lang-impl/src/com/intellij/lang/pratt/MutableMarker.java

   1 /*
   2  * Copyright (c) 2000-2005 by JetBrains s.r.o. All Rights Reserved.
   3  * Use is subject to license terms.
   4  */
   5 package com.intellij.lang.pratt;
   6
   7 import com.intellij.lang.PsiBuilder;
   8 import com.intellij.psi.tree.IElementType;
   9
  10 import java.util.LinkedList;
  11
  12 /**
  13  * @author peter
  14  */
  15 public class MutableMarker {
  16   enum Mode { READY, DROPPED, COMMITTED, ERROR }
  17
  18   private final PsiBuilder.Marker myStartMarker;
  19   private IElementType myResultType;
  20   private int myInitialPathLength;
  21   private LinkedList<IElementType> myPath;
  22   private Mode myMode;
  23
  24   public MutableMarker(final LinkedList<IElementType> path, final PsiBuilder.Marker startMarker, final int initialPathLength) {
  25     myPath = path;
  26     myStartMarker = startMarker;
  27     myInitialPathLength = initialPathLength;
  28     myMode = Mode.READY;
  29   }
  30
  31   public boolean isCommitted() {
  32     return myMode == Mode.COMMITTED;
  33   }
  34
  35   public boolean isDropped() {
  36     return myMode == Mode.DROPPED || myMode == Mode.ERROR;
  37   }
  38
  39   public MutableMarker setResultType(final IElementType resultType) {
  40     myResultType = resultType;
  41     return this;
  42   }
  43
  44   public IElementType getResultType() {
  45     return myResultType;
  46   }
  47
  48   public void finish() {
  49     assert myMode == Mode.READY;
  50     if (myResultType == null) {
  51       myMode = Mode.DROPPED;
  52       myStartMarker.drop();
  53     } else {
  54       myMode = Mode.COMMITTED;
  55       myStartMarker.done(myResultType);
  56       restorePath();
  57       myPath.addLast(myResultType);
  58     }
  59   }
  60
  61   private void restorePath() {
  62     while (myPath.size() > myInitialPathLength) {
  63       myPath.removeLast();
  64     }
  65   }
  66
  67   public MutableMarker precede() {
  68     return new MutableMarker(myPath, myStartMarker.precede(), myInitialPathLength);
  69   }
  70
  71   public void finish(final IElementType type) {
  72     setResultType(type);
  73     finish();
  74   }
  75
  76   public void drop() {
  77     assert myMode == Mode.READY;
  78     myMode = Mode.DROPPED;
  79     myStartMarker.drop();
  80   }
  81
  82   public void rollback() {
  83     assert myMode == Mode.READY;
  84     myMode = Mode.DROPPED;
  85     restorePath();
  86     myStartMarker.rollbackTo();
  87   }
  88
  89   public void error(final String message) {
  90     assert myMode == Mode.READY;
  91     myMode = Mode.ERROR;
  92     myStartMarker.error(message);
  93   }
  94 }