platform/platform-impl/src/com/intellij/openapi/editor/actions/CutLineBackwardAction.java

/*
 * Copyright 2000-2011 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 com.intellij.openapi.editor.actions;

import com.intellij.openapi.actionSystem.DataContext;
import com.intellij.openapi.editor.Document;
import com.intellij.openapi.editor.Editor;
import com.intellij.openapi.editor.actionSystem.EditorAction;
import com.intellij.openapi.editor.actionSystem.EditorWriteActionHandler;
import org.jetbrains.annotations.NotNull;

/**
 * Stands for emacs 'reverse-kill-line' action, i.e.
 * <a href="http://www.gnu.org/software/emacs/manual/html_node/emacs/Killing-by-Lines.html">'kill-line' action</a>
 * with negative argument.
 * 
 * @author Denis Zhdanov
 * @since 4/18/11 1:22 PM
 */
public class CutLineBackwardAction extends EditorAction {

  public CutLineBackwardAction() {
    super(new Handler());
  }

  static class Handler extends EditorWriteActionHandler {
    
    @Override
    public void executeWriteAction(Editor editor, DataContext dataContext) {
      final Document document = editor.getDocument();
      int caretOffset = editor.getCaretModel().getOffset();
      if (caretOffset <= 0) {
        return;
      }
      
      // The main idea is to kill everything between the current line start and caret and the whole previous line.
      
      final int caretLine = document.getLineNumber(caretOffset);
      int start;
      
      if (caretLine <= 0) {
        start = 0;
      }
      else {
        start = document.getLineStartOffset(caretLine - 1);
      }
      KillRingUtil.cut(editor, start, caretOffset);
    }
  }
}