plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/parser/parsing/statements/SwitchStatement.java

/*
 * Copyright 2000-2014 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jetbrains.plugins.groovy.lang.parser.parsing.statements;

import com.intellij.lang.PsiBuilder;
import com.intellij.psi.tree.IElementType;
import com.intellij.psi.tree.TokenSet;
import org.jetbrains.plugins.groovy.GroovyBundle;
import org.jetbrains.plugins.groovy.lang.lexer.GroovyTokenTypes;
import org.jetbrains.plugins.groovy.lang.parser.GroovyElementTypes;
import org.jetbrains.plugins.groovy.lang.parser.GroovyParser;
import org.jetbrains.plugins.groovy.lang.parser.parsing.statements.expressions.AssignmentExpression;
import org.jetbrains.plugins.groovy.lang.parser.parsing.statements.expressions.ExpressionStatement;
import org.jetbrains.plugins.groovy.lang.parser.parsing.util.ParserUtils;

/**
 * @author ilyas
 */
public class SwitchStatement {

  public static final TokenSet SKIP_SET = TokenSet.create(GroovyTokenTypes.kCASE, GroovyTokenTypes.kDEFAULT, GroovyTokenTypes.mRCURLY);

  public static void parseSwitch(PsiBuilder builder, GroovyParser parser) {
    PsiBuilder.Marker marker = builder.mark();
    ParserUtils.getToken(builder, GroovyTokenTypes.kSWITCH);

    if (!ParserUtils.getToken(builder, GroovyTokenTypes.mLPAREN, GroovyBundle.message("lparen.expected"))) {
      marker.done(GroovyElementTypes.SWITCH_STATEMENT);
      return;
    }
    if (!ExpressionStatement.argParse(builder, parser)) {
      builder.error(GroovyBundle.message("expression.expected"));
    }
    ParserUtils.getToken(builder, GroovyTokenTypes.mNLS);

    if (!ParserUtils.getToken(builder, GroovyTokenTypes.mRPAREN, GroovyBundle.message("rparen.expected"))) {
      builder.error(GroovyBundle.message("rparen.expected"));
      marker.done(GroovyElementTypes.SWITCH_STATEMENT);
      return;
    }
    PsiBuilder.Marker warn = builder.mark();
    ParserUtils.getToken(builder, GroovyTokenTypes.mNLS);

    if (!GroovyTokenTypes.mLCURLY.equals(builder.getTokenType())) {
      warn.rollbackTo();
      builder.error(GroovyBundle.message("case.block.expected"));
      marker.done(GroovyElementTypes.SWITCH_STATEMENT);
      return;
    }
    warn.drop();
    parseCaseBlock(builder, parser);
    marker.done(GroovyElementTypes.SWITCH_STATEMENT);
  }

  private static void parseCaseBlock(PsiBuilder builder, GroovyParser parser) {
    ParserUtils.getToken(builder, GroovyTokenTypes.mLCURLY);
    ParserUtils.getToken(builder, GroovyTokenTypes.mNLS);

    while (!ParserUtils.getToken(builder, GroovyTokenTypes.mRCURLY)) {
      if (builder.getTokenType() != GroovyTokenTypes.kCASE && builder.getTokenType() != GroovyTokenTypes.kDEFAULT) {
        builder.error("case, default or } expected");
        ParserUtils.skipCountingBraces(builder, SKIP_SET);
        if (builder.eof() || ParserUtils.getToken(builder, GroovyTokenTypes.mRCURLY)) {
          return;
        }
      }

      PsiBuilder.Marker sectionMarker = builder.mark();
      parseCaseLabel(builder, parser);

      final PsiBuilder.Marker warn = builder.mark();
      ParserUtils.getToken(builder, GroovyTokenTypes.mNLS);
      if (builder.getTokenType() == GroovyTokenTypes.mRCURLY) {
        warn.rollbackTo();
        builder.error(GroovyBundle.message("statement.expected"));
      }
      else {
        warn.drop();
        parser.parseSwitchCaseList(builder);
      }
      sectionMarker.done(GroovyElementTypes.CASE_SECTION);
      ParserUtils.getToken(builder, GroovyTokenTypes.mNLS);
    }
  }

  /**
   * Parses one or more sequential 'case' or 'default' labels
   */
  public static boolean parseCaseLabel(PsiBuilder builder, GroovyParser parser) {
    IElementType elem = builder.getTokenType();
    if (elem != GroovyTokenTypes.kCASE && elem != GroovyTokenTypes.kDEFAULT) {
      return false;
    }

    PsiBuilder.Marker label = builder.mark();
    builder.advanceLexer();
    if (GroovyTokenTypes.kCASE.equals(elem) && !AssignmentExpression.parse(builder, parser)) {
      builder.error(GroovyBundle.message("expression.expected"));
    }
    ParserUtils.getToken(builder, GroovyTokenTypes.mCOLON, GroovyBundle.message("colon.expected"));
    label.done(GroovyElementTypes.CASE_LABEL);
    PsiBuilder.Marker beforeNls = builder.mark();
    ParserUtils.getToken(builder, GroovyTokenTypes.mNLS);
    if (parseCaseLabel(builder, parser)) {
      beforeNls.drop();
    }
    else {
      beforeNls.rollbackTo();
    }
    return true;
  }
}