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// 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.change;
import com.google.common.base.Throwables;
import com.google.common.cache.Cache;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Sets;
import com.google.common.flogger.FluentLogger;
import com.google.common.primitives.Ints;
import com.google.gerrit.entities.Change;
import com.google.gerrit.entities.Project;
import com.google.gerrit.exceptions.StorageException;
import com.google.gerrit.extensions.restapi.Url;
import com.google.gerrit.git.ObjectIds;
import com.google.gerrit.index.IndexConfig;
import com.google.gerrit.metrics.Counter1;
import com.google.gerrit.metrics.Description;
import com.google.gerrit.metrics.Field;
import com.google.gerrit.metrics.MetricMaker;
import com.google.gerrit.server.cache.CacheModule;
import com.google.gerrit.server.logging.Metadata;
import com.google.gerrit.server.notedb.ChangeNotes;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gerrit.server.query.change.ChangeData;
import com.google.gerrit.server.query.change.InternalChangeQuery;
import com.google.inject.Inject;
import com.google.inject.Module;
import com.google.inject.Provider;
import com.google.inject.Singleton;
import com.google.inject.name.Named;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import java.util.Set;
import org.eclipse.jgit.errors.RepositoryNotFoundException;
@Singleton
public class ChangeFinder {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
private static final String CACHE_NAME = "changeid_project";
public static Module module() {
return new CacheModule() {
@Override
protected void configure() {
cache(CACHE_NAME, Change.Id.class, String.class).maximumWeight(1024);
}
};
}
public enum ChangeIdType {
ALL,
TRIPLET,
NUMERIC_ID,
I_HASH,
PROJECT_NUMERIC_ID,
COMMIT_HASH
}
private final IndexConfig indexConfig;
private final Cache<Change.Id, String> changeIdProjectCache;
private final Provider<InternalChangeQuery> queryProvider;
private final ChangeNotes.Factory changeNotesFactory;
private final Counter1<ChangeIdType> changeIdCounter;
@Inject
ChangeFinder(
IndexConfig indexConfig,
@Named(CACHE_NAME) Cache<Change.Id, String> changeIdProjectCache,
Provider<InternalChangeQuery> queryProvider,
ChangeNotes.Factory changeNotesFactory,
MetricMaker metricMaker) {
this.indexConfig = indexConfig;
this.changeIdProjectCache = changeIdProjectCache;
this.queryProvider = queryProvider;
this.changeNotesFactory = changeNotesFactory;
this.changeIdCounter =
metricMaker.newCounter(
"http/server/rest_api/change_id_type",
new Description("Total number of API calls per identifier type.")
.setRate()
.setUnit("requests"),
Field.ofEnum(ChangeIdType.class, "change_id_type", Metadata.Builder::changeIdType)
.description("The type of the change identifier.")
.build());
}
public Optional<ChangeNotes> findOne(String id) {
// Limit the maximum number of results to just 2 items for saving CPU cycles
// in reading change-notes.
List<ChangeNotes> ctls = find(id, 2);
if (ctls.size() != 1) {
return Optional.empty();
}
return Optional.of(ctls.get(0));
}
/**
* Find changes matching the given identifier.
*
* @param id change identifier.
* @return possibly-empty list of notes for all matching changes; may or may not be visible.
*/
public List<ChangeNotes> find(String id) {
return find(id, 0);
}
/**
* Find at most N changes matching the given identifier.
*
* @param id change identifier.
* @param queryLimit maximum number of changes to be returned
* @return possibly-empty list of notes for all matching changes; may or may not be visible.
*/
public List<ChangeNotes> find(String id, int queryLimit) {
if (id.isEmpty()) {
return Collections.emptyList();
}
int z = id.lastIndexOf('~');
int y = id.lastIndexOf('~', z - 1);
if (y < 0 && z > 0) {
// Try project~numericChangeId
Integer n = Ints.tryParse(id.substring(z + 1));
if (n != null) {
changeIdCounter.increment(ChangeIdType.PROJECT_NUMERIC_ID);
return fromProjectNumber(id.substring(0, z), n.intValue());
}
}
if (y < 0 && z < 0) {
// Try numeric changeId
Integer n = Ints.tryParse(id);
if (n != null) {
changeIdCounter.increment(ChangeIdType.NUMERIC_ID);
return find(Change.id(n));
}
}
// Use the index to search for changes, but don't return any stored fields,
// to force rereading in case the index is stale.
InternalChangeQuery query = queryProvider.get().noFields();
if (queryLimit > 0) {
query.setLimit(queryLimit);
}
// Try commit hash
if (id.matches("^([0-9a-fA-F]{" + ObjectIds.ABBREV_STR_LEN + "," + ObjectIds.STR_LEN + "})$")) {
changeIdCounter.increment(ChangeIdType.COMMIT_HASH);
return asChangeNotes(query.byCommit(id));
}
if (y > 0 && z > 0) {
// Try change triplet (project~branch~Ihash...)
Optional<ChangeTriplet> triplet = ChangeTriplet.parse(id, y, z);
if (triplet.isPresent()) {
ChangeTriplet t = triplet.get();
changeIdCounter.increment(ChangeIdType.TRIPLET);
return asChangeNotes(query.byBranchKey(t.branch(), t.id()));
}
}
// Try isolated Ihash... format ("Change-Id: Ihash").
List<ChangeNotes> notes = asChangeNotes(query.byKeyPrefix(id));
if (!notes.isEmpty()) {
changeIdCounter.increment(ChangeIdType.I_HASH);
}
return notes;
}
private List<ChangeNotes> fromProjectNumber(String project, int changeNumber) {
Change.Id cId = Change.id(changeNumber);
try {
return ImmutableList.of(
changeNotesFactory.createChecked(Project.NameKey.parse(project), cId));
} catch (NoSuchChangeException e) {
return Collections.emptyList();
} catch (StorageException e) {
// Distinguish between a RepositoryNotFoundException (project argument invalid) and
// other StorageExceptions (failure in the persistence layer).
if (Throwables.getRootCause(e) instanceof RepositoryNotFoundException) {
return Collections.emptyList();
}
throw e;
}
}
public Optional<ChangeNotes> findOne(Change.Id id) {
List<ChangeNotes> notes = find(id);
if (notes.size() != 1) {
return Optional.empty();
}
return Optional.of(notes.get(0));
}
/**
* @deprecated this method is not reliable in Gerrit instances with imported changes, since
* multiple changes can have the same change number and make the `changeIdProjectCache` cache
* pointless.
*/
@Deprecated(since = "3.10", forRemoval = true)
public List<ChangeNotes> find(Change.Id id) {
String project = changeIdProjectCache.getIfPresent(id);
if (project != null) {
return fromProjectNumber(project, id.get());
}
// Use the index to search for changes, but don't return any stored fields,
// to force rereading in case the index is stale.
InternalChangeQuery query = queryProvider.get().noFields();
List<ChangeData> r = query.byLegacyChangeId(id);
if (r.size() == 1) {
changeIdProjectCache.put(id, Url.encode(r.get(0).project().get()));
}
return asChangeNotes(r);
}
private List<ChangeNotes> asChangeNotes(List<ChangeData> cds) {
List<ChangeNotes> notes = new ArrayList<>(cds.size());
if (!indexConfig.separateChangeSubIndexes()) {
for (ChangeData cd : cds) {
try {
notes.add(cd.notes());
} catch (NoSuchChangeException e) {
logger.atWarning().log("Change %s seen in index, but missing in NoteDb", e.getMessage());
}
}
return notes;
}
// If an index implementation uses separate non-atomic subindexes, it's possible to temporarily
// observe a change as present in both subindexes, if this search is concurrent with a write.
// Dedup to avoid confusing the caller. We can choose an arbitrary ChangeData instance because
// the index results have no stored fields, so the data is already reloaded. (It's also possible
// that a change might appear in zero subindexes, but there's nothing we can do here to help
// this case.)
Set<Change.Id> seen = Sets.newHashSetWithExpectedSize(cds.size());
for (ChangeData cd : cds) {
if (seen.add(cd.virtualId())) {
try {
notes.add(cd.notes());
} catch (NoSuchChangeException e) {
logger.atWarning().log("Change %s seen in index, but missing in NoteDb", e.getMessage());
}
}
}
return notes;
}
}