com.google.gerrit.server.patch.DiffOperationsImpl Maven / Gradle / Ivy
// Copyright (C) 2020 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.patch;
import static com.google.gerrit.entities.Patch.COMMIT_MSG;
import static com.google.gerrit.entities.Patch.MERGE_LIST;
import com.google.auto.value.AutoValue;
import com.google.common.collect.ImmutableCollection;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.flogger.FluentLogger;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.entities.Patch;
import com.google.gerrit.entities.Patch.ChangeType;
import com.google.gerrit.entities.Project;
import com.google.gerrit.extensions.client.DiffPreferencesInfo;
import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
import com.google.gerrit.server.cache.CacheModule;
import com.google.gerrit.server.patch.diff.ModifiedFilesCache;
import com.google.gerrit.server.patch.diff.ModifiedFilesCacheImpl;
import com.google.gerrit.server.patch.diff.ModifiedFilesCacheKey;
import com.google.gerrit.server.patch.filediff.FileDiffCache;
import com.google.gerrit.server.patch.filediff.FileDiffCacheImpl;
import com.google.gerrit.server.patch.filediff.FileDiffCacheKey;
import com.google.gerrit.server.patch.filediff.FileDiffOutput;
import com.google.gerrit.server.patch.gitdiff.GitModifiedFilesCacheImpl;
import com.google.gerrit.server.patch.gitdiff.ModifiedFile;
import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl;
import com.google.gerrit.server.patch.gitfilediff.GitFileDiffCacheImpl.DiffAlgorithm;
import com.google.inject.Inject;
import com.google.inject.Module;
import com.google.inject.Singleton;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Collectors;
import org.eclipse.jgit.diff.DiffEntry;
import org.eclipse.jgit.diff.DiffFormatter;
import org.eclipse.jgit.lib.Config;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.util.io.DisabledOutputStream;
/**
* Provides different file diff operations. Uses the underlying Git/Gerrit caches to speed up the
* diff computation.
*/
@Singleton
public class DiffOperationsImpl implements DiffOperations {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
private static final ImmutableMap changeTypeMap =
ImmutableMap.of(
DiffEntry.ChangeType.ADD,
Patch.ChangeType.ADDED,
DiffEntry.ChangeType.MODIFY,
Patch.ChangeType.MODIFIED,
DiffEntry.ChangeType.DELETE,
Patch.ChangeType.DELETED,
DiffEntry.ChangeType.RENAME,
Patch.ChangeType.RENAMED,
DiffEntry.ChangeType.COPY,
Patch.ChangeType.COPIED);
private static final int RENAME_SCORE = 60;
private static final DiffAlgorithm DEFAULT_DIFF_ALGORITHM =
DiffAlgorithm.HISTOGRAM_WITH_FALLBACK_MYERS;
private static final Whitespace DEFAULT_WHITESPACE = Whitespace.IGNORE_NONE;
private final ModifiedFilesCache modifiedFilesCache;
private final FileDiffCache fileDiffCache;
private final BaseCommitUtil baseCommitUtil;
public static Module module() {
return new CacheModule() {
@Override
protected void configure() {
bind(DiffOperations.class).to(DiffOperationsImpl.class);
install(GitModifiedFilesCacheImpl.module());
install(ModifiedFilesCacheImpl.module());
install(GitFileDiffCacheImpl.module());
install(FileDiffCacheImpl.module());
}
};
}
@Inject
public DiffOperationsImpl(
ModifiedFilesCache modifiedFilesCache,
FileDiffCache fileDiffCache,
BaseCommitUtil baseCommit) {
this.modifiedFilesCache = modifiedFilesCache;
this.fileDiffCache = fileDiffCache;
this.baseCommitUtil = baseCommit;
}
@Override
public Map listModifiedFilesAgainstParent(
Project.NameKey project, ObjectId newCommit, int parent, DiffOptions diffOptions)
throws DiffNotAvailableException {
try {
DiffParameters diffParams = computeDiffParameters(project, newCommit, parent);
return getModifiedFiles(diffParams, diffOptions);
} catch (IOException e) {
throw new DiffNotAvailableException(
"Failed to evaluate the parent/base commit for commit " + newCommit, e);
}
}
@Override
public Map loadModifiedFilesAgainstParent(
Project.NameKey project,
ObjectId newCommit,
int parentNum,
DiffOptions diffOptions,
RevWalk revWalk,
Config repoConfig)
throws DiffNotAvailableException {
try {
DiffParameters diffParams = computeDiffParameters(project, newCommit, parentNum);
return loadModifiedFilesWithoutCache(project, diffParams, revWalk, repoConfig);
} catch (IOException e) {
throw new DiffNotAvailableException(
String.format(
"Failed to evaluate the parent/base commit for commit '%s' with parentNum=%d",
newCommit, parentNum),
e);
}
}
@Override
public Map listModifiedFiles(
Project.NameKey project, ObjectId oldCommit, ObjectId newCommit, DiffOptions diffOptions)
throws DiffNotAvailableException {
DiffParameters params =
DiffParameters.builder()
.project(project)
.newCommit(newCommit)
.baseCommit(oldCommit)
.comparisonType(ComparisonType.againstOtherPatchSet())
.build();
return getModifiedFiles(params, diffOptions);
}
@Override
public Map loadModifiedFiles(
Project.NameKey project,
ObjectId oldCommit,
ObjectId newCommit,
DiffOptions diffOptions,
RevWalk revWalk,
Config repoConfig)
throws DiffNotAvailableException {
DiffParameters params =
DiffParameters.builder()
.project(project)
.newCommit(newCommit)
.baseCommit(oldCommit)
.comparisonType(ComparisonType.againstOtherPatchSet())
.build();
return loadModifiedFilesWithoutCache(project, params, revWalk, repoConfig);
}
@Override
public FileDiffOutput getModifiedFileAgainstParent(
Project.NameKey project,
ObjectId newCommit,
int parent,
String fileName,
@Nullable DiffPreferencesInfo.Whitespace whitespace)
throws DiffNotAvailableException {
try {
DiffParameters diffParams = computeDiffParameters(project, newCommit, parent);
FileDiffCacheKey key =
createFileDiffCacheKey(
project,
diffParams.baseCommit(),
newCommit,
fileName,
DEFAULT_DIFF_ALGORITHM,
/* useTimeout= */ true,
whitespace);
return getModifiedFileForKey(key);
} catch (IOException e) {
throw new DiffNotAvailableException(
"Failed to evaluate the parent/base commit for commit " + newCommit, e);
}
}
@Override
public FileDiffOutput getModifiedFile(
Project.NameKey project,
ObjectId oldCommit,
ObjectId newCommit,
String fileName,
@Nullable DiffPreferencesInfo.Whitespace whitespace)
throws DiffNotAvailableException {
FileDiffCacheKey key =
createFileDiffCacheKey(
project,
oldCommit,
newCommit,
fileName,
DEFAULT_DIFF_ALGORITHM,
/* useTimeout= */ true,
whitespace);
return getModifiedFileForKey(key);
}
private ImmutableMap getModifiedFiles(
DiffParameters diffParams, DiffOptions diffOptions) throws DiffNotAvailableException {
try {
Project.NameKey project = diffParams.project();
ObjectId newCommit = diffParams.newCommit();
ObjectId oldCommit = diffParams.baseCommit();
ComparisonType cmp = diffParams.comparisonType();
ImmutableList modifiedFiles =
modifiedFilesCache.get(createModifiedFilesKey(project, oldCommit, newCommit));
List fileCacheKeys = new ArrayList<>();
fileCacheKeys.add(
createFileDiffCacheKey(
project,
oldCommit,
newCommit,
COMMIT_MSG,
DEFAULT_DIFF_ALGORITHM,
/* useTimeout= */ true,
/* whitespace= */ null));
if (cmp.isAgainstAutoMerge() || isMergeAgainstParent(cmp, project, newCommit)) {
fileCacheKeys.add(
createFileDiffCacheKey(
project,
oldCommit,
newCommit,
MERGE_LIST,
DEFAULT_DIFF_ALGORITHM,
/* useTimeout= */ true,
/*whitespace = */ null));
}
if (diffParams.skipFiles() == null) {
modifiedFiles.stream()
.map(
entity ->
createFileDiffCacheKey(
project,
oldCommit,
newCommit,
entity.newPath().isPresent()
? entity.newPath().get()
: entity.oldPath().get(),
DEFAULT_DIFF_ALGORITHM,
/* useTimeout= */ true,
/* whitespace= */ null))
.forEach(fileCacheKeys::add);
}
return getModifiedFilesForKeys(fileCacheKeys, diffOptions);
} catch (IOException e) {
throw new DiffNotAvailableException(e);
}
}
private FileDiffOutput getModifiedFileForKey(FileDiffCacheKey key)
throws DiffNotAvailableException {
Map diffList =
getModifiedFilesForKeys(ImmutableList.of(key), DiffOptions.DEFAULTS);
return diffList.containsKey(key.newFilePath())
? diffList.get(key.newFilePath())
: FileDiffOutput.empty(key.newFilePath(), key.oldCommit(), key.newCommit());
}
/**
* Lookup the file diffs for the input {@code keys}. For results where the cache reports negative
* results, e.g. due to timeouts in the cache loader, this method requests the diff again using
* the fallback algorithm {@link DiffAlgorithm#HISTOGRAM_NO_FALLBACK}.
*/
private ImmutableMap getModifiedFilesForKeys(
List keys, DiffOptions diffOptions) throws DiffNotAvailableException {
ImmutableMap fileDiffs = fileDiffCache.getAll(keys);
List fallbackKeys = new ArrayList<>();
ImmutableList.Builder result = ImmutableList.builder();
// Use the fallback diff algorithm for negative results
for (FileDiffCacheKey key : fileDiffs.keySet()) {
FileDiffOutput diff = fileDiffs.get(key);
if (diff.isNegative()) {
FileDiffCacheKey fallbackKey =
createFileDiffCacheKey(
key.project(),
key.oldCommit(),
key.newCommit(),
key.newFilePath(),
// Use the fallback diff algorithm
DiffAlgorithm.HISTOGRAM_NO_FALLBACK,
// We don't enforce timeouts with the fallback algorithm. Timeouts were introduced
// because of a bug in JGit that happens only when the histogram algorithm uses
// Myers as fallback. See https://bugs.chromium.org/p/gerrit/issues/detail?id=487
/* useTimeout= */ false,
key.whitespace());
fallbackKeys.add(fallbackKey);
} else {
result.add(diff);
}
}
result.addAll(fileDiffCache.getAll(fallbackKeys).values());
return mapByFilePath(result.build(), diffOptions);
}
/**
* Map a collection of {@link FileDiffOutput} based on their file paths. The result map keys
* represent the old file path for deleted files, or the new path otherwise.
*/
private ImmutableMap mapByFilePath(
ImmutableCollection fileDiffOutputs, DiffOptions diffOptions) {
ImmutableMap.Builder diffs = ImmutableMap.builder();
for (FileDiffOutput fileDiffOutput : fileDiffOutputs) {
if (fileDiffOutput.isEmpty()
|| (diffOptions.skipFilesWithAllEditsDueToRebase() && allDueToRebase(fileDiffOutput))) {
continue;
}
if (fileDiffOutput.changeType() == ChangeType.DELETED) {
diffs.put(fileDiffOutput.oldPath().get(), fileDiffOutput);
} else {
diffs.put(fileDiffOutput.newPath().get(), fileDiffOutput);
}
}
return diffs.build();
}
private static boolean allDueToRebase(FileDiffOutput fileDiffOutput) {
return fileDiffOutput.allEditsDueToRebase()
&& !(fileDiffOutput.changeType() == ChangeType.RENAMED
|| fileDiffOutput.changeType() == ChangeType.COPIED);
}
private boolean isMergeAgainstParent(ComparisonType cmp, Project.NameKey project, ObjectId commit)
throws IOException {
return (cmp.isAgainstParent() && baseCommitUtil.getNumParents(project, commit) > 1);
}
private static ModifiedFilesCacheKey createModifiedFilesKey(
Project.NameKey project, ObjectId aCommit, ObjectId bCommit) {
return ModifiedFilesCacheKey.builder()
.project(project)
.aCommit(aCommit)
.bCommit(bCommit)
.renameScore(RENAME_SCORE)
.build();
}
private static FileDiffCacheKey createFileDiffCacheKey(
Project.NameKey project,
ObjectId aCommit,
ObjectId bCommit,
String newPath,
DiffAlgorithm diffAlgorithm,
boolean useTimeout,
@Nullable Whitespace whitespace) {
whitespace = whitespace == null ? DEFAULT_WHITESPACE : whitespace;
return FileDiffCacheKey.builder()
.project(project)
.oldCommit(aCommit)
.newCommit(bCommit)
.newFilePath(newPath)
.renameScore(RENAME_SCORE)
.diffAlgorithm(diffAlgorithm)
.whitespace(whitespace)
.useTimeout(useTimeout)
.build();
}
/** Loads the modified file paths between two commits without inspecting the diff cache. */
private static Map loadModifiedFilesWithoutCache(
Project.NameKey project, DiffParameters diffParams, RevWalk revWalk, Config repoConfig)
throws DiffNotAvailableException {
ObjectId newCommit = diffParams.newCommit();
ObjectId oldCommit = diffParams.baseCommit();
try {
ObjectReader reader = revWalk.getObjectReader();
List diffEntries;
try (DiffFormatter df = new DiffFormatter(DisabledOutputStream.INSTANCE)) {
df.setReader(reader, repoConfig);
df.setDetectRenames(false);
diffEntries = df.scan(oldCommit.equals(ObjectId.zeroId()) ? null : oldCommit, newCommit);
}
List modifiedFiles =
diffEntries.stream()
.map(
entry ->
ModifiedFile.builder()
.changeType(toChangeType(entry.getChangeType()))
.oldPath(getGitPath(entry.getOldPath()))
.newPath(getGitPath(entry.getNewPath()))
.build())
.collect(Collectors.toList());
return DiffUtil.mergeRewrittenModifiedFiles(modifiedFiles).stream()
.collect(ImmutableMap.toImmutableMap(ModifiedFile::getDefaultPath, Function.identity()));
} catch (IOException e) {
throw new DiffNotAvailableException(
String.format(
"Failed to compute the modified files for project '%s',"
+ " old commit '%s', new commit '%s'.",
project, oldCommit.name(), newCommit.name()),
e);
}
}
private static Optional getGitPath(String path) {
return path.equals(DiffEntry.DEV_NULL) ? Optional.empty() : Optional.of(path);
}
private static Patch.ChangeType toChangeType(DiffEntry.ChangeType changeType) {
if (!changeTypeMap.containsKey(changeType)) {
throw new IllegalArgumentException("Unsupported type " + changeType);
}
return changeTypeMap.get(changeType);
}
@AutoValue
abstract static class DiffParameters {
abstract Project.NameKey project();
abstract ObjectId newCommit();
/**
* Base commit represents the old commit of the diff. For diffs against the root commit, this
* should be set to {@link ObjectId#zeroId()}.
*/
abstract ObjectId baseCommit();
abstract ComparisonType comparisonType();
@Nullable
abstract Integer parent();
/** Compute the diff for {@value Patch#COMMIT_MSG} and {@link Patch#MERGE_LIST} only. */
@Nullable
abstract Boolean skipFiles();
static Builder builder() {
return new AutoValue_DiffOperationsImpl_DiffParameters.Builder();
}
@AutoValue.Builder
abstract static class Builder {
abstract Builder project(Project.NameKey project);
abstract Builder newCommit(ObjectId newCommit);
abstract Builder baseCommit(ObjectId baseCommit);
abstract Builder parent(@Nullable Integer parent);
abstract Builder skipFiles(@Nullable Boolean skipFiles);
abstract Builder comparisonType(ComparisonType comparisonType);
public abstract DiffParameters build();
}
}
/** Compute Diff parameters - the base commit and the comparison type - using the input args. */
private DiffParameters computeDiffParameters(
Project.NameKey project, ObjectId newCommit, Integer parent) throws IOException {
DiffParameters.Builder result =
DiffParameters.builder().project(project).newCommit(newCommit).parent(parent);
if (parent > 0) {
result.baseCommit(baseCommitUtil.getBaseCommit(project, newCommit, parent));
result.comparisonType(ComparisonType.againstParent(parent));
return result.build();
}
int numParents = baseCommitUtil.getNumParents(project, newCommit);
if (numParents == 0) {
result.baseCommit(ObjectId.zeroId());
result.comparisonType(ComparisonType.againstRoot());
return result.build();
}
if (numParents == 1) {
result.baseCommit(baseCommitUtil.getBaseCommit(project, newCommit, parent));
result.comparisonType(ComparisonType.againstParent(1));
return result.build();
}
if (numParents > 2) {
logger.atFine().log(
"Diff against auto-merge for merge commits "
+ "with more than two parents is not supported. Commit %s has %d parents."
+ " Falling back to the diff against the first parent.",
newCommit, numParents);
result.baseCommit(baseCommitUtil.getBaseCommit(project, newCommit, 1).getId());
result.comparisonType(ComparisonType.againstParent(1));
result.skipFiles(true);
} else {
result.baseCommit(baseCommitUtil.getBaseCommit(project, newCommit, null));
result.comparisonType(ComparisonType.againstAutoMerge());
}
return result.build();
}
}
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