Transport layer send (compression) path

src/core/ext/transport/chttp2/transport/chttp2_transport.c

@@ -668,6 +668,7 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   grpc_chttp2_incoming_metadata_buffer_init(&s->metadata_buffer[1], arena);
   grpc_chttp2_data_parser_init(&s->data_parser);
   grpc_slice_buffer_init(&s->flow_controlled_buffer);
+  grpc_slice_buffer_init(&s->compressed_data_buffer);
   grpc_slice_buffer_init(&s->decompressed_data_buffer);
   s->deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
   GRPC_CLOSURE_INIT(&s->complete_fetch_locked, complete_fetch_locked, s,
@@ -707,6 +708,7 @@ static void destroy_stream_locked(grpc_exec_ctx *exec_ctx, void *sp,
   grpc_slice_buffer_destroy_internal(exec_ctx,
                                      &s->unprocessed_incoming_frames_buffer);
   grpc_slice_buffer_destroy_internal(exec_ctx, &s->frame_storage);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &s->compressed_data_buffer);
   grpc_slice_buffer_destroy_internal(exec_ctx, &s->decompressed_data_buffer);
 
   grpc_chttp2_list_remove_stalled_by_transport(t, s);
@@ -758,6 +760,10 @@ static void destroy_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   grpc_chttp2_transport *t = (grpc_chttp2_transport *)gt;
   grpc_chttp2_stream *s = (grpc_chttp2_stream *)gs;
 
+  if (s->stream_compression_ctx != NULL) {
+    grpc_stream_compression_context_destroy(s->stream_compression_ctx);
+    s->stream_compression_ctx = NULL;
+  }
   if (s->stream_decompression_ctx != NULL) {
     grpc_stream_compression_context_destroy(s->stream_decompression_ctx);
     s->stream_decompression_ctx = NULL;

src/core/ext/transport/chttp2/transport/internal.h

@@ -522,12 +522,21 @@ struct grpc_chttp2_stream {
 
   /** Whether stream compression send is enabled or not */
   bool stream_compression_recv_enabled;
+  /** Whether stream compression recv is enabled or not */
+  bool stream_compression_send_enabled;
   /** Whether bytes stored in unprocessed_incoming_byte_stream is decompressed
    */
   bool unprocessed_incoming_frames_decompressed;
   /** Stream compression decompress context */
   grpc_stream_compression_context *stream_decompression_ctx;
-
+  /** Stream compression compress context */
+  grpc_stream_compression_context *stream_compression_ctx;
+
+  /** Buffer storing data that is compressed but not sent */
+  grpc_slice_buffer compressed_data_buffer;
+  /** Amount of uncompressed bytes sent out when compressed_data_buffer is
+   * emptied */
+  size_t uncompressed_data_size;
   /** Temporary buffer storing decompressed data */
   grpc_slice_buffer decompressed_data_buffer;
 };

src/core/ext/transport/chttp2/transport/writing.c

@@ -303,7 +303,8 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
     }
     if (sent_initial_metadata) {
       /* send any body bytes, if allowed by flow control */
-      if (s->flow_controlled_buffer.length > 0) {
+      if (s->flow_controlled_buffer.length > 0 ||
+          s->compressed_data_buffer.length > 0) {
         uint32_t stream_outgoing_window = (uint32_t)GPR_MAX(
             0,
             s->outgoing_window_delta +
@@ -314,21 +315,63 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
                        [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
             GPR_MIN(stream_outgoing_window, t->outgoing_window));
         if (max_outgoing > 0) {
-          uint32_t send_bytes =
+          bool is_last_data_frame;
-              (uint32_t)GPR_MIN(max_outgoing, s->flow_controlled_buffer.length);
+          bool is_last_frame;
-          bool is_last_data_frame =
+          if (s->stream_compression_send_enabled) {
-              s->fetching_send_message == NULL &&
+            while ((s->flow_controlled_buffer.length > 0 ||
-              send_bytes == s->flow_controlled_buffer.length;
+                    s->compressed_data_buffer.length > 0) &&
-          bool is_last_frame =
+                   max_outgoing > 0) {
-              is_last_data_frame && s->send_trailing_metadata != NULL &&
+              if (s->compressed_data_buffer.length > 0) {
-              grpc_metadata_batch_is_empty(s->send_trailing_metadata);
+                uint32_t send_bytes = (uint32_t)GPR_MIN(
-          grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer, send_bytes,
+                    max_outgoing, s->compressed_data_buffer.length);
-                                  is_last_frame, &s->stats.outgoing,
+                is_last_data_frame =
-                                  &t->outbuf);
+                    (send_bytes == s->compressed_data_buffer.length &&
-          GRPC_CHTTP2_FLOW_DEBIT_STREAM("write", t, s, outgoing_window_delta,
+                     s->flow_controlled_buffer.length == 0 &&
-                                        send_bytes);
+                     s->fetching_send_message == NULL);
-          GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("write", t, outgoing_window,
+                is_last_frame =
-                                           send_bytes);
+                    is_last_data_frame && s->send_trailing_metadata != NULL &&
+                    grpc_metadata_batch_is_empty(s->send_trailing_metadata);
+                grpc_chttp2_encode_data(s->id, &s->compressed_data_buffer,
+                                        send_bytes, is_last_frame,
+                                        &s->stats.outgoing, &t->outbuf);
+                GRPC_CHTTP2_FLOW_DEBIT_STREAM(
+                    "write", t, s, outgoing_window_delta, send_bytes);
+                GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("write", t, outgoing_window,
+                                                 send_bytes);
+                max_outgoing -= send_bytes;
+                if (s->compressed_data_buffer.length == 0) {
+                  s->sending_bytes += s->uncompressed_data_size;
+                }
+              } else {
+                if (s->stream_compression_ctx == NULL) {
+                  s->stream_compression_ctx =
+                      grpc_stream_compression_context_create(
+                          GRPC_STREAM_COMPRESSION_COMPRESS);
+                }
+                s->uncompressed_data_size = s->flow_controlled_buffer.length;
+                GPR_ASSERT(grpc_stream_compress(
+                    s->stream_compression_ctx, &s->flow_controlled_buffer,
+                    &s->compressed_data_buffer, NULL, ~(size_t)0,
+                    GRPC_STREAM_COMPRESSION_FLUSH_SYNC));
+              }
+            }
+          } else {
+            uint32_t send_bytes = (uint32_t)GPR_MIN(
+                max_outgoing, s->flow_controlled_buffer.length);
+            is_last_data_frame = s->fetching_send_message == NULL &&
+                                 send_bytes == s->flow_controlled_buffer.length;
+            is_last_frame =
+                is_last_data_frame && s->send_trailing_metadata != NULL &&
+                grpc_metadata_batch_is_empty(s->send_trailing_metadata);
+            grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer,
+                                    send_bytes, is_last_frame,
+                                    &s->stats.outgoing, &t->outbuf);
+            GRPC_CHTTP2_FLOW_DEBIT_STREAM("write", t, s, outgoing_window_delta,
+                                          send_bytes);
+            GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("write", t, outgoing_window,
+                                             send_bytes);
+            s->sending_bytes += send_bytes;
+          }
           t->ping_state.pings_before_data_required =
               t->ping_policy.max_pings_without_data;
           if (!t->is_client) {
@@ -345,9 +388,9 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
                                                     &s->stats.outgoing));
             }
           }
-          s->sending_bytes += send_bytes;
           now_writing = true;
-          if (s->flow_controlled_buffer.length > 0) {
+          if (s->flow_controlled_buffer.length > 0 ||
+              s->compressed_data_buffer.length > 0) {
             GRPC_CHTTP2_STREAM_REF(s, "chttp2_writing:fork");
             grpc_chttp2_list_add_writable_stream(t, s);
           }
@@ -361,7 +404,8 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
       }
       if (s->send_trailing_metadata != NULL &&
           s->fetching_send_message == NULL &&
-          s->flow_controlled_buffer.length == 0) {
+          s->flow_controlled_buffer.length == 0 &&
+          s->compressed_data_buffer.length == 0) {
         GRPC_CHTTP2_IF_TRACING(gpr_log(GPR_INFO, "sending trailing_metadata"));
         if (grpc_metadata_batch_is_empty(s->send_trailing_metadata)) {
           grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer, 0, true,