| // Copyright (C) 2010 The Android Open Source Project |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package com.google.gerrit.server.git; |
| |
| import com.google.common.base.Objects; |
| |
| import org.eclipse.jgit.dircache.DirCache; |
| import org.eclipse.jgit.dircache.DirCacheBuilder; |
| import org.eclipse.jgit.dircache.DirCacheEditor; |
| import org.eclipse.jgit.dircache.DirCacheEditor.DeletePath; |
| import org.eclipse.jgit.dircache.DirCacheEditor.PathEdit; |
| import org.eclipse.jgit.dircache.DirCacheEntry; |
| import org.eclipse.jgit.errors.ConfigInvalidException; |
| import org.eclipse.jgit.errors.IncorrectObjectTypeException; |
| import org.eclipse.jgit.errors.MissingObjectException; |
| import org.eclipse.jgit.lib.AnyObjectId; |
| import org.eclipse.jgit.lib.CommitBuilder; |
| import org.eclipse.jgit.lib.Config; |
| import org.eclipse.jgit.lib.Constants; |
| import org.eclipse.jgit.lib.FileMode; |
| import org.eclipse.jgit.lib.ObjectId; |
| import org.eclipse.jgit.lib.ObjectInserter; |
| import org.eclipse.jgit.lib.ObjectLoader; |
| import org.eclipse.jgit.lib.ObjectReader; |
| import org.eclipse.jgit.lib.Ref; |
| import org.eclipse.jgit.lib.RefUpdate; |
| import org.eclipse.jgit.lib.Repository; |
| import org.eclipse.jgit.revwalk.RevCommit; |
| import org.eclipse.jgit.revwalk.RevTree; |
| import org.eclipse.jgit.revwalk.RevWalk; |
| import org.eclipse.jgit.treewalk.TreeWalk; |
| import org.eclipse.jgit.util.RawParseUtils; |
| |
| import java.io.IOException; |
| |
| /** |
| * Support for metadata stored within a version controlled branch. |
| * <p> |
| * Implementors are responsible for supplying implementations of the onLoad and |
| * onSave methods to read from the repository, or format an update that can |
| * later be written back to the repository. |
| */ |
| public abstract class VersionedMetaData { |
| private RevCommit revision; |
| private ObjectReader reader; |
| private ObjectInserter inserter; |
| private DirCache newTree; |
| |
| /** @return name of the reference storing this configuration. */ |
| protected abstract String getRefName(); |
| |
| protected abstract void onLoad() throws IOException, ConfigInvalidException; |
| |
| protected abstract void onSave(CommitBuilder commit) throws IOException, |
| ConfigInvalidException; |
| |
| /** @return revision of the metadata that was loaded. */ |
| public ObjectId getRevision() { |
| return revision != null ? revision.copy() : null; |
| } |
| |
| /** Initialize in-memory as though the repository branch doesn't exist. */ |
| public void createInMemory() { |
| try { |
| revision = null; |
| onLoad(); |
| } catch (IOException err) { |
| throw new RuntimeException("Unexpected IOException", err); |
| } catch (ConfigInvalidException err) { |
| throw new RuntimeException("Unexpected ConfigInvalidException", err); |
| } |
| } |
| |
| /** |
| * Load the current version from the branch. |
| * <p> |
| * The repository is not held after the call completes, allowing the |
| * application to retain this object for long periods of time. |
| * |
| * @param db repository to access. |
| * @throws IOException |
| * @throws ConfigInvalidException |
| */ |
| public void load(Repository db) throws IOException, ConfigInvalidException { |
| Ref ref = db.getRef(getRefName()); |
| load(db, ref != null ? ref.getObjectId() : null); |
| } |
| |
| /** |
| * Load a specific version from the repository. |
| * <p> |
| * This method is primarily useful for applying updates to a specific revision |
| * that was shown to an end-user in the user interface. If there are conflicts |
| * with another user's concurrent changes, these will be automatically |
| * detected at commit time. |
| * <p> |
| * The repository is not held after the call completes, allowing the |
| * application to retain this object for long periods of time. |
| * |
| * @param db repository to access. |
| * @param id revision to load. |
| * @throws IOException |
| * @throws ConfigInvalidException |
| */ |
| public void load(Repository db, ObjectId id) throws IOException, |
| ConfigInvalidException { |
| if (id != null) { |
| reader = db.newObjectReader(); |
| try { |
| revision = new RevWalk(reader).parseCommit(id); |
| onLoad(); |
| } finally { |
| reader.release(); |
| reader = null; |
| } |
| } else { |
| // The branch does not yet exist. |
| revision = null; |
| onLoad(); |
| } |
| } |
| |
| public void load(MetaDataUpdate update) throws IOException, |
| ConfigInvalidException { |
| load(update.getRepository()); |
| } |
| |
| public void load(MetaDataUpdate update, ObjectId id) throws IOException, |
| ConfigInvalidException { |
| load(update.getRepository(), id); |
| } |
| |
| /** |
| * Update this metadata branch, recording a new commit on its reference. |
| * |
| * @param update helper information to define the update that will occur. |
| * @return the commit that was created |
| * @throws IOException if there is a storage problem and the update cannot be |
| * executed as requested or if it failed because of a concurrent |
| * update to the same reference |
| */ |
| public RevCommit commit(MetaDataUpdate update) throws IOException { |
| BatchMetaDataUpdate batch = openUpdate(update); |
| try { |
| batch.write(update.getCommitBuilder()); |
| return batch.commit(); |
| } finally { |
| batch.close(); |
| } |
| } |
| |
| /** |
| * Creates a new commit and a new ref based on this commit. |
| * |
| * @param update helper information to define the update that will occur. |
| * @param refName name of the ref that should be created |
| * @return the commit that was created |
| * @throws IOException if there is a storage problem and the update cannot be |
| * executed as requested or if it failed because of a concurrent |
| * update to the same reference |
| */ |
| public RevCommit commitToNewRef(MetaDataUpdate update, String refName) throws IOException { |
| BatchMetaDataUpdate batch = openUpdate(update); |
| try { |
| batch.write(update.getCommitBuilder()); |
| return batch.createRef(refName); |
| } finally { |
| batch.close(); |
| } |
| } |
| |
| public interface BatchMetaDataUpdate { |
| void write(CommitBuilder commit) throws IOException; |
| void write(VersionedMetaData config, CommitBuilder commit) throws IOException; |
| RevCommit createRef(String refName) throws IOException; |
| RevCommit commit() throws IOException; |
| RevCommit commitAt(ObjectId revision) throws IOException; |
| void close(); |
| } |
| |
| public BatchMetaDataUpdate openUpdate(final MetaDataUpdate update) throws IOException { |
| final Repository db = update.getRepository(); |
| |
| reader = db.newObjectReader(); |
| inserter = db.newObjectInserter(); |
| final RevWalk rw = new RevWalk(reader); |
| final RevTree tree = revision != null ? rw.parseTree(revision) : null; |
| newTree = readTree(tree); |
| return new BatchMetaDataUpdate() { |
| AnyObjectId src = revision; |
| AnyObjectId srcTree = tree; |
| |
| @Override |
| public void write(CommitBuilder commit) throws IOException { |
| write(VersionedMetaData.this, commit); |
| } |
| |
| private void doSave(VersionedMetaData config, CommitBuilder commit) throws IOException { |
| DirCache nt = config.newTree; |
| ObjectReader r = config.reader; |
| ObjectInserter i = config.inserter; |
| try { |
| config.newTree = newTree; |
| config.reader = reader; |
| config.inserter = inserter; |
| config.onSave(commit); |
| } catch (ConfigInvalidException e) { |
| throw new IOException("Cannot update " + getRefName() + " in " |
| + db.getDirectory() + ": " + e.getMessage(), e); |
| } finally { |
| config.newTree = nt; |
| config.reader = r; |
| config.inserter = i; |
| } |
| } |
| |
| @Override |
| public void write(VersionedMetaData config, CommitBuilder commit) throws IOException { |
| doSave(config, commit); |
| |
| final ObjectId res = newTree.writeTree(inserter); |
| if (res.equals(srcTree)) { |
| // If there are no changes to the content, don't create the commit. |
| return; |
| } |
| |
| commit.setTreeId(res); |
| if (src != null) { |
| commit.addParentId(src); |
| } |
| |
| src = inserter.insert(commit); |
| srcTree = res; |
| } |
| |
| @Override |
| public RevCommit createRef(String refName) throws IOException { |
| if (Objects.equal(src, revision)) { |
| return revision; |
| } |
| |
| RefUpdate ru = db.updateRef(refName); |
| ru.setExpectedOldObjectId(ObjectId.zeroId()); |
| ru.setNewObjectId(src); |
| ru.disableRefLog(); |
| inserter.flush(); |
| RefUpdate.Result result = ru.update(); |
| switch (result) { |
| case NEW: |
| revision = rw.parseCommit(ru.getNewObjectId()); |
| update.fireGitRefUpdatedEvent(ru); |
| return revision; |
| default: |
| throw new IOException("Cannot update " + ru.getName() + " in " |
| + db.getDirectory() + ": " + ru.getResult()); |
| } |
| } |
| |
| @Override |
| public RevCommit commit() throws IOException { |
| return commitAt(revision); |
| } |
| |
| @Override |
| public RevCommit commitAt(ObjectId expected) throws IOException { |
| if (Objects.equal(src, expected)) { |
| return revision; |
| } |
| |
| RefUpdate ru = db.updateRef(getRefName()); |
| if (expected != null) { |
| ru.setExpectedOldObjectId(expected); |
| } else { |
| ru.setExpectedOldObjectId(ObjectId.zeroId()); |
| } |
| ru.setNewObjectId(src); |
| ru.disableRefLog(); |
| inserter.flush(); |
| |
| switch (ru.update(rw)) { |
| case NEW: |
| case FAST_FORWARD: |
| revision = rw.parseCommit(ru.getNewObjectId()); |
| update.fireGitRefUpdatedEvent(ru); |
| return revision; |
| |
| default: |
| throw new IOException("Cannot update " + ru.getName() + " in " |
| + db.getDirectory() + ": " + ru.getResult()); |
| } |
| } |
| |
| @Override |
| public void close() { |
| newTree = null; |
| |
| if (inserter != null) { |
| inserter.release(); |
| inserter = null; |
| } |
| |
| if (reader != null) { |
| reader.release(); |
| reader = null; |
| } |
| } |
| }; |
| } |
| |
| private DirCache readTree(RevTree tree) throws IOException, |
| MissingObjectException, IncorrectObjectTypeException { |
| DirCache dc = DirCache.newInCore(); |
| if (tree != null) { |
| DirCacheBuilder b = dc.builder(); |
| b.addTree(new byte[0], DirCacheEntry.STAGE_0, reader, tree); |
| b.finish(); |
| } |
| return dc; |
| } |
| |
| protected Config readConfig(String fileName) throws IOException, |
| ConfigInvalidException { |
| Config rc = new Config(); |
| String text = readUTF8(fileName); |
| if (!text.isEmpty()) { |
| try { |
| rc.fromText(text); |
| } catch (ConfigInvalidException err) { |
| throw new ConfigInvalidException("Invalid config file " + fileName |
| + " in commit" + revision.name(), err); |
| } |
| } |
| return rc; |
| } |
| |
| protected String readUTF8(String fileName) throws IOException { |
| byte[] raw = readFile(fileName); |
| return raw.length != 0 ? RawParseUtils.decode(raw) : ""; |
| } |
| |
| protected byte[] readFile(String fileName) throws IOException { |
| if (revision == null) { |
| return new byte[] {}; |
| } |
| |
| TreeWalk tw = TreeWalk.forPath(reader, fileName, revision.getTree()); |
| if (tw != null) { |
| ObjectLoader obj = reader.open(tw.getObjectId(0), Constants.OBJ_BLOB); |
| return obj.getCachedBytes(Integer.MAX_VALUE); |
| |
| } else { |
| return new byte[] {}; |
| } |
| } |
| |
| protected ObjectId getObjectId(String fileName) throws IOException { |
| if (revision == null) { |
| return null; |
| } |
| |
| TreeWalk tw = TreeWalk.forPath(reader, fileName, revision.getTree()); |
| if (tw != null) { |
| return tw.getObjectId(0); |
| } |
| |
| return null; |
| } |
| |
| protected static void set(Config rc, String section, String subsection, |
| String name, String value) { |
| if (value != null) { |
| rc.setString(section, subsection, name, value); |
| } else { |
| rc.unset(section, subsection, name); |
| } |
| } |
| |
| protected static void set(Config rc, String section, String subsection, |
| String name, boolean value) { |
| if (value) { |
| rc.setBoolean(section, subsection, name, value); |
| } else { |
| rc.unset(section, subsection, name); |
| } |
| } |
| |
| protected static <E extends Enum<?>> void set(Config rc, String section, |
| String subsection, String name, E value, E defaultValue) { |
| if (value != defaultValue) { |
| rc.setEnum(section, subsection, name, value); |
| } else { |
| rc.unset(section, subsection, name); |
| } |
| } |
| |
| protected void saveConfig(String fileName, Config cfg) throws IOException { |
| saveUTF8(fileName, cfg.toText()); |
| } |
| |
| protected void saveUTF8(String fileName, String text) throws IOException { |
| saveFile(fileName, text != null ? Constants.encode(text) : null); |
| } |
| |
| protected void saveFile(String fileName, byte[] raw) throws IOException { |
| DirCacheEditor editor = newTree.editor(); |
| if (raw != null && 0 < raw.length) { |
| final ObjectId blobId = inserter.insert(Constants.OBJ_BLOB, raw); |
| editor.add(new PathEdit(fileName) { |
| @Override |
| public void apply(DirCacheEntry ent) { |
| ent.setFileMode(FileMode.REGULAR_FILE); |
| ent.setObjectId(blobId); |
| } |
| }); |
| } else { |
| editor.add(new DeletePath(fileName)); |
| } |
| editor.finish(); |
| } |
| } |
