platform/lang-impl/src/com/intellij/indentation/IndentationParser.java

   1 package com.intellij.indentation;
   2
   3 import com.intellij.lang.ASTNode;
   4 import com.intellij.lang.PsiBuilder;
   5 import com.intellij.lang.PsiParser;
   6 import com.intellij.openapi.util.Pair;
   7 import com.intellij.psi.tree.IElementType;
   8 import org.jetbrains.annotations.NotNull;
   9
  10 import java.util.Stack;
  11
  12 /**
  13  * @author oleg
  14  */
  15 public abstract class IndentationParser implements PsiParser {
  16   private final IElementType myEolTokenType;
  17   private final IElementType myIndentTokenType;
  18   private final IElementType myBlockElementType;
  19
  20   public IndentationParser(final IElementType blockElementType,
  21                            final IElementType eolTokenType,
  22                            final IElementType indentTokenType) {
  23     myBlockElementType = blockElementType;
  24     myEolTokenType = eolTokenType;
  25     myIndentTokenType = indentTokenType;
  26   }
  27
  28   @NotNull
  29   public ASTNode parse(final IElementType root, final PsiBuilder builder) {
  30     final PsiBuilder.Marker fileMarker = builder.mark();
  31
  32     final Stack<Pair<Integer, PsiBuilder.Marker>> stack = new Stack<Pair<Integer, PsiBuilder.Marker>>();
  33     stack.push(Pair.create(0, builder.mark()));
  34
  35     PsiBuilder.Marker startLineMarker = null;
  36     int currentIndent = 0;
  37     boolean eolSeen = false;
  38
  39     while (!builder.eof()) {
  40       final IElementType type = builder.getTokenType();
  41       // EOL
  42       if (type == myEolTokenType) {
  43         // Handle variant with several EOLs
  44         if (startLineMarker == null){
  45           startLineMarker = builder.mark();
  46         }
  47         eolSeen = true;
  48       } else
  49
  50       // Indent
  51       {
  52         if (type == myIndentTokenType){
  53           //noinspection ConstantConditions
  54           currentIndent = builder.getTokenText().length();
  55         } else
  56
  57         if (eolSeen) {
  58           if (startLineMarker != null){
  59             startLineMarker.rollbackTo();
  60             startLineMarker = null;
  61           }
  62           // Close indentation blocks
  63           while (!stack.isEmpty() && currentIndent < stack.peek().first){
  64             stack.pop().second.done(myBlockElementType);
  65           }
  66
  67           if (!stack.isEmpty()) {
  68             final Pair<Integer, PsiBuilder.Marker> pair = stack.peek();
  69             if (currentIndent == pair.first) {
  70               stack.pop().second.done(myBlockElementType);
  71               passEOLsAndIndents(builder);
  72               stack.push(Pair.create(currentIndent, builder.mark()));
  73             }
  74             if (currentIndent > pair.first) {
  75               passEOLsAndIndents(builder);
  76               stack.push(Pair.create(currentIndent, builder.mark()));
  77             }
  78           }
  79           eolSeen = false;
  80           currentIndent = 0;
  81         }
  82       }
  83       builder.advanceLexer();
  84     }
  85
  86     // Close all left opened markers
  87     if (startLineMarker != null){
  88       startLineMarker.drop();
  89     }
  90     while (!stack.isEmpty()){
  91       stack.pop().second.done(myBlockElementType);
  92     }
  93
  94     fileMarker.done(root);
  95     return builder.getTreeBuilt();
  96   }
  97
  98   private void passEOLsAndIndents(final PsiBuilder builder) {
  99     IElementType tokenType = builder.getTokenType();
 100     while (tokenType == myEolTokenType || tokenType == myIndentTokenType){
 101       builder.advanceLexer();
 102       tokenType = builder.getTokenType();
 103     }
 104   }
 105 }