Add support for forced prebuffering.

[cubemap] / stream.h

diff --git a/stream.h b/stream.h
index 33fb55eeeab9180589d57275b182f806dcb3b9a3..4947c3fbd7fdf11a43b8456a78f4a0c80812c58f 100644 (file)
--- a/stream.h
+++ b/stream.h
@@ -11,15 +11,19 @@
 #include <string>
 #include <vector>
 
-class MarkPool;
 class StreamProto;
 struct Client;
 
+enum StreamStartSuitability {
+       NOT_SUITABLE_FOR_STREAM_START,
+       SUITABLE_FOR_STREAM_START,
+};
+
 struct Stream {
        // Must be in sync with StreamConfig::Encoding.
        enum Encoding { STREAM_ENCODING_RAW = 0, STREAM_ENCODING_METACUBE };
 
-       Stream(const std::string &stream_id, size_t backlog_size, Encoding encoding);
+       Stream(const std::string &stream_id, size_t backlog_size, size_t prebuffering_bytes, Encoding encoding);
        ~Stream();
 
        // Serialization/deserialization.
@@ -29,7 +33,12 @@ struct Stream {
        // Changes the backlog size, restructuring the data as needed.
        void set_backlog_size(size_t new_size);
 
-       std::string stream_id;
+       // Mutex protecting <queued_data> and <queued_data_last_starting_point>.
+       // Note that if you want to hold both this and the owning server's
+       // <mutex> you will need to take <mutex> before this one.
+       mutable pthread_mutex_t queued_data_mutex;
+
+       std::string url;
 
        // The HTTP response header, without the trailing double newline.
        std::string http_header;
@@ -54,9 +63,21 @@ struct Stream {
        // How many bytes <data_fd> can hold (the buffer size).
        size_t backlog_size;
 
+       // How many bytes we need to have in the backlog before we start
+       // sending (in practice, we will then send all of them at once,
+       // and then start sending at the normal rate thereafter).
+       // This is basically to force a buffer on the client, which can help
+       // if the client expects us to be able to fill up the buffer much
+       // faster than realtime (ie., it expects a static file).
+       size_t prebuffering_bytes;
+
        // How many bytes this stream have received. Can very well be larger
        // than <backlog_size>, since the buffer wraps.
        size_t bytes_received;
+
+       // The last point in the stream that is suitable to start new clients at
+       // (after having sent the header). -1 if no such point exists yet.
+       ssize_t last_suitable_starting_point;
        
        // Clients that are in SENDING_DATA, but that we don't listen on,
        // because we currently don't have any data for them.
@@ -67,13 +88,17 @@ struct Stream {
        // <sleeping_clients>).
        std::vector<Client *> to_process;
 
-       // What pool to fetch marks from, or NULL.
-       MarkPool *mark_pool;
+       // Maximum pacing rate for the stream.
+       uint32_t pacing_rate;
 
-       // Queued data, if any. Protected by the owning Server's <queued_data_mutex>.
+       // Queued data, if any. Protected by <queued_data_mutex>.
        // The data pointers in the iovec are owned by us.
        std::vector<iovec> queued_data;
 
+       // Index of the last element in queued_data that is suitable to start streaming at.
+       // -1 if none. Protected by <queued_data_mutex>.
+       int queued_data_last_starting_point;
+
        // Put client to sleep, since there is no more data for it; we will on
        // longer listen on POLLOUT until we get more data. Also, it will be put
        // in the list of clients to wake up when we do.
@@ -81,11 +106,10 @@ struct Stream {
 
        // Add more data to <queued_data>, adding Metacube headers if needed.
        // Does not take ownership of <data>.
-       // You should hold the owning Server's <queued_data_mutex>.
-       void add_data_deferred(const char *data, size_t bytes);
+       void add_data_deferred(const char *data, size_t bytes, StreamStartSuitability suitable_for_stream_start);
 
        // Add queued data to the stream, if any.
-       // You should hold the owning Server's <mutex> _and_ <queued_data_mutex>.
+       // You should hold the owning Server's <mutex>.
        void process_queued_data();
 
 private: