lang-impl/src/com/intellij/lang/pratt/PrattBuilderImpl.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.codeInsight.daemon.JavaErrorMessages;
   8 import com.intellij.lang.PsiBuilder;
   9 import com.intellij.lang.impl.PsiBuilderImpl;
  10 import com.intellij.lexer.Lexer;
  11 import com.intellij.openapi.util.Trinity;
  12 import com.intellij.psi.tree.IElementType;
  13 import org.jetbrains.annotations.NotNull;
  14 import org.jetbrains.annotations.Nullable;
  15
  16 import java.util.LinkedList;
  17
  18 /**
  19  * @author peter
  20  */
  21 public class PrattBuilderImpl extends PrattBuilder implements PrattBuilderFacade {
  22   private final PrattBuilder myParentBuilder;
  23   private final PsiBuilder myBuilder;
  24   private final LinkedList<IElementType> myLeftSiblings = new LinkedList<IElementType>();
  25   private boolean myParsingStarted;
  26   private String myExpectedMessage;
  27   private int myPriority = Integer.MIN_VALUE;
  28   private MutableMarker myStartMarker;
  29
  30   private PrattBuilderImpl(final PsiBuilder builder, final PrattBuilder parent) {
  31     myBuilder = builder;
  32     myParentBuilder = parent;
  33   }
  34
  35   public static PrattBuilderImpl createBuilder(final PsiBuilder builder) {
  36     return new PrattBuilderImpl(builder, null);
  37   }
  38
  39   public PrattBuilderFacade expecting(final String expectedMessage) {
  40     myExpectedMessage = expectedMessage;
  41     return this;
  42   }
  43
  44   public PrattBuilderFacade withLowestPriority(final int priority) {
  45     myPriority = priority;
  46     return this;
  47   }
  48
  49   public Lexer getLexer() {
  50     return ((PsiBuilderImpl) myBuilder).getLexer();
  51   }
  52
  53   public MutableMarker mark() {
  54     return new MutableMarker(myLeftSiblings, myBuilder.mark(), myLeftSiblings.size());
  55   }
  56
  57   @Nullable
  58   public IElementType parse() {
  59     checkParsed();
  60     return myLeftSiblings.size() != 1 ? null : myLeftSiblings.getLast();
  61   }
  62
  63   protected PrattBuilderFacade createChildBuilder() {
  64     assert myParsingStarted;
  65     return new PrattBuilderImpl(myBuilder, this) {
  66       protected void doParse() {
  67         super.doParse();
  68         PrattBuilderImpl.this.myLeftSiblings.addAll(getResultTypes());
  69       }
  70     };
  71   }
  72
  73   protected void doParse() {
  74     if (isEof()) {
  75       error(myExpectedMessage != null ? myExpectedMessage : JavaErrorMessages.message("unexpected.eof"));
  76       return;
  77     }
  78
  79     TokenParser parser = findParser();
  80     if (parser == null) {
  81       error(myExpectedMessage != null ? myExpectedMessage : JavaErrorMessages.message("unexpected.token"));
  82       return;
  83     }
  84
  85     myStartMarker = mark();
  86     while (!isEof()) {
  87       int startOffset = myBuilder.getCurrentOffset();
  88
  89       if (!parser.parseToken(this)) break;
  90
  91       assert startOffset < myBuilder.getCurrentOffset() : "Endless loop on " + getTokenType();
  92
  93       parser = findParser();
  94       if (parser == null) break;
  95     }
  96     myStartMarker.drop();
  97   }
  98
  99   @Nullable
 100   private TokenParser findParser() {
 101     final IElementType tokenType = getTokenType();
 102     for (final Trinity<Integer, PathPattern, TokenParser> trinity : PrattRegistry.getParsers(tokenType)) {
 103       if (trinity.first > myPriority && trinity.second.accepts(this)) {
 104         return trinity.third;
 105       }
 106     }
 107     return null;
 108   }
 109
 110   public boolean assertToken(final PrattTokenType type, @NotNull final String errorMessage) {
 111     return _checkToken(type, errorMessage);
 112   }
 113
 114   public boolean checkToken(final PrattTokenType type) {
 115     return _checkToken(type, null);
 116   }
 117
 118   private boolean _checkToken(final PrattTokenType type, @Nullable String errorMessage) {
 119     if (isToken(type)) {
 120       advance();
 121       return true;
 122     }
 123     if (errorMessage != null) {
 124       error(errorMessage);
 125     }
 126     return false;
 127   }
 128
 129   public void advance() {
 130     myLeftSiblings.addLast(getTokenType());
 131     myBuilder.advanceLexer();
 132   }
 133
 134   public void error(final String errorText) {
 135     final PsiBuilder.Marker marker = myBuilder.mark();
 136     myBuilder.error(errorText);
 137     marker.drop();
 138   }
 139
 140   @Nullable
 141   public IElementType getTokenType() {
 142     return myBuilder.getTokenType();
 143   }
 144
 145   @Nullable
 146   public String getTokenText() {
 147     return myBuilder.getTokenText();
 148   }
 149
 150   public void reduce(@NotNull final IElementType type) {
 151     myStartMarker.finish(type);
 152     myStartMarker = myStartMarker.precede();
 153   }
 154
 155   @NotNull
 156   public LinkedList<IElementType> getResultTypes() {
 157     checkParsed();
 158     return myLeftSiblings;
 159   }
 160
 161   private void checkParsed() {
 162     if (!myParsingStarted) {
 163       myParsingStarted = true;
 164       doParse();
 165     }
 166   }
 167
 168   public PrattBuilder getParent() {
 169     return myParentBuilder;
 170   }
 171
 172   public int getPriority() {
 173     return myPriority;
 174   }
 175 }