| // Copyright 2012 Google Inc. All Rights Reserved. |
| // |
| // 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.gitiles; |
| |
| import static com.google.common.base.MoreObjects.toStringHelper; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Predicates.not; |
| import static com.google.common.collect.Collections2.filter; |
| import static java.util.Objects.hash; |
| import static org.eclipse.jgit.lib.Constants.R_HEADS; |
| import static org.eclipse.jgit.lib.Constants.R_TAGS; |
| |
| import com.google.common.base.Function; |
| import com.google.common.base.Predicate; |
| import com.google.common.base.Predicates; |
| import com.google.common.base.Throwables; |
| import com.google.common.cache.Cache; |
| import com.google.common.cache.CacheBuilder; |
| import com.google.common.collect.Collections2; |
| import com.google.common.util.concurrent.ExecutionError; |
| |
| import org.eclipse.jgit.errors.IncorrectObjectTypeException; |
| import org.eclipse.jgit.errors.MissingObjectException; |
| import org.eclipse.jgit.lib.ObjectId; |
| import org.eclipse.jgit.lib.Ref; |
| import org.eclipse.jgit.lib.RefDatabase; |
| import org.eclipse.jgit.lib.Repository; |
| import org.eclipse.jgit.revwalk.RevCommit; |
| import org.eclipse.jgit.revwalk.RevSort; |
| import org.eclipse.jgit.revwalk.RevWalk; |
| |
| import java.io.IOException; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Objects; |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.TimeUnit; |
| |
| /** Cache of per-user object visibility. */ |
| public class VisibilityCache { |
| private static class Key { |
| private final Object user; |
| private final String repositoryName; |
| private final ObjectId objectId; |
| |
| private Key(Object user, String repositoryName, ObjectId objectId) { |
| this.user = checkNotNull(user, "user"); |
| this.repositoryName = checkNotNull(repositoryName, "repositoryName"); |
| this.objectId = checkNotNull(objectId, "objectId").copy(); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (o instanceof Key) { |
| Key k = (Key) o; |
| return Objects.equals(user, k.user) |
| && Objects.equals(repositoryName, k.repositoryName) |
| && Objects.equals(objectId, k.objectId); |
| } |
| return false; |
| } |
| |
| @Override |
| public int hashCode() { |
| return hash(user, repositoryName, objectId); |
| } |
| |
| @Override |
| public String toString() { |
| return toStringHelper(this) |
| .add("user", user) |
| .add("repositoryName", repositoryName) |
| .add("objectId", objectId) |
| .toString(); |
| } |
| } |
| |
| private final Cache<Key, Boolean> cache; |
| private final boolean topoSort; |
| |
| public static CacheBuilder<Object, Object> defaultBuilder() { |
| return CacheBuilder.newBuilder().maximumSize(1 << 10).expireAfterWrite(30, TimeUnit.MINUTES); |
| } |
| |
| public VisibilityCache(boolean topoSort) { |
| this(topoSort, defaultBuilder()); |
| } |
| |
| public VisibilityCache(boolean topoSort, CacheBuilder<Object, Object> builder) { |
| this.cache = builder.build(); |
| this.topoSort = topoSort; |
| } |
| |
| public Cache<?, Boolean> getCache() { |
| return cache; |
| } |
| |
| boolean isVisible( |
| final Repository repo, |
| final RevWalk walk, |
| GitilesAccess access, |
| final ObjectId id, |
| final ObjectId... knownReachable) |
| throws IOException { |
| try { |
| return cache.get( |
| new Key(access.getUserKey(), access.getRepositoryName(), id), |
| new Callable<Boolean>() { |
| @Override |
| public Boolean call() throws IOException { |
| return isVisible(repo, walk, id, Arrays.asList(knownReachable)); |
| } |
| }); |
| } catch (ExecutionException e) { |
| Throwables.propagateIfInstanceOf(e.getCause(), IOException.class); |
| throw new IOException(e); |
| } catch (ExecutionError e) { |
| // markUninteresting may overflow on pathological repos with very long |
| // merge chains. Play it safe and return false rather than letting the |
| // error propagate. |
| if (e.getCause() instanceof StackOverflowError) { |
| return false; |
| } |
| throw e; |
| } |
| } |
| |
| private boolean isVisible( |
| Repository repo, RevWalk walk, ObjectId id, Collection<ObjectId> knownReachable) |
| throws IOException { |
| RevCommit commit; |
| try { |
| commit = walk.parseCommit(id); |
| } catch (IncorrectObjectTypeException e) { |
| return false; |
| } |
| |
| // If any reference directly points at the requested object, permit display. |
| // Common for displays of pending patch sets in Gerrit Code Review, or |
| // bookmarks to the commit a tag points at. |
| Collection<Ref> allRefs = repo.getRefDatabase().getRefs(RefDatabase.ALL).values(); |
| for (Ref ref : allRefs) { |
| ref = repo.getRefDatabase().peel(ref); |
| if (id.equals(ref.getObjectId()) || id.equals(ref.getPeeledObjectId())) { |
| return true; |
| } |
| } |
| |
| // Check heads first under the assumption that most requests are for refs |
| // close to a head. Tags tend to be much further back in history and just |
| // clutter up the priority queue in the common case. |
| return isReachableFrom(walk, commit, knownReachable) |
| || isReachableFromRefs(walk, commit, filter(allRefs, refStartsWith(R_HEADS))) |
| || isReachableFromRefs(walk, commit, filter(allRefs, refStartsWith(R_TAGS))) |
| || isReachableFromRefs(walk, commit, filter(allRefs, otherRefs())); |
| } |
| |
| private static Predicate<Ref> refStartsWith(final String prefix) { |
| return new Predicate<Ref>() { |
| @Override |
| public boolean apply(Ref ref) { |
| return ref.getName().startsWith(prefix); |
| } |
| }; |
| } |
| |
| @SuppressWarnings("unchecked") |
| private static Predicate<Ref> otherRefs() { |
| return not( |
| Predicates.<Ref>or( |
| refStartsWith(R_HEADS), refStartsWith(R_TAGS), refStartsWith("refs/changes/"))); |
| } |
| |
| private boolean isReachableFromRefs(RevWalk walk, RevCommit commit, Collection<Ref> refs) |
| throws IOException { |
| return isReachableFrom( |
| walk, |
| commit, |
| Collections2.transform( |
| refs, |
| new Function<Ref, ObjectId>() { |
| @Override |
| public ObjectId apply(Ref ref) { |
| if (ref.getPeeledObjectId() != null) { |
| return ref.getPeeledObjectId(); |
| } else { |
| return ref.getObjectId(); |
| } |
| } |
| })); |
| } |
| |
| private boolean isReachableFrom(RevWalk walk, RevCommit commit, Collection<ObjectId> ids) |
| throws IOException { |
| if (ids.isEmpty()) { |
| return false; |
| } |
| walk.reset(); |
| if (topoSort) { |
| walk.sort(RevSort.TOPO); |
| } |
| walk.markStart(commit); |
| for (ObjectId id : ids) { |
| markUninteresting(walk, id); |
| } |
| // If the commit is reachable from any given tip, it will appear to be |
| // uninteresting to the RevWalk and no output will be produced. |
| return walk.next() == null; |
| } |
| |
| private static void markUninteresting(RevWalk walk, ObjectId id) throws IOException { |
| if (id == null) { |
| return; |
| } |
| try { |
| walk.markUninteresting(walk.parseCommit(id)); |
| } catch (IncorrectObjectTypeException | MissingObjectException e) { |
| // Do nothing, doesn't affect reachability. |
| } |
| } |
| } |