PushCertificateStore.java
/*
* Copyright (C) 2015, 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 static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
import static org.eclipse.jgit.lib.Constants.OBJ_COMMIT;
import static org.eclipse.jgit.lib.FileMode.TYPE_FILE;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import org.eclipse.jgit.dircache.DirCache;
import org.eclipse.jgit.dircache.DirCacheEditor;
import org.eclipse.jgit.dircache.DirCacheEditor.PathEdit;
import org.eclipse.jgit.dircache.DirCacheEntry;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.BatchRefUpdate;
import org.eclipse.jgit.lib.CommitBuilder;
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.PersonIdent;
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.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.treewalk.filter.AndTreeFilter;
import org.eclipse.jgit.treewalk.filter.PathFilter;
import org.eclipse.jgit.treewalk.filter.PathFilterGroup;
import org.eclipse.jgit.treewalk.filter.TreeFilter;
/**
* Storage for recorded push certificates.
* <p>
* Push certificates are stored in a special ref {@code refs/meta/push-certs}.
* The filenames in the tree are ref names followed by the special suffix
* <code>@{cert}</code>, and the contents are the latest push cert affecting
* that ref. The special suffix allows storing certificates for both refs/foo
* and refs/foo/bar in case those both existed at some point.
*
* @since 4.1
*/
public class PushCertificateStore implements AutoCloseable {
/** Ref name storing push certificates. */
static final String REF_NAME =
Constants.R_REFS + "meta/push-certs"; //$NON-NLS-1$
private static class PendingCert {
PushCertificate cert;
PersonIdent ident;
Collection<ReceiveCommand> matching;
PendingCert(PushCertificate cert, PersonIdent ident,
Collection<ReceiveCommand> matching) {
this.cert = cert;
this.ident = ident;
this.matching = matching;
}
}
private final Repository db;
private final List<PendingCert> pending;
ObjectReader reader;
RevCommit commit;
/**
* Create a new store backed by the given repository.
*
* @param db
* the repository.
*/
public PushCertificateStore(Repository db) {
this.db = db;
pending = new ArrayList<>();
}
/**
* {@inheritDoc}
* <p>
* Close resources opened by this store.
* <p>
* If {@link #get(String)} was called, closes the cached object reader
* created by that method. Does not close the underlying repository.
*/
@Override
public void close() {
if (reader != null) {
reader.close();
reader = null;
commit = null;
}
}
/**
* Get latest push certificate associated with a ref.
* <p>
* Lazily opens {@code refs/meta/push-certs} and reads from the repository as
* necessary. The state is cached between calls to {@code get}; to reread the,
* call {@link #close()} first.
*
* @param refName
* the ref name to get the certificate for.
* @return last certificate affecting the ref, or null if no cert was recorded
* for the last update to this ref.
* @throws java.io.IOException
* if a problem occurred reading the repository.
*/
public PushCertificate get(String refName) throws IOException {
if (reader == null) {
load();
}
try (TreeWalk tw = newTreeWalk(refName)) {
return read(tw);
}
}
/**
* Iterate over all push certificates affecting a ref.
* <p>
* Only includes push certificates actually stored in the tree; see class
* Javadoc for conditions where this might not include all push certs ever
* seen for this ref.
* <p>
* The returned iterable may be iterated multiple times, and push certs will
* be re-read from the current state of the store on each call to {@link
* Iterable#iterator()}. However, method calls on the returned iterator may
* fail if {@code save} or {@code close} is called on the enclosing store
* during iteration.
*
* @param refName
* the ref name to get certificates for.
* @return iterable over certificates; must be fully iterated in order to
* close resources.
*/
public Iterable<PushCertificate> getAll(String refName) {
return () -> new Iterator<>() {
private final String path = pathName(refName);
private PushCertificate next;
private RevWalk rw;
{
try {
if (reader == null) {
load();
}
if (commit != null) {
rw = new RevWalk(reader);
rw.setTreeFilter(AndTreeFilter.create(
PathFilterGroup.create(Collections
.singleton(PathFilter.create(path))),
TreeFilter.ANY_DIFF));
rw.setRewriteParents(false);
rw.markStart(rw.parseCommit(commit));
} else {
rw = null;
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
@Override
public boolean hasNext() {
try {
if (next == null) {
if (rw == null) {
return false;
}
try {
RevCommit c = rw.next();
if (c != null) {
try (TreeWalk tw = TreeWalk.forPath(
rw.getObjectReader(), path,
c.getTree())) {
next = read(tw);
}
} else {
next = null;
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
return next != null;
} finally {
if (next == null && rw != null) {
rw.close();
rw = null;
}
}
}
@Override
public PushCertificate next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
PushCertificate n = next;
next = null;
return n;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
void load() throws IOException {
close();
reader = db.newObjectReader();
Ref ref = db.getRefDatabase().exactRef(REF_NAME);
if (ref == null) {
// No ref, same as empty.
return;
}
try (RevWalk rw = new RevWalk(reader)) {
commit = rw.parseCommit(ref.getObjectId());
}
}
static PushCertificate read(TreeWalk tw) throws IOException {
if (tw == null || (tw.getRawMode(0) & TYPE_FILE) != TYPE_FILE) {
return null;
}
ObjectLoader loader =
tw.getObjectReader().open(tw.getObjectId(0), OBJ_BLOB);
try (InputStream in = loader.openStream();
Reader r = new BufferedReader(
new InputStreamReader(in, UTF_8))) {
return PushCertificateParser.fromReader(r);
}
}
/**
* Put a certificate to be saved to the store.
* <p>
* Writes the contents of this certificate for each ref mentioned. It is up
* to the caller to ensure this certificate accurately represents the state
* of the ref.
* <p>
* Pending certificates added to this method are not returned by
* {@link #get(String)} and {@link #getAll(String)} until after calling
* {@link #save()}.
*
* @param cert
* certificate to store.
* @param ident
* identity for the commit that stores this certificate. Pending
* certificates are sorted by identity timestamp during
* {@link #save()}.
*/
public void put(PushCertificate cert, PersonIdent ident) {
put(cert, ident, null);
}
/**
* Put a certificate to be saved to the store, matching a set of commands.
* <p>
* Like {@link #put(PushCertificate, PersonIdent)}, except a value is only
* stored for a push certificate if there is a corresponding command in the
* list that exactly matches the old/new values mentioned in the push
* certificate.
* <p>
* Pending certificates added to this method are not returned by
* {@link #get(String)} and {@link #getAll(String)} until after calling
* {@link #save()}.
*
* @param cert
* certificate to store.
* @param ident
* identity for the commit that stores this certificate. Pending
* certificates are sorted by identity timestamp during
* {@link #save()}.
* @param matching
* only store certs for the refs listed in this list whose values
* match the commands in the cert.
*/
public void put(PushCertificate cert, PersonIdent ident,
Collection<ReceiveCommand> matching) {
pending.add(new PendingCert(cert, ident, matching));
}
/**
* Save pending certificates to the store.
* <p>
* One commit is created per certificate added with
* {@link #put(PushCertificate, PersonIdent)}, in order of identity
* timestamps, and a single ref update is performed.
* <p>
* The pending list is cleared if and only the ref update fails, which
* allows for easy retries in case of lock failure.
*
* @return the result of attempting to update the ref.
* @throws java.io.IOException
* if there was an error reading from or writing to the
* repository.
*/
public RefUpdate.Result save() throws IOException {
ObjectId newId = write();
if (newId == null) {
return RefUpdate.Result.NO_CHANGE;
}
try (ObjectInserter inserter = db.newObjectInserter()) {
RefUpdate.Result result = updateRef(newId);
switch (result) {
case FAST_FORWARD:
case NEW:
case NO_CHANGE:
pending.clear();
break;
default:
break;
}
return result;
} finally {
close();
}
}
/**
* Save pending certificates to the store in an existing batch ref update.
* <p>
* One commit is created per certificate added with
* {@link #put(PushCertificate, PersonIdent)}, in order of identity
* timestamps, all commits are flushed, and a single command is added to the
* batch.
* <p>
* The cached ref value and pending list are <em>not</em> cleared. If the
* ref update succeeds, the caller is responsible for calling
* {@link #close()} and/or {@link #clear()}.
*
* @param batch
* update to save to.
* @return whether a command was added to the batch.
* @throws java.io.IOException
* if there was an error reading from or writing to the
* repository.
*/
public boolean save(BatchRefUpdate batch) throws IOException {
ObjectId newId = write();
if (newId == null || newId.equals(commit)) {
return false;
}
batch.addCommand(new ReceiveCommand(
commit != null ? commit : ObjectId.zeroId(), newId, REF_NAME));
return true;
}
/**
* Clear pending certificates added with {@link #put(PushCertificate,
* PersonIdent)}.
*/
public void clear() {
pending.clear();
}
private ObjectId write() throws IOException {
if (pending.isEmpty()) {
return null;
}
if (reader == null) {
load();
}
sortPending(pending);
ObjectId curr = commit;
DirCache dc = newDirCache();
try (ObjectInserter inserter = db.newObjectInserter()) {
for (PendingCert pc : pending) {
curr = saveCert(inserter, dc, pc, curr);
}
inserter.flush();
return curr;
}
}
private static void sortPending(List<PendingCert> pending) {
Collections.sort(pending, (PendingCert a, PendingCert b) -> Long.signum(
a.ident.getWhen().getTime() - b.ident.getWhen().getTime()));
}
private DirCache newDirCache() throws IOException {
if (commit != null) {
return DirCache.read(reader, commit.getTree());
}
return DirCache.newInCore();
}
private ObjectId saveCert(ObjectInserter inserter, DirCache dc,
PendingCert pc, ObjectId curr) throws IOException {
Map<String, ReceiveCommand> byRef;
if (pc.matching != null) {
byRef = new HashMap<>();
for (ReceiveCommand cmd : pc.matching) {
if (byRef.put(cmd.getRefName(), cmd) != null) {
throw new IllegalStateException();
}
}
} else {
byRef = null;
}
DirCacheEditor editor = dc.editor();
String certText = pc.cert.toText() + pc.cert.getSignature();
final ObjectId certId = inserter.insert(OBJ_BLOB, certText.getBytes(UTF_8));
boolean any = false;
for (ReceiveCommand cmd : pc.cert.getCommands()) {
if (byRef != null && !commandsEqual(cmd, byRef.get(cmd.getRefName()))) {
continue;
}
any = true;
editor.add(new PathEdit(pathName(cmd.getRefName())) {
@Override
public void apply(DirCacheEntry ent) {
ent.setFileMode(FileMode.REGULAR_FILE);
ent.setObjectId(certId);
}
});
}
if (!any) {
return curr;
}
editor.finish();
CommitBuilder cb = new CommitBuilder();
cb.setAuthor(pc.ident);
cb.setCommitter(pc.ident);
cb.setTreeId(dc.writeTree(inserter));
if (curr != null) {
cb.setParentId(curr);
} else {
cb.setParentIds(Collections.<ObjectId> emptyList());
}
cb.setMessage(buildMessage(pc.cert));
return inserter.insert(OBJ_COMMIT, cb.build());
}
private static boolean commandsEqual(ReceiveCommand c1, ReceiveCommand c2) {
if (c1 == null || c2 == null) {
return c1 == c2;
}
return c1.getRefName().equals(c2.getRefName())
&& c1.getOldId().equals(c2.getOldId())
&& c1.getNewId().equals(c2.getNewId());
}
private RefUpdate.Result updateRef(ObjectId newId) throws IOException {
RefUpdate ru = db.updateRef(REF_NAME);
ru.setExpectedOldObjectId(commit != null ? commit : ObjectId.zeroId());
ru.setNewObjectId(newId);
ru.setRefLogIdent(pending.get(pending.size() - 1).ident);
ru.setRefLogMessage(JGitText.get().storePushCertReflog, false);
try (RevWalk rw = new RevWalk(reader)) {
return ru.update(rw);
}
}
private TreeWalk newTreeWalk(String refName) throws IOException {
if (commit == null) {
return null;
}
return TreeWalk.forPath(reader, pathName(refName), commit.getTree());
}
static String pathName(String refName) {
return refName + "@{cert}"; //$NON-NLS-1$
}
private static String buildMessage(PushCertificate cert) {
StringBuilder sb = new StringBuilder();
if (cert.getCommands().size() == 1) {
sb.append(MessageFormat.format(
JGitText.get().storePushCertOneRef,
cert.getCommands().get(0).getRefName()));
} else {
sb.append(MessageFormat.format(
JGitText.get().storePushCertMultipleRefs,
Integer.valueOf(cert.getCommands().size())));
}
return sb.append('\n').toString();
}
}