diff: make DiffContent implement UserDataHolder

platform/diff-api/src/com/intellij/diff/contents/DiffContent.java

@@ -18,6 +18,7 @@ package com.intellij.diff.contents;
 import com.intellij.diff.requests.DiffRequest;
 import com.intellij.openapi.fileEditor.OpenFileDescriptor;
 import com.intellij.openapi.fileTypes.FileType;
+import com.intellij.openapi.util.UserDataHolder;
 import org.jetbrains.annotations.CalledInAwt;
 import org.jetbrains.annotations.Nullable;
 
@@ -26,7 +27,7 @@ import org.jetbrains.annotations.Nullable;
  *
  * @see DiffRequest
  */
-public interface DiffContent {
+public interface DiffContent extends UserDataHolder {
   @Nullable
   FileType getContentType();
 

platform/diff-api/src/com/intellij/diff/contents/DiffContentBase.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2000-2015 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.diff.contents;
+
+import com.intellij.openapi.fileEditor.OpenFileDescriptor;
+import com.intellij.openapi.util.UserDataHolderBase;
+import org.jetbrains.annotations.CalledInAwt;
+import org.jetbrains.annotations.Nullable;
+
+public abstract class DiffContentBase extends UserDataHolderBase implements DiffContent {
+  @Nullable
+  @Override
+  public OpenFileDescriptor getOpenFileDescriptor() {
+    return null;
+  }
+
+  @Override
+  @CalledInAwt
+  public void onAssigned(boolean isAssigned) {
+  }
+}

platform/diff-api/src/com/intellij/diff/contents/EmptyContent.java

@@ -15,7 +15,6 @@
  */
 package com.intellij.diff.contents;
 
-import com.intellij.openapi.fileEditor.OpenFileDescriptor;
 import com.intellij.openapi.fileTypes.FileType;
 import org.jetbrains.annotations.Nullable;
 
@@ -24,20 +23,10 @@ import org.jetbrains.annotations.Nullable;
  * <p/>
  * ex: 'Before' state for new file
  */
-public class EmptyContent implements DiffContent {
+public class EmptyContent extends DiffContentBase {
   @Nullable
   @Override
   public FileType getContentType() {
     return null;
   }
-
-  @Nullable
-  @Override
-  public OpenFileDescriptor getOpenFileDescriptor() {
-    return null;
-  }
-
-  @Override
-  public void onAssigned(boolean isAssigned) {
-  }
 }

platform/diff-impl/src/com/intellij/diff/actions/DocumentFragmentContent.java

@@ -15,6 +15,7 @@
  */
 package com.intellij.diff.actions;
 
+import com.intellij.diff.contents.DiffContentBase;
 import com.intellij.diff.contents.DocumentContent;
 import com.intellij.openapi.command.undo.UndoManager;
 import com.intellij.openapi.editor.Document;
@@ -35,7 +36,7 @@ import java.nio.charset.Charset;
 /**
  * Represents sub text of other content. Original content should provide not null document.
  */
-public class DocumentFragmentContent implements DocumentContent {
+public class DocumentFragmentContent extends DiffContentBase implements DocumentContent {
   // TODO: reuse DocumentWindow ?
 
   @NotNull private final DocumentContent myOriginal;

platform/diff-impl/src/com/intellij/diff/contents/DirectoryContentImpl.java

@@ -22,7 +22,7 @@ import com.intellij.openapi.vfs.VirtualFile;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-public class DirectoryContentImpl implements DiffContent, DirectoryContent {
+public class DirectoryContentImpl extends DiffContentBase implements DirectoryContent {
   @NotNull private final VirtualFile myFile;
   @Nullable private final Project myProject;
 
@@ -50,8 +50,4 @@ public class DirectoryContentImpl implements DiffContent, DirectoryContent {
   public FileType getContentType() {
     return null;
   }
-
-  @Override
-  public void onAssigned(boolean isAssigned) {
-  }
 }

platform/diff-impl/src/com/intellij/diff/contents/DocumentContentImpl.java

@@ -28,7 +28,7 @@ import java.nio.charset.Charset;
 /**
  * Allows to compare some text associated with document.
  */
-public class DocumentContentImpl implements DiffContent, DocumentContent {
+public class DocumentContentImpl extends DiffContentBase implements DocumentContent {
   @NotNull private final Document myDocument;
 
   @Nullable private final FileType myType;
@@ -94,8 +94,4 @@ public class DocumentContentImpl implements DiffContent, DocumentContent {
   public Charset getCharset() {
     return myCharset;
   }
-
-  @Override
-  public void onAssigned(boolean isAssigned) {
-  }
 }

platform/diff-impl/src/com/intellij/diff/contents/FileContentImpl.java

@@ -25,7 +25,7 @@ import org.jetbrains.annotations.Nullable;
 /**
  * Allows to compare files
  */
-public class FileContentImpl implements FileContent {
+public class FileContentImpl extends DiffContentBase implements FileContent {
   @NotNull private final VirtualFile myFile;
   @Nullable private final Project myProject;
   @NotNull private final FileType myType;
@@ -60,8 +60,4 @@ public class FileContentImpl implements FileContent {
   public String getFilePath() {
     return myFile.getPath();
   }
-
-  @Override
-  public void onAssigned(boolean isAssigned) {
-  }
 }

plugins/svn4idea/src/org/jetbrains/idea/svn/difftool/properties/SvnPropertiesDiffRequest.java

@@ -1,6 +1,7 @@
 package org.jetbrains.idea.svn.difftool.properties;
 
 import com.intellij.diff.contents.DiffContent;
+import com.intellij.diff.contents.DiffContentBase;
 import com.intellij.diff.contents.EmptyContent;
 import com.intellij.diff.requests.ContentDiffRequest;
 import com.intellij.openapi.fileEditor.OpenFileDescriptor;
@@ -65,7 +66,7 @@ public class SvnPropertiesDiffRequest extends ContentDiffRequest {
     return myContents;
   }
 
-  public static class PropertyContent implements DiffContent {
+  public static class PropertyContent extends DiffContentBase {
     @NotNull private final List<PropertyData> myProperties;
 
     public PropertyContent(@NotNull List<PropertyData> properties) {
@@ -82,15 +83,5 @@ public class SvnPropertiesDiffRequest extends ContentDiffRequest {
     public FileType getContentType() {
       return null;
     }
-
-    @Nullable
-    @Override
-    public OpenFileDescriptor getOpenFileDescriptor() {
-      return null;
-    }
-
-    @Override
-    public void onAssigned(boolean isAssigned) {
-    }
   }
 }