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- /*
- * Copyright (C) 2011, 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.storage.dht;
-
- import static org.eclipse.jgit.lib.Ref.Storage.LOOSE;
- import static org.eclipse.jgit.lib.Ref.Storage.NEW;
- import static org.eclipse.jgit.storage.dht.RefDataUtil.NONE;
-
- import java.io.IOException;
- import java.util.Collections;
- import java.util.List;
- import java.util.Map;
- import java.util.Set;
- import java.util.concurrent.TimeoutException;
- import java.util.concurrent.atomic.AtomicReference;
-
- import org.eclipse.jgit.errors.MissingObjectException;
- import org.eclipse.jgit.generated.storage.dht.proto.GitStore.RefData;
- import org.eclipse.jgit.lib.AnyObjectId;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.lib.ObjectIdSubclassMap;
- import org.eclipse.jgit.lib.Ref;
- import org.eclipse.jgit.lib.RefDatabase;
- import org.eclipse.jgit.lib.RefRename;
- import org.eclipse.jgit.lib.SymbolicRef;
- import org.eclipse.jgit.revwalk.RevObject;
- import org.eclipse.jgit.revwalk.RevTag;
- import org.eclipse.jgit.revwalk.RevWalk;
- import org.eclipse.jgit.storage.dht.RefDataUtil.IdWithChunk;
- import org.eclipse.jgit.storage.dht.spi.Context;
- import org.eclipse.jgit.storage.dht.spi.Database;
- import org.eclipse.jgit.util.RefList;
- import org.eclipse.jgit.util.RefMap;
-
- /** Repository references stored on top of a DHT database. */
- public class DhtRefDatabase extends RefDatabase {
- private final DhtRepository repository;
-
- private final Database db;
-
- private final AtomicReference<RefCache> cache;
-
- DhtRefDatabase(DhtRepository repository, Database db) {
- this.repository = repository;
- this.db = db;
- this.cache = new AtomicReference<RefCache>();
- }
-
- DhtRepository getRepository() {
- return repository;
- }
-
- ChunkKey findChunk(AnyObjectId id) {
- RefCache c = cache.get();
- if (c != null) {
- IdWithChunk i = c.hints.get(id);
- if (i != null)
- return i.getChunkKey();
- }
- return null;
- }
-
- @Override
- public Ref getRef(String needle) throws IOException {
- RefCache curr = readRefs();
- for (String prefix : SEARCH_PATH) {
- DhtRef ref = curr.ids.get(prefix + needle);
- if (ref != null) {
- ref = resolve(ref, 0, curr.ids);
- return ref;
- }
- }
- return null;
- }
-
- private DhtRef getOneRef(String refName) throws IOException {
- RefCache curr = readRefs();
- DhtRef ref = curr.ids.get(refName);
- if (ref != null)
- return resolve(ref, 0, curr.ids);
- return ref;
- }
-
- @Override
- public List<Ref> getAdditionalRefs() {
- return Collections.emptyList();
- }
-
- @Override
- public Map<String, Ref> getRefs(String prefix) throws IOException {
- RefCache curr = readRefs();
- RefList<DhtRef> packed = RefList.emptyList();
- RefList<DhtRef> loose = curr.ids;
- RefList.Builder<DhtRef> sym = new RefList.Builder<DhtRef>(curr.sym.size());
-
- for (int idx = 0; idx < curr.sym.size(); idx++) {
- DhtRef ref = curr.sym.get(idx);
- String name = ref.getName();
- ref = resolve(ref, 0, loose);
- if (ref != null && ref.getObjectId() != null) {
- sym.add(ref);
- } else {
- // A broken symbolic reference, we have to drop it from the
- // collections the client is about to receive. Should be a
- // rare occurrence so pay a copy penalty.
- int toRemove = loose.find(name);
- if (0 <= toRemove)
- loose = loose.remove(toRemove);
- }
- }
-
- return new RefMap(prefix, packed, loose, sym.toRefList());
- }
-
- private DhtRef resolve(DhtRef ref, int depth, RefList<DhtRef> loose)
- throws IOException {
- if (!ref.isSymbolic())
- return ref;
-
- DhtRef dst = (DhtRef) ref.getTarget();
-
- if (MAX_SYMBOLIC_REF_DEPTH <= depth)
- return null; // claim it doesn't exist
-
- dst = loose.get(dst.getName());
- if (dst == null)
- return ref;
-
- dst = resolve(dst, depth + 1, loose);
- if (dst == null)
- return null;
-
- return new DhtSymbolicRef(
- ref.getName(),
- dst,
- ((DhtSymbolicRef) ref).getRefData());
- }
-
- @Override
- public Ref peel(Ref ref) throws IOException {
- final Ref oldLeaf = ref.getLeaf();
- if (oldLeaf.isPeeled() || oldLeaf.getObjectId() == null)
- return ref;
-
- DhtRef newLeaf = doPeel(oldLeaf);
-
- RefCache cur = readRefs();
- int idx = cur.ids.find(oldLeaf.getName());
- if (0 <= idx && cur.ids.get(idx) == oldLeaf) {
- RefList<DhtRef> newList = cur.ids.set(idx, newLeaf);
- if (cache.compareAndSet(cur, new RefCache(newList, cur)))
- cachePeeledState(oldLeaf, newLeaf);
- }
-
- return recreate(ref, newLeaf);
- }
-
- private void cachePeeledState(Ref oldLeaf, Ref newLeaf) {
- // TODO(spearce) Use an ExecutorService here
- try {
- RepositoryKey repo = repository.getRepositoryKey();
- RefKey key = RefKey.create(repo, newLeaf.getName());
- RefData oldData = ((DhtRef) oldLeaf).getRefData();
- RefData newData = ((DhtRef) newLeaf).getRefData();
- db.ref().compareAndPut(key, oldData, newData);
- } catch (TimeoutException e) {
- // Ignore a timeout here, we were only trying to update
- // a cached value to save peeling costs in the future.
-
- } catch (DhtException e) {
- // Ignore a database error, this was only an attempt to
- // fix a value that could be cached to save time later.
- }
- }
-
- private DhtRef doPeel(final Ref leaf) throws MissingObjectException,
- IOException {
- RevWalk rw = new RevWalk(getRepository());
- try {
- DhtReader ctx = (DhtReader) rw.getObjectReader();
- RevObject obj = rw.parseAny(leaf.getObjectId());
- RefData.Builder d = RefData.newBuilder(((DhtRef) leaf).getRefData());
-
- ChunkKey oKey = ctx.findChunk(leaf.getObjectId());
- if (oKey != null)
- d.getTargetBuilder().setChunkKey(oKey.asString());
- else
- d.getTargetBuilder().clearChunkKey();
-
- if (obj instanceof RevTag) {
- ObjectId pId = rw.peel(obj);
- d.getPeeledBuilder().setObjectName(pId.name());
-
- ChunkKey pKey = ctx.findChunk(pId);
- if (pKey != null)
- d.getPeeledBuilder().setChunkKey(pKey.asString());
- else
- d.getPeeledBuilder().clearChunkKey();
- } else {
- d.clearPeeled();
- }
-
- d.setIsPeeled(true);
- d.setSequence(d.getSequence() + 1);
- return new DhtObjectIdRef(leaf.getName(), d.build());
- } finally {
- rw.release();
- }
- }
-
- private static Ref recreate(final Ref old, final Ref leaf) {
- if (old.isSymbolic()) {
- Ref dst = recreate(old.getTarget(), leaf);
- return new SymbolicRef(old.getName(), dst);
- }
- return leaf;
- }
-
- @Override
- public DhtRefUpdate newUpdate(String refName, boolean detach)
- throws IOException {
- boolean detachingSymbolicRef = false;
- DhtRef ref = getOneRef(refName);
- if (ref == null)
- ref = new DhtObjectIdRef(refName, NONE);
- else
- detachingSymbolicRef = detach && ref.isSymbolic();
-
- if (detachingSymbolicRef) {
- RefData src = ((DhtRef) ref.getLeaf()).getRefData();
- RefData.Builder b = RefData.newBuilder(ref.getRefData());
- b.clearSymref();
- b.setTarget(src.getTarget());
- ref = new DhtObjectIdRef(refName, b.build());
- }
-
- RepositoryKey repo = repository.getRepositoryKey();
- DhtRefUpdate update = new DhtRefUpdate(this, repo, db, ref);
- if (detachingSymbolicRef)
- update.setDetachingSymbolicRef();
- return update;
- }
-
- @Override
- public RefRename newRename(String fromName, String toName)
- throws IOException {
- DhtRefUpdate src = newUpdate(fromName, true);
- DhtRefUpdate dst = newUpdate(toName, true);
- return new DhtRefRename(src, dst);
- }
-
- @Override
- public boolean isNameConflicting(String refName) throws IOException {
- RefList<DhtRef> all = readRefs().ids;
-
- // Cannot be nested within an existing reference.
- int lastSlash = refName.lastIndexOf('/');
- while (0 < lastSlash) {
- String needle = refName.substring(0, lastSlash);
- if (all.contains(needle))
- return true;
- lastSlash = refName.lastIndexOf('/', lastSlash - 1);
- }
-
- // Cannot be the container of an existing reference.
- String prefix = refName + '/';
- int idx = -(all.find(prefix) + 1);
- if (idx < all.size() && all.get(idx).getName().startsWith(prefix))
- return true;
- return false;
- }
-
- @Override
- public void create() {
- // Nothing to do.
- }
-
- @Override
- public void close() {
- clearCache();
- }
-
- void clearCache() {
- cache.set(null);
- }
-
- void stored(String refName, RefData newData) {
- DhtRef ref = fromData(refName, newData);
- RefCache oldCache, newCache;
- do {
- oldCache = cache.get();
- if (oldCache == null)
- return;
-
- RefList<DhtRef> ids = oldCache.ids.put(ref);
- RefList<DhtRef> sym = oldCache.sym;
-
- if (ref.isSymbolic()) {
- sym = sym.put(ref);
- } else {
- int p = sym.find(refName);
- if (0 <= p)
- sym = sym.remove(p);
- }
-
- newCache = new RefCache(ids, sym, oldCache.hints);
- } while (!cache.compareAndSet(oldCache, newCache));
- }
-
- void removed(String refName) {
- RefCache oldCache, newCache;
- do {
- oldCache = cache.get();
- if (oldCache == null)
- return;
-
- int p;
-
- RefList<DhtRef> ids = oldCache.ids;
- p = ids.find(refName);
- if (0 <= p)
- ids = ids.remove(p);
-
- RefList<DhtRef> sym = oldCache.sym;
- p = sym.find(refName);
- if (0 <= p)
- sym = sym.remove(p);
-
- newCache = new RefCache(ids, sym, oldCache.hints);
- } while (!cache.compareAndSet(oldCache, newCache));
- }
-
- private RefCache readRefs() throws DhtException {
- RefCache c = cache.get();
- if (c == null) {
- try {
- c = read();
- } catch (TimeoutException e) {
- throw new DhtTimeoutException(e);
- }
- cache.set(c);
- }
- return c;
- }
-
- private RefCache read() throws DhtException, TimeoutException {
- RefList.Builder<DhtRef> id = new RefList.Builder<DhtRef>();
- RefList.Builder<DhtRef> sym = new RefList.Builder<DhtRef>();
- ObjectIdSubclassMap<IdWithChunk> hints = new ObjectIdSubclassMap<IdWithChunk>();
-
- for (Map.Entry<RefKey, RefData> e : scan()) {
- DhtRef ref = fromData(e.getKey().getName(), e.getValue());
-
- if (ref.isSymbolic())
- sym.add(ref);
- id.add(ref);
-
- if (ref.getObjectId() instanceof IdWithChunk
- && !hints.contains(ref.getObjectId()))
- hints.add((IdWithChunk) ref.getObjectId());
- if (ref.getPeeledObjectId() instanceof IdWithChunk
- && !hints.contains(ref.getPeeledObjectId()))
- hints.add((IdWithChunk) ref.getPeeledObjectId());
- }
-
- id.sort();
- sym.sort();
-
- return new RefCache(id.toRefList(), sym.toRefList(), hints);
- }
-
- static DhtRef fromData(String name, RefData data) {
- if (data.hasSymref())
- return new DhtSymbolicRef(name, data);
- else
- return new DhtObjectIdRef(name, data);
- }
-
- private static ObjectId idFrom(RefData.Id src) {
- ObjectId id = ObjectId.fromString(src.getObjectName());
- if (!src.hasChunkKey())
- return id;
- return new IdWithChunk(id, ChunkKey.fromString(src.getChunkKey()));
- }
-
- private Set<Map.Entry<RefKey, RefData>> scan() throws DhtException,
- TimeoutException {
- // TODO(spearce) Do we need to perform READ_REPAIR here?
- RepositoryKey repo = repository.getRepositoryKey();
- return db.ref().getAll(Context.LOCAL, repo).entrySet();
- }
-
- private static class RefCache {
- final RefList<DhtRef> ids;
-
- final RefList<DhtRef> sym;
-
- final ObjectIdSubclassMap<IdWithChunk> hints;
-
- RefCache(RefList<DhtRef> ids, RefList<DhtRef> sym,
- ObjectIdSubclassMap<IdWithChunk> hints) {
- this.ids = ids;
- this.sym = sym;
- this.hints = hints;
- }
-
- RefCache(RefList<DhtRef> ids, RefCache old) {
- this(ids, old.sym, old.hints);
- }
- }
-
- static interface DhtRef extends Ref {
- RefData getRefData();
- }
-
- private static class DhtSymbolicRef extends SymbolicRef implements DhtRef {
- private final RefData data;
-
- DhtSymbolicRef(String refName,RefData data) {
- super(refName, new DhtObjectIdRef(data.getSymref(), NONE));
- this.data = data;
- }
-
- DhtSymbolicRef(String refName, Ref target, RefData data) {
- super(refName, target);
- this.data = data;
- }
-
- public RefData getRefData() {
- return data;
- }
- }
-
- private static class DhtObjectIdRef implements DhtRef {
- private final String name;
- private final RefData data;
- private final ObjectId objectId;
- private final ObjectId peeledId;
-
- DhtObjectIdRef(String name, RefData data) {
- this.name = name;
- this.data = data;
- this.objectId = data.hasTarget() ? idFrom(data.getTarget()) : null;
- this.peeledId = data.hasPeeled() ? idFrom(data.getPeeled()) : null;
- }
-
- public String getName() {
- return name;
- }
-
- public boolean isSymbolic() {
- return false;
- }
-
- public Ref getLeaf() {
- return this;
- }
-
- public Ref getTarget() {
- return this;
- }
-
- public ObjectId getObjectId() {
- return objectId;
- }
-
- public Ref.Storage getStorage() {
- return data.hasTarget() ? LOOSE : NEW;
- }
-
- public boolean isPeeled() {
- return data.getIsPeeled();
- }
-
- public ObjectId getPeeledObjectId() {
- return peeledId;
- }
-
- public RefData getRefData() {
- return data;
- }
- }
- }
|