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// Copyright (C) 2009 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 java.nio.charset.StandardCharsets.UTF_8;
import com.google.gerrit.entities.Patch;
import com.google.gerrit.exceptions.NoSuchEntityException;
import com.google.gerrit.server.patch.filediff.FileDiffOutput;
import java.io.IOException;
import java.util.Map;
import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;
/** State supporting processing of a single {@link Patch} instance. */
public class PatchFile {
private final Repository repo;
private final FileDiffOutput diff;
private final RevTree aTree;
private final RevTree bTree;
// Full text of both sides of the file. For standard files, these are not directly reconstructable
// from the PatchListEntry, which comes from the PatchListCache and only contains the diff between
// the two blobs. This is intentional, to avoid storing entire large blobs in the cache. For
// regular files, the full text is initialized from the repo lazily only when necessary, e.g. in
// getLine. Although it's a safe assumption that any caller constructing a PatchSet will want to
// read some content, we don't know in advance which side they are interested in.
//
// For special files like COMMIT_MSG, the full text is loaded eagerly during the constructor.
// TODO(dborowitz): I see why the logic is different, but I don't see why it needs to be eager.
private Text a;
private Text b;
public PatchFile(Repository repo, Map<String, FileDiffOutput> modifiedFiles, String fileName)
throws IOException {
this.repo = repo;
this.diff =
modifiedFiles.entrySet().stream()
.filter(f -> f.getKey().equals(fileName))
.map(Map.Entry::getValue)
.findFirst()
.orElse(FileDiffOutput.empty(fileName, ObjectId.zeroId(), ObjectId.zeroId()));
if (Patch.PATCHSET_LEVEL.equals(fileName)) {
aTree = null;
bTree = null;
return;
}
try (ObjectReader reader = repo.newObjectReader();
RevWalk rw = new RevWalk(reader)) {
final RevCommit bCommit = rw.parseCommit(diff.newCommitId());
if (Patch.COMMIT_MSG.equals(fileName)) {
if (diff.comparisonType().isAgainstParentOrAutoMerge()) {
a = Text.EMPTY;
} else {
// For the initial commit, we have an empty tree on Side A
RevObject object = rw.parseAny(diff.oldCommitId());
a = object instanceof RevCommit ? Text.forCommit(reader, object) : Text.EMPTY;
}
b = Text.forCommit(reader, bCommit);
aTree = null;
bTree = null;
} else if (Patch.MERGE_LIST.equals(fileName)) {
// For the initial commit, we have an empty tree on Side A
RevObject object = rw.parseAny(diff.oldCommitId());
a =
object instanceof RevCommit
? Text.forMergeList(diff.comparisonType(), reader, object)
: Text.EMPTY;
b = Text.forMergeList(diff.comparisonType(), reader, bCommit);
aTree = null;
bTree = null;
} else {
if (diff.oldCommitId() != null) {
if (diff.oldCommitId().equals(ObjectId.zeroId())) {
// DiffOperations returns ObjectId.zeroId if newCommit is a root commit, i.e. has no
// parents.
aTree = null;
} else {
aTree = rw.parseTree(diff.oldCommitId());
}
} else {
final RevCommit p = bCommit.getParent(0);
rw.parseHeaders(p);
aTree = p.getTree();
}
bTree = bCommit.getTree();
}
}
}
private String getOldName() {
String name = FilePathAdapter.getOldPath(diff.oldPath(), diff.changeType());
if (name != null) {
return name;
}
return FilePathAdapter.getNewPath(diff.oldPath(), diff.newPath(), diff.changeType());
}
/**
* Extract a line from the file, as a string.
*
* @param file the file index to extract.
* @param line the line number to extract (1 based; 1 is the first line).
* @return the string version of the file line.
* @throws IOException the patch or complete file content cannot be read.
*/
public String getLine(int file, int line) throws IOException, NoSuchEntityException {
switch (file) {
case 0:
if (a == null) {
a = load(aTree, getOldName());
}
return a.getString(line - 1);
case 1:
if (b == null) {
b =
load(
bTree,
FilePathAdapter.getNewPath(diff.oldPath(), diff.newPath(), diff.changeType()));
}
return b.getString(line - 1);
default:
throw new NoSuchEntityException();
}
}
private Text load(ObjectId tree, String path)
throws MissingObjectException, IncorrectObjectTypeException, CorruptObjectException,
IOException {
if (path == null || Patch.PATCHSET_LEVEL.equals(path)) {
return Text.EMPTY;
}
final TreeWalk tw = TreeWalk.forPath(repo, path, tree);
if (tw == null) {
return Text.EMPTY;
}
if (tw.getFileMode(0).getObjectType() == Constants.OBJ_BLOB) {
return new Text(repo.open(tw.getObjectId(0), Constants.OBJ_BLOB));
} else if (tw.getFileMode(0).getObjectType() == Constants.OBJ_COMMIT) {
String str = "Subproject commit " + ObjectId.toString(tw.getObjectId(0));
return new Text(str.getBytes(UTF_8));
} else {
return Text.EMPTY;
}
}
}