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// Copyright (C) 2017 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.filediff;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.collect.ImmutableSet.toImmutableSet;
import static com.google.common.collect.Multimaps.toMultimap;
import com.google.auto.value.AutoValue;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Multimap;
import com.google.common.flogger.FluentLogger;
import com.google.gerrit.entities.Patch;
import com.google.gerrit.server.patch.DiffMappings;
import com.google.gerrit.server.patch.GitPositionTransformer;
import com.google.gerrit.server.patch.GitPositionTransformer.Mapping;
import com.google.gerrit.server.patch.GitPositionTransformer.OmitPositionOnConflict;
import com.google.gerrit.server.patch.GitPositionTransformer.Position;
import com.google.gerrit.server.patch.GitPositionTransformer.PositionedEntity;
import com.google.gerrit.server.patch.GitPositionTransformer.Range;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Stream;
/**
* Transformer of edits regarding their base trees. An edit describes a difference between {@code
* treeA} and {@code treeB}. This class allows to describe the edit as a difference between {@code
* treeA'} and {@code treeB'} given the transformation of {@code treeA} to {@code treeA'} and {@code
* treeB} to {@code treeB'}. Edits which can't be transformed due to conflicts with the
* transformation are omitted.
*/
class EditTransformer {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
private final GitPositionTransformer positionTransformer =
new GitPositionTransformer(OmitPositionOnConflict.INSTANCE);
private ImmutableList<ContextAwareEdit> edits;
/**
* Creates a new {@code EditTransformer} for the edits contained in the specified {@code
* FileEdits}s.
*
* @param fileEdits a list of {@code FileEdits}s containing the edits
*/
public EditTransformer(List<FileEdits> fileEdits) {
// TODO(ghareeb): Can we replace FileEdits with another entity from the new refactored
// diff cache implementation? e.g. one of the GitFileDiffCache entities
edits = fileEdits.stream().flatMap(EditTransformer::toEdits).collect(toImmutableList());
}
/**
* Transforms the references of side A of the edits. If the edits describe differences between
* {@code treeA} and {@code treeB} and the specified {@code FileEdits}s define a transformation
* from {@code treeA} to {@code treeA'}, the resulting edits will be defined as differences
* between {@code treeA'} and {@code treeB}. Edits which can't be transformed due to conflicts
* with the transformation are omitted.
*
* @param transformingEntries a list of {@code FileEdits}s defining the transformation of {@code
* treeA} to {@code treeA'}
*/
public void transformReferencesOfSideA(ImmutableList<FileEdits> transformingEntries) {
transformEdits(transformingEntries, SideAStrategy.INSTANCE);
}
/**
* Transforms the references of side B of the edits. If the edits describe differences between
* {@code treeA} and {@code treeB} and the specified {@code FileEdits}s define a transformation
* from {@code treeB} to {@code treeB'}, the resulting edits will be defined as differences
* between {@code treeA} and {@code treeB'}. Edits which can't be transformed due to conflicts
* with the transformation are omitted.
*
* @param transformingEntries a list of {@code PatchListEntry}s defining the transformation of
* {@code treeB} to {@code treeB'}
*/
public void transformReferencesOfSideB(ImmutableList<FileEdits> transformingEntries) {
transformEdits(transformingEntries, SideBStrategy.INSTANCE);
}
/**
* Returns the transformed edits per file path they modify in {@code treeB'}.
*
* @return the transformed edits per file path
*/
public Multimap<String, ContextAwareEdit> getEditsPerFilePath() {
return edits.stream()
.collect(
toMultimap(
c -> {
String path =
c.getNewFilePath().isPresent()
? c.getNewFilePath().get()
: c.getOldFilePath().get();
return path;
},
Function.identity(),
ArrayListMultimap::create));
}
public static Stream<ContextAwareEdit> toEdits(FileEdits in) {
ImmutableList<Edit> edits = in.edits();
if (edits.isEmpty()) {
return Stream.of(ContextAwareEdit.createForNoContentEdit(in.oldPath(), in.newPath()));
}
return edits.stream().map(edit -> ContextAwareEdit.create(in.oldPath(), in.newPath(), edit));
}
private void transformEdits(List<FileEdits> inputs, SideStrategy sideStrategy) {
ImmutableList<PositionedEntity<ContextAwareEdit>> positionedEdits =
edits.stream()
.map(edit -> toPositionedEntity(edit, sideStrategy))
.collect(toImmutableList());
ImmutableSet<Mapping> mappings =
inputs.stream().map(DiffMappings::toMapping).collect(toImmutableSet());
edits =
positionTransformer.transform(positionedEdits, mappings).stream()
.map(PositionedEntity::getEntityAtUpdatedPosition)
.collect(toImmutableList());
}
private static PositionedEntity<ContextAwareEdit> toPositionedEntity(
ContextAwareEdit edit, SideStrategy sideStrategy) {
return PositionedEntity.create(
edit, sideStrategy::extractPosition, sideStrategy::createEditAtNewPosition);
}
@AutoValue
abstract static class ContextAwareEdit {
static ContextAwareEdit create(Optional<String> oldPath, Optional<String> newPath, Edit edit) {
// TODO(ghareeb): Look if the new FileEdits class is capable of representing renames/copies
// and in this case we can get rid of the ContextAwareEdit class.
return create(
oldPath, newPath, edit.beginA(), edit.endA(), edit.beginB(), edit.endB(), false);
}
static ContextAwareEdit createForNoContentEdit(
Optional<String> oldPath, Optional<String> newPath) {
// Remove the warning in createEditAtNewPosition() if we switch to an empty range instead of
// (-1:-1, -1:-1) in the future.
return create(oldPath, newPath, -1, -1, -1, -1, false);
}
static ContextAwareEdit create(
Optional<String> oldFilePath,
Optional<String> newFilePath,
int beginA,
int endA,
int beginB,
int endB,
boolean filePathAdjusted) {
Optional<String> adjustedFilePath = oldFilePath.isPresent() ? oldFilePath : newFilePath;
boolean implicitRename =
newFilePath.isPresent()
&& oldFilePath.isPresent()
&& !Objects.equals(oldFilePath.get(), newFilePath.get())
&& filePathAdjusted;
return new AutoValue_EditTransformer_ContextAwareEdit(
adjustedFilePath, newFilePath, beginA, endA, beginB, endB, implicitRename);
}
public abstract Optional<String> getOldFilePath();
public abstract Optional<String> getNewFilePath();
public abstract int getBeginA();
public abstract int getEndA();
public abstract int getBeginB();
public abstract int getEndB();
// Used for equals(), for which this value is important.
public abstract boolean isImplicitRename();
public Optional<org.eclipse.jgit.diff.Edit> toEdit() {
if (getBeginA() < 0) {
return Optional.empty();
}
return Optional.of(
new org.eclipse.jgit.diff.Edit(getBeginA(), getEndA(), getBeginB(), getEndB()));
}
}
private interface SideStrategy {
Position extractPosition(ContextAwareEdit edit);
ContextAwareEdit createEditAtNewPosition(ContextAwareEdit edit, Position newPosition);
}
private enum SideAStrategy implements SideStrategy {
INSTANCE;
@Override
public Position extractPosition(ContextAwareEdit edit) {
String filePath =
edit.getOldFilePath().isPresent()
? edit.getOldFilePath().get()
: edit.getNewFilePath().get();
return Position.builder()
.filePath(filePath)
.lineRange(Range.create(edit.getBeginA(), edit.getEndA()))
.build();
}
@Override
public ContextAwareEdit createEditAtNewPosition(ContextAwareEdit edit, Position newPosition) {
// Use an empty range at Gerrit "file level" if no target range is available. Such an empty
// range should not occur right now but this should be a safe fallback if something changes
// in the future.
Range updatedRange = newPosition.lineRange().orElseGet(() -> Range.create(-1, -1));
if (!newPosition.lineRange().isPresent()) {
logger.atWarning().log(
"Position %s has an empty range which is unexpected for the edits-due-to-rebase"
+ " computation. This is likely a regression!",
newPosition);
}
// Same as for the range above. PATCHSET_LEVEL is a safe fallback.
String updatedFilePath = newPosition.filePath().orElse(Patch.PATCHSET_LEVEL);
if (!newPosition.filePath().isPresent()) {
logger.atWarning().log(
"Position %s has an empty file path which is unexpected for the edits-due-to-rebase"
+ " computation. This is likely a regression!",
newPosition);
}
return ContextAwareEdit.create(
Optional.of(updatedFilePath),
edit.getNewFilePath(),
updatedRange.start(),
updatedRange.end(),
edit.getBeginB(),
edit.getEndB(),
!Objects.equals(edit.getOldFilePath(), Optional.of(updatedFilePath)));
}
}
private enum SideBStrategy implements SideStrategy {
INSTANCE;
@Override
public Position extractPosition(ContextAwareEdit edit) {
String filePath =
edit.getNewFilePath().isPresent()
? edit.getNewFilePath().get()
: edit.getOldFilePath().get();
return Position.builder()
.filePath(filePath)
.lineRange(Range.create(edit.getBeginB(), edit.getEndB()))
.build();
}
@Override
public ContextAwareEdit createEditAtNewPosition(ContextAwareEdit edit, Position newPosition) {
// Use an empty range at Gerrit "file level" if no target range is available. Such an empty
// range should not occur right now but this should be a safe fallback if something changes
// in the future.
Range updatedRange = newPosition.lineRange().orElseGet(() -> Range.create(-1, -1));
// Same as far the range above. PATCHSET_LEVEL is a safe fallback.
Optional<String> updatedFilePath =
Optional.of(newPosition.filePath().orElse(Patch.PATCHSET_LEVEL));
return ContextAwareEdit.create(
edit.getOldFilePath(),
updatedFilePath,
edit.getBeginA(),
edit.getEndA(),
updatedRange.start(),
updatedRange.end(),
!Objects.equals(edit.getNewFilePath(), updatedFilePath));
}
}
}