inspections/impl/com/intellij/codeInspection/dataFlow/instructions/ConditionalGotoInstruction.java

   1 /*
   2  * Created by IntelliJ IDEA.
   3  * User: max
   4  * Date: Jan 26, 2002
   5  * Time: 10:48:29 PM
   6  * To change template for new class use
   7  * Code Style | Class Templates options (Tools | IDE Options).
   8  */
   9 package com.intellij.codeInspection.dataFlow.instructions;
  10
  11
  12 import com.intellij.codeInspection.dataFlow.DataFlowRunner;
  13 import com.intellij.codeInspection.dataFlow.DfaInstructionState;
  14 import com.intellij.codeInspection.dataFlow.DfaMemoryState;
  15 import com.intellij.codeInspection.dataFlow.InstructionVisitor;
  16 import com.intellij.codeInspection.dataFlow.value.DfaValue;
  17 import com.intellij.psi.PsiElement;
  18
  19 import java.util.ArrayList;
  20
  21 public class ConditionalGotoInstruction extends BranchingInstruction {
  22   private int myOffset;
  23   private final boolean myIsNegated;
  24
  25   public ConditionalGotoInstruction(int myOffset, boolean isNegated, PsiElement psiAnchor) {
  26     this.myOffset = myOffset;
  27     myIsNegated = isNegated;
  28     setPsiAnchor(psiAnchor);
  29   }
  30
  31   public DfaInstructionState[] apply(DataFlowRunner runner, DfaMemoryState memState) {
  32     DfaValue cond = memState.pop();
  33
  34     DfaValue condTrue;
  35     DfaValue condFalse;
  36
  37     if (myIsNegated) {
  38       condFalse = cond;
  39       condTrue = cond.createNegated();
  40     } else {
  41       condTrue = cond;
  42       condFalse = cond.createNegated();
  43     }
  44
  45     if (condTrue == runner.getFactory().getConstFactory().getTrue()) {
  46       markBranchReachable(true);
  47       return new DfaInstructionState[] {new DfaInstructionState(runner.getInstruction(getOffset()), memState)};
  48     }
  49
  50     if (condFalse == runner.getFactory().getConstFactory().getTrue()) {
  51       markBranchReachable(false);
  52       return new DfaInstructionState[] {new DfaInstructionState(runner.getInstruction(getIndex() + 1), memState)};
  53     }
  54
  55     ArrayList<DfaInstructionState> result = new ArrayList<DfaInstructionState>();
  56
  57     DfaMemoryState thenState = memState.createCopy();
  58     DfaMemoryState elseState = memState.createCopy();
  59
  60     if (thenState.applyCondition(condTrue)) {
  61       result.add(new DfaInstructionState(runner.getInstruction(getOffset()), thenState));
  62       markBranchReachable(true);
  63     }
  64
  65     if (elseState.applyCondition(condFalse)) {
  66       result.add(new DfaInstructionState(runner.getInstruction(getIndex() + 1), elseState));
  67       markBranchReachable(false);
  68     }
  69
  70     return result.toArray(new DfaInstructionState[result.size()]);
  71   }
  72
  73   @Override
  74   public DfaInstructionState[] accept(DataFlowRunner runner, DfaMemoryState stateBefore, InstructionVisitor visitor) {
  75     return visitor.visitConditionalGoto(this, runner, stateBefore);
  76   }
  77
  78   private void markBranchReachable(boolean isTrueBranch) {
  79     if (isTrueBranch ^ myIsNegated) {
  80       setTrueReachable();
  81     }
  82     else {
  83       setFalseReachable();
  84     }
  85   }
  86
  87   public String toString() {
  88     return "cond_goto " + myOffset;
  89   }
  90
  91   public int getOffset() {
  92     return myOffset;
  93   }
  94
  95   public void setOffset(int offset) {
  96     myOffset = offset;
  97   }
  98 }