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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.googlesource.gerrit.plugins.analytics.common
import org.eclipse.jgit.diff.{DiffFormatter, RawTextComparator}
import org.eclipse.jgit.lib.{ObjectId, Repository}
import org.eclipse.jgit.revwalk.RevWalk
import org.eclipse.jgit.treewalk.{CanonicalTreeParser, EmptyTreeIterator}
import org.eclipse.jgit.util.io.DisabledOutputStream
import ManagedResource.use
import scala.collection.JavaConversions._
case class CommitsStatistics(numFiles: Int, addedLines: Int, deletedLines: Int)
object CommitsStatistics {
val Empty = CommitsStatistics(0, 0, 0)
}
class Statistics(repo: Repository) {
def find(objectIds: Seq[ObjectId]): CommitsStatistics =
objectIds.foldLeft(CommitsStatistics(0, 0, 0)) {
(acc, objectId) => {
val stats = find(objectId)
CommitsStatistics(acc.numFiles + stats.numFiles, acc.addedLines + stats.addedLines, acc.deletedLines + stats.deletedLines)
}
}
def find(objectId: ObjectId): CommitsStatistics = {
// I can imagine this kind of statistics is already being available in Gerrit but couldn't understand how to access it
// which Injection can be useful for this task?
use(new RevWalk(repo)) { rw =>
val reader = repo.newObjectReader()
val commit = rw.parseCommit(objectId)
val oldTree = {
// protects against initial commit
if (commit.getParentCount == 0)
new EmptyTreeIterator
else
new CanonicalTreeParser(null, reader, rw.parseCommit(commit.getParent(0).getId).getTree)
}
val newTree = new CanonicalTreeParser(null, reader, commit.getTree)
val df = new DiffFormatter(DisabledOutputStream.INSTANCE)
df.setRepository(repo)
df.setDiffComparator(RawTextComparator.DEFAULT)
df.setDetectRenames(true)
val diffs = df.scan(oldTree, newTree)
case class Lines(deleted: Int, added: Int) {
def +(other: Lines) = Lines(deleted + other.deleted, added + other.added)
}
val lines = (for {
diff <- diffs
edit <- df.toFileHeader(diff).toEditList
} yield Lines(edit.getEndA - edit.getBeginA, edit.getEndB - edit.getBeginB)).fold(Lines(0, 0))(_ + _)
CommitsStatistics(diffs.size, lines.added, lines.deleted)
}
}
}