com.google.gerrit.server.git.meta.VersionedMetaData Maven / Gradle / Ivy
// 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.meta;
import static com.google.common.base.Preconditions.checkArgument;
import com.google.common.base.MoreObjects;
import com.google.common.flogger.FluentLogger;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.server.git.LockFailureException;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import java.util.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.BatchRefUpdate;
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.transport.ReceiveCommand;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.util.ChangeIdUtil;
import org.eclipse.jgit.util.RawParseUtils;
/**
* Support for metadata stored within a version controlled branch.
*
* 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 static final FluentLogger logger = FluentLogger.forEnclosingClass();
/**
* Path information that does not hold references to any repository data structures, allowing the
* application to retain this object for long periods of time.
*/
public static class PathInfo {
public final FileMode fileMode;
public final String path;
public final ObjectId objectId;
protected PathInfo(TreeWalk tw) {
fileMode = tw.getFileMode(0);
path = tw.getPathString();
objectId = tw.getObjectId(0);
}
}
/** The revision at which the data was loaded. Is null for data yet to be created. */
@Nullable protected RevCommit revision;
protected Project.NameKey projectName;
protected RevWalk rw;
protected ObjectReader reader;
protected ObjectInserter inserter;
protected DirCache newTree;
/** @return name of the reference storing this configuration. */
protected abstract String getRefName();
/** Set up the metadata, parsing any state from the loaded revision. */
protected abstract void onLoad() throws IOException, ConfigInvalidException;
/**
* Save any changes to the metadata in a commit.
*
* @return true if the commit should proceed, false to abort.
* @throws IOException
* @throws ConfigInvalidException
*/
protected abstract boolean onSave(CommitBuilder commit)
throws IOException, ConfigInvalidException;
/** @return revision of the metadata that was loaded. */
@Nullable
public ObjectId getRevision() {
return revision != null ? revision.copy() : null;
}
/**
* Load the current version from the branch.
*
*
The repository is not held after the call completes, allowing the application to retain this
* object for long periods of time.
*
* @param projectName the name of the project
* @param db repository to access.
* @throws IOException
* @throws ConfigInvalidException
*/
public void load(Project.NameKey projectName, Repository db)
throws IOException, ConfigInvalidException {
Ref ref = db.getRefDatabase().exactRef(getRefName());
load(projectName, db, ref != null ? ref.getObjectId() : null);
}
/**
* Load a specific version from the repository.
*
*
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.
*
*
The repository is not held after the call completes, allowing the application to retain this
* object for long periods of time.
*
* @param projectName the name of the project
* @param db repository to access.
* @param id revision to load.
* @throws IOException
* @throws ConfigInvalidException
*/
public void load(Project.NameKey projectName, Repository db, @Nullable ObjectId id)
throws IOException, ConfigInvalidException {
try (RevWalk walk = new RevWalk(db)) {
load(projectName, walk, id);
}
}
/**
* Load a specific version from an open walk.
*
*
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.
*
*
The caller retains ownership of the walk and is responsible for closing it. However, this
* instance does not hold a reference to the walk or the repository after the call completes,
* allowing the application to retain this object for long periods of time.
*
* @param projectName the name of the project
* @param walk open walk to access to access.
* @param id revision to load.
* @throws IOException
* @throws ConfigInvalidException
*/
public void load(Project.NameKey projectName, RevWalk walk, ObjectId id)
throws IOException, ConfigInvalidException {
this.projectName = projectName;
this.rw = walk;
this.reader = walk.getObjectReader();
try {
revision = id != null ? walk.parseCommit(id) : null;
onLoad();
} finally {
this.rw = null;
this.reader = null;
}
}
public void load(MetaDataUpdate update) throws IOException, ConfigInvalidException {
load(update.getProjectName(), update.getRepository());
}
public void load(MetaDataUpdate update, ObjectId id) throws IOException, ConfigInvalidException {
load(update.getProjectName(), update.getRepository(), id);
}
/**
* Update this metadata branch, recording a new commit on its reference. This method mutates its
* receiver.
*
* @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 {
try (BatchMetaDataUpdate batch = openUpdate(update)) {
batch.write(update.getCommitBuilder());
return batch.commit();
}
}
/**
* Creates a new commit and a new ref based on this commit. This method mutates its receiver.
*
* @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 {
try (BatchMetaDataUpdate batch = openUpdate(update)) {
batch.write(update.getCommitBuilder());
return batch.createRef(refName);
}
}
public interface BatchMetaDataUpdate extends AutoCloseable {
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;
@Override
void close();
}
/**
* Open a batch of updates to the same metadata ref.
*
*
This allows making multiple commits to a single metadata ref, at the end of which is a
* single ref update. For batching together updates to multiple refs (each consisting of one or
* more commits against their respective refs), create the {@link MetaDataUpdate} with a {@link
* BatchRefUpdate}.
*
*
A ref update produced by this {@link BatchMetaDataUpdate} is only committed if there is no
* associated {@link BatchRefUpdate}. As a result, the configured ref updated event is not fired
* if there is an associated batch.
*
* @param update helper info about the update.
* @throws IOException if the update failed.
*/
public BatchMetaDataUpdate openUpdate(MetaDataUpdate update) throws IOException {
final Repository db = update.getRepository();
inserter = db.newObjectInserter();
reader = inserter.newReader();
final RevWalk rw = new RevWalk(reader);
final RevTree tree = revision != null ? rw.parseTree(revision) : null;
newTree = readTree(tree);
return new BatchMetaDataUpdate() {
RevCommit src = revision;
AnyObjectId srcTree = tree;
@Override
public void write(CommitBuilder commit) throws IOException {
write(VersionedMetaData.this, commit);
}
private boolean doSave(VersionedMetaData config, CommitBuilder commit) throws IOException {
DirCache nt = config.newTree;
ObjectReader r = config.reader;
ObjectInserter i = config.inserter;
RevCommit c = config.revision;
try {
config.newTree = newTree;
config.reader = reader;
config.inserter = inserter;
config.revision = src;
return 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;
config.revision = c;
}
}
@Override
public void write(VersionedMetaData config, CommitBuilder commit) throws IOException {
checkSameRef(config);
if (!doSave(config, commit)) {
return;
}
ObjectId res = newTree.writeTree(inserter);
if (res.equals(srcTree) && !update.allowEmpty() && (commit.getTreeId() == null)) {
// If there are no changes to the content, don't create the commit.
return;
}
// If changes are made to the DirCache and those changes are written as
// a commit and then the tree ID is set for the CommitBuilder, then
// those previous DirCache changes will be ignored and the commit's
// tree will be replaced with the ID in the CommitBuilder. The same is
// true if you explicitly set tree ID in a commit and then make changes
// to the DirCache; that tree ID will be ignored and replaced by that of
// the tree for the updated DirCache.
if (commit.getTreeId() == null) {
commit.setTreeId(res);
} else {
// In this case, the caller populated the tree without using DirCache.
res = commit.getTreeId();
}
if (src != null) {
commit.addParentId(src);
}
if (update.insertChangeId()) {
ObjectId id =
ChangeIdUtil.computeChangeId(
res,
getRevision(),
commit.getAuthor(),
commit.getCommitter(),
commit.getMessage());
commit.setMessage(ChangeIdUtil.insertId(commit.getMessage(), id));
}
src = rw.parseCommit(inserter.insert(commit));
srcTree = res;
}
private void checkSameRef(VersionedMetaData other) {
String thisRef = VersionedMetaData.this.getRefName();
String otherRef = other.getRefName();
checkArgument(
otherRef.equals(thisRef),
"cannot add %s for %s to %s on %s",
other.getClass().getSimpleName(),
otherRef,
BatchMetaDataUpdate.class.getSimpleName(),
thisRef);
}
@Override
public RevCommit createRef(String refName) throws IOException {
if (Objects.equals(src, revision)) {
return revision;
}
return updateRef(ObjectId.zeroId(), src, refName);
}
@Override
public RevCommit commit() throws IOException {
return commitAt(revision);
}
@Override
public RevCommit commitAt(ObjectId expected) throws IOException {
if (Objects.equals(src, expected)) {
return revision;
}
return updateRef(MoreObjects.firstNonNull(expected, ObjectId.zeroId()), src, getRefName());
}
@Override
public void close() {
newTree = null;
rw.close();
if (inserter != null) {
inserter.close();
inserter = null;
}
if (reader != null) {
reader.close();
reader = null;
}
}
private RevCommit updateRef(AnyObjectId oldId, AnyObjectId newId, String refName)
throws IOException {
BatchRefUpdate bru = update.getBatch();
if (bru != null) {
bru.addCommand(new ReceiveCommand(oldId.toObjectId(), newId.toObjectId(), refName));
inserter.flush();
revision = rw.parseCommit(newId);
return revision;
}
RefUpdate ru = db.updateRef(refName);
ru.setExpectedOldObjectId(oldId);
ru.setNewObjectId(newId);
ru.setRefLogIdent(update.getCommitBuilder().getAuthor());
String message = update.getCommitBuilder().getMessage();
if (message == null) {
message = "meta data update";
}
try (BufferedReader reader = new BufferedReader(new StringReader(message))) {
// read the subject line and use it as reflog message
ru.setRefLogMessage("commit: " + reader.readLine(), true);
}
inserter.flush();
RefUpdate.Result result = ru.update();
switch (result) {
case NEW:
case FAST_FORWARD:
revision = rw.parseCommit(ru.getNewObjectId());
update.fireGitRefUpdatedEvent(ru);
return revision;
case LOCK_FAILURE:
throw new LockFailureException(
"Cannot update "
+ ru.getName()
+ " in "
+ db.getDirectory()
+ ": "
+ ru.getResult(),
ru);
case FORCED:
case IO_FAILURE:
case NOT_ATTEMPTED:
case NO_CHANGE:
case REJECTED:
case REJECTED_CURRENT_BRANCH:
case RENAMED:
case REJECTED_MISSING_OBJECT:
case REJECTED_OTHER_REASON:
default:
throw new IOException(
"Cannot update "
+ ru.getName()
+ " in "
+ db.getDirectory()
+ ": "
+ ru.getResult());
}
}
};
}
protected 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) {
StringBuilder msg =
new StringBuilder("Invalid config file ")
.append(fileName)
.append(" in commit ")
.append(revision.name());
if (err.getCause() != null) {
msg.append(": ").append(err.getCause());
}
throw new ConfigInvalidException(msg.toString(), 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[] {};
}
logger.atFine().log(
"Read file '%s' from ref '%s' of project '%s' from revision '%s'",
fileName, getRefName(), projectName, revision.name());
try (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);
}
}
return new byte[] {};
}
@Nullable
protected ObjectId getObjectId(String fileName) throws IOException {
if (revision == null) {
return null;
}
try (TreeWalk tw = TreeWalk.forPath(reader, fileName, revision.getTree())) {
if (tw != null) {
return tw.getObjectId(0);
}
}
return null;
}
public List getPathInfos(boolean recursive) throws IOException {
try (TreeWalk tw = new TreeWalk(reader)) {
tw.addTree(revision.getTree());
tw.setRecursive(recursive);
List paths = new ArrayList<>();
while (tw.next()) {
paths.add(new PathInfo(tw));
}
return paths;
}
}
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 > 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 {
logger.atFine().log(
"Save file '%s' in ref '%s' of project '%s'", fileName, getRefName(), projectName);
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();
}
}