Image diffs

Ticket 88: https://dev.gitblit.com/tickets/gitblit.git/88

Based on Lea Verou's pure CSS slider:
http://lea.verou.me/2014/07/image-comparison-slider-with-pure-css/

* Add a callback interface, pass it through DiffUtils to the
  GitBlitDiffFormatter. Is needed because the rendering needs access
  to the repositoryName and other things that are known only at higher
  levels.
  
* New class ImageDiffHandler responsible for rendering an image diff.
  Called for all binary diffs, doesn't do anything if it's not an
  image. HTML is generated via JSoup: no worries about forgetting to
  close a tag, not about HTML escaping, nor about XSS.
  
* The 3 diff pages set up such an ImageDIffHandler and pass it along.

* CSS changes: from Lea Verou, with some minor improvements.

I think in the long run there'll be no way around rewriting the
HTML diff formatter from scratch, not using the standard JGit
DiffFormatter at all.

1 files changed, 96 insertions, 1 deletions

diff --git a/src/main/java/com/gitblit/utils/DiffUtils.java b/src/main/java/com/gitblit/utils/DiffUtils.java
index f597b946..b30a203d 100644
--- a/src/main/java/com/gitblit/utils/DiffUtils.java
+++ b/src/main/java/com/gitblit/utils/DiffUtils.java
@@ -52,6 +52,27 @@ public class DiffUtils {
 	private static final Logger LOGGER = LoggerFactory.getLogger(DiffUtils.class);

 

 	/**

+	 * Callback interface for binary diffs. All the getDiff methods here take an optional handler;

+	 * if given and the {@link DiffOutputType} is {@link DiffOutputType#HTML HTML}, it is responsible

+	 * for displaying a binary diff.

+	 */

+	public interface BinaryDiffHandler {

+

+		/**

+		 * Renders a binary diff. The result must be valid HTML, it will be inserted into an HTML table cell.

+		 * May return {@code null} if the default behavior (which is typically just a textual note "Bnary

+		 * files differ") is desired.

+		 *

+		 * @param diffEntry

+		 *            current diff entry

+		 *

+		 * @return the rendered diff as HTML, or {@code null} if the default is desired.

+		 */

+		public String renderBinaryDiff(final DiffEntry diffEntry);

+

+	}

+

+	/**

 	 * Enumeration for the diff output types.

 	 */

 	public static enum DiffOutputType {

@@ -181,6 +202,23 @@ public class DiffUtils {
 	}

 

 	/**

+	 * Returns the complete diff of the specified commit compared to its primary parent.

+	 *

+	 * @param repository

+	 * @param commit

+	 * @param outputType

+	 * @param handler

+	 *            to use for rendering binary diffs if {@code outputType} is {@link DiffOutputType#HTML HTML}.

+	 *            May be {@code null}, resulting in the default behavior.

+	 * @return the diff

+	 */

+	public static DiffOutput getCommitDiff(Repository repository, RevCommit commit,

+			DiffOutputType outputType, BinaryDiffHandler handler) {

+		return getDiff(repository, null, commit, null, outputType, handler);

+	}

+

+

+	/**

 	 * Returns the diff for the specified file or folder from the specified

 	 * commit compared to its primary parent.

 	 *

@@ -196,6 +234,24 @@ public class DiffUtils {
 	}

 

 	/**

+	 * Returns the diff for the specified file or folder from the specified

+	 * commit compared to its primary parent.

+	 *

+	 * @param repository

+	 * @param commit

+	 * @param path

+	 * @param outputType

+	 * @param handler

+	 *            to use for rendering binary diffs if {@code outputType} is {@link DiffOutputType#HTML HTML}.

+	 *            May be {@code null}, resulting in the default behavior.

+	 * @return the diff

+	 */

+	public static DiffOutput getDiff(Repository repository, RevCommit commit, String path,

+			DiffOutputType outputType, BinaryDiffHandler handler) {

+		return getDiff(repository, null, commit, path, outputType, handler);

+	}

+

+	/**

 	 * Returns the complete diff between the two specified commits.

 	 *

 	 * @param repository

@@ -210,6 +266,23 @@ public class DiffUtils {
 	}

 

 	/**

+	 * Returns the complete diff between the two specified commits.

+	 *

+	 * @param repository

+	 * @param baseCommit

+	 * @param commit

+	 * @param outputType

+	 * @param handler

+	 *            to use for rendering binary diffs if {@code outputType} is {@link DiffOutputType#HTML HTML}.

+	 *            May be {@code null}, resulting in the default behavior.

+	 * @return the diff

+	 */

+	public static DiffOutput getDiff(Repository repository, RevCommit baseCommit, RevCommit commit,

+			DiffOutputType outputType, BinaryDiffHandler handler) {

+		return getDiff(repository, baseCommit, commit, null, outputType, handler);

+	}

+

+	/**

 	 * Returns the diff between two commits for the specified file.

 	 *

 	 * @param repository

@@ -225,6 +298,28 @@ public class DiffUtils {
 	 */

 	public static DiffOutput getDiff(Repository repository, RevCommit baseCommit, RevCommit commit,

 			String path, DiffOutputType outputType) {

+		return getDiff(repository, baseCommit, commit, path, outputType, null);

+	}

+

+	/**

+	 * Returns the diff between two commits for the specified file.

+	 *

+	 * @param repository

+	 * @param baseCommit

+	 *            if base commit is null the diff is to the primary parent of

+	 *            the commit.

+	 * @param commit

+	 * @param path

+	 *            if the path is specified, the diff is restricted to that file

+	 *            or folder. if unspecified, the diff is for the entire commit.

+	 * @param outputType

+	 * @param handler

+	 *            to use for rendering binary diffs if {@code outputType} is {@link DiffOutputType#HTML HTML}.

+	 *            May be {@code null}, resulting in the default behavior.

+	 * @return the diff

+	 */

+	public static DiffOutput getDiff(Repository repository, RevCommit baseCommit, RevCommit commit, String path, DiffOutputType outputType,

+			final BinaryDiffHandler handler) {

 		DiffStat stat = null;

 		String diff = null;

 		try {

@@ -233,7 +328,7 @@ public class DiffUtils {
 			DiffFormatter df;

 			switch (outputType) {

 			case HTML:

-				df = new GitBlitDiffFormatter(commit.getName(), path);

+				df = new GitBlitDiffFormatter(commit.getName(), path, handler);

 				break;

 			case PLAIN:

 			default: