| // 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.filediff; |
| |
| import static org.eclipse.jgit.lib.Constants.OBJ_BLOB; |
| |
| import com.google.common.collect.Iterables; |
| import com.google.gerrit.common.Nullable; |
| import com.google.gerrit.entities.Patch; |
| import com.google.gerrit.entities.Patch.FileMode; |
| import com.google.gerrit.exceptions.StorageException; |
| import java.io.IOException; |
| import java.util.Collection; |
| import java.util.Optional; |
| import org.eclipse.jgit.lib.AbbreviatedObjectId; |
| import org.eclipse.jgit.lib.ObjectId; |
| import org.eclipse.jgit.lib.ObjectReader; |
| import org.eclipse.jgit.revwalk.RevTree; |
| import org.eclipse.jgit.treewalk.TreeWalk; |
| |
| /** Helper class for computing the size of a file in a given git tree. */ |
| class FileSizeEvaluator { |
| private final ObjectReader reader; |
| private final RevTree tree; |
| |
| FileSizeEvaluator(ObjectReader reader, RevTree tree) { |
| this.reader = reader; |
| this.tree = tree; |
| } |
| |
| /** |
| * Computes the file size identified by the {@code path} parameter at the given git tree |
| * identified by {@code gitTreeId}. |
| */ |
| long compute(AbbreviatedObjectId gitTreeId, Patch.FileMode mode, String path) throws IOException { |
| if (!isBlob(mode)) { |
| return 0; |
| } |
| ObjectId fileId = |
| toObjectId(reader, gitTreeId).orElseGet(() -> lookupObjectId(reader, path, tree)); |
| if (ObjectId.zeroId().equals(fileId)) { |
| return 0; |
| } |
| return reader.getObjectSize(fileId, OBJ_BLOB); |
| } |
| |
| private static ObjectId lookupObjectId(ObjectReader reader, String path, RevTree tree) { |
| // This variant is very expensive. |
| try (TreeWalk treeWalk = TreeWalk.forPath(reader, path, tree)) { |
| return treeWalk != null ? treeWalk.getObjectId(0) : ObjectId.zeroId(); |
| } catch (IOException e) { |
| throw new StorageException(e); |
| } |
| } |
| |
| private static Optional<ObjectId> toObjectId( |
| ObjectReader reader, @Nullable AbbreviatedObjectId abbreviatedId) throws IOException { |
| if (abbreviatedId == null) { |
| // In theory, DiffEntry#getOldId or DiffEntry#getNewId can be null for pure renames or pure |
| // mode changes (e.g. DiffEntry#modify doesn't set the IDs). However, the method we call for |
| // diffs (DiffFormatter#scan) seems to always produce DiffEntries with set IDs, even for pure |
| // renames. |
| return Optional.empty(); |
| } |
| if (abbreviatedId.isComplete()) { |
| // With the current JGit version and the method we call for diffs (DiffFormatter#scan), |
| // this |
| // is the only code path taken right now. |
| return Optional.ofNullable(abbreviatedId.toObjectId()); |
| } |
| Collection<ObjectId> objectIds = reader.resolve(abbreviatedId); |
| // It seems very unlikely that an ObjectId which was just abbreviated by the diff |
| // computation |
| // now can't be resolved to exactly one ObjectId. The API allows this possibility, though. |
| return objectIds.size() == 1 |
| ? Optional.of(Iterables.getOnlyElement(objectIds)) |
| : Optional.empty(); |
| } |
| |
| private static boolean isBlob(Patch.FileMode mode) { |
| return mode.equals(FileMode.REGULAR_FILE) |
| || mode.equals(FileMode.EXECUTABLE_FILE) |
| || mode.equals(FileMode.SYMLINK); |
| } |
| } |