platform/platform-impl/src/com/intellij/openapi/diff/impl/EmptyDiffViewer.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.diff.impl;

import com.intellij.openapi.actionSystem.ActionManager;
import com.intellij.openapi.actionSystem.DataKey;
import com.intellij.openapi.actionSystem.DataSink;
import com.intellij.openapi.diff.*;
import com.intellij.openapi.ui.Splitter;
import com.intellij.openapi.vcs.AbstractDataProviderPanel;
import com.intellij.util.LineSeparator;
import com.intellij.util.ui.UIUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import javax.swing.*;
import java.awt.*;

/**
 * This viewer is shown, when the compared contents are equal or differ only in line separators.
 *
 * @author Irina.Chernushina
 * @author Kirill Likhodedov
 */
public class EmptyDiffViewer implements DiffViewer {
  private DiffRequest myRequest;

  @Override
  public boolean canShowRequest(DiffRequest request) {
    return true;
  }

  @Override
  public void setDiffRequest(DiffRequest request) {
    myRequest = request;
  }

  @Override
  public JComponent getComponent() {
    final JPanel result = new AbstractDataProviderPanel(new BorderLayout(), false) {
      @Override
      public void calcData(DataKey key, DataSink sink) {
        final Object data = myRequest.getGenericData().get(key.getName());
        if (data != null) {
          sink.put(key, data);
        }
      }
    };

    final ActionManager actionManager = ActionManager.getInstance();
    final DiffToolbarComponent toolbarComponent = new DiffToolbarComponent(result);
    final DiffRequest.ToolbarAddons addons = new DiffRequest.ToolbarAddons() {
      @Override
      public void customize(DiffToolbar toolbar) {
        toolbar.addAction(actionManager.getAction("DiffPanel.Toolbar"));
        toolbar.addAction(actionManager.getAction("ContextHelp"));
        toolbar.addSeparator();
      }
    };
    toolbarComponent.resetToolbar(addons);
    final DiffToolbarImpl toolbar = toolbarComponent.getToolbar();
    myRequest.customizeToolbar(toolbar);
    /*group.addAction(actionManager.getAction("Diff.PrevChange"));
    group.addAction(actionManager.getAction("Diff.NextChange"));*/

    result.add(toolbarComponent, BorderLayout.NORTH);

    DiffContent content1 = myRequest.getContents()[0];
    DiffContent content2 = myRequest.getContents()[1];

    LineSeparator sep1 = content1.getLineSeparator();
    LineSeparator sep2 = content2.getLineSeparator();

    final JPanel messagePanel = createMessagePanel(sep1, sep2);

    if (LineSeparator.knownAndDifferent(sep1, sep2)) {
      assert sep1 != null && sep2 != null: "Separators should have been checked for nullity. sep1: " + sep1 + ", sep2: " + sep2;

      JComponent title1 = createTitleComponent(myRequest.getContentTitles()[0], sep1, true);
      JComponent title2 = createTitleComponent(myRequest.getContentTitles()[1], sep2, false);

      Splitter titlePanel = new Splitter(false, 0.5F, 0.5F, 0.5F);
      titlePanel.setFirstComponent(title1);
      titlePanel.setSecondComponent(title2);
      titlePanel.setDividerWidth(1);

      JPanel rootPanel = new JPanel(new BorderLayout());
      rootPanel.add(titlePanel, BorderLayout.NORTH);
      rootPanel.add(messagePanel);
      result.add(rootPanel, BorderLayout.CENTER);
    }
    else {
      result.add(messagePanel, BorderLayout.CENTER);
    }
    return result;
  }

  @NotNull
  private JPanel createMessagePanel(@Nullable LineSeparator sep1, @Nullable LineSeparator sep2) {
    String message;
    if (DiffUtil.oneIsUnknown(myRequest.getContents()[0], myRequest.getContents()[1])) {
      message = DiffBundle.message("diff.can.not.show.unknown");
    }
    else if (LineSeparator.knownAndDifferent(sep1, sep2)) {
      message = DiffBundle.message("diff.contents.have.differences.only.in.line.separators.message.text");
    }
    else {
      message = DiffBundle.message("diff.contents.are.identical.message.text");
    }

    final JLabel label = new JLabel(message);
    label.setForeground(UIUtil.getInactiveTextColor());
    final JPanel wrapper = new JPanel(new GridBagLayout());
    wrapper.add(label, new GridBagConstraints(0,0,1,1,0,0,GridBagConstraints.CENTER, GridBagConstraints.NONE, new Insets(1,1,1,1), 0,0));
    return wrapper;
  }

  private static JComponent createTitleComponent(String title, LineSeparator sep1, boolean left) {
    JComponent panel = DiffPanelImpl.createComponentForTitle(title, sep1, left);
    panel.setBorder(BorderFactory.createEmptyBorder(UIUtil.DEFAULT_VGAP, UIUtil.DEFAULT_HGAP, UIUtil.DEFAULT_VGAP, UIUtil.DEFAULT_HGAP));
    return panel;
  }

  @Nullable
  @Override
  public JComponent getPreferredFocusedComponent() {
    return null;
  }

  @Override
  public int getContentsNumber() {
    return 0;
  }

  @Override
  public boolean acceptsType(DiffViewerType type) {
    return DiffViewerType.empty.equals(type);
  }
}