Java tutorial
/* * Copyright (C) 2008-2010, 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.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.HashSet; 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.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 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()); } /** * 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); final HashSet<ObjectId> inc = new HashSet<>(); final HashSet<ObjectId> exc = new HashSet<>(); inc.addAll(include.values()); for (RevCommit r : assume) exc.add(r.getId()); packWriter.setIndexDisabled(true); packWriter.setDeltaBaseAsOffset(true); packWriter.setThin(!exc.isEmpty()); packWriter.setReuseValidatingObjects(false); if (exc.isEmpty()) { packWriter.setTagTargets(tagTargets); } packWriter.preparePack(monitor, inc, exc); 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; } }