net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/CastExpression.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.compiler.ast;
  12
  13 import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
  15 import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
  16 import net.sourceforge.phpdt.internal.compiler.impl.Constant;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.ArrayBinding;
  18 import net.sourceforge.phpdt.internal.compiler.lookup.BaseTypeBinding;
  19 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  20 import net.sourceforge.phpdt.internal.compiler.lookup.MethodBinding;
  21 import net.sourceforge.phpdt.internal.compiler.lookup.ReferenceBinding;
  22 import net.sourceforge.phpdt.internal.compiler.lookup.Scope;
  23 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  24
  25 public class CastExpression extends Expression {
  26
  27         public Expression expression;
  28         public Expression type;
  29         public boolean needRuntimeCheckcast;
  30
  31         //expression.implicitConversion holds the cast for baseType casting
  32         public CastExpression(Expression e, Expression t) {
  33                 expression = e;
  34                 type = t;
  35
  36                 //due to the fact an expression may start with ( and that a cast also start with (
  37                 //the field is an expression....it can be a TypeReference OR a NameReference Or
  38                 //an expression <--this last one is invalid.......
  39
  40                 // :-( .............
  41
  42                 //if (type instanceof TypeReference )
  43                 //      flag = IsTypeReference ;
  44                 //else
  45                 //      if (type instanceof NameReference)
  46                 //              flag = IsNameReference ;
  47                 //      else
  48                 //              flag = IsExpression ;
  49
  50         }
  51
  52         public FlowInfo analyseCode(
  53                 BlockScope currentScope,
  54                 FlowContext flowContext,
  55                 FlowInfo flowInfo) {
  56
  57                 return expression
  58                         .analyseCode(currentScope, flowContext, flowInfo)
  59                         .unconditionalInits();
  60         }
  61
  62         public final void areTypesCastCompatible(
  63                 BlockScope scope,
  64                 TypeBinding castType,
  65                 TypeBinding expressionType) {
  66
  67                 // see specifications 5.5
  68                 // handle errors and process constant when needed
  69
  70                 // if either one of the type is null ==>
  71                 // some error has been already reported some where ==>
  72                 // we then do not report an obvious-cascade-error.
  73
  74                 needRuntimeCheckcast = false;
  75                 if (castType == null || expressionType == null) return;
  76
  77                 // identity conversion cannot be performed upfront, due to side-effects
  78                 // like constant propagation
  79
  80                 if (castType.isBaseType()) {
  81                         if (expressionType.isBaseType()) {
  82                                 if (expressionType == castType) {
  83                                         expression.implicitWidening(castType, expressionType);
  84                                         constant = expression.constant; //use the same constant
  85                                         return;
  86                                 }
  87                                 if (expressionType.isCompatibleWith(castType)
  88                                         || BaseTypeBinding.isNarrowing(castType.id, expressionType.id)) {
  89                                         expression.implicitConversion = (castType.id << 4) + expressionType.id;
  90                                         if (expression.constant != Constant.NotAConstant)
  91                                                 constant = expression.constant.castTo(expression.implicitConversion);
  92                                         return;
  93                                 }
  94                         }
  95                         scope.problemReporter().typeCastError(this, castType, expressionType);
  96                         return;
  97                 }
  98
  99                 //-----------cast to something which is NOT a base type--------------------------
 100                 if (expressionType == NullBinding) {
 101                         //      if (castType.isArrayType()){ // 26903 - need checkcast when casting null to array type
 102                         //              needRuntimeCheckcast = true;
 103                         //      }
 104                         return; //null is compatible with every thing
 105                 }
 106                 if (expressionType.isBaseType()) {
 107                         scope.problemReporter().typeCastError(this, castType, expressionType);
 108                         return;
 109                 }
 110
 111                 if (expressionType.isArrayType()) {
 112                         if (castType == expressionType) return; // identity conversion
 113
 114                         if (castType.isArrayType()) {
 115                                 //------- (castType.isArray) expressionType.isArray -----------
 116                                 TypeBinding exprElementType = ((ArrayBinding) expressionType).elementsType(scope);
 117                                 if (exprElementType.isBaseType()) {
 118                                         // <---stop the recursion-------
 119                                         if (((ArrayBinding) castType).elementsType(scope) == exprElementType)
 120                                                 needRuntimeCheckcast = true;
 121                                         else
 122                                                 scope.problemReporter().typeCastError(this, castType, expressionType);
 123                                         return;
 124                                 }
 125                                 // recursively on the elements...
 126                                 areTypesCastCompatible(
 127                                         scope,
 128                                         ((ArrayBinding) castType).elementsType(scope),
 129                                         exprElementType);
 130                                 return;
 131                         } else if (
 132                                 castType.isClass()) {
 133                                 //------(castType.isClass) expressionType.isArray ---------------
 134                                 if (scope.isJavaLangObject(castType))
 135                                         return;
 136                         } else { //------- (castType.isInterface) expressionType.isArray -----------
 137                                 if (scope.isJavaLangCloneable(castType) || scope.isJavaIoSerializable(castType)) {
 138                                         needRuntimeCheckcast = true;
 139                                         return;
 140                                 }
 141                         }
 142                         scope.problemReporter().typeCastError(this, castType, expressionType);
 143                         return;
 144                 }
 145
 146                 if (expressionType.isClass()) {
 147                         if (castType.isArrayType()) {
 148                                 // ---- (castType.isArray) expressionType.isClass -------
 149                                 if (scope.isJavaLangObject(expressionType)) { // potential runtime error
 150                                         needRuntimeCheckcast = true;
 151                                         return;
 152                                 }
 153                         } else if (castType.isClass()) { // ----- (castType.isClass) expressionType.isClass ------
 154                                 if (expressionType.isCompatibleWith(castType)){ // no runtime error
 155                                         if (castType.id == T_String) constant = expression.constant; // (String) cst is still a constant
 156                                         return;
 157                                 }
 158                                 if (castType.isCompatibleWith(expressionType)) {
 159                                         // potential runtime  error
 160                                         needRuntimeCheckcast = true;
 161                                         return;
 162                                 }
 163                         } else { // ----- (castType.isInterface) expressionType.isClass -------
 164                                 if (((ReferenceBinding) expressionType).isFinal()) {
 165                                         // no subclass for expressionType, thus compile-time check is valid
 166                                         if (expressionType.isCompatibleWith(castType))
 167                                                 return;
 168                                 } else { // a subclass may implement the interface ==> no check at compile time
 169                                         needRuntimeCheckcast = true;
 170                                         return;
 171                                 }
 172                         }
 173                         scope.problemReporter().typeCastError(this, castType, expressionType);
 174                         return;
 175                 }
 176
 177                 //      if (expressionType.isInterface()) { cannot be anything else
 178                 if (castType.isArrayType()) {
 179                         // ----- (castType.isArray) expressionType.isInterface ------
 180                         if (scope.isJavaLangCloneable(expressionType)
 181                                 || scope.isJavaIoSerializable(expressionType)) // potential runtime error
 182                                 needRuntimeCheckcast = true;
 183                         else
 184                                 scope.problemReporter().typeCastError(this, castType, expressionType);
 185                         return;
 186                 } else if (castType.isClass()) { // ----- (castType.isClass) expressionType.isInterface --------
 187                         if (scope.isJavaLangObject(castType)) // no runtime error
 188                                 return;
 189                         if (((ReferenceBinding) castType).isFinal()) {
 190                                 // no subclass for castType, thus compile-time check is valid
 191                                 if (!castType.isCompatibleWith(expressionType)) {
 192                                         // potential runtime error
 193                                         scope.problemReporter().typeCastError(this, castType, expressionType);
 194                                         return;
 195                                 }
 196                         }
 197                 } else { // ----- (castType.isInterface) expressionType.isInterface -------
 198                         if (castType == expressionType) return; // identity conversion
 199                         if (Scope.compareTypes(castType, expressionType) == NotRelated) {
 200                                 MethodBinding[] castTypeMethods = ((ReferenceBinding) castType).methods();
 201                                 MethodBinding[] expressionTypeMethods =
 202                                         ((ReferenceBinding) expressionType).methods();
 203                                 int exprMethodsLength = expressionTypeMethods.length;
 204                                 for (int i = 0, castMethodsLength = castTypeMethods.length; i < castMethodsLength; i++)
 205                                         for (int j = 0; j < exprMethodsLength; j++) {
 206                                                 if ((castTypeMethods[i].returnType != expressionTypeMethods[j].returnType)
 207                                                                 && (castTypeMethods[i].selector == expressionTypeMethods[j].selector)
 208                                                                 && castTypeMethods[i].areParametersEqual(expressionTypeMethods[j])) {
 209                                                         scope.problemReporter().typeCastError(this, castType, expressionType);
 210                                                 }
 211                                         }
 212                         }
 213                 }
 214                 needRuntimeCheckcast = true;
 215                 return;
 216         }
 217
 218         /**
 219          * Cast expression code generation
 220          *
 221          * @param currentScope net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
 222          * @param codeStream net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
 223          * @param valueRequired boolean
 224          */
 225 //      public void generateCode(
 226 //              BlockScope currentScope,
 227 //              CodeStream codeStream,
 228 //              boolean valueRequired) {
 229 //
 230 //              int pc = codeStream.position;
 231 //              if (constant != NotAConstant) {
 232 //                      if (valueRequired
 233 //                              || needRuntimeCheckcast) { // Added for: 1F1W9IG: IVJCOM:WINNT - Compiler omits casting check
 234 //                              codeStream.generateConstant(constant, implicitConversion);
 235 //                              if (needRuntimeCheckcast) {
 236 //                                      codeStream.checkcast(this.resolvedType);
 237 //                                      if (!valueRequired)
 238 //                                              codeStream.pop();
 239 //                              }
 240 //                      }
 241 //                      codeStream.recordPositionsFrom(pc, this.sourceStart);
 242 //                      return;
 243 //              }
 244 //              expression.generateCode(
 245 //                      currentScope,
 246 //                      codeStream,
 247 //                      valueRequired || needRuntimeCheckcast);
 248 //              if (needRuntimeCheckcast) {
 249 //                      codeStream.checkcast(this.resolvedType);
 250 //                      if (!valueRequired)
 251 //                              codeStream.pop();
 252 //              } else {
 253 //                      if (valueRequired)
 254 //                              codeStream.generateImplicitConversion(implicitConversion);
 255 //              }
 256 //              codeStream.recordPositionsFrom(pc, this.sourceStart);
 257 //      }
 258
 259         public Expression innermostCastedExpression(){
 260                 Expression current = this.expression;
 261                 while (current instanceof CastExpression) {
 262                         current = ((CastExpression) current).expression;
 263                 }
 264                 return current;
 265         }
 266         public StringBuffer printExpression(int indent, StringBuffer output) {
 267
 268                 output.append('(');
 269                 type.print(0, output).append(") "); //$NON-NLS-1$
 270                 return expression.printExpression(0, output);
 271         }
 272
 273         public TypeBinding resolveType(BlockScope scope) {
 274                 // compute a new constant if the cast is effective
 275
 276                 // due to the fact an expression may start with ( and that a cast can also start with (
 277                 // the field is an expression....it can be a TypeReference OR a NameReference Or
 278                 // any kind of Expression <-- this last one is invalid.......
 279
 280                 constant = Constant.NotAConstant;
 281                 implicitConversion = T_undefined;
 282                 if ((type instanceof TypeReference) || (type instanceof NameReference)) {
 283                         this.resolvedType = type.resolveType(scope);
 284                         TypeBinding castedExpressionType = expression.resolveType(scope);
 285                         if (this.resolvedType != null && castedExpressionType != null) {
 286                                 areTypesCastCompatible(scope, this.resolvedType, castedExpressionType);
 287                         }
 288                         return this.resolvedType;
 289                 } else { // expression as a cast !!!!!!!!
 290                         TypeBinding castedExpressionType = expression.resolveType(scope);
 291                         if (castedExpressionType == null) return null;
 292                         scope.problemReporter().invalidTypeReference(type);
 293                         return null;
 294                 }
 295         }
 296
 297         public String toStringExpression() {
 298
 299                 return "(" + type.toString(0) + ") " + //$NON-NLS-2$ //$NON-NLS-1$
 300                 expression.toStringExpression();
 301         }
 302
 303         public void traverse(
 304             ASTVisitor visitor,
 305                 BlockScope blockScope) {
 306
 307                 if (visitor.visit(this, blockScope)) {
 308                         type.traverse(visitor, blockScope);
 309                         expression.traverse(visitor, blockScope);
 310                 }
 311                 visitor.endVisit(this, blockScope);
 312         }
 313 }