platform/vcs-api/src/com/intellij/openapi/vcs/history/DiffFromHistoryHandler.java

/*
 * Copyright 2000-2012 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.vcs.history;

import com.intellij.openapi.actionSystem.AnActionEvent;
import com.intellij.openapi.vcs.FilePath;
import org.jetbrains.annotations.NotNull;

/**
 * This handler is called when the user selects one or two revisions in the file history and invokes "Show Diff",
 * or selected one revision and invokes "Show Diff with Local"
 * Default handler is implemented in {@code vcs-impl}.
 * Custom handlers should be returned via {@link VcsHistoryProvider#getHistoryDiffHandler()}.
 *
 * @author Kirill Likhodedov
 */
public interface DiffFromHistoryHandler {

  /**
   * Show diff when a single revision is selected in the file history panel.
   *
   * @param e                AnActionEvent which happened, when user invoked "Show Diff".
   * @param filePath         the file which history is shown.
   * @param previousRevision the previous revision in the list displayed file history panel, may be {@link VcsFileRevision#NULL}.
   * @param revision         the revision selected in the file history panel.
   */
  void showDiffForOne(@NotNull AnActionEvent e,
                      @NotNull FilePath filePath,
                      @NotNull VcsFileRevision previousRevision,
                      @NotNull VcsFileRevision revision);

  /**
   * Show diff for 2 revisions selected from the file history panel,
   * or "Show Diff with Local" (then the second revision is a {@link CurrentRevision}.
   * The order of selected revisions is not defined.
   *
   * @param filePath  the file which history is shown.
   * @param revision1 one of the selected revisions.
   * @param revision2 another selected revision.
   */
  void showDiffForTwo(@NotNull FilePath filePath, @NotNull VcsFileRevision revision1, @NotNull VcsFileRevision revision2);

}