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

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v0.5
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v05.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.IAbstractSyntaxTreeVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.impl.*;
  15 import net.sourceforge.phpdt.internal.compiler.codegen.*;
  16 import net.sourceforge.phpdt.internal.compiler.flow.*;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.*;
  18
  19 public class CastExpression extends Expression {
  20
  21         public Expression expression;
  22         public Expression type;
  23         public boolean needRuntimeCheckcast;
  24         public TypeBinding castTb;
  25
  26         //expression.implicitConversion holds the cast for baseType casting
  27         public CastExpression(Expression e, Expression t) {
  28                 expression = e;
  29                 type = t;
  30
  31                 //due to the fact an expression may start with ( and that a cast also start with (
  32                 //the field is an expression....it can be a TypeReference OR a NameReference Or
  33                 //an expression <--this last one is invalid.......
  34
  35                 // :-( .............
  36
  37                 //if (type instanceof TypeReference )
  38                 //      flag = IsTypeReference ;
  39                 //else
  40                 //      if (type instanceof NameReference)
  41                 //              flag = IsNameReference ;
  42                 //      else
  43                 //              flag = IsExpression ;
  44
  45         }
  46
  47         public FlowInfo analyseCode(
  48                 BlockScope currentScope,
  49                 FlowContext flowContext,
  50                 FlowInfo flowInfo) {
  51
  52                 return expression
  53                         .analyseCode(currentScope, flowContext, flowInfo)
  54                         .unconditionalInits();
  55         }
  56
  57         public final void areTypesCastCompatible(
  58                 BlockScope scope,
  59                 TypeBinding castTb,
  60                 TypeBinding expressionTb) {
  61
  62                 // see specifications p.68
  63                 // handle errors and process constant when needed
  64
  65                 // if either one of the type is null ==>
  66                 // some error has been already reported some where ==>
  67                 // we then do not report an obvious-cascade-error.
  68
  69                 needRuntimeCheckcast = false;
  70                 if (castTb == null || expressionTb == null)
  71                         return;
  72                 if (castTb.isBaseType()) {
  73                         if (expressionTb.isBaseType()) {
  74                                 if (expressionTb == castTb) {
  75                                         constant = expression.constant; //use the same constant
  76                                         return;
  77                                 }
  78                                 if (scope.areTypesCompatible(expressionTb, castTb)
  79                                         || BaseTypeBinding.isNarrowing(castTb.id, expressionTb.id)) {
  80                                         expression.implicitConversion = (castTb.id << 4) + expressionTb.id;
  81                                         if (expression.constant != Constant.NotAConstant)
  82                                                 constant = expression.constant.castTo(expression.implicitConversion);
  83                                         return;
  84                                 }
  85                         }
  86                         scope.problemReporter().typeCastError(this, castTb, expressionTb);
  87                         return;
  88                 }
  89
  90                 //-----------cast to something which is NOT a base type--------------------------
  91                 if (expressionTb == NullBinding)
  92                         return; //null is compatible with every thing
  93
  94                 if (expressionTb.isBaseType()) {
  95                         scope.problemReporter().typeCastError(this, castTb, expressionTb);
  96                         return;
  97                 }
  98
  99                 if (expressionTb.isArrayType()) {
 100                         if (castTb.isArrayType()) {
 101                                 //------- (castTb.isArray) expressionTb.isArray -----------
 102                                 TypeBinding expressionEltTb = ((ArrayBinding) expressionTb).elementsType(scope);
 103                                 if (expressionEltTb.isBaseType()) {
 104                                         // <---stop the recursion-------
 105                                         if (((ArrayBinding) castTb).elementsType(scope) == expressionEltTb)
 106                                                 needRuntimeCheckcast = true;
 107                                         else
 108                                                 scope.problemReporter().typeCastError(this, castTb, expressionTb);
 109                                         return;
 110                                 }
 111                                 // recursively on the elements...
 112                                 areTypesCastCompatible(
 113                                         scope,
 114                                         ((ArrayBinding) castTb).elementsType(scope),
 115                                         expressionEltTb);
 116                                 return;
 117                         } else if (
 118                                 castTb.isClass()) {
 119                                 //------(castTb.isClass) expressionTb.isArray ---------------
 120                                 if (scope.isJavaLangObject(castTb))
 121                                         return;
 122                         } else { //------- (castTb.isInterface) expressionTb.isArray -----------
 123                                 if (scope.isJavaLangCloneable(castTb) || scope.isJavaIoSerializable(castTb)) {
 124                                         needRuntimeCheckcast = true;
 125                                         return;
 126                                 }
 127                         }
 128                         scope.problemReporter().typeCastError(this, castTb, expressionTb);
 129                         return;
 130                 }
 131
 132                 if (expressionTb.isClass()) {
 133                         if (castTb.isArrayType()) {
 134                                 // ---- (castTb.isArray) expressionTb.isClass -------
 135                                 if (scope.isJavaLangObject(expressionTb)) { // potential runtime error
 136                                         needRuntimeCheckcast = true;
 137                                         return;
 138                                 }
 139                         } else if (
 140                                 castTb.isClass()) { // ----- (castTb.isClass) expressionTb.isClass ------
 141                                 if (scope.areTypesCompatible(expressionTb, castTb)) // no runtime error
 142                                         return;
 143                                 if (scope.areTypesCompatible(castTb, expressionTb)) {
 144                                         // potential runtime  error
 145                                         needRuntimeCheckcast = true;
 146                                         return;
 147                                 }
 148                         } else { // ----- (castTb.isInterface) expressionTb.isClass -------
 149                                 if (((ReferenceBinding) expressionTb).isFinal()) {
 150                                         // no subclass for expressionTb, thus compile-time check is valid
 151                                         if (scope.areTypesCompatible(expressionTb, castTb))
 152                                                 return;
 153                                 } else { // a subclass may implement the interface ==> no check at compile time
 154                                         needRuntimeCheckcast = true;
 155                                         return;
 156                                 }
 157                         }
 158                         scope.problemReporter().typeCastError(this, castTb, expressionTb);
 159                         return;
 160                 }
 161
 162                 //      if (expressionTb.isInterface()) { cannot be anything else
 163                 if (castTb.isArrayType()) {
 164                         // ----- (castTb.isArray) expressionTb.isInterface ------
 165                         if (scope.isJavaLangCloneable(expressionTb)
 166                                 || scope.isJavaIoSerializable(expressionTb)) // potential runtime error
 167                                 needRuntimeCheckcast = true;
 168                         else
 169                                 scope.problemReporter().typeCastError(this, castTb, expressionTb);
 170                         return;
 171                 } else if (
 172                         castTb.isClass()) { // ----- (castTb.isClass) expressionTb.isInterface --------
 173                         if (scope.isJavaLangObject(castTb)) // no runtime error
 174                                 return;
 175                         if (((ReferenceBinding) castTb).isFinal()) {
 176                                 // no subclass for castTb, thus compile-time check is valid
 177                                 if (!scope.areTypesCompatible(castTb, expressionTb)) {
 178                                         // potential runtime error
 179                                         scope.problemReporter().typeCastError(this, castTb, expressionTb);
 180                                         return;
 181                                 }
 182                         }
 183                 } else { // ----- (castTb.isInterface) expressionTb.isInterface -------
 184                         if (castTb != expressionTb
 185                                 && (Scope.compareTypes(castTb, expressionTb) == NotRelated)) {
 186                                 MethodBinding[] castTbMethods = ((ReferenceBinding) castTb).methods();
 187                                 MethodBinding[] expressionTbMethods =
 188                                         ((ReferenceBinding) expressionTb).methods();
 189                                 int exprMethodsLength = expressionTbMethods.length;
 190                                 for (int i = 0, castMethodsLength = castTbMethods.length;
 191                                         i < castMethodsLength;
 192                                         i++)
 193                                         for (int j = 0; j < exprMethodsLength; j++)
 194                                                 if (castTbMethods[i].returnType != expressionTbMethods[j].returnType)
 195                                                         if (castTbMethods[i].selector == expressionTbMethods[j].selector)
 196                                                                 if (castTbMethods[i].areParametersEqual(expressionTbMethods[j]))
 197                                                                         scope.problemReporter().typeCastError(this, castTb, expressionTb);
 198                         }
 199                 }
 200                 needRuntimeCheckcast = true;
 201                 return;
 202         }
 203
 204         /**
 205          * Cast expression code generation
 206          *
 207          * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
 208          * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
 209          * @param valueRequired boolean
 210          */
 211         public void generateCode(
 212                 BlockScope currentScope,
 213                 CodeStream codeStream,
 214                 boolean valueRequired) {
 215
 216                 int pc = codeStream.position;
 217                 if (constant != NotAConstant) {
 218                         if (valueRequired
 219                                 || needRuntimeCheckcast) { // Added for: 1F1W9IG: IVJCOM:WINNT - Compiler omits casting check
 220                                 codeStream.generateConstant(constant, implicitConversion);
 221                                 if (needRuntimeCheckcast) {
 222                                         codeStream.checkcast(castTb);
 223                                         if (!valueRequired)
 224                                                 codeStream.pop();
 225                                 }
 226                         }
 227                         codeStream.recordPositionsFrom(pc, this.sourceStart);
 228                         return;
 229                 }
 230                 expression.generateCode(
 231                         currentScope,
 232                         codeStream,
 233                         valueRequired || needRuntimeCheckcast);
 234                 if (needRuntimeCheckcast) {
 235                         codeStream.checkcast(castTb);
 236                         if (!valueRequired)
 237                                 codeStream.pop();
 238                 } else {
 239                         if (valueRequired)
 240                                 codeStream.generateImplicitConversion(implicitConversion);
 241                 }
 242                 codeStream.recordPositionsFrom(pc, this.sourceStart);
 243         }
 244
 245         public TypeBinding resolveType(BlockScope scope) {
 246                 // compute a new constant if the cast is effective
 247
 248                 // due to the fact an expression may start with ( and that a cast can also start with (
 249                 // the field is an expression....it can be a TypeReference OR a NameReference Or
 250                 // any kind of Expression <-- this last one is invalid.......
 251
 252                 constant = Constant.NotAConstant;
 253                 implicitConversion = T_undefined;
 254                 TypeBinding expressionTb = expression.resolveType(scope);
 255                 if (expressionTb == null)
 256                         return null;
 257
 258                 if ((type instanceof TypeReference) || (type instanceof NameReference)) {
 259                         if ((castTb = type.resolveType(scope)) == null)
 260                                 return null;
 261                         areTypesCastCompatible(scope, castTb, expressionTb);
 262                         return castTb;
 263                 } else { // expression as a cast !!!!!!!!
 264                         scope.problemReporter().invalidTypeReference(type);
 265                         return null;
 266                 }
 267         }
 268
 269         public String toStringExpression() {
 270
 271                 return "(" + type.toString(0) + ") " + //$NON-NLS-2$ //$NON-NLS-1$
 272                 expression.toStringExpression();
 273         }
 274
 275         public void traverse(
 276                 IAbstractSyntaxTreeVisitor visitor,
 277                 BlockScope blockScope) {
 278
 279                 if (visitor.visit(this, blockScope)) {
 280                         type.traverse(visitor, blockScope);
 281                         expression.traverse(visitor, blockScope);
 282                 }
 283                 visitor.endVisit(this, blockScope);
 284         }
 285 }