From e214c40b1189e46cd3325793fd50a894d1ad4da1 Mon Sep 17 00:00:00 2001
From: akwizgran <akwizgran@users.sourceforge.net>
Date: Fri, 14 Oct 2011 22:48:16 +0100
Subject: [PATCH] Code cleanup and comments.
---
.../transport/stream/StreamConnection.java | 85 +++++++++++--------
1 file changed, 51 insertions(+), 34 deletions(-)
diff --git a/components/net/sf/briar/transport/stream/StreamConnection.java b/components/net/sf/briar/transport/stream/StreamConnection.java
index b0a5325df0..d901ccdc43 100644
--- a/components/net/sf/briar/transport/stream/StreamConnection.java
+++ b/components/net/sf/briar/transport/stream/StreamConnection.java
@@ -52,9 +52,9 @@ abstract class StreamConnection implements DatabaseListener {
protected final ContactId contactId;
protected final StreamTransportConnection connection;
- // The following fields must only be accessed with this's lock held
+ // These fields must only be accessed with this's lock held
private int writerFlags = 0;
- private Collection<MessageId> outgoingOffer = null;
+ private Collection<MessageId> offered = null;
private Collection<MessageId> requested = null;
private Offer incomingOffer = null;
@@ -107,6 +107,7 @@ abstract class StreamConnection implements DatabaseListener {
db.receiveBatch(contactId, b);
} else if(proto.hasOffer()) {
Offer o = proto.readOffer();
+ // Store the incoming offer and notify the writer
synchronized(this) {
writerFlags |= Flags.OFFER_RECEIVED;
incomingOffer = o;
@@ -114,31 +115,33 @@ abstract class StreamConnection implements DatabaseListener {
}
} else if(proto.hasRequest()) {
Request r = proto.readRequest();
- Collection<MessageId> offered, seen, unseen;
+ // Retrieve the offered message IDs
+ Collection<MessageId> off;
synchronized(this) {
- if(outgoingOffer == null)
+ if(offered == null)
throw new IOException("Unexpected request packet");
- offered = outgoingOffer;
+ off = offered;
+ offered = null;
}
// Work out which messages were requested
BitSet b = r.getBitmap();
- seen = new ArrayList<MessageId>();
- unseen = new LinkedList<MessageId>();
+ Collection<MessageId> req = new LinkedList<MessageId>();
+ Collection<MessageId> seen = new ArrayList<MessageId>();
int i = 0;
- for(MessageId m : offered) {
- if(b.get(i++)) unseen.add(m);
+ for(MessageId m : off) {
+ if(b.get(i++)) req.add(m);
else seen.add(m);
}
+ // Mark the unrequested messages as seen
+ db.setSeen(contactId, seen);
+ // Store the requested message IDs and notify the writer
synchronized(this) {
- assert outgoingOffer != null;
- if(requested != null && !requested.isEmpty())
+ if(requested != null)
throw new IOException("Unexpected request packet");
- outgoingOffer = null;
- requested = unseen;
+ requested = req;
writerFlags |= Flags.REQUEST_RECEIVED;
notifyAll();
}
- db.setSeen(contactId, seen);
} else if(proto.hasSubscriptionUpdate()) {
SubscriptionUpdate s = proto.readSubscriptionUpdate();
db.receiveSubscriptionUpdate(contactId, s);
@@ -179,12 +182,12 @@ abstract class StreamConnection implements DatabaseListener {
sendAcks(ackWriter);
State state = State.SEND_OFFER;
// Main loop
- boolean close = false;
- while(!close) {
+ while(true) {
int flags = 0;
switch(state) {
case SEND_OFFER:
+ // Try to send an offer
if(sendOffer(offerWriter)) state = State.AWAIT_REQUEST;
else state = State.IDLE;
break;
@@ -203,8 +206,8 @@ abstract class StreamConnection implements DatabaseListener {
// Handle the flags in approximate order of urgency
if((flags & Flags.CONTACTS_UPDATED) != 0) {
if(!db.getContacts().contains(contactId)) {
- close = true;
- break;
+ connection.dispose(true);
+ return;
}
}
if((flags & Flags.TRANSPORTS_UPDATED) != 0) {
@@ -220,6 +223,7 @@ abstract class StreamConnection implements DatabaseListener {
sendRequest(requestWriter);
}
if((flags & Flags.REQUEST_RECEIVED) != 0) {
+ // Should only be received in state AWAIT_REQUEST
throw new IOException("Unexpected request packet");
}
if((flags & Flags.MESSAGES_ADDED) != 0) {
@@ -241,8 +245,8 @@ abstract class StreamConnection implements DatabaseListener {
// Handle the flags in approximate order of urgency
if((flags & Flags.CONTACTS_UPDATED) != 0) {
if(!db.getContacts().contains(contactId)) {
- close = true;
- break;
+ connection.dispose(true);
+ return;
}
}
if((flags & Flags.TRANSPORTS_UPDATED) != 0) {
@@ -274,8 +278,8 @@ abstract class StreamConnection implements DatabaseListener {
// Handle the flags in approximate order of urgency
if((flags & Flags.CONTACTS_UPDATED) != 0) {
if(!db.getContacts().contains(contactId)) {
- close = true;
- break;
+ connection.dispose(true);
+ return;
}
}
if((flags & Flags.TRANSPORTS_UPDATED) != 0) {
@@ -291,12 +295,13 @@ abstract class StreamConnection implements DatabaseListener {
sendRequest(requestWriter);
}
if((flags & Flags.REQUEST_RECEIVED) != 0) {
+ // Should only be received in state AWAIT_REQUEST
throw new IOException("Unexpected request packet");
}
if((flags & Flags.MESSAGES_ADDED) != 0) {
// Ignored in this state
}
- // Send a batch if possible, otherwise an offer
+ // Try to send a batch
if(!sendBatch(batchWriter)) state = State.SEND_OFFER;
break;
}
@@ -317,35 +322,47 @@ abstract class StreamConnection implements DatabaseListener {
}
private boolean sendBatch(BatchWriter b) throws DbException, IOException {
- Collection<MessageId> ids;
+ Collection<MessageId> req;
+ // Retrieve the requested message IDs
synchronized(this) {
- assert outgoingOffer == null;
+ assert offered == null;
assert requested != null;
- ids = requested;
+ req = requested;
+ }
+ // Try to generate a batch, updating the collection of message IDs
+ boolean anyAdded = db.generateBatch(contactId, b, req);
+ // If no more batches can be generated, discard the remaining IDs
+ if(!anyAdded) {
+ synchronized(this) {
+ assert offered == null;
+ assert requested == req;
+ requested = null;
+ }
}
- boolean anyAdded = db.generateBatch(contactId, b, ids);
- if(!anyAdded) ids.clear();
return anyAdded;
}
private boolean sendOffer(OfferWriter o) throws DbException, IOException {
- Collection<MessageId> ids = db.generateOffer(contactId, o);
+ // Generate an offer
+ Collection<MessageId> off = db.generateOffer(contactId, o);
+ // Store the offered message IDs
synchronized(this) {
- assert outgoingOffer == null;
- assert requested == null || requested.isEmpty();
- outgoingOffer = ids;
+ assert offered == null;
+ assert requested == null;
+ offered = off;
}
- boolean anyOffered = !ids.isEmpty();
- return anyOffered;
+ return !off.isEmpty();
}
private void sendRequest(RequestWriter r) throws DbException, IOException {
Offer o;
+ // Retrieve the incoming offer
synchronized(this) {
assert incomingOffer != null;
o = incomingOffer;
incomingOffer = null;
}
+ // Process the offer and generate a request
db.receiveOffer(contactId, o, r);
}
--
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