From 8dd7ec93e7bffa08b542c9fbc9805fde3763166d Mon Sep 17 00:00:00 2001
From: akwizgran <akwizgran@users.sourceforge.net>
Date: Wed, 21 Sep 2011 17:51:17 +0100
Subject: [PATCH] DatabaseComponent.generateAck() now returns a boolean.
The return value indicates whether any batch IDs were written.
AckWriter.finish() and Database.removeBatchesToAck() are only called
if at least one batch ID was written.
---
.../sf/briar/api/db/DatabaseComponent.java | 7 +++--
components/net/sf/briar/db/Database.java | 2 +-
.../sf/briar/db/DatabaseComponentImpl.java | 30 +++++++++++++++----
3 files changed, 30 insertions(+), 9 deletions(-)
diff --git a/api/net/sf/briar/api/db/DatabaseComponent.java b/api/net/sf/briar/api/db/DatabaseComponent.java
index 4228f41062..8f54a123fe 100644
--- a/api/net/sf/briar/api/db/DatabaseComponent.java
+++ b/api/net/sf/briar/api/db/DatabaseComponent.java
@@ -69,8 +69,11 @@ public interface DatabaseComponent {
/** Adds a locally generated private message to the database. */
void addLocalPrivateMessage(Message m, ContactId c) throws DbException;
- /** Generates an acknowledgement for the given contact. */
- void generateAck(ContactId c, AckWriter a) throws DbException,
+ /**
+ * Generates an acknowledgement for the given contact.
+ * @return True if any batch IDs were added to the acknowledgement.
+ */
+ boolean generateAck(ContactId c, AckWriter a) throws DbException,
IOException;
/**
diff --git a/components/net/sf/briar/db/Database.java b/components/net/sf/briar/db/Database.java
index f6e679a0ac..99809c23a9 100644
--- a/components/net/sf/briar/db/Database.java
+++ b/components/net/sf/briar/db/Database.java
@@ -161,7 +161,7 @@ interface Database<T> {
* Returns the IDs of any batches received from the given contact that need
* to be acknowledged.
* <p>
- * Locking: contacts read, messageStatuses write.
+ * Locking: contacts read, messageStatuses read.
*/
Collection<BatchId> getBatchesToAck(T txn, ContactId c) throws DbException;
diff --git a/components/net/sf/briar/db/DatabaseComponentImpl.java b/components/net/sf/briar/db/DatabaseComponentImpl.java
index 8b8c7d5c98..a0f7a3b2fc 100644
--- a/components/net/sf/briar/db/DatabaseComponentImpl.java
+++ b/components/net/sf/briar/db/DatabaseComponentImpl.java
@@ -377,20 +377,21 @@ DatabaseCleaner.Callback {
}
}
- public void generateAck(ContactId c, AckWriter a) throws DbException,
+ public boolean generateAck(ContactId c, AckWriter a) throws DbException,
IOException {
contactLock.readLock().lock();
try {
if(!containsContact(c)) throw new NoSuchContactException();
- messageStatusLock.writeLock().lock();
+ Collection<BatchId> sent = new ArrayList<BatchId>();
+ messageStatusLock.readLock().lock();
try {
T txn = db.startTransaction();
try {
Collection<BatchId> acks = db.getBatchesToAck(txn, c);
- Collection<BatchId> sent = new ArrayList<BatchId>();
- for(BatchId b : acks) if(a.writeBatchId(b)) sent.add(b);
- a.finish();
- db.removeBatchesToAck(txn, c, sent);
+ for(BatchId b : acks) {
+ if(!a.writeBatchId(b)) break;
+ sent.add(b);
+ }
if(LOG.isLoggable(Level.FINE))
LOG.fine("Added " + acks.size() + " acks");
db.commitTransaction(txn);
@@ -401,6 +402,23 @@ DatabaseCleaner.Callback {
db.abortTransaction(txn);
throw e;
}
+ } finally {
+ messageStatusLock.readLock().unlock();
+ }
+ // Record the contents of the ack, unless it's empty
+ if(sent.isEmpty()) return false;
+ a.finish();
+ messageStatusLock.writeLock().lock();
+ try {
+ T txn = db.startTransaction();
+ try {
+ db.removeBatchesToAck(txn, c, sent);
+ db.commitTransaction(txn);
+ return true;
+ } catch(DbException e) {
+ db.abortTransaction(txn);
+ throw e;
+ }
} finally {
messageStatusLock.writeLock().unlock();
}
--
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