opendev/gerrit
Code Issues Proposed changes

ReceiveCommits: Split the history negotation hook out

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Advertising history to support finding a common merge base isn't
entirely part of ReceiveCommits. Its just a feature hacked into the
code to support Gerrit Code Review's unique workflow where clients
are frequently behind the server.

Pull this code into its own hook, fired after the ReceiveCommits
specific hook that hides refs/changes and shows open changes as
additional objects.

This refactoring is mostly selfish; the server environment at Google
can benefit from these two unrelated concepts being separate hooks.

Change-Id: I91536f79d7605daf6136eaf8c5417729bfe56c15
This commit is contained in:
Shawn Pearce
2015-09-14 22:49:43 -07:00
parent 1912561ec1
commit 1ca0129613
3 changed files with 165 additions and 65 deletions
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74
gerrit-server/src/main/java/com/google/gerrit/server/git/ReceiveCommitsAdvertiseRefsHook.java
View File

@@ -28,11 +28,8 @@ 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;
@@ -41,6 +38,7 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
@@ -89,15 +87,11 @@ public class ReceiveCommitsAdvertiseRefsHook implements AdvertiseRefsHook {
r.put(name, e.getValue());
}
}
rp.setAdvertisedRefs(r, advertiseHistory(r.values(), rp));
rp.setAdvertisedRefs(r, advertiseOpenChanges());
}
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.
private Set<ObjectId> advertiseOpenChanges() {
// Advertise some recent open changes, in case a commit is based on one.
final int limit = 32;
try {
Set<PatchSet.Id> toGet = Sets.newHashSetWithExpectedSize(limit);
@@ -110,68 +104,18 @@ public class ReceiveCommitsAdvertiseRefsHook implements AdvertiseRefsHook {
toGet.add(id);
}
}
Set<ObjectId> r = Sets.newHashSetWithExpectedSize(toGet.size());
for (PatchSet ps : db.patchSets().get(toGet)) {
if (ps.getRevision() != null && ps.getRevision().get() != null) {
toInclude.add(ObjectId.fromString(ps.getRevision().get()));
r.add(ObjectId.fromString(ps.getRevision().get()));
}
}
return r;
} catch (OrmException err) {
log.error("Cannot list open changes of " + projectName, err);
return Collections.emptySet();
}
// 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) {