Add in-memory updating support to NoteMap

NoteMap now supports editing in-memory, allowing applications to
modify the NoteMap once it has been loaded from the branch.  The
ability to write the branch back to tree objects is not yet done,
so the edits are strictly transient.

Change-Id: I63448954abfca2a8e3e95369cd84c0d1176cdb79
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit.test/tst/org/eclipse/jgit/notes/LeafBucketTest.java

@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.notes;
+
+import java.io.IOException;
+
+import junit.framework.TestCase;
+
+import org.eclipse.jgit.lib.AnyObjectId;
+import org.eclipse.jgit.lib.MutableObjectId;
+
+public class LeafBucketTest extends TestCase {
+	public void testEmpty() {
+		LeafBucket b = new LeafBucket(0);
+		assertNull(b.get(id(0x00), null));
+		assertNull(b.get(id(0x01), null));
+		assertNull(b.get(id(0xfe), null));
+	}
+
+	public void testParseFive() {
+		LeafBucket b = new LeafBucket(0);
+
+		b.parseOneEntry(id(0x11), id(0x81));
+		b.parseOneEntry(id(0x22), id(0x82));
+		b.parseOneEntry(id(0x33), id(0x83));
+		b.parseOneEntry(id(0x44), id(0x84));
+		b.parseOneEntry(id(0x55), id(0x85));
+
+		assertNull(b.get(id(0x01), null));
+		assertEquals(id(0x81), b.get(id(0x11), null));
+		assertEquals(id(0x82), b.get(id(0x22), null));
+		assertEquals(id(0x83), b.get(id(0x33), null));
+		assertEquals(id(0x84), b.get(id(0x44), null));
+		assertEquals(id(0x85), b.get(id(0x55), null));
+		assertNull(b.get(id(0x66), null));
+	}
+
+	public void testSetFive_InOrder() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+
+		assertSame(b, b.set(id(0x11), id(0x81), null));
+		assertSame(b, b.set(id(0x22), id(0x82), null));
+		assertSame(b, b.set(id(0x33), id(0x83), null));
+		assertSame(b, b.set(id(0x44), id(0x84), null));
+		assertSame(b, b.set(id(0x55), id(0x85), null));
+
+		assertNull(b.get(id(0x01), null));
+		assertEquals(id(0x81), b.get(id(0x11), null));
+		assertEquals(id(0x82), b.get(id(0x22), null));
+		assertEquals(id(0x83), b.get(id(0x33), null));
+		assertEquals(id(0x84), b.get(id(0x44), null));
+		assertEquals(id(0x85), b.get(id(0x55), null));
+		assertNull(b.get(id(0x66), null));
+	}
+
+	public void testSetFive_ReverseOrder() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+
+		assertSame(b, b.set(id(0x55), id(0x85), null));
+		assertSame(b, b.set(id(0x44), id(0x84), null));
+		assertSame(b, b.set(id(0x33), id(0x83), null));
+		assertSame(b, b.set(id(0x22), id(0x82), null));
+		assertSame(b, b.set(id(0x11), id(0x81), null));
+
+		assertNull(b.get(id(0x01), null));
+		assertEquals(id(0x81), b.get(id(0x11), null));
+		assertEquals(id(0x82), b.get(id(0x22), null));
+		assertEquals(id(0x83), b.get(id(0x33), null));
+		assertEquals(id(0x84), b.get(id(0x44), null));
+		assertEquals(id(0x85), b.get(id(0x55), null));
+		assertNull(b.get(id(0x66), null));
+	}
+
+	public void testSetFive_MixedOrder() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+
+		assertSame(b, b.set(id(0x11), id(0x81), null));
+		assertSame(b, b.set(id(0x33), id(0x83), null));
+		assertSame(b, b.set(id(0x55), id(0x85), null));
+
+		assertSame(b, b.set(id(0x22), id(0x82), null));
+		assertSame(b, b.set(id(0x44), id(0x84), null));
+
+		assertNull(b.get(id(0x01), null));
+		assertEquals(id(0x81), b.get(id(0x11), null));
+		assertEquals(id(0x82), b.get(id(0x22), null));
+		assertEquals(id(0x83), b.get(id(0x33), null));
+		assertEquals(id(0x84), b.get(id(0x44), null));
+		assertEquals(id(0x85), b.get(id(0x55), null));
+		assertNull(b.get(id(0x66), null));
+	}
+
+	public void testSet_Replace() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+
+		assertSame(b, b.set(id(0x11), id(0x81), null));
+		assertEquals(id(0x81), b.get(id(0x11), null));
+
+		assertSame(b, b.set(id(0x11), id(0x01), null));
+		assertEquals(id(0x01), b.get(id(0x11), null));
+	}
+
+	public void testRemoveMissingNote() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+		assertNull(b.get(id(0x11), null));
+		assertSame(b, b.set(id(0x11), null, null));
+		assertNull(b.get(id(0x11), null));
+	}
+
+	public void testRemoveFirst() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+
+		assertSame(b, b.set(id(0x11), id(0x81), null));
+		assertSame(b, b.set(id(0x22), id(0x82), null));
+		assertSame(b, b.set(id(0x33), id(0x83), null));
+		assertSame(b, b.set(id(0x44), id(0x84), null));
+		assertSame(b, b.set(id(0x55), id(0x85), null));
+
+		assertSame(b, b.set(id(0x11), null, null));
+
+		assertNull(b.get(id(0x01), null));
+		assertNull(b.get(id(0x11), null));
+		assertEquals(id(0x82), b.get(id(0x22), null));
+		assertEquals(id(0x83), b.get(id(0x33), null));
+		assertEquals(id(0x84), b.get(id(0x44), null));
+		assertEquals(id(0x85), b.get(id(0x55), null));
+		assertNull(b.get(id(0x66), null));
+	}
+
+	public void testRemoveMiddle() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+
+		assertSame(b, b.set(id(0x11), id(0x81), null));
+		assertSame(b, b.set(id(0x22), id(0x82), null));
+		assertSame(b, b.set(id(0x33), id(0x83), null));
+		assertSame(b, b.set(id(0x44), id(0x84), null));
+		assertSame(b, b.set(id(0x55), id(0x85), null));
+
+		assertSame(b, b.set(id(0x33), null, null));
+
+		assertNull(b.get(id(0x01), null));
+		assertEquals(id(0x81), b.get(id(0x11), null));
+		assertEquals(id(0x82), b.get(id(0x22), null));
+		assertNull(b.get(id(0x33), null));
+		assertEquals(id(0x84), b.get(id(0x44), null));
+		assertEquals(id(0x85), b.get(id(0x55), null));
+		assertNull(b.get(id(0x66), null));
+	}
+
+	public void testRemoveLast() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+
+		assertSame(b, b.set(id(0x11), id(0x81), null));
+		assertSame(b, b.set(id(0x22), id(0x82), null));
+		assertSame(b, b.set(id(0x33), id(0x83), null));
+		assertSame(b, b.set(id(0x44), id(0x84), null));
+		assertSame(b, b.set(id(0x55), id(0x85), null));
+
+		assertSame(b, b.set(id(0x55), null, null));
+
+		assertNull(b.get(id(0x01), null));
+		assertEquals(id(0x81), b.get(id(0x11), null));
+		assertEquals(id(0x82), b.get(id(0x22), null));
+		assertEquals(id(0x83), b.get(id(0x33), null));
+		assertEquals(id(0x84), b.get(id(0x44), null));
+		assertNull(b.get(id(0x55), null));
+		assertNull(b.get(id(0x66), null));
+	}
+
+	public void testRemoveMakesEmpty() throws IOException {
+		LeafBucket b = new LeafBucket(0);
+
+		assertSame(b, b.set(id(0x11), id(0x81), null));
+		assertEquals(id(0x81), b.get(id(0x11), null));
+
+		assertNull(b.set(id(0x11), null, null));
+		assertNull(b.get(id(0x11), null));
+	}
+
+	private static AnyObjectId id(int first) {
+		MutableObjectId id = new MutableObjectId();
+		id.setByte(1, first);
+		return id;
+	}
+}

org.eclipse.jgit.test/tst/org/eclipse/jgit/notes/NoteMapTest.java

@@ -44,6 +44,8 @@
 package org.eclipse.jgit.notes;
 
 import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.lib.MutableObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
 import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.lib.RepositoryTestCase;
@@ -56,17 +58,21 @@ public class NoteMapTest extends RepositoryTestCase {
 
 	private ObjectReader reader;
 
+	private ObjectInserter inserter;
+
 	@Override
 	protected void setUp() throws Exception {
 		super.setUp();
 
 		tr = new TestRepository<Repository>(db);
 		reader = db.newObjectReader();
+		inserter = db.newObjectInserter();
 	}
 
 	@Override
 	protected void tearDown() throws Exception {
 		reader.release();
+		inserter.release();
 		super.tearDown();
 	}
 
@@ -182,6 +188,99 @@ public class NoteMapTest extends RepositoryTestCase {
 		assertEquals(exp, RawParseUtils.decode(act));
 	}
 
+	public void testCreateFromEmpty() throws Exception {
+		RevBlob a = tr.blob("a");
+		RevBlob b = tr.blob("b");
+		RevBlob data1 = tr.blob("data1");
+		RevBlob data2 = tr.blob("data2");
+
+		NoteMap map = NoteMap.newEmptyMap();
+		assertFalse("no a", map.contains(a));
+		assertFalse("no b", map.contains(b));
+
+		map.set(a, data1);
+		map.set(b, data2);
+
+		assertEquals(data1, map.get(a));
+		assertEquals(data2, map.get(b));
+
+		map.remove(a);
+		map.remove(b);
+
+		assertFalse("no a", map.contains(a));
+		assertFalse("no b", map.contains(b));
+
+		map.set(a, "data1", inserter);
+		assertEquals(data1, map.get(a));
+
+		map.set(a, null, inserter);
+		assertFalse("no a", map.contains(a));
+	}
+
+	public void testEditFlat() throws Exception {
+		RevBlob a = tr.blob("a");
+		RevBlob b = tr.blob("b");
+		RevBlob data1 = tr.blob("data1");
+		RevBlob data2 = tr.blob("data2");
+
+		RevCommit r = tr.commit() //
+				.add(a.name(), data1) //
+				.add(b.name(), data2) //
+				.create();
+		tr.parseBody(r);
+
+		NoteMap map = NoteMap.read(reader, r);
+		map.set(a, data2);
+		map.set(b, null);
+		map.set(data1, b);
+		map.set(data2, null);
+
+		assertEquals(data2, map.get(a));
+		assertEquals(b, map.get(data1));
+		assertFalse("no b", map.contains(b));
+		assertFalse("no data2", map.contains(data2));
+
+		MutableObjectId id = new MutableObjectId();
+		for (int p = 42; p > 0; p--) {
+			id.setByte(1, p);
+			map.set(id, data1);
+		}
+
+		for (int p = 42; p > 0; p--) {
+			id.setByte(1, p);
+			assertTrue("contains " + id, map.contains(id));
+		}
+	}
+
+	public void testEditFanout2_38() throws Exception {
+		RevBlob a = tr.blob("a");
+		RevBlob b = tr.blob("b");
+		RevBlob data1 = tr.blob("data1");
+		RevBlob data2 = tr.blob("data2");
+
+		RevCommit r = tr.commit() //
+				.add(fanout(2, a.name()), data1) //
+				.add(fanout(2, b.name()), data2) //
+				.create();
+		tr.parseBody(r);
+
+		NoteMap map = NoteMap.read(reader, r);
+		map.set(a, data2);
+		map.set(b, null);
+		map.set(data1, b);
+		map.set(data2, null);
+
+		assertEquals(data2, map.get(a));
+		assertEquals(b, map.get(data1));
+		assertFalse("no b", map.contains(b));
+		assertFalse("no data2", map.contains(data2));
+
+		map.set(a, null);
+		map.set(data1, null);
+		assertFalse("no a", map.contains(a));
+		assertFalse("no data1", map.contains(data1));
+	}
+
 	private static String fanout(int prefix, String name) {
 		StringBuilder r = new StringBuilder();
 		int i = 0;

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

@@ -84,6 +84,9 @@ class FanoutBucket extends InMemoryNoteBucket {
 	 */
 	private final NoteBucket[] table;
 
+	/** Number of non-null slots in {@link #table}. */
+	private int cnt;
+
 	FanoutBucket(int prefixLen) {
 		super(prefixLen);
 		table = new NoteBucket[256];
@@ -91,6 +94,7 @@ class FanoutBucket extends InMemoryNoteBucket {
 
 	void parseOneEntry(int cell, ObjectId id) {
 		table[cell] = new LazyNoteBucket(id);
+		cnt++;
 	}
 
 	@Override
@@ -99,6 +103,39 @@ class FanoutBucket extends InMemoryNoteBucket {
 		return b != null ? b.get(objId, or) : null;
 	}
 
+	@Override
+	InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
+			ObjectReader or) throws IOException {
+		int cell = cell(noteOn);
+		NoteBucket b = table[cell];
+
+		if (b == null) {
+			if (noteData == null)
+				return this;
+
+			LeafBucket n = new LeafBucket(prefixLen + 2);
+			table[cell] = n.set(noteOn, noteData, or);
+			cnt++;
+			return this;
+
+		} else {
+			NoteBucket n = b.set(noteOn, noteData, or);
+			if (n == null) {
+				table[cell] = null;
+				cnt--;
+
+				if (cnt == 0)
+					return null;
+
+				return this;
+
+			} else if (n != b) {
+				table[cell] = n;
+			}
+			return this;
+		}
+	}
+
 	private int cell(AnyObjectId id) {
 		return id.getByte(prefixLen >> 1);
 	}
@@ -115,6 +152,12 @@ class FanoutBucket extends InMemoryNoteBucket {
 			return load(objId, or).get(objId, or);
 		}
 
+		@Override
+		InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
+				ObjectReader or) throws IOException {
+			return load(noteOn, or).set(noteOn, noteData, or);
+		}
+
 		private NoteBucket load(AnyObjectId objId, ObjectReader or)
 				throws IOException {
 			AbbreviatedObjectId p = objId.abbreviate(prefixLen + 2);

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

@@ -43,6 +43,8 @@
 
 package org.eclipse.jgit.notes;
 
+import java.io.IOException;
+
 import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectReader;
@@ -96,6 +98,34 @@ class LeafBucket extends InMemoryNoteBucket {
 		return 0 <= idx ? notes[idx].getData() : null;
 	}
 
+	InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
+			ObjectReader or) throws IOException {
+		int p = search(noteOn);
+		if (0 <= p) {
+			if (noteData != null) {
+				notes[p].setData(noteData.copy());
+				return this;
+
+			} else {
+				System.arraycopy(notes, p + 1, notes, p, cnt - p - 1);
+				cnt--;
+				return 0 < cnt ? this : null;
+			}
+
+		} else if (noteData != null) {
+			growIfFull();
+			p = -(p + 1);
+			if (p < cnt)
+				System.arraycopy(notes, p, notes, p + 1, cnt - p);
+			notes[p] = new Note(noteOn, noteData.copy());
+			cnt++;
+			return this;
+
+		} else {
+			return this;
+		}
+	}
+
 	void parseOneEntry(AnyObjectId noteOn, AnyObjectId noteData) {
 		growIfFull();
 		notes[cnt++] = new Note(noteOn, noteData.copy());

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

@@ -58,4 +58,7 @@ import org.eclipse.jgit.lib.ObjectReader;
 abstract class NoteBucket {
 	abstract ObjectId get(AnyObjectId objId, ObjectReader reader)
 			throws IOException;
+
+	abstract InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData,
+			ObjectReader reader) throws IOException;
 }

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

@@ -51,7 +51,9 @@ import org.eclipse.jgit.errors.LargeObjectException;
 import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.lib.AbbreviatedObjectId;
 import org.eclipse.jgit.lib.AnyObjectId;
+import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
 import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevTree;
@@ -65,6 +67,17 @@ import org.eclipse.jgit.revwalk.RevTree;
  * shared {@code ObjectReader} at the proper times.
  */
 public class NoteMap {
+	/**
+	 * Construct a new empty note map.
+	 *
+	 * @return an empty note map.
+	 */
+	public static NoteMap newEmptyMap() {
+		NoteMap r = new NoteMap(null /* no reader */);
+		r.root = new LeafBucket(0);
+		return r;
+	}
+
 	/**
 	 * Load a collection of notes from a branch.
 	 *
@@ -213,6 +226,89 @@ public class NoteMap {
 			return null;
 	}
 
+	/**
+	 * Attach (or remove) a note on an object.
+	 *
+	 * If no note exists, a new note is stored. If a note already exists for the
+	 * given object, it is replaced (or removed).
+	 *
+	 * This method only updates the map in memory.
+	 *
+	 * If the caller wants to attach a UTF-8 encoded string message to an
+	 * object, {@link #set(AnyObjectId, String, ObjectInserter)} is a convenient
+	 * way to encode and update a note in one step.
+	 *
+	 * @param noteOn
+	 *            the object to attach the note to. This same ObjectId can later
+	 *            be used as an argument to {@link #get(AnyObjectId)} or
+	 *            {@link #getCachedBytes(AnyObjectId, int)} to read back the
+	 *            {@code noteData}.
+	 * @param noteData
+	 *            data to associate with the note. This must be the ObjectId of
+	 *            a blob that already exists in the repository. If null the note
+	 *            will be deleted, if present.
+	 * @throws IOException
+	 *             a portion of the note space is not accessible.
+	 */
+	public void set(AnyObjectId noteOn, ObjectId noteData) throws IOException {
+		InMemoryNoteBucket newRoot = root.set(noteOn, noteData, reader);
+		if (newRoot == null) {
+			newRoot = new LeafBucket(0);
+			newRoot.nonNotes = root.nonNotes;
+		}
+		root = newRoot;
+	}
+
+	/**
+	 * Attach a note to an object.
+	 *
+	 * If no note exists, a new note is stored. If a note already exists for the
+	 * given object, it is replaced (or removed).
+	 *
+	 * @param noteOn
+	 *            the object to attach the note to. This same ObjectId can later
+	 *            be used as an argument to {@link #get(AnyObjectId)} or
+	 *            {@link #getCachedBytes(AnyObjectId, int)} to read back the
+	 *            {@code noteData}.
+	 * @param noteData
+	 *            text to store in the note. The text will be UTF-8 encoded when
+	 *            stored in the repository. If null the note will be deleted, if
+	 *            the empty string a note with the empty string will be stored.
+	 * @param ins
+	 *            inserter to write the encoded {@code noteData} out as a blob.
+	 *            The caller must ensure the inserter is flushed before the
+	 *            updated note map is made available for reading.
+	 * @throws IOException
+	 *             the note data could not be stored in the repository.
+	 */
+	public void set(AnyObjectId noteOn, String noteData, ObjectInserter ins)
+			throws IOException {
+		ObjectId dataId;
+		if (noteData != null) {
+			byte[] dataUTF8 = Constants.encode(noteData);
+			dataId = ins.insert(Constants.OBJ_BLOB, dataUTF8);
+		} else {
+			dataId = null;
+		}
+		set(noteOn, dataId);
+	}
+
+	/**
+	 * Remove a note from an object.
+	 *
+	 * If no note exists, no action is performed.
+	 *
+	 * This method only updates the map in memory.
+	 *
+	 * @param noteOn
+	 *            the object to remove the note from.
+	 * @throws IOException
+	 *             a portion of the note space is not accessible.
+	 */
+	public void remove(AnyObjectId noteOn) throws IOException {
+		set(noteOn, null);
+	}
+
 	private void load(ObjectId rootTree) throws MissingObjectException,
 			IncorrectObjectTypeException, CorruptObjectException, IOException {
 		AbbreviatedObjectId none = AbbreviatedObjectId.fromString("");