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