opendev/gerrit
Code Issues Proposed changes

Refactor the ChangeMessage UUID generation to a common utility

Browse Source 
We also now only hit the database for a new change message sequence
number once each application startup, or once every 2^31 messages.
Since the application startup is going to be the more frequent case
we should only hit the database once.

Signed-off-by: Shawn O. Pearce <sop@google.com>
This commit is contained in:
Shawn O. Pearce
2009-01-13 16:12:46 -08:00
parent 4b1386454d
commit 673d2b2e3a
2 changed files with 60 additions and 6 deletions
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16
appjar/src/main/java/com/google/gerrit/git/MergeOp.java
View File

@@ -20,6 +20,7 @@ import com.google.gerrit.client.reviewdb.ChangeMessage;
import com.google.gerrit.client.reviewdb.PatchSet;
import com.google.gerrit.client.reviewdb.ReviewDb;
import com.google.gerrit.client.rpc.Common;
import com.google.gerrit.server.ChangeUtil;
import com.google.gerrit.server.GerritServer;
import com.google.gwtorm.client.OrmException;
import com.google.gwtorm.client.Transaction;
@@ -39,8 +40,6 @@ import org.spearce.jgit.merge.Merger;
import org.spearce.jgit.revwalk.RevCommit;
import org.spearce.jgit.revwalk.RevSort;
import org.spearce.jgit.revwalk.RevWalk;
import org.spearce.jgit.util.Base64;
import org.spearce.jgit.util.NB;
import java.io.IOException;
import java.util.ArrayList;
@@ -442,9 +441,12 @@ public class MergeOp {
}
private ChangeMessage message(final Change c, final String body) {
final byte[] raw = new byte[4];
NB.encodeInt32(raw, 0, schema.nextChangeMessageId());
final String uuid = Base64.encodeBytes(raw);
final String uuid;
try {
uuid = ChangeUtil.messageUUID(schema);
} catch (OrmException e) {
return null;
}
final ChangeMessage m =
new ChangeMessage(new ChangeMessage.Key(c.getId(), uuid), null);
m.setMessage(body);
@@ -486,7 +488,9 @@ public class MergeOp {
try {
final Transaction txn = schema.beginTransaction();
schema.changes().update(Collections.singleton(c), txn);
schema.changeMessages().insert(Collections.singleton(msg), txn);
if (msg != null) {
schema.changeMessages().insert(Collections.singleton(msg), txn);
}
txn.commit();
break;
} catch (OrmException e) {

50
appjar/src/main/java/com/google/gerrit/server/ChangeUtil.java Normal file
View File

@@ -0,0 +1,50 @@
// 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.server;
import com.google.gerrit.client.reviewdb.ReviewDb;
import com.google.gwtorm.client.OrmException;
import org.spearce.jgit.util.Base64;
import org.spearce.jgit.util.NB;
public class ChangeUtil {
private static int uuidPrefix;
private static int uuidSeq;
/**
* Generate a new unique identifier for change message entities.
*
* @param db the database connection, used to increment the change message
* allocation sequence.
* @return the new unique identifier.
* @throws OrmException the database couldn't be incremented.
*/
public static String messageUUID(final ReviewDb db) throws OrmException {
final byte[] raw = new byte[8];
fill(raw, db);
return Base64.encodeBytes(raw);
}
private static synchronized void fill(byte[] raw, ReviewDb db)
throws OrmException {
if (uuidSeq == 0) {
uuidPrefix = db.nextChangeMessageId();
uuidSeq = Integer.MAX_VALUE;
}
NB.encodeInt32(raw, 0, uuidPrefix);
NB.encodeInt32(raw, 4, uuidSeq--);
}
}