Starting the encode path

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

@@ -595,23 +595,21 @@ void grpc_chttp2_hpack_compressor_set_max_table_size(
 
 void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
                                grpc_chttp2_hpack_compressor *c,
-                               uint32_t stream_id,
-                               grpc_metadata_batch *metadata, int is_eof,
-                               size_t max_frame_size,
-                               grpc_transport_one_way_stats *stats,
+                               grpc_metadata_batch *metadata,
+                               const grpc_encode_header_options *options,
                                grpc_slice_buffer *outbuf) {
   framer_state st;
   grpc_linked_mdelem *l;
   gpr_timespec deadline;
 
-  GPR_ASSERT(stream_id != 0);
+  GPR_ASSERT(options->stream_id != 0);
 
   st.seen_regular_header = 0;
-  st.stream_id = stream_id;
+  st.stream_id = options->stream_id;
   st.output = outbuf;
   st.is_first_frame = 1;
-  st.stats = stats;
-  st.max_frame_size = max_frame_size;
+  st.stats = options->stats;
+  st.max_frame_size = options->max_frame_size;
 
   /* Encode a metadata batch; store the returned values, representing
      a metadata element that needs to be unreffed back into the metadata
@@ -630,5 +628,5 @@ void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
     deadline_enc(exec_ctx, c, deadline, &st);
   }
 
-  finish_frame(&st, 1, is_eof);
+  finish_frame(&st, 1, options->is_eof);
 }

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

@@ -90,11 +90,18 @@ void grpc_chttp2_hpack_compressor_set_max_table_size(
 void grpc_chttp2_hpack_compressor_set_max_usable_size(
     grpc_chttp2_hpack_compressor *c, uint32_t max_table_size);
 
+typedef struct {
+  uint32_t stream_id;
+  bool is_eof;
+  bool use_true_binary_metadata;
+  size_t max_frame_size;
+  grpc_transport_one_way_stats *stats;
+} grpc_encode_header_options;
+
 void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
-                               grpc_chttp2_hpack_compressor *c, uint32_t id,
-                               grpc_metadata_batch *metadata, int is_eof,
-                               size_t max_frame_size,
-                               grpc_transport_one_way_stats *stats,
+                               grpc_chttp2_hpack_compressor *c,
+                               grpc_metadata_batch *metadata,
+                               const grpc_encode_header_options *options,
                                grpc_slice_buffer *outbuf);
 
 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_ENCODER_H */

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

@@ -219,10 +219,18 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
 
     /* send initial metadata if it's available */
     if (!sent_initial_metadata && s->send_initial_metadata) {
-      grpc_chttp2_encode_header(
-          exec_ctx, &t->hpack_compressor, s->id, s->send_initial_metadata, 0,
-          t->settings[GRPC_ACKED_SETTINGS][GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
-          &s->stats.outgoing, &t->outbuf);
+      grpc_encode_header_options hopt = {
+          .stream_id = s->id,
+          .is_eof = false,
+          .use_true_binary_metadata =
+              t->settings
+                  [GRPC_ACKED_SETTINGS]
+                  [GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA] != 0,
+          .max_frame_size = t->settings[GRPC_ACKED_SETTINGS]
+                                       [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
+          .stats = &s->stats.outgoing};
+      grpc_chttp2_encode_header(exec_ctx, &t->hpack_compressor,
+                                s->send_initial_metadata, &hopt, &t->outbuf);
       s->send_initial_metadata = NULL;
       s->sent_initial_metadata = true;
       sent_initial_metadata = true;
@@ -300,11 +308,21 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
           grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer, 0, true,
                                   &s->stats.outgoing, &t->outbuf);
         } else {
-          grpc_chttp2_encode_header(
-              exec_ctx, &t->hpack_compressor, s->id, s->send_trailing_metadata,
-              true, t->settings[GRPC_ACKED_SETTINGS]
-                               [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
-              &s->stats.outgoing, &t->outbuf);
+          grpc_encode_header_options hopt = {
+              .stream_id = s->id,
+              .is_eof = true,
+              .use_true_binary_metadata =
+                  t->settings
+                      [GRPC_ACKED_SETTINGS]
+                      [GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA] !=
+                  0,
+              .max_frame_size =
+                  t->settings[GRPC_ACKED_SETTINGS]
+                             [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
+              .stats = &s->stats.outgoing};
+          grpc_chttp2_encode_header(exec_ctx, &t->hpack_compressor,
+                                    s->send_trailing_metadata, &hopt,
+                                    &t->outbuf);
         }
         s->send_trailing_metadata = NULL;
         s->sent_trailing_metadata = true;