Merge "Remove unnecessary note fanout when removing notes"

org.eclipse.jgit/src/org/eclipse/jgit/notes/FanoutBucket.java

@@ -158,6 +158,33 @@ public void remove() {
 		};
 	}
 
+	@Override
+	int estimateSize(AnyObjectId noteOn, ObjectReader or) throws IOException {
+		// If most of this fan-out is full, estimate it should still be split.
+		if (LeafBucket.MAX_SIZE * 3 / 4 <= cnt)
+			return 1 + LeafBucket.MAX_SIZE;
+
+		// Due to the uniform distribution of ObjectIds, having less nodes full
+		// indicates a good chance the total number of children below here
+		// is less than the MAX_SIZE split point. Get a more accurate count.
+
+		MutableObjectId id = new MutableObjectId();
+		id.fromObjectId(noteOn);
+
+		int sz = 0;
+		for (int cell = 0; cell < 256; cell++) {
+			NoteBucket b = table[cell];
+			if (b == null)
+				continue;
+
+			id.setByte(prefixLen >> 1, cell);
+			sz += b.estimateSize(id, or);
+			if (LeafBucket.MAX_SIZE < sz)
+				break;
+		}
+		return sz;
+	}
+
 	@Override
 	InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
 			ObjectReader or) throws IOException {
@@ -182,6 +209,15 @@ InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
 				if (cnt == 0)
 					return null;
 
+				if (estimateSize(noteOn, or) < LeafBucket.MAX_SIZE) {
+					// We are small enough to just contract to a single leaf.
+					InMemoryNoteBucket r = new LeafBucket(prefixLen);
+					for (Iterator<Note> i = iterator(noteOn, or); i.hasNext();)
+						r = r.append(i.next());
+					r.nonNotes = nonNotes;
+					return r;
+				}
+
 				return this;
 
 			} else if (n != b) {
@@ -268,6 +304,11 @@ Iterator<Note> iterator(AnyObjectId objId, ObjectReader reader)
 			return load(objId, reader).iterator(objId, reader);
 		}
 
+		@Override
+		int estimateSize(AnyObjectId objId, ObjectReader or) throws IOException {
+			return load(objId, or).estimateSize(objId, or);
+		}
+
 		@Override
 		InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
 				ObjectReader or) throws IOException {

org.eclipse.jgit/src/org/eclipse/jgit/notes/LeafBucket.java

@@ -129,6 +129,11 @@ public void remove() {
 		};
 	}
 
+	@Override
+	int estimateSize(AnyObjectId noteOn, ObjectReader or) throws IOException {
+		return cnt;
+	}
+
 	InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
 			ObjectReader or) throws IOException {
 		int p = search(noteOn);

org.eclipse.jgit/src/org/eclipse/jgit/notes/NoteBucket.java

@@ -64,6 +64,9 @@ abstract ObjectId get(AnyObjectId objId, ObjectReader reader)
 	abstract Iterator<Note> iterator(AnyObjectId objId, ObjectReader reader)
 			throws IOException;
 
+	abstract int estimateSize(AnyObjectId noteOn, ObjectReader or)
+			throws IOException;
+
 	abstract InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
 			ObjectReader reader) throws IOException;