Add support for deduplicating headers/short responses.

[cubemap] / client.h

diff --git a/client.h b/client.h
index 666e3b417c1e6db142bc2c34d759be902dc27d56..8f9f682e268e291935278f91cedda3257dc1bae5 100644 (file)
--- a/client.h
+++ b/client.h
@@ -5,7 +5,11 @@
 
 #include <stddef.h>
 #include <time.h>
+
+#include <memory>
 #include <string>
+#include <unordered_map>
+#include <vector>
 
 #include "tlse.h"
 
@@ -30,8 +34,8 @@ struct Client {
        Client(int sock);
 
        // Serialization/deserialization.
-       Client(const ClientProto &serialized, Stream *stream);
-       ClientProto serialize() const;
+       Client(const ClientProto &serialized, const std::vector<std::shared_ptr<const std::string>> &short_responses, Stream *stream);
+       ClientProto serialize(std::unordered_map<const std::string *, size_t> *short_response_pool) const;
 
        ClientStats get_stats() const;
 
@@ -47,7 +51,7 @@ struct Client {
        std::string user_agent;
 
        enum State { READING_REQUEST, SENDING_HEADER, SENDING_DATA, SENDING_SHORT_RESPONSE, WAITING_FOR_KEYFRAME, PREBUFFERING };
-       State state;
+       State state = READING_REQUEST;
 
        // The HTTP request, as sent by the client. If we are in READING_REQUEST,
        // this might not be finished.
@@ -56,38 +60,71 @@ struct Client {
        // What stream we're connecting to; parsed from <request>.
        // Not relevant for READING_REQUEST.
        std::string url;
-       Stream *stream;
+       Stream *stream = nullptr;
+
+       // Whether we should close the connection after sending the response.
+       // Not relevant for READING_REQUEST. Must be true if http_11 is false.
+       bool close_after_response;
+
+       // Whether the request came in over HTTP/1.1 or higher.
+       bool http_11;
 
        // The header we want to send, or the response with headers if we know
        // it in its entirety after reading the request (typically an error).
        // This is nominally a copy of Stream::header, but since that might
        // change on reconnects etc., we keep a local copy here. Only relevant
        // for SENDING_HEADER or SENDING_SHORT_RESPONSE; blank otherwise.
-       std::string header_or_short_response;
+       //
+       // Must start with the string "HTTP/1.0 ", which will be changed to 1.1
+       // if relevant.
+       const std::string *header_or_short_response = nullptr;
+
+       // <header_or_short_response> can come from two distinct places; it can be
+       // local to the Client object, or it can be shared between many Clients
+       // (typically HLS playlists, that can be so large that they are expensive
+       // to hold in many copies). <header_or_short_response> will point to exactly
+       // one of these, which should be cleared out/dereferenced when it is
+       // no longer needed.
+       //
+       // The use of shared_ptr is somewhat overkill since we don't need
+       // to access the HLS playlists from multiple threads, but it's not a
+       // big deal for us.
+       std::string header_or_short_response_holder;
+       std::shared_ptr<const std::string> header_or_short_response_ref;
 
        // Number of bytes we've sent of the header. Only relevant for SENDING_HEADER
        // or SENDING_SHORT_RESPONSE.
-       size_t header_or_short_response_bytes_sent;
+       size_t header_or_short_response_bytes_sent = 0;
 
        // Number of bytes we are into the stream (ie., the end of last send).
        // -1 means we want to send from the end of the backlog (the normal case),
        // although only at a keyframe.
        // -2 means we want to send from the _beginning_ of the backlog.
+       // -3 means we sent the header only.
+       static const size_t STREAM_POS_AT_END = -1;
+       static const size_t STREAM_POS_AT_START = -2;
+       static const size_t STREAM_POS_HEADER_ONLY = -3;
+
        // Once we go into WAITING_FOR_KEYFRAME, PREBUFFERING or SENDING_DATA,
        // these negative values will be translated to real numbers.
-       size_t stream_pos;
+       size_t stream_pos = 0;
+
+       // Position at which to end the stream (one-past-the-end, used for fragments).
+       // -1 means never to end; this is the common case.
+       static const size_t STREAM_POS_NO_END = -1;
+       size_t stream_pos_end = 0;
 
        // Number of bytes we've sent of data. Only relevant for SENDING_DATA.
-       size_t bytes_sent;
+       size_t bytes_sent = 0;
 
        // Number of times we've skipped forward due to the backlog being too big,
        // and how many bytes we've skipped over in all. Only relevant for SENDING_DATA.
-       size_t bytes_lost, num_loss_events;
+       size_t bytes_lost = 0, num_loss_events = 0;
 
-       TLSContext *tls_context;
-       const unsigned char *tls_data_to_send;
-       unsigned tls_data_left_to_send;
-       bool in_ktls_mode;
+       TLSContext *tls_context = nullptr;
+       const unsigned char *tls_data_to_send = nullptr;
+       unsigned tls_data_left_to_send = 0;
+       bool in_ktls_mode = false;
 };
 
 #endif  // !defined(_CLIENT_H)