notification when changes to current file are present on shelf

platform/platform-resources/src/componentSets/VCS.xml

@@ -102,4 +102,7 @@
     <component><interface-class>com.intellij.openapi.vcs.contentAnnotation.ContentAnnotationCache</interface-class>
       <implementation-class>com.intellij.openapi.vcs.contentAnnotation.ContentAnnotationCacheImpl</implementation-class></component>
   </project-components>
+  <extensions defaultExtensionNs="com.intellij">
+    <editorNotificationProvider implementation="com.intellij.openapi.vcs.changes.shelf.ShelvedChangesNotificationProvider"/>
+  </extensions>
 </idea-plugin>

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/shelf/ShelvedChangesNotificationProvider.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2000-2017 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.changes.shelf;
+
+import com.intellij.openapi.fileEditor.FileEditor;
+import com.intellij.openapi.project.DumbAware;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.Key;
+import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.ui.EditorNotificationPanel;
+import com.intellij.ui.EditorNotifications;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class ShelvedChangesNotificationProvider extends EditorNotifications.Provider<EditorNotificationPanel> implements DumbAware {
+  private static final Key<EditorNotificationPanel> KEY = Key.create("file.changes.present.on.shelf.notification.panel");
+  final Project myProject;
+
+  public ShelvedChangesNotificationProvider(Project project) {
+    myProject = project;
+    myProject.getMessageBus().connect(project).subscribe(ShelveChangesManager.SHELF_TOPIC, new ChangeListener() {
+      @Override
+      public void stateChanged(ChangeEvent e) {
+        EditorNotifications.getInstance(myProject).updateAllNotifications();
+      }
+    });
+  }
+
+  @NotNull
+  @Override
+  public Key<EditorNotificationPanel> getKey() {
+    return KEY;
+  }
+
+  @Nullable
+  @Override
+  public EditorNotificationPanel createNotificationPanel(@NotNull VirtualFile file, @NotNull FileEditor fileEditor) {
+    final String path = file.getPath();
+    final List<ShelvedChangeList> foundChangeLists = ShelveChangesManager.getInstance(myProject).getShelvedChangeLists()
+      .stream().filter(l -> findChange(path, l).isPresent()).collect(Collectors.toList());
+    if (foundChangeLists.isEmpty()) {
+      return null;
+    }
+    final EditorNotificationPanel notificationPanel = new EditorNotificationPanel();
+    final int size = foundChangeLists.size();
+    notificationPanel.setText("Changes to this file are present in " + size + " shelved change list" + (size > 1 ? "s" : ""));
+    final int nameLength = size == 1 ? 50 : size == 2 ? 35 : 20;
+    foundChangeLists.stream().limit(3).forEach(
+      l -> notificationPanel.createActionLabel("Show '" + StringUtil.shortenTextWithEllipsis(l.toString(), nameLength, 0, true) + '\'',
+                                               () -> findChange(path, l).ifPresent(
+                                                 c -> ShelvedChangesViewManager.getInstance(myProject).showChangeInView(c))));
+    return notificationPanel;
+  }
+
+  private Optional<ShelvedChange> findChange(String path, ShelvedChangeList shelvedChangeList) {
+    return shelvedChangeList.getChanges(myProject).stream().filter(c -> path.endsWith(c.getBeforePath())).findAny();
+  }
+}

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/shelf/ShelvedChangesViewManager.java

@@ -320,10 +320,18 @@ public class ShelvedChangesViewManager implements ProjectComponent {
     }
   }
 
+  public void showChangeInView(final ShelvedChange change) {
+    showTargetInView(change);
+  }
+
   public void activateView(final ShelvedChangeList list) {
+    showTargetInView(list);
+  }
+
+  private void showTargetInView(Object target) {
     Runnable runnable = () -> {
-      if (list != null) {
-        TreeUtil.selectNode(myTree, TreeUtil.findNodeWithObject(myRoot, list));
+      if (target != null) {
+        TreeUtil.selectNode(myTree, TreeUtil.findNodeWithObject(myRoot, target));
       }
       myContentManager.setSelectedContent(myContent);
       ToolWindow window = ToolWindowManager.getInstance(myProject).getToolWindow(ChangesViewContentManager.TOOLWINDOW_ID);