Int, Type.Object);

  73. 

  74. 	InternalTypeMap.put(Type.String, Type.String);

  75. 	InternalTypeMap.put(Type.String, Type.Boolean);

  76. 	InternalTypeMap.put(Type.String, Type.Real);

  77. 	InternalTypeMap.put(Type.String, Type.Reference);

  78.         InternalTypeMap.put(Type.String, Type.Object);

  79.         InternalTypeMap.put(Type.String, Type.ObjectString);

  80. 

  81. 	InternalTypeMap.put(Type.NodeSet, Type.NodeSet);

  82. 	InternalTypeMap.put(Type.NodeSet, Type.Boolean);

  83. 	InternalTypeMap.put(Type.NodeSet, Type.Real);

  84. 	InternalTypeMap.put(Type.NodeSet, Type.String);

  85. 	InternalTypeMap.put(Type.NodeSet, Type.Node);

  86. 	InternalTypeMap.put(Type.NodeSet, Type.Reference);

  87. 	InternalTypeMap.put(Type.NodeSet, Type.Object);

  88. 

  89. 	InternalTypeMap.put(Type.Node, Type.Node);

  90. 	InternalTypeMap.put(Type.Node, Type.Boolean);

  91. 	InternalTypeMap.put(Type.Node, Type.Real);

  92. 	InternalTypeMap.put(Type.Node, Type.String);

  93. 	InternalTypeMap.put(Type.Node, Type.NodeSet);

  94. 	InternalTypeMap.put(Type.Node, Type.Reference);

  95. 	InternalTypeMap.put(Type.Node, Type.Object);

  96. 

  97. 	InternalTypeMap.put(Type.ResultTree, Type.ResultTree);

  98. 	InternalTypeMap.put(Type.ResultTree, Type.Boolean);

  99. 	InternalTypeMap.put(Type.ResultTree, Type.Real);

  100. 	InternalTypeMap.put(Type.ResultTree, Type.String);

  101. 	InternalTypeMap.put(Type.ResultTree, Type.NodeSet);

  102. 	InternalTypeMap.put(Type.ResultTree, Type.Reference);

  103. 	InternalTypeMap.put(Type.ResultTree, Type.Object);

  104. 

  105. 	InternalTypeMap.put(Type.Reference, Type.Reference);

  106. 	InternalTypeMap.put(Type.Reference, Type.Boolean);

  107. 	InternalTypeMap.put(Type.Reference, Type.Int);

  108. 	InternalTypeMap.put(Type.Reference, Type.Real);

  109. 	InternalTypeMap.put(Type.Reference, Type.String);

  110. 	InternalTypeMap.put(Type.Reference, Type.Node);

  111. 	InternalTypeMap.put(Type.Reference, Type.NodeSet);

  112. 	InternalTypeMap.put(Type.Reference, Type.ResultTree);

  113. 	InternalTypeMap.put(Type.Reference, Type.Object);

  114. 

  115. 	InternalTypeMap.put(Type.Object, Type.String);

  116. 	InternalTypeMap.put(Type.ObjectString, Type.String);

  117. 

  118. 	InternalTypeMap.put(Type.Void, Type.String);

  119.     }

  120. 

  121.     private boolean _typeTest = false;

  122. 

  123.     /**

  124.      * Construct a cast expression and check that the conversion is 

  125.      * valid by calling typeCheck().

  126.      */

  127.     public CastExpr(Expression left, Type type) throws TypeCheckError {

  128. 	_left = left;

  129. 	_type = type;		// use inherited field

  130. 

  131. 	if ((_left instanceof Step) && (_type == Type.Boolean)) {

  132. 	    Step step = (Step)_left;

  133. 	    if ((step.getAxis() == Axis.SELF) && (step.getNodeType() != -1)) 

  134. 		_typeTest = true;

  135. 	}

  136. 	

  137. 	// check if conversion is valid

  138. 	setParser(left.getParser());

  139. 	setParent(left.getParent());

  140. 	left.setParent(this);

  141. 	typeCheck(left.getParser().getSymbolTable());

  142.     }

  143. 		

  144.     public Expression getExpr() {

  145. 	return _left;

  146.     }

  147. 

  148.     /**

  149.      * Returns true if this expressions contains a call to position(). This is

  150.      * needed for context changes in node steps containing multiple predicates.

  151.      */

  152.     public boolean hasPositionCall() {

  153. 	return(_left.hasPositionCall());

  154.     }

  155. 

  156.     public boolean hasLastCall() {

  157. 	return(_left.hasLastCall());

  158.     }

  159. 

  160.     public String toString() {

  161. 	return "cast(" + _left + ", " + _type + ")";

  162.     }

  163. 

  164.     /**

  165.      * Type checking a cast expression amounts to verifying that the  

  166.      * type conversion is legal. Cast expressions are created during 

  167.      * type checking, but typeCheck() is usually not called on them. 

  168.      * As a result, this method is called from the constructor.

  169.      */	

  170.     public Type typeCheck(SymbolTable stable) throws TypeCheckError {

  171. 	Type tleft = _left.getType();

  172. 	if (tleft == null) {

  173. 	    tleft = _left.typeCheck(stable);

  174. 	}

  175. 	if (tleft instanceof NodeType) {

  176. 	    tleft = Type.Node;	// multiple instances

  177. 	}

  178. 	else if (tleft instanceof ResultTreeType) {

  179. 	    tleft = Type.ResultTree; // multiple instances

  180. 	}

  181. 	if (InternalTypeMap.maps(tleft, _type) != null) {

  182. 	    return _type;

  183. 	}

  184. 	// throw new TypeCheckError(this);	

  185. 	throw new TypeCheckError(new ErrorMsg(

  186. 	    ErrorMsg.DATA_CONVERSION_ERR, tleft.toString(), _type.toString()));

  187.     }

  188. 

  189.     public void translateDesynthesized(ClassGenerator classGen, 

  190. 				       MethodGenerator methodGen) {

  191. 	FlowList fl;

  192. 	final Type ltype = _left.getType();

  193. 

  194. 	// This is a special case for the self:: axis. Instead of letting

  195. 	// the Step object create and iterator that we cast back to a single

  196. 	// node, we simply ask the DOM for the node type.

  197. 	if (_typeTest) {

  198. 	    final ConstantPoolGen cpg = classGen.getConstantPool();

  199. 	    final InstructionList il = methodGen.getInstructionList();

  200. 

  201. 	    final int idx = cpg.addInterfaceMethodref(DOM_INTF,

  202. 						      "getExpandedTypeID",

  203.                                                       "(I)I");

  204. 	    il.append(new SIPUSH((short)((Step)_left).getNodeType()));

  205. 	    il.append(methodGen.loadDOM());

  206. 	    il.append(methodGen.loadContextNode());

  207. 	    il.append(new INVOKEINTERFACE(idx, 2));

  208. 	    _falseList.add(il.append(new IF_ICMPNE(null)));

  209. 	}

  210. 	else {

  211. 

  212. 	    _left.translate(classGen, methodGen);

  213. 	    if (_type != ltype) {

  214. 		_left.startIterator(classGen, methodGen);

  215. 		if (_type instanceof BooleanType) {

  216. 		    fl = ltype.translateToDesynthesized(classGen, methodGen,

  217. 							_type);

  218. 		    if (fl != null) {

  219. 			_falseList.append(fl);

  220. 		    }

  221. 		}

  222. 		else {

  223. 		    ltype.translateTo(classGen, methodGen, _type);	

  224. 		}

  225. 	    }

  226. 	}

  227.     }

  228. 

  229.     public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

  230. 	final Type ltype = _left.getType();

  231. 	_left.translate(classGen, methodGen);

  232. 	if (_type.identicalTo(ltype) == false) {

  233. 	    _left.startIterator(classGen, methodGen);

  234. 	    ltype.translateTo(classGen, methodGen, _type);

  235. 	}

  236.     }

  237. }