]> git.sesse.net Git - cubemap/blobdiff - server.cpp
Tweak the MutexLock implementation slightly, so as to confuse Coverity less.
[cubemap] / server.cpp
index 5bd0d555c18194ca112a04b21cb3d9344272722e..4442b34cee7899661bae68e15e1ed223018abdc2 100644 (file)
@@ -20,7 +20,7 @@
 #include "accesslog.h"
 #include "log.h"
 #include "markpool.h"
-#include "metacube.h"
+#include "metacube2.h"
 #include "mutexlock.h"
 #include "parse.h"
 #include "server.h"
@@ -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();
@@ -181,8 +194,9 @@ void Server::add_client_from_serialized(const ClientProto &client)
                exit(1);
        }
 
-       if (client_ptr->state == Client::SENDING_DATA && 
-           client_ptr->stream_pos == client_ptr->stream->bytes_received) {
+       if (client_ptr->state == Client::WAITING_FOR_KEYFRAME ||
+           (client_ptr->state == Client::SENDING_DATA &&
+            client_ptr->stream_pos == client_ptr->stream->bytes_received)) {
                client_ptr->stream->put_client_to_sleep(client_ptr);
        } else {
                process_client(client_ptr);
@@ -256,11 +270,11 @@ void Server::set_mark_pool(int stream_index, MarkPool *mark_pool)
        streams[stream_index]->mark_pool = mark_pool;
 }
 
-void Server::add_data_deferred(int stream_index, const char *data, size_t bytes)
+void Server::add_data_deferred(int stream_index, const char *data, size_t bytes, StreamStartSuitability suitable_for_stream_start)
 {
        MutexLock lock(&queued_data_mutex);
        assert(stream_index >= 0 && stream_index < ssize_t(streams.size()));
-       streams[stream_index]->add_data_deferred(data, bytes);
+       streams[stream_index]->add_data_deferred(data, bytes, suitable_for_stream_start);
 }
 
 // See the .h file for postconditions after this function.     
@@ -367,36 +381,47 @@ sending_header_or_error_again:
                        return;
                }
 
-               // Start sending from the end. In other words, we won't send any of the backlog,
-               // but we'll start sending immediately as we get data.
+               // Start sending from the first keyframe we get. In other
+               // words, we won't send any of the backlog, but we'll start
+               // sending immediately as we get the next keyframe block.
                // 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);
+                       client->state = Client::SENDING_DATA;
+               } 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->state = Client::WAITING_FOR_KEYFRAME;
+               }
                client->stream->put_client_to_sleep(client);
                return;
        }
+       case Client::WAITING_FOR_KEYFRAME: {
+               Stream *stream = client->stream;
+               if (ssize_t(client->stream_pos) > stream->last_suitable_starting_point) {
+                       // We haven't received a keyframe since this stream started waiting,
+                       // so keep on waiting for one.
+                       // This is postcondition #3.
+                       stream->put_client_to_sleep(client);
+                       return;
+               }
+               client->stream_pos = stream->last_suitable_starting_point;
+               client->state = Client::SENDING_DATA;
+               // Fall through.
+       }
        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 +465,26 @@ 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 +500,15 @@ 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.
        }
@@ -489,10 +542,11 @@ void Server::construct_header(Client *client)
                        "Content-encoding: metacube\r\n" +
                        "\r\n";
                if (!stream->stream_header.empty()) {
-                       metacube_block_header hdr;
-                       memcpy(hdr.sync, METACUBE_SYNC, sizeof(hdr.sync));
+                       metacube2_block_header hdr;
+                       memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
                        hdr.size = htonl(stream->stream_header.size());
-                       hdr.flags = htonl(METACUBE_FLAGS_HEADER);
+                       hdr.flags = htons(METACUBE_FLAGS_HEADER);
+                       hdr.csum = htons(metacube2_compute_crc(&hdr));
                        client->header_or_error.append(
                                string(reinterpret_cast<char *>(&hdr), sizeof(hdr)));
                }