BundleWriter.java
/*
* Copyright (C) 2008-2010, Google Inc. and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.transport;
import static java.nio.charset.StandardCharsets.UTF_8;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.internal.storage.pack.CachedPack;
import org.eclipse.jgit.internal.storage.pack.PackWriter;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.storage.pack.PackConfig;
/**
* Creates a Git bundle file, for sneaker-net transport to another system.
* <p>
* Bundles generated by this class can be later read in from a file URI using
* the bundle transport, or from an application controlled buffer by the more
* generic {@link org.eclipse.jgit.transport.TransportBundleStream}.
* <p>
* Applications creating bundles need to call one or more <code>include</code>
* calls to reflect which objects should be available as refs in the bundle for
* the other side to fetch. At least one include is required to create a valid
* bundle file, and duplicate names are not permitted.
* <p>
* Optional <code>assume</code> calls can be made to declare commits which the
* recipient must have in order to fetch from the bundle file. Objects reachable
* from these assumed commits can be used as delta bases in order to reduce the
* overall bundle size.
*/
public class BundleWriter {
private final Repository db;
private final ObjectReader reader;
private final Map<String, ObjectId> include;
private final Set<RevCommit> assume;
private final Set<ObjectId> tagTargets;
private final List<CachedPack> cachedPacks = new ArrayList<>();
private PackConfig packConfig;
private ObjectCountCallback callback;
/**
* Create a writer for a bundle.
*
* @param repo
* repository where objects are stored.
*/
public BundleWriter(Repository repo) {
db = repo;
reader = null;
include = new TreeMap<>();
assume = new HashSet<>();
tagTargets = new HashSet<>();
}
/**
* Create a writer for a bundle.
*
* @param or
* reader for reading objects. Will be closed at the end of {@link
* #writeBundle(ProgressMonitor, OutputStream)}, but readers may be
* reused after closing.
* @since 4.8
*/
public BundleWriter(ObjectReader or) {
db = null;
reader = or;
include = new TreeMap<>();
assume = new HashSet<>();
tagTargets = new HashSet<>();
}
/**
* Set the configuration used by the pack generator.
*
* @param pc
* configuration controlling packing parameters. If null the
* source repository's settings will be used, or the default
* settings if constructed without a repo.
*/
public void setPackConfig(PackConfig pc) {
this.packConfig = pc;
}
/**
* Include an object (and everything reachable from it) in the bundle.
*
* @param name
* name the recipient can discover this object as from the
* bundle's list of advertised refs . The name must be a valid
* ref format and must not have already been included in this
* bundle writer.
* @param id
* object to pack. Multiple refs may point to the same object.
*/
public void include(String name, AnyObjectId id) {
boolean validRefName = Repository.isValidRefName(name) || Constants.HEAD.equals(name);
if (!validRefName)
throw new IllegalArgumentException(MessageFormat.format(JGitText.get().invalidRefName, name));
if (include.containsKey(name))
throw new IllegalStateException(JGitText.get().duplicateRef + name);
include.put(name, id.toObjectId());
}
/**
* Include a single ref (a name/object pair) in the bundle.
* <p>
* This is a utility function for:
* <code>include(r.getName(), r.getObjectId())</code>.
*
* @param r
* the ref to include.
*/
public void include(Ref r) {
include(r.getName(), r.getObjectId());
if (r.getPeeledObjectId() != null)
tagTargets.add(r.getPeeledObjectId());
else if (r.getObjectId() != null
&& r.getName().startsWith(Constants.R_HEADS))
tagTargets.add(r.getObjectId());
}
/**
* Add objects to the bundle file.
*
* <p>
* When this method is used, object traversal is disabled and specified pack
* files are directly saved to the Git bundle file.
*
* <p>
* Unlike {@link #include}, this doesn't affect the refs. Even if the
* objects are not reachable from any ref, they will be included in the
* bundle file.
*
* @param c
* pack to include
* @since 5.9
*/
public void addObjectsAsIs(Collection<? extends CachedPack> c) {
cachedPacks.addAll(c);
}
/**
* Assume a commit is available on the recipient's side.
* <p>
* In order to fetch from a bundle the recipient must have any assumed
* commit. Each assumed commit is explicitly recorded in the bundle header
* to permit the recipient to validate it has these objects.
*
* @param c
* the commit to assume being available. This commit should be
* parsed and not disposed in order to maximize the amount of
* debugging information available in the bundle stream.
*/
public void assume(RevCommit c) {
if (c != null)
assume.add(c);
}
/**
* Generate and write the bundle to the output stream.
* <p>
* This method can only be called once per BundleWriter instance.
*
* @param monitor
* progress monitor to report bundle writing status to.
* @param os
* the stream the bundle is written to. The stream should be
* buffered by the caller. The caller is responsible for closing
* the stream.
* @throws java.io.IOException
* an error occurred reading a local object's data to include in
* the bundle, or writing compressed object data to the output
* stream.
*/
public void writeBundle(ProgressMonitor monitor, OutputStream os)
throws IOException {
try (PackWriter packWriter = newPackWriter()) {
packWriter.setObjectCountCallback(callback);
packWriter.setIndexDisabled(true);
packWriter.setDeltaBaseAsOffset(true);
packWriter.setReuseValidatingObjects(false);
if (cachedPacks.isEmpty()) {
HashSet<ObjectId> inc = new HashSet<>();
HashSet<ObjectId> exc = new HashSet<>();
inc.addAll(include.values());
for (RevCommit r : assume) {
exc.add(r.getId());
}
if (exc.isEmpty()) {
packWriter.setTagTargets(tagTargets);
}
packWriter.setThin(!exc.isEmpty());
packWriter.preparePack(monitor, inc, exc);
} else {
packWriter.preparePack(cachedPacks);
}
final Writer w = new OutputStreamWriter(os, UTF_8);
w.write(TransportBundle.V2_BUNDLE_SIGNATURE);
w.write('\n');
final char[] tmp = new char[Constants.OBJECT_ID_STRING_LENGTH];
for (RevCommit a : assume) {
w.write('-');
a.copyTo(tmp, w);
if (a.getRawBuffer() != null) {
w.write(' ');
w.write(a.getShortMessage());
}
w.write('\n');
}
for (Map.Entry<String, ObjectId> e : include.entrySet()) {
e.getValue().copyTo(tmp, w);
w.write(' ');
w.write(e.getKey());
w.write('\n');
}
w.write('\n');
w.flush();
packWriter.writePack(monitor, monitor, os);
}
}
private PackWriter newPackWriter() {
PackConfig pc = packConfig;
if (pc == null) {
pc = db != null ? new PackConfig(db) : new PackConfig();
}
return new PackWriter(pc, reader != null ? reader : db.newObjectReader());
}
/**
* Set the {@link org.eclipse.jgit.transport.ObjectCountCallback}.
* <p>
* It should be set before calling
* {@link #writeBundle(ProgressMonitor, OutputStream)}.
* <p>
* This callback will be passed on to
* {@link org.eclipse.jgit.internal.storage.pack.PackWriter#setObjectCountCallback}.
*
* @param callback
* the callback to set
* @return this object for chaining.
* @since 4.1
*/
public BundleWriter setObjectCountCallback(ObjectCountCallback callback) {
this.callback = callback;
return this;
}
}