| // Copyright 2009 Google Inc. |
| // |
| // 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.git; |
| |
| import com.google.gerrit.client.reviewdb.Branch; |
| import com.google.gerrit.server.GerritServer; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.concurrent.ScheduledThreadPoolExecutor; |
| import java.util.concurrent.TimeUnit; |
| |
| public class MergeQueue { |
| private static ScheduledThreadPoolExecutor pool; |
| private static final Map<Branch.NameKey, MergeEntry> active = |
| new HashMap<Branch.NameKey, MergeEntry>(); |
| |
| public static void terminate() { |
| final ScheduledThreadPoolExecutor p = shutdown(); |
| if (p != null) { |
| boolean isTerminated; |
| do { |
| try { |
| isTerminated = p.awaitTermination(10, TimeUnit.SECONDS); |
| } catch (InterruptedException ie) { |
| isTerminated = false; |
| } |
| } while (!isTerminated); |
| } |
| } |
| |
| private static synchronized ScheduledThreadPoolExecutor shutdown() { |
| final ScheduledThreadPoolExecutor p = pool; |
| if (p != null) { |
| p.shutdown(); |
| pool = null; |
| return p; |
| } |
| return null; |
| } |
| |
| public static void merge(final Branch.NameKey branch) { |
| if (start(branch)) { |
| try { |
| mergeImpl(branch); |
| } finally { |
| finish(branch); |
| } |
| } |
| } |
| |
| public static synchronized boolean start(final Branch.NameKey branch) { |
| final MergeEntry e = active.get(branch); |
| if (e == null) { |
| // Let the caller attempt this merge, its the only one interested |
| // in processing this branch right now. |
| // |
| active.put(branch, new MergeEntry(branch)); |
| return true; |
| } else { |
| // Request that the job queue handle this merge later. |
| // |
| e.needMerge = true; |
| return false; |
| } |
| } |
| |
| public static synchronized void finish(final Branch.NameKey branch) { |
| final MergeEntry e = active.get(branch); |
| if (e == null) { |
| // Not registered for a build? Shouldn't happen but ignore it. |
| // |
| return; |
| } |
| |
| if (!e.needMerge) { |
| // No additional merges are in progress, we can delete it. |
| // |
| active.remove(branch); |
| return; |
| } |
| |
| if (!e.jobScheduled) { |
| // No job has been scheduled to execute this branch, but it needs |
| // to run a merge again. |
| // |
| if (pool == null) { |
| pool = new ScheduledThreadPoolExecutor(1); |
| } |
| |
| e.jobScheduled = true; |
| pool.schedule(new Runnable() { |
| public void run() { |
| unschedule(e); |
| try { |
| mergeImpl(e.dest); |
| } finally { |
| finish(e.dest); |
| } |
| } |
| }, 0, TimeUnit.SECONDS); |
| } |
| } |
| |
| private static synchronized void unschedule(final MergeEntry e) { |
| e.jobScheduled = false; |
| e.needMerge = false; |
| } |
| |
| private static void mergeImpl(final Branch.NameKey branch) { |
| try { |
| new MergeOp(GerritServer.getInstance(), branch).merge(); |
| } catch (Throwable e) { |
| // TODO we should have better logging than stderr |
| e.printStackTrace(); |
| } |
| } |
| |
| private static class MergeEntry { |
| final Branch.NameKey dest; |
| boolean needMerge; |
| boolean jobScheduled; |
| |
| MergeEntry(final Branch.NameKey d) { |
| dest = d; |
| } |
| } |
| } |