Refactored packagename to net.sourceforge.phpdt.internal.compiler.ast
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / compiler / ast / DoStatement.java
index 1a80333..32dfabd 100644 (file)
+/*******************************************************************************
+ * Copyright (c) 2000, 2003 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials 
+ * are made available under the terms of the Common Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v10.html
+ * 
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
 package net.sourceforge.phpdt.internal.compiler.ast;
 
-/**
- * @author Matthieu Casanova
- */
+import net.sourceforge.phpdt.internal.compiler.ASTVisitor;
+import net.sourceforge.phpdt.internal.compiler.codegen.Label;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
+import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
+import net.sourceforge.phpdt.internal.compiler.flow.LoopingFlowContext;
+import net.sourceforge.phpdt.internal.compiler.impl.Constant;
+import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
+import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
+
 public class DoStatement extends Statement {
 
+       public Expression condition;
+       public Statement action;
+
+       private Label breakLabel, continueLabel;
+
+       // for local variables table attributes
+       int mergedInitStateIndex = -1;
+
+       public DoStatement(Expression condition, Statement action, int s, int e) {
+
+               this.sourceStart = s;
+               this.sourceEnd = e;
+               this.condition = condition;
+               this.action = action;
+       }
+
+       public FlowInfo analyseCode(
+               BlockScope currentScope,
+               FlowContext flowContext,
+               FlowInfo flowInfo) {
+
+               breakLabel = new Label();
+               continueLabel = new Label();
+               LoopingFlowContext loopingContext =
+                       new LoopingFlowContext(
+                               flowContext,
+                               this,
+                               breakLabel,
+                               continueLabel,
+                               currentScope);
+
+               Constant cst = condition.constant;
+               boolean isConditionTrue = cst != NotAConstant && cst.booleanValue() == true;
+               cst = condition.optimizedBooleanConstant();
+               boolean isConditionOptimizedTrue = cst != NotAConstant && cst.booleanValue() == true;
+               boolean isConditionOptimizedFalse = cst != NotAConstant && cst.booleanValue() == false;
+
+               int previousMode = flowInfo.reachMode();
+                               
+               if ((action != null) && !action.isEmptyBlock()) {
+                       flowInfo = action.analyseCode(currentScope, loopingContext, flowInfo);
+
+                       // code generation can be optimized when no need to continue in the loop
+                       if (!flowInfo.isReachable() && !loopingContext.initsOnContinue.isReachable()) {
+                               continueLabel = null;
+                       }
+               }
+               /* Reset reach mode, to address following scenario.
+                *   final blank;
+                *   do { if (true) break; else blank = 0; } while(false);
+                *   blank = 1; // may be initialized already 
+                */
+               flowInfo.setReachMode(previousMode);
+               
+               flowInfo =
+                       condition.analyseCode(
+                               currentScope,
+                               loopingContext,
+                               (action == null
+                                       ? flowInfo
+                                       : (flowInfo.mergedWith(loopingContext.initsOnContinue))));
+               if (!isConditionOptimizedFalse && continueLabel != null) {
+                       loopingContext.complainOnFinalAssignmentsInLoop(currentScope, flowInfo);
+               }
+
+               // infinite loop
+               FlowInfo mergedInfo;
+               if (isConditionTrue) {
+                       mergedInfo = loopingContext.initsOnBreak;
+                       if (!mergedInfo.isReachable()) mergedInfo.addPotentialInitializationsFrom(flowInfo.initsWhenFalse());
+               } else {
+                       // end of loop: either condition false or break
+                       mergedInfo =
+                               flowInfo.initsWhenFalse().unconditionalInits().mergedWith(
+                                       loopingContext.initsOnBreak);
+                       if (isConditionOptimizedTrue && !loopingContext.initsOnBreak.isReachable()) {
+                               mergedInfo.setReachMode(FlowInfo.UNREACHABLE);
+                       }
+               }
+               mergedInitStateIndex =
+                       currentScope.methodScope().recordInitializationStates(mergedInfo);
+               return mergedInfo;
+       }
+
+       /**
+        * Do statement code generation
+        *
+        */
+//     public void generateCode(BlockScope currentScope, CodeStream codeStream) {
+//
+//             if ((bits & IsReachableMASK) == 0) {
+//                     return;
+//             }
+//             int pc = codeStream.position;
+//
+//             // labels management
+//             Label actionLabel = new Label(codeStream);
+//             actionLabel.place();
+//             breakLabel.codeStream = codeStream;
+//             if (continueLabel != null) {
+//                     continueLabel.codeStream = codeStream;
+//             }
+//
+//             // generate action
+//             if (action != null) {
+//                     action.generateCode(currentScope, codeStream);
+//             }
+//             // generate condition
+//             if (continueLabel != null) {
+//                     continueLabel.place();
+//                     condition.generateOptimizedBoolean(
+//                             currentScope,
+//                             codeStream,
+//                             actionLabel,
+//                             null,
+//                             true);
+//             }
+//             breakLabel.place();
+//
+//             // May loose some local variable initializations : affecting the local variable attributes
+//             if (mergedInitStateIndex != -1) {
+//                     codeStream.removeNotDefinitelyAssignedVariables(
+//                             currentScope,
+//                             mergedInitStateIndex);
+//             }
+//             codeStream.recordPositionsFrom(pc, this.sourceStart);
+//
+//     }
+
+       public void resetStateForCodeGeneration() {
+               if (this.breakLabel != null) {
+                       this.breakLabel.resetStateForCodeGeneration();
+               }
+               if (this.continueLabel != null) {
+                       this.continueLabel.resetStateForCodeGeneration();
+               }
+       }
+
+       public void resolve(BlockScope scope) {
+
+               TypeBinding type = condition.resolveTypeExpecting(scope, BooleanBinding);
+               condition.implicitWidening(type, type);
+               if (action != null)
+                       action.resolve(scope);
+       }
+       public StringBuffer printStatement(int indent, StringBuffer output) {
+
+               printIndent(indent, output).append("do"); //$NON-NLS-1$
+               if (action == null)
+                       output.append(" ;\n"); //$NON-NLS-1$
+               else {
+                       output.append('\n');
+                       action.printStatement(indent + 1, output).append('\n');
+               }
+               output.append("while ("); //$NON-NLS-1$
+               return condition.printExpression(0, output).append(");"); //$NON-NLS-1$
+       }
+       public String toString(int tab) {
+
+               String inFront, s = tabString(tab);
+               inFront = s;
+               s = s + "do"; //$NON-NLS-1$
+               if (action == null)
+                       s = s + " {}\n"; //$NON-NLS-1$
+               else if (action instanceof Block)
+                       s = s + "\n" + action.toString(tab + 1) + "\n"; //$NON-NLS-2$ //$NON-NLS-1$
+               else
+                       s = s + " {\n" + action.toString(tab + 1) + ";}\n"; //$NON-NLS-1$ //$NON-NLS-2$
+               s = s + inFront + "while (" + condition.toStringExpression() + ")"; //$NON-NLS-1$ //$NON-NLS-2$
+               return s;
+       }
+
+       public void traverse(ASTVisitor visitor, BlockScope scope) {
 
-  /** The condition expression. */
-  public Expression condition;
-  /** The action of the while. (it could be a block) */
-  public Statement action;
-
-  public DoStatement(Expression condition,
-                     Statement action,
-                     int sourceStart,
-                     int sourceEnd) {
-    super(sourceStart, sourceEnd);
-    this.condition = condition;
-    this.action = action;
-  }
-
-  /**
-   * Return the object into String.
-   * @param tab how many tabs (not used here
-   * @return a String
-   */
-  public String toString(int tab) {
-    final String s = tabString(tab);
-    final StringBuffer buff = new StringBuffer("do "); //$NON-NLS-1$
-    if (action == null) {
-      buff.append(" {} ;"); //$NON-NLS-1$
-    } else {
-      buff.append("\n").append(action.toString(tab + 1)); //$NON-NLS-1$
-    }
-    buff.append(s).append(" while (");
-    buff.append(condition.toStringExpression()).append(")");   //$NON-NLS-1$
-    return buff.toString();
-  }
+               if (visitor.visit(this, scope)) {
+                       if (action != null) {
+                               action.traverse(visitor, scope);
+                       }
+                       condition.traverse(visitor, scope);
+               }
+               visitor.endVisit(this, scope);
+       }
 }