MergeUtil: Use InMemoryInserter for dry runs
As in Ifd9d768d, making flush a no-op is not sufficient to ensure
nothing gets written to the repo.
Bug: Issue 6965
Change-Id: If08e8184b484a0e7ba41fd3e11130d6fb26ed6c6
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeKindCacheImpl.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeKindCacheImpl.java
index f3d1455..389d53a 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeKindCacheImpl.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeKindCacheImpl.java
@@ -27,6 +27,7 @@
import com.google.gerrit.server.cache.CacheModule;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.git.InMemoryInserter;
import com.google.gerrit.server.git.MergeUtil;
import com.google.gerrit.server.project.ProjectCache;
import com.google.gerrit.server.project.ProjectState;
@@ -39,6 +40,7 @@
import org.eclipse.jgit.errors.LargeObjectException;
import org.eclipse.jgit.lib.Config;
import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.merge.ThreeWayMerger;
import org.eclipse.jgit.revwalk.RevCommit;
@@ -217,10 +219,10 @@
// A trivial rebase can be detected by looking for the next commit
// having the same tree as would exist when the prior commit is
// cherry-picked onto the next commit's new first parent.
- ThreeWayMerger merger = MergeUtil.newThreeWayMerger(
- repo, MergeUtil.createDryRunInserter(repo), key.strategyName);
- merger.setBase(prior.getParent(0));
- try {
+ try (ObjectInserter ins = new InMemoryInserter(repo)) {
+ ThreeWayMerger merger =
+ MergeUtil.newThreeWayMerger(repo, ins, key.strategyName);
+ merger.setBase(prior.getParent(0));
if (merger.merge(next.getParent(0), prior)
&& merger.getResultTreeId().equals(next.getTree())) {
return ChangeKind.TRIVIAL_REBASE;
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/git/InMemoryInserter.java b/gerrit-server/src/main/java/com/google/gerrit/server/git/InMemoryInserter.java
new file mode 100644
index 0000000..4c7f637
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/git/InMemoryInserter.java
@@ -0,0 +1,142 @@
+// Copyright (C) 2016 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 static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.collect.ImmutableList;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.lib.AbbreviatedObjectId;
+import org.eclipse.jgit.lib.AnyObjectId;
+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.Repository;
+import org.eclipse.jgit.transport.PackParser;
+
+public class InMemoryInserter extends ObjectInserter {
+ private final ObjectReader reader;
+ private final Map<ObjectId, InsertedObject> inserted = new LinkedHashMap<>();
+ private final boolean closeReader;
+
+ public InMemoryInserter(ObjectReader reader) {
+ this.reader = checkNotNull(reader);
+ closeReader = false;
+ }
+
+ public InMemoryInserter(Repository repo) {
+ this.reader = repo.newObjectReader();
+ closeReader = true;
+ }
+
+ @Override
+ public ObjectId insert(int type, long length, InputStream in) throws IOException {
+ return insert(InsertedObject.create(type, in));
+ }
+
+ @Override
+ public ObjectId insert(int type, byte[] data) {
+ return insert(type, data, 0, data.length);
+ }
+
+ @Override
+ public ObjectId insert(int type, byte[] data, int off, int len) {
+ return insert(InsertedObject.create(type, data, off, len));
+ }
+
+ public ObjectId insert(InsertedObject obj) {
+ inserted.put(obj.id(), obj);
+ return obj.id();
+ }
+
+ @Override
+ public PackParser newPackParser(InputStream in) {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public ObjectReader newReader() {
+ return new Reader();
+ }
+
+ @Override
+ public void flush() {
+ // Do nothing; objects are not written to the repo.
+ }
+
+ @Override
+ public void close() {
+ if (closeReader) {
+ reader.close();
+ }
+ }
+
+ public ImmutableList<InsertedObject> getInsertedObjects() {
+ return ImmutableList.copyOf(inserted.values());
+ }
+
+ public void clear() {
+ inserted.clear();
+ }
+
+ private class Reader extends ObjectReader {
+ @Override
+ public ObjectReader newReader() {
+ return new Reader();
+ }
+
+ @Override
+ public Collection<ObjectId> resolve(AbbreviatedObjectId id) throws IOException {
+ Set<ObjectId> result = new HashSet<>();
+ for (ObjectId insId : inserted.keySet()) {
+ if (id.prefixCompare(insId) == 0) {
+ result.add(insId);
+ }
+ }
+ result.addAll(reader.resolve(id));
+ return result;
+ }
+
+ @Override
+ public ObjectLoader open(AnyObjectId objectId, int typeHint) throws IOException {
+ InsertedObject obj = inserted.get(objectId);
+ if (obj == null) {
+ return reader.open(objectId, typeHint);
+ }
+ if (typeHint != OBJ_ANY && obj.type() != typeHint) {
+ throw new IncorrectObjectTypeException(objectId.copy(), typeHint);
+ }
+ return obj.newLoader();
+ }
+
+ @Override
+ public Set<ObjectId> getShallowCommits() throws IOException {
+ return reader.getShallowCommits();
+ }
+
+ @Override
+ public void close() {
+ // Do nothing; this class owns no open resources.
+ }
+ }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/git/InsertedObject.java b/gerrit-server/src/main/java/com/google/gerrit/server/git/InsertedObject.java
new file mode 100644
index 0000000..8a766af
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/git/InsertedObject.java
@@ -0,0 +1,54 @@
+// Copyright (C) 2016 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.auto.value.AutoValue;
+import com.google.protobuf.ByteString;
+import java.io.IOException;
+import java.io.InputStream;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
+import org.eclipse.jgit.lib.ObjectLoader;
+
+@AutoValue
+public abstract class InsertedObject {
+ static InsertedObject create(int type, InputStream in) throws IOException {
+ return create(type, ByteString.readFrom(in));
+ }
+
+ static InsertedObject create(int type, ByteString bs) {
+ ObjectId id;
+ try (ObjectInserter.Formatter fmt = new ObjectInserter.Formatter()) {
+ id = fmt.idFor(type, bs.size(), bs.newInput());
+ } catch (IOException e) {
+ throw new IllegalStateException(e);
+ }
+ return new AutoValue_InsertedObject(id, type, bs);
+ }
+
+ static InsertedObject create(int type, byte[] src, int off, int len) {
+ return create(type, ByteString.copyFrom(src, off, len));
+ }
+
+ public abstract ObjectId id();
+
+ public abstract int type();
+
+ public abstract ByteString data();
+
+ ObjectLoader newLoader() {
+ return new ObjectLoader.SmallObject(type(), data().toByteArray());
+ }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeUtil.java b/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeUtil.java
index 2025e99..13476ef 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeUtil.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeUtil.java
@@ -66,13 +66,12 @@
import org.eclipse.jgit.revwalk.RevFlag;
import org.eclipse.jgit.revwalk.RevSort;
import org.eclipse.jgit.revwalk.RevWalk;
-import org.eclipse.jgit.transport.PackParser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
-import java.io.InputStream;
import java.io.UnsupportedEncodingException;
+
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
@@ -353,9 +352,9 @@
return false;
}
- ThreeWayMerger m = newThreeWayMerger(repo, createDryRunInserter(repo));
- try {
- return m.merge(new AnyObjectId[] {mergeTip, toMerge});
+ try (ObjectInserter ins = new InMemoryInserter(repo)) {
+ return newThreeWayMerger(repo, ins)
+ .merge(new AnyObjectId[] {mergeTip, toMerge});
} catch (LargeObjectException e) {
log.warn("Cannot merge due to LargeObjectException: " + toMerge.name());
return false;
@@ -401,8 +400,8 @@
// taking the delta relative to that one parent and redoing
// that on the current merge tip.
//
- try {
- ThreeWayMerger m = newThreeWayMerger(repo, createDryRunInserter(repo));
+ try (ObjectInserter ins = new InMemoryInserter(repo)) {
+ ThreeWayMerger m = newThreeWayMerger(repo, ins);
m.setBase(toMerge.getParent(0));
return m.merge(mergeTip, toMerge);
} catch (IOException e) {
@@ -429,26 +428,6 @@
}
}
- public static ObjectInserter createDryRunInserter(Repository db) {
- final ObjectInserter delegate = db.newObjectInserter();
- return new ObjectInserter.Filter() {
- @Override
- protected ObjectInserter delegate() {
- return delegate;
- }
-
- @Override
- public PackParser newPackParser(InputStream in) throws IOException {
- throw new UnsupportedOperationException();
- }
-
- @Override
- public void flush() throws IOException {
- // Do nothing.
- }
- };
- }
-
public CodeReviewCommit mergeOneCommit(PersonIdent author,
PersonIdent committer, Repository repo, CodeReviewRevWalk rw,
ObjectInserter inserter, RevFlag canMergeFlag, Branch.NameKey destBranch,
