platform/platform-api/src/com/intellij/openapi/actionSystem/ActionGroupUtil.java

/*
 * Copyright 2000-2009 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.actionSystem;

import com.intellij.openapi.actionSystem.ex.ActionUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class ActionGroupUtil {
  private static Presentation getPresentation(AnAction action, Map<AnAction, Presentation> action2presentation) {
    Presentation presentation = action2presentation.get(action);
    if (presentation == null) {
      presentation = action.getTemplatePresentation().clone();
      action2presentation.put(action, presentation);
    }
    return presentation;
  }

  public static boolean isGroupEmpty(@NotNull ActionGroup actionGroup, @NotNull AnActionEvent e) {
    return isGroupEmpty(actionGroup, e, new HashMap<AnAction, Presentation>());
  }

  private static boolean isGroupEmpty(@NotNull ActionGroup actionGroup,
                                                   @NotNull AnActionEvent e,
                                                   @NotNull Map<AnAction, Presentation> action2presentation) {
    AnAction[] actions = actionGroup.getChildren(e);
    for (AnAction action : actions) {
      if (action instanceof Separator) continue;
      if (isActionEnabledAndVisible(e, action2presentation, action)) {
        if (action instanceof ActionGroup) {
          if (!isGroupEmpty((ActionGroup)action, e, action2presentation)) {
            return false;
          }
          // else continue for-loop
        }
        else {
          return false;
        }
      }
    }
    return true;
  }

  @Nullable
  public static AnAction getSingleActiveAction(@NotNull ActionGroup actionGroup, @NotNull AnActionEvent e) {
    List<AnAction> children = getEnabledChildren(actionGroup, e, new HashMap<AnAction, Presentation>());
    if (children.size() == 1) {
      return children.get(0);
    }
    return null;
  }

  private static List<AnAction> getEnabledChildren(@NotNull ActionGroup actionGroup,
                                                   @NotNull AnActionEvent e,
                                                   @NotNull Map<AnAction, Presentation> action2presentation) {
    List<AnAction> result = new ArrayList<AnAction>();
    AnAction[] actions = actionGroup.getChildren(e);
    for (AnAction action : actions) {
      if (action instanceof ActionGroup) {
        if (isActionEnabledAndVisible(e, action2presentation, action)) {
          result.addAll(getEnabledChildren((ActionGroup)action, e, action2presentation));
        }
      }
      else if (!(action instanceof Separator)) {
        if (isActionEnabledAndVisible(e, action2presentation, action)) {
          result.add(action);
        }
      }
    }
    return result;
  }

  private static boolean isActionEnabledAndVisible(@NotNull final AnActionEvent e,
                                                   @NotNull final Map<AnAction, Presentation> action2presentation,
                                                   @NotNull final AnAction action) {
    Presentation presentation = getPresentation(action, action2presentation);
    AnActionEvent event = new AnActionEvent(e.getInputEvent(),
                                            e.getDataContext(),
                                            ActionPlaces.UNKNOWN,
                                            presentation,
                                            ActionManager.getInstance(),
                                            e.getModifiers());
    event.setInjectedContext(action.isInInjectedContext());
    ActionUtil.performDumbAwareUpdate(action, event, false);

    return presentation.isEnabled() && presentation.isVisible();
  }
}