X-Git-Url: https://git.sesse.net/?p=cubemap;a=blobdiff_plain;f=server.cpp;h=7acf501236e1ee2db9cac22db0b72a5ddf8ecf69;hp=5bd0d555c18194ca112a04b21cb3d9344272722e;hb=cabe676b1637ad3d7193d59090f43d271253e81a;hpb=9abb89bcf7940e2ada9d708f86a218a56334f68d

diff --git a/server.cpp b/server.cpp
index 5bd0d55..7acf501 100644
--- a/server.cpp
+++ b/server.cpp
@@ -113,6 +113,19 @@ CubemapStateProto Server::serialize()
 	// We don't serialize anything queued, so empty the queues.
 	process_queued_data();
 
+	// Set all clients in a consistent state before serializing
+	// (ie., they have no remaining lost data). Otherwise, increasing
+	// the backlog could take clients into a newly valid area of the backlog,
+	// sending a stream of zeros instead of skipping the data as it should.
+	//
+	// TODO: Do this when clients are added back from serialized state instead;
+	// it would probably be less wasteful.
+	for (map<int, Client>::iterator client_it = clients.begin();
+	     client_it != clients.end();
+	     ++client_it) {
+		skip_lost_data(&client_it->second);
+	}
+
 	CubemapStateProto serialized;
 	for (map<int, Client>::const_iterator client_it = clients.begin();
 	     client_it != clients.end();
@@ -371,32 +384,28 @@ sending_header_or_error_again:
 		// but we'll start sending immediately as we get data.
 		// This is postcondition #3.
 		client->state = Client::SENDING_DATA;
-		client->stream_pos = client->stream->bytes_received;
+		if (client->stream_pos == size_t(-2)) {
+			client->stream_pos = std::min<size_t>(
+			    client->stream->bytes_received - client->stream->backlog_size,
+			    0);
+		} else {
+			// client->stream_pos should be -1, but it might not be,
+			// if we have clients from an older version.
+			client->stream_pos = client->stream->bytes_received;
+		}
 		client->stream->put_client_to_sleep(client);
 		return;
 	}
 	case Client::SENDING_DATA: {
-sending_data_again:
-		// See if there's some data we've lost. Ideally, we should drop to a block boundary,
-		// but resync will be the mux's problem.
+		skip_lost_data(client);
 		Stream *stream = client->stream;
+
+sending_data_again:
 		size_t bytes_to_send = stream->bytes_received - client->stream_pos;
+		assert(bytes_to_send <= stream->backlog_size);
 		if (bytes_to_send == 0) {
 			return;
 		}
-		if (bytes_to_send > stream->backlog_size) {
-			size_t bytes_lost = bytes_to_send - stream->backlog_size;
-			client->stream_pos = stream->bytes_received - stream->backlog_size;
-			client->bytes_lost += bytes_lost;
-			++client->num_loss_events;
-			bytes_to_send = stream->backlog_size;
-
-			double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
-			log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
-			        client->remote_addr.c_str(),
-			        (long long int)(bytes_lost),
-				100.0 * loss_fraction);
-		}
 
 		// See if we need to split across the circular buffer.
 		bool more_data = false;
@@ -440,6 +449,26 @@ sending_data_again:
 	}
 }
 
+// See if there's some data we've lost. Ideally, we should drop to a block boundary,
+// but resync will be the mux's problem.
+void Server::skip_lost_data(Client *client)
+{
+	Stream *stream = client->stream;
+	size_t bytes_to_send = stream->bytes_received - client->stream_pos;
+	if (bytes_to_send > stream->backlog_size) {
+		size_t bytes_lost = bytes_to_send - stream->backlog_size;
+		client->stream_pos = stream->bytes_received - stream->backlog_size;
+		client->bytes_lost += bytes_lost;
+		++client->num_loss_events;
+
+		double loss_fraction = double(client->bytes_lost) / double(client->bytes_lost + client->bytes_sent);
+		log(WARNING, "[%s] Client lost %lld bytes (total loss: %.2f%%), maybe too slow connection",
+			client->remote_addr.c_str(),
+			(long long int)(bytes_lost),
+			100.0 * loss_fraction);
+	}
+}
+
 int Server::parse_request(Client *client)
 {
 	vector<string> lines = split_lines(client->request);
@@ -455,7 +484,15 @@ int Server::parse_request(Client *client)
 		return 400;  // Should maybe be 405 instead?
 	}
 
-	map<string, int>::const_iterator url_map_it = url_map.find(request_tokens[1]);
+	string url = request_tokens[1];
+	if (url.find("?backlog") == url.size() - 8) {
+		client->stream_pos = -2;
+		url = url.substr(0, url.size() - 8);
+	} else {
+		client->stream_pos = -1;
+	}
+
+	map<string, int>::const_iterator url_map_it = url_map.find(url);
 	if (url_map_it == url_map.end()) {
 		return 404;  // Not found.
 	}