net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/Block.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.codegen.CodeStream;
  15 import net.sourceforge.phpdt.internal.compiler.codegen.Label;
  16 import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
  17 import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
  18 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  19
  20 public class Block extends Statement {
  21
  22         public Statement[] statements;
  23         public int explicitDeclarations;
  24         // the number of explicit declaration , used to create scope
  25         public BlockScope scope;
  26         public static final Block None = new Block(0);
  27
  28         public Block(int explicitDeclarations) {
  29                 this.explicitDeclarations = explicitDeclarations;
  30         }
  31
  32         public FlowInfo analyseCode(
  33                 BlockScope currentScope,
  34                 FlowContext flowContext,
  35                 FlowInfo flowInfo) {
  36
  37                 // empty block
  38                 if (statements == null)
  39                         return flowInfo;
  40                 for (int i = 0, max = statements.length; i < max; i++) {
  41                         Statement stat;
  42                         if (!flowInfo.complainIfUnreachable((stat = statements[i]), scope)) {
  43                                 flowInfo = stat.analyseCode(scope, flowContext, flowInfo);
  44                         }
  45                 }
  46                 return flowInfo;
  47         }
  48
  49         public static final Block EmptyWith(int sourceStart, int sourceEnd) {
  50
  51                 //return an empty block which position is s and e
  52                 Block bk = new Block(0);
  53                 bk.sourceStart = sourceStart;
  54                 bk.sourceEnd = sourceEnd;
  55                 return bk;
  56         }
  57
  58         /**
  59          * Code generation for a block
  60          */
  61         public void generateCode(BlockScope currentScope, CodeStream codeStream) {
  62
  63                 if ((bits & IsReachableMASK) == 0) {
  64                         return;
  65                 }
  66                 int pc = codeStream.position;
  67                 if (statements != null) {
  68                         for (int i = 0, max = statements.length; i < max; i++) {
  69                                 statements[i].generateCode(scope, codeStream);
  70                         }
  71                 } // for local variable debug attributes
  72                 if (scope != currentScope) { // was really associated with its own scope
  73                         codeStream.exitUserScope(scope);
  74                 }
  75                 codeStream.recordPositionsFrom(pc, this.sourceStart);
  76         }
  77
  78         public boolean isEmptyBlock() {
  79
  80                 return statements == null;
  81         }
  82
  83         public void resolve(BlockScope upperScope) {
  84
  85                 if (statements != null) {
  86                         scope =
  87                                 explicitDeclarations == 0
  88                                         ? upperScope
  89                                         : new BlockScope(upperScope, explicitDeclarations);
  90                         int i = 0, length = statements.length;
  91                         while (i < length)
  92                                 statements[i++].resolve(scope);
  93                 }
  94         }
  95
  96         public void resolveUsing(BlockScope givenScope) {
  97
  98                 // this optimized resolve(...) is sent only on none empty blocks
  99                 scope = givenScope;
 100                 if (statements != null) {
 101                         int i = 0, length = statements.length;
 102                         while (i < length)
 103                                 statements[i++].resolve(scope);
 104                 }
 105         }
 106
 107         public String toString(int tab) {
 108
 109                 String s = tabString(tab);
 110                 if (this.statements == null) {
 111                         s += "{\n"; //$NON-NLS-1$
 112                         s += tabString(tab);
 113                         s += "}"; //$NON-NLS-1$
 114                         return s;
 115                 }
 116                 s += "{\n"; //$NON-NLS-1$
 117                 s += this.toStringStatements(tab);
 118                 s += tabString(tab);
 119                 s += "}"; //$NON-NLS-1$
 120                 return s;
 121         }
 122
 123         public String toStringStatements(int tab) {
 124
 125                 if (this.statements == null)
 126                         return ""; //$NON-NLS-1$
 127                 StringBuffer buffer = new StringBuffer();
 128                 for (int i = 0; i < statements.length; i++) {
 129                         buffer.append(statements[i].toString(tab + 1));
 130                         if (statements[i] instanceof Block) {
 131                                 buffer.append("\n"); //$NON-NLS-1$
 132                         } else {
 133                                 buffer.append(";\n"); //$NON-NLS-1$
 134                         }
 135                 };
 136                 return buffer.toString();
 137         }
 138
 139         public void traverse(
 140                 IAbstractSyntaxTreeVisitor visitor,
 141                 BlockScope blockScope) {
 142
 143                 if (visitor.visit(this, blockScope)) {
 144                         if (statements != null) {
 145                                 int statementLength = statements.length;
 146                                 for (int i = 0; i < statementLength; i++)
 147                                         statements[i].traverse(visitor, scope);
 148                         }
 149                 }
 150                 visitor.endVisit(this, blockScope);
 151         }
 152
 153         /**
 154          * Dispatch the call on its last statement.
 155          */
 156         public void branchChainTo(Label label) {
 157                  if (this.statements != null) {
 158                         this.statements[statements.length - 1].branchChainTo(label);
 159                  }
 160         }
 161
 162 }