Java tutorial
// Copyright (C) 2010 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.git; import static org.eclipse.jgit.lib.RefDatabase.ALL; import com.google.common.collect.Maps; import com.google.common.collect.Sets; import com.google.gerrit.reviewdb.client.PatchSet; import com.google.gerrit.reviewdb.client.Project; import com.google.gerrit.reviewdb.client.RefNames; import com.google.gerrit.reviewdb.server.ReviewDb; import com.google.gerrit.server.query.change.ChangeData; import com.google.gerrit.server.query.change.InternalChangeQuery; import com.google.gerrit.server.util.MagicBranch; import com.google.gwtorm.server.OrmException; import com.google.inject.Provider; import org.eclipse.jgit.lib.Constants; import org.eclipse.jgit.lib.ObjectId; import org.eclipse.jgit.lib.Ref; import org.eclipse.jgit.revwalk.RevCommit; import org.eclipse.jgit.revwalk.RevWalk; import org.eclipse.jgit.transport.AdvertiseRefsHook; import org.eclipse.jgit.transport.BaseReceivePack; import org.eclipse.jgit.transport.ServiceMayNotContinueException; import org.eclipse.jgit.transport.UploadPack; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.util.Map; import java.util.Set; /** Exposes only the non refs/changes/ reference names. */ public class ReceiveCommitsAdvertiseRefsHook implements AdvertiseRefsHook { private static final Logger log = LoggerFactory.getLogger(ReceiveCommitsAdvertiseRefsHook.class); private final ReviewDb db; private final Provider<InternalChangeQuery> queryProvider; private final Project.NameKey projectName; public ReceiveCommitsAdvertiseRefsHook(ReviewDb db, Provider<InternalChangeQuery> queryProvider, Project.NameKey projectName) { this.db = db; this.queryProvider = queryProvider; this.projectName = projectName; } @Override public void advertiseRefs(UploadPack us) { throw new UnsupportedOperationException("ReceiveCommitsAdvertiseRefsHook cannot be used for UploadPack"); } @Override public void advertiseRefs(BaseReceivePack rp) throws ServiceMayNotContinueException { Map<String, Ref> oldRefs = rp.getAdvertisedRefs(); if (oldRefs == null) { try { oldRefs = rp.getRepository().getRefDatabase().getRefs(ALL); } catch (ServiceMayNotContinueException e) { throw e; } catch (IOException e) { ServiceMayNotContinueException ex = new ServiceMayNotContinueException(); ex.initCause(e); throw ex; } } Map<String, Ref> r = Maps.newHashMapWithExpectedSize(oldRefs.size()); for (Map.Entry<String, Ref> e : oldRefs.entrySet()) { String name = e.getKey(); if (!skip(name)) { r.put(name, e.getValue()); } } rp.setAdvertisedRefs(r, advertiseHistory(r.values(), rp)); } private Set<ObjectId> advertiseHistory(Iterable<Ref> sending, BaseReceivePack rp) { Set<ObjectId> toInclude = Sets.newHashSet(); // Advertise some recent open changes, in case a commit is based one. final int limit = 32; try { Set<PatchSet.Id> toGet = Sets.newHashSetWithExpectedSize(limit); for (ChangeData cd : queryProvider.get().enforceVisibility(true).setLimit(limit) .byProjectOpen(projectName)) { PatchSet.Id id = cd.change().currentPatchSetId(); if (id != null) { toGet.add(id); } } for (PatchSet ps : db.patchSets().get(toGet)) { if (ps.getRevision() != null && ps.getRevision().get() != null) { toInclude.add(ObjectId.fromString(ps.getRevision().get())); } } } catch (OrmException err) { log.error("Cannot list open changes of " + projectName, err); } // Size of an additional ".have" line. final int haveLineLen = 4 + Constants.OBJECT_ID_STRING_LENGTH + 1 + 5 + 1; // Maximum number of bytes to "waste" in the advertisement with // a peek at this repository's current reachable history. final int maxExtraSize = 8192; // Number of recent commits to advertise immediately, hoping to // show a client a nearby merge base. final int base = 64; // Number of commits to skip once base has already been shown. final int step = 16; // Total number of commits to extract from the history. final int max = maxExtraSize / haveLineLen; // Scan history until the advertisement is full. Set<ObjectId> alreadySending = Sets.newHashSet(); RevWalk rw = rp.getRevWalk(); for (Ref ref : sending) { try { if (ref.getObjectId() != null) { alreadySending.add(ref.getObjectId()); rw.markStart(rw.parseCommit(ref.getObjectId())); } } catch (IOException badCommit) { continue; } } int stepCnt = 0; RevCommit c; try { while ((c = rw.next()) != null && toInclude.size() < max) { if (alreadySending.contains(c) || toInclude.contains(c) || c.getParentCount() > 1) { // Do nothing } else if (toInclude.size() < base) { toInclude.add(c); } else { stepCnt = ++stepCnt % step; if (stepCnt == 0) { toInclude.add(c); } } } } catch (IOException err) { log.error("Error trying to advertise history on " + projectName, err); } rw.reset(); return toInclude; } private static boolean skip(String name) { return name.startsWith(RefNames.REFS_CHANGES) || name.startsWith(RefNames.REFS_CACHE_AUTOMERGE) || MagicBranch.isMagicBranch(name); } }