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343 lines
10 KiB
343 lines
10 KiB
/* |
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* Copyright (C) 2010, Sasa Zivkov <sasa.zivkov@sap.com> |
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* and other copyright owners as documented in the project's IP log. |
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* |
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* This program and the accompanying materials are made available |
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* under the terms of the Eclipse Distribution License v1.0 which |
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* accompanies this distribution, is reproduced below, and is |
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* available at http://www.eclipse.org/org/documents/edl-v10.php |
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* |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or |
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* without modification, are permitted provided that the following |
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* conditions are met: |
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* |
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* - Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* - Redistributions in binary form must reproduce the above |
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* copyright notice, this list of conditions and the following |
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* disclaimer in the documentation and/or other materials provided |
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* with the distribution. |
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* |
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* - Neither the name of the Eclipse Foundation, Inc. nor the |
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* names of its contributors may be used to endorse or promote |
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* products derived from this software without specific prior |
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* written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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package org.eclipse.jgit.notes; |
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import java.io.IOException; |
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import org.eclipse.jgit.errors.MissingObjectException; |
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import org.eclipse.jgit.lib.AbbreviatedObjectId; |
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import org.eclipse.jgit.lib.AnyObjectId; |
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import org.eclipse.jgit.lib.MutableObjectId; |
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import org.eclipse.jgit.lib.ObjectId; |
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import org.eclipse.jgit.lib.ObjectInserter; |
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import org.eclipse.jgit.lib.ObjectReader; |
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import org.eclipse.jgit.lib.Repository; |
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import org.eclipse.jgit.merge.MergeStrategy; |
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import org.eclipse.jgit.merge.Merger; |
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import org.eclipse.jgit.merge.ThreeWayMerger; |
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/** |
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* Three-way note tree merge. |
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* <p> |
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* Direct implementation of NoteMap merger without using |
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* {@link org.eclipse.jgit.treewalk.TreeWalk} and |
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* {@link org.eclipse.jgit.treewalk.AbstractTreeIterator} |
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*/ |
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public class NoteMapMerger { |
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private static final FanoutBucket EMPTY_FANOUT = new FanoutBucket(0); |
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private static final LeafBucket EMPTY_LEAF = new LeafBucket(0); |
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private final Repository db; |
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private final NoteMerger noteMerger; |
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private final MergeStrategy nonNotesMergeStrategy; |
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private final ObjectReader reader; |
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private final ObjectInserter inserter; |
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private final MutableObjectId objectIdPrefix; |
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/** |
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* Constructs a NoteMapMerger with custom |
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* {@link org.eclipse.jgit.notes.NoteMerger} and custom |
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* {@link org.eclipse.jgit.merge.MergeStrategy}. |
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* |
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* @param db |
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* Git repository |
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* @param noteMerger |
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* note merger for merging conflicting changes on a note |
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* @param nonNotesMergeStrategy |
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* merge strategy for merging non-note entries |
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*/ |
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public NoteMapMerger(Repository db, NoteMerger noteMerger, |
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MergeStrategy nonNotesMergeStrategy) { |
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this.db = db; |
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this.reader = db.newObjectReader(); |
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this.inserter = db.newObjectInserter(); |
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this.noteMerger = noteMerger; |
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this.nonNotesMergeStrategy = nonNotesMergeStrategy; |
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this.objectIdPrefix = new MutableObjectId(); |
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} |
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/** |
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* Constructs a NoteMapMerger with |
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* {@link org.eclipse.jgit.notes.DefaultNoteMerger} as the merger for notes |
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* and the {@link org.eclipse.jgit.merge.MergeStrategy#RESOLVE} as the |
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* strategy for resolving conflicts on non-notes |
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* |
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* @param db |
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* Git repository |
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*/ |
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public NoteMapMerger(Repository db) { |
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this(db, new DefaultNoteMerger(), MergeStrategy.RESOLVE); |
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} |
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/** |
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* Performs the merge. |
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* |
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* @param base |
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* base version of the note tree |
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* @param ours |
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* ours version of the note tree |
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* @param theirs |
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* theirs version of the note tree |
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* @return merge result as a new NoteMap |
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* @throws java.io.IOException |
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*/ |
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public NoteMap merge(NoteMap base, NoteMap ours, NoteMap theirs) |
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throws IOException { |
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try { |
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InMemoryNoteBucket mergedBucket = merge(0, base.getRoot(), |
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ours.getRoot(), theirs.getRoot()); |
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inserter.flush(); |
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return NoteMap.newMap(mergedBucket, reader); |
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} finally { |
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reader.close(); |
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inserter.close(); |
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} |
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} |
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/** |
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* This method is called only when it is known that there is some difference |
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* between base, ours and theirs. |
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* |
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* @param treeDepth |
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* @param base |
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* @param ours |
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* @param theirs |
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* @return merge result as an InMemoryBucket |
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* @throws IOException |
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*/ |
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private InMemoryNoteBucket merge(int treeDepth, InMemoryNoteBucket base, |
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InMemoryNoteBucket ours, InMemoryNoteBucket theirs) |
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throws IOException { |
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InMemoryNoteBucket result; |
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if (base instanceof FanoutBucket || ours instanceof FanoutBucket |
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|| theirs instanceof FanoutBucket) { |
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result = mergeFanoutBucket(treeDepth, asFanout(base), |
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asFanout(ours), asFanout(theirs)); |
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} else { |
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result = mergeLeafBucket(treeDepth, (LeafBucket) base, |
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(LeafBucket) ours, (LeafBucket) theirs); |
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} |
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result.nonNotes = mergeNonNotes(nonNotes(base), nonNotes(ours), |
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nonNotes(theirs)); |
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return result; |
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} |
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private FanoutBucket asFanout(InMemoryNoteBucket bucket) { |
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if (bucket == null) |
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return EMPTY_FANOUT; |
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if (bucket instanceof FanoutBucket) |
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return (FanoutBucket) bucket; |
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return ((LeafBucket) bucket).split(); |
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} |
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private static NonNoteEntry nonNotes(InMemoryNoteBucket b) { |
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return b == null ? null : b.nonNotes; |
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} |
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private InMemoryNoteBucket mergeFanoutBucket(int treeDepth, |
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FanoutBucket base, |
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FanoutBucket ours, FanoutBucket theirs) throws IOException { |
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FanoutBucket result = new FanoutBucket(treeDepth * 2); |
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// walking through entries of base, ours, theirs |
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for (int i = 0; i < 256; i++) { |
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NoteBucket b = base.getBucket(i); |
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NoteBucket o = ours.getBucket(i); |
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NoteBucket t = theirs.getBucket(i); |
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if (equals(o, t)) |
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addIfNotNull(result, i, o); |
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else if (equals(b, o)) |
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addIfNotNull(result, i, t); |
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else if (equals(b, t)) |
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addIfNotNull(result, i, o); |
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else { |
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objectIdPrefix.setByte(treeDepth, i); |
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InMemoryNoteBucket mergedBucket = merge(treeDepth + 1, |
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FanoutBucket.loadIfLazy(b, objectIdPrefix, reader), |
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FanoutBucket.loadIfLazy(o, objectIdPrefix, reader), |
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FanoutBucket.loadIfLazy(t, objectIdPrefix, reader)); |
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result.setBucket(i, mergedBucket); |
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} |
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} |
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return result.contractIfTooSmall(objectIdPrefix, reader); |
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} |
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private static boolean equals(NoteBucket a, NoteBucket b) { |
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if (a == null && b == null) |
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return true; |
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return a != null && b != null && a.getTreeId().equals(b.getTreeId()); |
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} |
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private void addIfNotNull(FanoutBucket b, int cell, NoteBucket child) |
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throws IOException { |
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if (child == null) |
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return; |
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if (child instanceof InMemoryNoteBucket) |
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b.setBucket(cell, ((InMemoryNoteBucket) child).writeTree(inserter)); |
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else |
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b.setBucket(cell, child.getTreeId()); |
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} |
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private InMemoryNoteBucket mergeLeafBucket(int treeDepth, LeafBucket bb, |
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LeafBucket ob, LeafBucket tb) throws MissingObjectException, |
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IOException { |
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bb = notNullOrEmpty(bb); |
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ob = notNullOrEmpty(ob); |
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tb = notNullOrEmpty(tb); |
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InMemoryNoteBucket result = new LeafBucket(treeDepth * 2); |
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int bi = 0, oi = 0, ti = 0; |
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while (bi < bb.size() || oi < ob.size() || ti < tb.size()) { |
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Note b = get(bb, bi), o = get(ob, oi), t = get(tb, ti); |
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Note min = min(b, o, t); |
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b = sameNoteOrNull(min, b); |
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o = sameNoteOrNull(min, o); |
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t = sameNoteOrNull(min, t); |
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if (sameContent(o, t)) |
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result = addIfNotNull(result, o); |
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else if (sameContent(b, o)) |
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result = addIfNotNull(result, t); |
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else if (sameContent(b, t)) |
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result = addIfNotNull(result, o); |
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else |
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result = addIfNotNull(result, |
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noteMerger.merge(b, o, t, reader, inserter)); |
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if (b != null) |
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bi++; |
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if (o != null) |
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oi++; |
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if (t != null) |
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ti++; |
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} |
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return result; |
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} |
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private static LeafBucket notNullOrEmpty(LeafBucket b) { |
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return b != null ? b : EMPTY_LEAF; |
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} |
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private static Note get(LeafBucket b, int i) { |
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return i < b.size() ? b.get(i) : null; |
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} |
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private static Note min(Note b, Note o, Note t) { |
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Note min = b; |
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if (min == null || (o != null && o.compareTo(min) < 0)) |
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min = o; |
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if (min == null || (t != null && t.compareTo(min) < 0)) |
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min = t; |
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return min; |
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} |
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private static Note sameNoteOrNull(Note min, Note other) { |
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return sameNote(min, other) ? other : null; |
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} |
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private static boolean sameNote(Note a, Note b) { |
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if (a == null && b == null) |
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return true; |
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return a != null && b != null && AnyObjectId.isEqual(a, b); |
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} |
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private static boolean sameContent(Note a, Note b) { |
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if (a == null && b == null) |
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return true; |
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return a != null && b != null |
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&& AnyObjectId.isEqual(a.getData(), b.getData()); |
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} |
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private static InMemoryNoteBucket addIfNotNull(InMemoryNoteBucket result, |
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Note note) { |
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if (note != null) { |
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return result.append(note); |
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} |
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return result; |
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} |
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private NonNoteEntry mergeNonNotes(NonNoteEntry baseList, |
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NonNoteEntry oursList, NonNoteEntry theirsList) throws IOException { |
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if (baseList == null && oursList == null && theirsList == null) |
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return null; |
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ObjectId baseId = write(baseList); |
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ObjectId oursId = write(oursList); |
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ObjectId theirsId = write(theirsList); |
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inserter.flush(); |
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Merger m = nonNotesMergeStrategy.newMerger(db, true); |
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if (m instanceof ThreeWayMerger) |
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((ThreeWayMerger) m).setBase(baseId); |
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if (!m.merge(oursId, theirsId)) |
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throw new NotesMergeConflictException(baseList, oursList, |
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theirsList); |
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ObjectId resultTreeId = m.getResultTreeId(); |
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AbbreviatedObjectId none = AbbreviatedObjectId.fromString(""); //$NON-NLS-1$ |
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return NoteParser.parse(none, resultTreeId, reader).nonNotes; |
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} |
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private ObjectId write(NonNoteEntry list) |
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throws IOException { |
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LeafBucket b = new LeafBucket(0); |
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b.nonNotes = list; |
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return b.writeTree(inserter); |
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} |
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}
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