Abort rename detection in a timely manner if cancelled

If progress monitor is cancelled break loops in rename detection by
throwing a CanceledException.

Bug: 536324
Change-Id: Ia3511fb749d2a5d45005e72c156b874ab7a0da26
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

6 files changed, 80 insertions, 25 deletions

diff --git a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
index 826be11d5c..2150d5ce3e 100644
--- a/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
+++ b/org.eclipse.jgit/resources/org/eclipse/jgit/internal/JGitText.properties
@@ -579,6 +579,7 @@ remoteNameCantBeNull=Remote name can't be null.
 renameBranchFailedBecauseTag=Can not rename as Ref {0} is a tag
 renameBranchFailedUnknownReason=Rename failed with unknown reason
 renameBranchUnexpectedResult=Unexpected rename result {0}
+renameCancelled=Rename detection was cancelled
 renameFileFailed=Could not rename file {0} to {1}
 renamesAlreadyFound=Renames have already been found.
 renamesBreakingModifies=Breaking apart modified file pairs
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/blame/BlameGenerator.java b/org.eclipse.jgit/src/org/eclipse/jgit/blame/BlameGenerator.java
index 9cec645679..8234941668 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/blame/BlameGenerator.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/blame/BlameGenerator.java
@@ -52,6 +52,7 @@ import java.util.Collection;
 import java.util.Collections;
 
 import org.eclipse.jgit.annotations.Nullable;
+import org.eclipse.jgit.api.errors.CanceledException;
 import org.eclipse.jgit.blame.Candidate.BlobCandidate;
 import org.eclipse.jgit.blame.Candidate.ReverseCandidate;
 import org.eclipse.jgit.blame.ReverseWalk.ReverseCommit;
@@ -627,9 +628,15 @@ public class BlameGenerator implements AutoCloseable {
 		if (n.sourceCommit == null)
 			return result(n);
 
-		DiffEntry r = findRename(parent, n.sourceCommit, n.sourcePath);
-		if (r == null)
+		DiffEntry r;
+		try {
+			r = findRename(parent, n.sourceCommit, n.sourcePath);
+			if (r == null) {
+				return result(n);
+			}
+		} catch (CanceledException e) {
 			return result(n);
+		}
 
 		if (0 == r.getOldId().prefixCompare(n.sourceBlob)) {
 			// A 100% rename without any content change can also
@@ -687,7 +694,8 @@ public class BlameGenerator implements AutoCloseable {
 		return false;
 	}
 
-	private boolean processMerge(Candidate n) throws IOException {
+	private boolean processMerge(Candidate n)
+			throws IOException {
 		int pCnt = n.getParentCount();
 
 		// If any single parent exactly matches the merge, follow only
@@ -714,9 +722,15 @@ public class BlameGenerator implements AutoCloseable {
 				if (ids != null && ids[pIdx] != null)
 					continue;
 
-				DiffEntry r = findRename(parent, n.sourceCommit, n.sourcePath);
-				if (r == null)
+				DiffEntry r;
+				try {
+					r = findRename(parent, n.sourceCommit, n.sourcePath);
+					if (r == null) {
+						continue;
+					}
+				} catch (CanceledException e) {
 					continue;
+				}
 
 				if (n instanceof ReverseCandidate) {
 					if (ids == null)
@@ -1021,7 +1035,7 @@ public class BlameGenerator implements AutoCloseable {
 	}
 
 	private DiffEntry findRename(RevCommit parent, RevCommit commit,
-			PathFilter path) throws IOException {
+			PathFilter path) throws IOException, CanceledException {
 		if (renameDetector == null)
 			return null;
 
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffFormatter.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffFormatter.java
index 7aaa50030f..b70ff4b2be 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffFormatter.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffFormatter.java
@@ -62,6 +62,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
+import org.eclipse.jgit.api.errors.CanceledException;
 import org.eclipse.jgit.diff.DiffAlgorithm.SupportedAlgorithm;
 import org.eclipse.jgit.diff.DiffEntry.ChangeType;
 import org.eclipse.jgit.dircache.DirCacheIterator;
@@ -577,7 +578,11 @@ public class DiffFormatter implements AutoCloseable {
 			throws IOException {
 		renameDetector.reset();
 		renameDetector.addAll(files);
-		return renameDetector.compute(reader, progressMonitor);
+		try {
+			return renameDetector.compute(reader, progressMonitor);
+		} catch (CanceledException e) {
+			return Collections.emptyList();
+		}
 	}
 
 	private boolean isAdd(List<DiffEntry> files) {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/RenameDetector.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RenameDetector.java
index 7bb217d04d..8336cf249f 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/diff/RenameDetector.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/RenameDetector.java
@@ -55,6 +55,7 @@ import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 
+import org.eclipse.jgit.api.errors.CanceledException;
 import org.eclipse.jgit.diff.DiffEntry.ChangeType;
 import org.eclipse.jgit.diff.SimilarityIndex.TableFullException;
 import org.eclipse.jgit.internal.JGitText;
@@ -320,7 +321,11 @@ public class RenameDetector {
 	 *             file contents cannot be read from the repository.
 	 */
 	public List<DiffEntry> compute() throws IOException {
-		return compute(NullProgressMonitor.INSTANCE);
+		try {
+			return compute(NullProgressMonitor.INSTANCE);
+		} catch (CanceledException e) {
+			return Collections.emptyList();
+		}
 	}
 
 	/**
@@ -332,8 +337,11 @@ public class RenameDetector {
 	 *         representing all files that have been changed.
 	 * @throws java.io.IOException
 	 *             file contents cannot be read from the repository.
+	 * @throws CanceledException
+	 *             if rename detection was cancelled
 	 */
-	public List<DiffEntry> compute(ProgressMonitor pm) throws IOException {
+	public List<DiffEntry> compute(ProgressMonitor pm)
+			throws IOException, CanceledException {
 		if (!done) {
 			try {
 				return compute(objectReader, pm);
@@ -355,9 +363,11 @@ public class RenameDetector {
 	 *         representing all files that have been changed.
 	 * @throws java.io.IOException
 	 *             file contents cannot be read from the repository.
+	 * @throws CanceledException
+	 *             if rename detection was cancelled
 	 */
 	public List<DiffEntry> compute(ObjectReader reader, ProgressMonitor pm)
-			throws IOException {
+			throws IOException, CanceledException {
 		final ContentSource cs = ContentSource.create(reader);
 		return compute(new ContentSource.Pair(cs, cs), pm);
 	}
@@ -373,9 +383,11 @@ public class RenameDetector {
 	 *         representing all files that have been changed.
 	 * @throws java.io.IOException
 	 *             file contents cannot be read from the repository.
+	 * @throws CanceledException
+	 *             if rename detection was cancelled
 	 */
 	public List<DiffEntry> compute(ContentSource.Pair reader, ProgressMonitor pm)
-			throws IOException {
+			throws IOException, CanceledException {
 		if (!done) {
 			done = true;
 
@@ -415,8 +427,15 @@ public class RenameDetector {
 		done = false;
 	}
 
+	private void advanceOrCancel(ProgressMonitor pm) throws CanceledException {
+		if (pm.isCancelled()) {
+			throw new CanceledException(JGitText.get().renameCancelled);
+		}
+		pm.update(1);
+	}
+
 	private void breakModifies(ContentSource.Pair reader, ProgressMonitor pm)
-			throws IOException {
+			throws IOException, CanceledException {
 		ArrayList<DiffEntry> newEntries = new ArrayList<>(entries.size());
 
 		pm.beginTask(JGitText.get().renamesBreakingModifies, entries.size());
@@ -437,13 +456,13 @@ public class RenameDetector {
 			} else {
 				newEntries.add(e);
 			}
-			pm.update(1);
+			advanceOrCancel(pm);
 		}
 
 		entries = newEntries;
 	}
 
-	private void rejoinModifies(ProgressMonitor pm) {
+	private void rejoinModifies(ProgressMonitor pm) throws CanceledException {
 		HashMap<String, DiffEntry> nameMap = new HashMap<>();
 		ArrayList<DiffEntry> newAdded = new ArrayList<>(added.size());
 
@@ -452,7 +471,7 @@ public class RenameDetector {
 
 		for (DiffEntry src : deleted) {
 			nameMap.put(src.oldPath, src);
-			pm.update(1);
+			advanceOrCancel(pm);
 		}
 
 		for (DiffEntry dst : added) {
@@ -468,7 +487,7 @@ public class RenameDetector {
 			} else {
 				newAdded.add(dst);
 			}
-			pm.update(1);
+			advanceOrCancel(pm);
 		}
 
 		added = newAdded;
@@ -498,7 +517,7 @@ public class RenameDetector {
 
 	private void findContentRenames(ContentSource.Pair reader,
 			ProgressMonitor pm)
-			throws IOException {
+			throws IOException, CanceledException {
 		int cnt = Math.max(added.size(), deleted.size());
 		if (getRenameLimit() == 0 || cnt <= getRenameLimit()) {
 			SimilarityRenameDetector d;
@@ -516,7 +535,7 @@ public class RenameDetector {
 	}
 
 	@SuppressWarnings("unchecked")
-	private void findExactRenames(ProgressMonitor pm) {
+	private void findExactRenames(ProgressMonitor pm) throws CanceledException {
 		pm.beginTask(JGitText.get().renamesFindingExact, //
 				added.size() + added.size() + deleted.size()
 						+ added.size() * deleted.size());
@@ -562,7 +581,7 @@ public class RenameDetector {
 			} else {
 				left.add(a);
 			}
-			pm.update(1);
+			advanceOrCancel(pm);
 		}
 
 		for (List<DiffEntry> adds : nonUniqueAdds) {
@@ -604,6 +623,10 @@ public class RenameDetector {
 						int score = SimilarityRenameDetector.nameScore(addedName, deletedName);
 						matrix[mNext] = SimilarityRenameDetector.encode(score, delIdx, addIdx);
 						mNext++;
+						if (pm.isCancelled()) {
+							throw new CanceledException(
+									JGitText.get().renameCancelled);
+						}
 					}
 				}
 
@@ -617,7 +640,7 @@ public class RenameDetector {
 					DiffEntry a = adds.get(addIdx);
 
 					if (a == null) {
-						pm.update(1);
+						advanceOrCancel(pm);
 						continue; // was already matched earlier
 					}
 
@@ -635,11 +658,12 @@ public class RenameDetector {
 
 					entries.add(DiffEntry.pair(type, d, a, 100));
 					adds.set(addIdx, null); // Claim the destination was matched.
-					pm.update(1);
+					advanceOrCancel(pm);
 				}
 			} else {
 				left.addAll(adds);
 			}
+			advanceOrCancel(pm);
 		}
 		added = left;
 
@@ -692,7 +716,8 @@ public class RenameDetector {
 
 	@SuppressWarnings("unchecked")
 	private HashMap<AbbreviatedObjectId, Object> populateMap(
-			List<DiffEntry> diffEntries, ProgressMonitor pm) {
+			List<DiffEntry> diffEntries, ProgressMonitor pm)
+			throws CanceledException {
 		HashMap<AbbreviatedObjectId, Object> map = new HashMap<>();
 		for (DiffEntry de : diffEntries) {
 			Object old = map.put(id(de), de);
@@ -706,7 +731,7 @@ public class RenameDetector {
 				((List<DiffEntry>) old).add(de);
 				map.put(id(de), old);
 			}
-			pm.update(1);
+			advanceOrCancel(pm);
 		}
 		return map;
 	}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/SimilarityRenameDetector.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/SimilarityRenameDetector.java
index 653658be3c..71e391c737 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/diff/SimilarityRenameDetector.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/SimilarityRenameDetector.java
@@ -52,6 +52,7 @@ import java.util.Arrays;
 import java.util.BitSet;
 import java.util.List;
 
+import org.eclipse.jgit.api.errors.CanceledException;
 import org.eclipse.jgit.diff.DiffEntry.ChangeType;
 import org.eclipse.jgit.diff.SimilarityIndex.TableFullException;
 import org.eclipse.jgit.internal.JGitText;
@@ -128,7 +129,7 @@ class SimilarityRenameDetector {
 		renameScore = score;
 	}
 
-	void compute(ProgressMonitor pm) throws IOException {
+	void compute(ProgressMonitor pm) throws IOException, CanceledException {
 		if (pm == null)
 			pm = NullProgressMonitor.INSTANCE;
 
@@ -142,6 +143,9 @@ class SimilarityRenameDetector {
 		// we have looked at everything that is above our minimum score.
 		//
 		for (--mNext; mNext >= 0; mNext--) {
+			if (pm.isCancelled()) {
+				throw new CanceledException(JGitText.get().renameCancelled);
+			}
 			long ent = matrix[mNext];
 			int sIdx = srcFile(ent);
 			int dIdx = dstFile(ent);
@@ -209,7 +213,8 @@ class SimilarityRenameDetector {
 		return r;
 	}
 
-	private int buildMatrix(ProgressMonitor pm) throws IOException {
+	private int buildMatrix(ProgressMonitor pm)
+			throws IOException, CanceledException {
 		// Allocate for the worst-case scenario where every pair has a
 		// score that we need to consider. We might not need that many.
 		//
@@ -234,6 +239,10 @@ class SimilarityRenameDetector {
 			SimilarityIndex s = null;
 
 			for (int dstIdx = 0; dstIdx < dsts.size(); dstIdx++) {
+				if (pm.isCancelled()) {
+					throw new CanceledException(JGitText.get().renameCancelled);
+				}
+
 				DiffEntry dstEnt = dsts.get(dstIdx);
 
 				if (!isFile(dstEnt.newMode)) {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
index a3cbc22e82..2373b97bd1 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/JGitText.java
@@ -640,6 +640,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String renameBranchFailedBecauseTag;
 	/***/ public String renameBranchFailedUnknownReason;
 	/***/ public String renameBranchUnexpectedResult;
+	/***/ public String renameCancelled;
 	/***/ public String renameFileFailed;
 	/***/ public String renamesAlreadyFound;
 	/***/ public String renamesBreakingModifies;