4 // Representation of a single, muxed (we only really care about bytes/blocks) stream.
5 // Fed by Input, sent out by Server (to Client).
17 enum StreamStartSuitability {
18 NOT_SUITABLE_FOR_STREAM_START,
19 SUITABLE_FOR_STREAM_START,
23 // Must be in sync with StreamConfig::Encoding.
24 enum Encoding { STREAM_ENCODING_RAW = 0, STREAM_ENCODING_METACUBE };
26 Stream(const std::string &stream_id, size_t backlog_size, Encoding encoding);
29 // Serialization/deserialization.
30 Stream(const StreamProto &serialized, int data_fd);
31 StreamProto serialize();
33 // Changes the backlog size, restructuring the data as needed.
34 void set_backlog_size(size_t new_size);
36 // Mutex protecting <queued_data> and <queued_data_last_starting_point>.
37 // Note that if you want to hold both this and the owning server's
38 // <mutex> you will need to take <mutex> before this one.
39 mutable pthread_mutex_t queued_data_mutex;
43 // The HTTP response header, without the trailing double newline.
44 std::string http_header;
46 // The video stream header (if any).
47 std::string stream_header;
49 // What encoding we apply to the outgoing data (usually raw, but can also
50 // be Metacube, for reflecting to another Cubemap instance).
53 // The stream data itself, stored in a circular buffer.
55 // We store our data in a file, so that we can send the data to the
56 // kernel only once (with write()). We then use sendfile() for each
57 // client, which effectively zero-copies it out of the kernel's buffer
58 // cache. This is significantly more efficient than doing write() from
59 // a userspace memory buffer, since the latter makes the kernel copy
60 // the same data from userspace many times.
63 // How many bytes <data_fd> can hold (the buffer size).
66 // How many bytes this stream have received. Can very well be larger
67 // than <backlog_size>, since the buffer wraps.
68 size_t bytes_received;
70 // The last point in the stream that is suitable to start new clients at
71 // (after having sent the header). -1 if no such point exists yet.
72 ssize_t last_suitable_starting_point;
74 // Clients that are in SENDING_DATA, but that we don't listen on,
75 // because we currently don't have any data for them.
76 // See put_client_to_sleep() and wake_up_all_clients().
77 std::vector<Client *> sleeping_clients;
79 // Clients that we recently got data for (when they were in
80 // <sleeping_clients>).
81 std::vector<Client *> to_process;
83 // Maximum pacing rate for the stream.
86 // Queued data, if any. Protected by <queued_data_mutex>.
87 // The data pointers in the iovec are owned by us.
88 std::vector<iovec> queued_data;
90 // Index of the last element in queued_data that is suitable to start streaming at.
91 // -1 if none. Protected by <queued_data_mutex>.
92 int queued_data_last_starting_point;
94 // Put client to sleep, since there is no more data for it; we will on
95 // longer listen on POLLOUT until we get more data. Also, it will be put
96 // in the list of clients to wake up when we do.
97 void put_client_to_sleep(Client *client);
99 // Add more data to <queued_data>, adding Metacube headers if needed.
100 // Does not take ownership of <data>.
101 void add_data_deferred(const char *data, size_t bytes, StreamStartSuitability suitable_for_stream_start);
103 // Add queued data to the stream, if any.
104 // You should hold the owning Server's <mutex>.
105 void process_queued_data();
108 Stream(const Stream& other);
110 // Adds data directly to the stream file descriptor, without adding headers or
111 // going through <queued_data>.
112 // You should hold the owning Server's <mutex>.
113 void add_data_raw(const std::vector<iovec> &data);
116 #endif // !defined(_STREAM_H)