/*
* Copyright (C) 2008-2013, Google Inc.
* Copyright (C) 2016, Laurent Delaigue <laurent.delaigue@obeo.fr>
* 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
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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package org.eclipse.jgit.merge;
import java.io.IOException;
import java.text.MessageFormat;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.NoMergeBaseException;
import org.eclipse.jgit.errors.NoMergeBaseException.MergeBaseFailureReason;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.revwalk.filter.RevFilter;
import org.eclipse.jgit.treewalk.AbstractTreeIterator;
import org.eclipse.jgit.treewalk.CanonicalTreeParser;
/**
* Instance of a specific {@link MergeStrategy} for a single {@link Repository}.
*/
public abstract class Merger {
/** The repository this merger operates on. */
protected final Repository db;
/** Reader to support {@link #walk} and other object loading. */
protected ObjectReader reader;
/** A RevWalk for computing merge bases, or listing incoming commits. */
protected RevWalk walk;
private ObjectInserter inserter;
/** The original objects supplied in the merge; this can be any tree-ish. */
protected RevObject[] sourceObjects;
/** If {@link #sourceObjects}[i] is a commit, this is the commit. */
protected RevCommit[] sourceCommits;
/** The trees matching every entry in {@link #sourceObjects}. */
protected RevTree[] sourceTrees;
/**
* A progress monitor.
*
* @since 4.2
*/
protected ProgressMonitor monitor = NullProgressMonitor.INSTANCE;
/**
* Create a new merge instance for a repository.
*
* @param local
* the repository this merger will read and write data on.
*/
protected Merger(final Repository local) {
db = local;
inserter = db.newObjectInserter();
reader = inserter.newReader();
walk = new RevWalk(reader);
}
/**
* @return the repository this merger operates on.
*/
public Repository getRepository() {
return db;
}
/** @return an object writer to create objects in {@link #getRepository()}. */
public ObjectInserter getObjectInserter() {
return inserter;
}
/**
* Set the inserter this merger will use to create objects.
* <p>
* If an inserter was already set on this instance (such as by a prior set,
* or a prior call to {@link #getObjectInserter()}), the prior inserter as
* well as the in-progress walk will be released.
*
* @param oi
* the inserter instance to use. Must be associated with the
* repository instance returned by {@link #getRepository()}.
*/
public void setObjectInserter(ObjectInserter oi) {
walk.close();
reader.close();
inserter.close();
inserter = oi;
reader = oi.newReader();
walk = new RevWalk(reader);
}
/**
* Merge together two or more tree-ish objects.
* <p>
* Any tree-ish may be supplied as inputs. Commits and/or tags pointing at
* trees or commits may be passed as input objects.
*
* @param tips
* source trees to be combined together. The merge base is not
* included in this set.
* @return true if the merge was completed without conflicts; false if the
* merge strategy cannot handle this merge or there were conflicts
* preventing it from automatically resolving all paths.
* @throws IncorrectObjectTypeException
* one of the input objects is not a commit, but the strategy
* requires it to be a commit.
* @throws IOException
* one or more sources could not be read, or outputs could not
* be written to the Repository.
*/
public boolean merge(final AnyObjectId... tips) throws IOException {
return merge(true, tips);
}
/**
* Merge together two or more tree-ish objects.
* <p>
* Any tree-ish may be supplied as inputs. Commits and/or tags pointing at
* trees or commits may be passed as input objects.
*
* @since 3.5
* @param flush
* whether to flush the underlying object inserter when finished to
* store any content-merged blobs and virtual merged bases; if
* false, callers are responsible for flushing.
* @param tips
* source trees to be combined together. The merge base is not
* included in this set.
* @return true if the merge was completed without conflicts; false if the
* merge strategy cannot handle this merge or there were conflicts
* preventing it from automatically resolving all paths.
* @throws IncorrectObjectTypeException
* one of the input objects is not a commit, but the strategy
* requires it to be a commit.
* @throws IOException
* one or more sources could not be read, or outputs could not
* be written to the Repository.
*/
public boolean merge(final boolean flush, final AnyObjectId... tips)
throws IOException {
sourceObjects = new RevObject[tips.length];
for (int i = 0; i < tips.length; i++)
sourceObjects[i] = walk.parseAny(tips[i]);
sourceCommits = new RevCommit[sourceObjects.length];
for (int i = 0; i < sourceObjects.length; i++) {
try {
sourceCommits[i] = walk.parseCommit(sourceObjects[i]);
} catch (IncorrectObjectTypeException err) {
sourceCommits[i] = null;
}
}
sourceTrees = new RevTree[sourceObjects.length];
for (int i = 0; i < sourceObjects.length; i++)
sourceTrees[i] = walk.parseTree(sourceObjects[i]);
try {
boolean ok = mergeImpl();
if (ok && flush)
inserter.flush();
return ok;
} finally {
if (flush)
inserter.close();
reader.close();
}
}
/**
* @return the ID of the commit that was used as merge base for merging, or
* null if no merge base was used or it was set manually
* @since 3.2
*/
public abstract ObjectId getBaseCommitId();
/**
* Return the merge base of two commits.
*
* @param a
* the first commit in {@link #sourceObjects}.
* @param b
* the second commit in {@link #sourceObjects}.
* @return the merge base of two commits
* @throws IncorrectObjectTypeException
* one of the input objects is not a commit.
* @throws IOException
* objects are missing or multiple merge bases were found.
* @since 3.0
*/
protected RevCommit getBaseCommit(RevCommit a, RevCommit b)
throws IncorrectObjectTypeException, IOException {
walk.reset();
walk.setRevFilter(RevFilter.MERGE_BASE);
walk.markStart(a);
walk.markStart(b);
final RevCommit base = walk.next();
if (base == null)
return null;
final RevCommit base2 = walk.next();
if (base2 != null) {
throw new NoMergeBaseException(
MergeBaseFailureReason.MULTIPLE_MERGE_BASES_NOT_SUPPORTED,
MessageFormat.format(
JGitText.get().multipleMergeBasesFor, a.name(), b.name(),
base.name(), base2.name()));
}
return base;
}
/**
* Open an iterator over a tree.
*
* @param treeId
* the tree to scan; must be a tree (not a treeish).
* @return an iterator for the tree.
* @throws IncorrectObjectTypeException
* the input object is not a tree.
* @throws IOException
* the tree object is not found or cannot be read.
*/
protected AbstractTreeIterator openTree(final AnyObjectId treeId)
throws IncorrectObjectTypeException, IOException {
return new CanonicalTreeParser(null, reader, treeId);
}
/**
* Execute the merge.
* <p>
* This method is called from {@link #merge(AnyObjectId[])} after the
* {@link #sourceObjects}, {@link #sourceCommits} and {@link #sourceTrees}
* have been populated.
*
* @return true if the merge was completed without conflicts; false if the
* merge strategy cannot handle this merge or there were conflicts
* preventing it from automatically resolving all paths.
* @throws IncorrectObjectTypeException
* one of the input objects is not a commit, but the strategy
* requires it to be a commit.
* @throws IOException
* one or more sources could not be read, or outputs could not
* be written to the Repository.
*/
protected abstract boolean mergeImpl() throws IOException;
/**
* @return resulting tree, if {@link #merge(AnyObjectId[])} returned true.
*/
public abstract ObjectId getResultTreeId();
/**
* Set a progress monitor.
*
* @param monitor
* Monitor to use, can be null to indicate no progress reporting
* is desired.
* @since 4.2
*/
public void setProgressMonitor(ProgressMonitor monitor) {
if (monitor == null) {
this.monitor = NullProgressMonitor.INSTANCE;
} else {
this.monitor = monitor;
}
}
}