Fixes to surface/call.c to consider the channel's default compression level.

src/core/lib/surface/call.c

@@ -178,8 +178,8 @@ struct grpc_call {
   /* Call stats: only valid after trailing metadata received */
   grpc_transport_stream_stats stats;
 
-  /* Compression algorithm for the call */
+  /* Compression algorithm for *incoming* data */
-  grpc_compression_algorithm compression_algorithm;
+  grpc_compression_algorithm incoming_compression_algorithm;
   /* Supported encodings (compression algorithms), a bitset */
   uint32_t encodings_accepted_by_peer;
 
@@ -406,16 +406,16 @@ static void set_status_code(grpc_call *call, status_source source,
   /* TODO(ctiller): what to do about the flush that was previously here */
 }
 
-static void set_compression_algorithm(grpc_call *call,
+static void set_incoming_compression_algorithm(
-                                      grpc_compression_algorithm algo) {
+    grpc_call *call, grpc_compression_algorithm algo) {
-  call->compression_algorithm = algo;
+  call->incoming_compression_algorithm = algo;
 }
 
 grpc_compression_algorithm grpc_call_test_only_get_compression_algorithm(
     grpc_call *call) {
   grpc_compression_algorithm algorithm;
   gpr_mu_lock(&call->mu);
-  algorithm = call->compression_algorithm;
+  algorithm = call->incoming_compression_algorithm;
   gpr_mu_unlock(&call->mu);
   return algorithm;
 }
@@ -968,9 +968,9 @@ static grpc_mdelem *recv_initial_filter(void *callp, grpc_mdelem *elem) {
   if (elem == NULL) {
     return NULL;
   } else if (elem->key == GRPC_MDSTR_GRPC_ENCODING) {
-    GPR_TIMER_BEGIN("compression_algorithm", 0);
+    GPR_TIMER_BEGIN("incoming_compression_algorithm", 0);
-    set_compression_algorithm(call, decode_compression(elem));
+    set_incoming_compression_algorithm(call, decode_compression(elem));
-    GPR_TIMER_END("compression_algorithm", 0);
+    GPR_TIMER_END("incoming_compression_algorithm", 0);
     return NULL;
   } else if (elem->key == GRPC_MDSTR_GRPC_ACCEPT_ENCODING) {
     GPR_TIMER_BEGIN("encodings_accepted_by_peer", 0);
@@ -1133,9 +1133,9 @@ static void process_data_after_md(grpc_exec_ctx *exec_ctx, batch_control *bctl,
   } else {
     call->test_only_last_message_flags = call->receiving_stream->flags;
     if ((call->receiving_stream->flags & GRPC_WRITE_INTERNAL_COMPRESS) &&
-        (call->compression_algorithm > GRPC_COMPRESS_NONE)) {
+        (call->incoming_compression_algorithm > GRPC_COMPRESS_NONE)) {
       *call->receiving_buffer = grpc_raw_compressed_byte_buffer_create(
-          NULL, 0, call->compression_algorithm);
+          NULL, 0, call->incoming_compression_algorithm);
     } else {
       *call->receiving_buffer = grpc_raw_byte_buffer_create(NULL, 0);
     }
@@ -1323,17 +1323,25 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         grpc_metadata compression_md;
         memset(&compression_md, 0, sizeof(grpc_metadata));
         size_t additional_metadata_count = 0;
-        if (op->data.send_initial_metadata.maybe_compression_level.is_set &&
+        grpc_compression_level effective_compression_level;
-            op->data.send_initial_metadata.maybe_compression_level
+        bool level_set = false;
-                    .compression_level > GRPC_COMPRESS_LEVEL_NONE) {
+        if (op->data.send_initial_metadata.maybe_compression_level.is_set) {
           if (call->is_client) {
             error = GRPC_CALL_ERROR_NOT_ON_CLIENT;
             goto done_with_error;
           }
+          effective_compression_level =
+              op->data.send_initial_metadata.maybe_compression_level
+                  .compression_level;
+          level_set = true;
+        } else {
+          level_set = grpc_channel_default_compression_level(
+              call->channel, &effective_compression_level);
+        }
+        if (level_set) {
           const grpc_compression_algorithm calgo =
               compression_algorithm_for_level_locked(
-                  call, op->data.send_initial_metadata.maybe_compression_level
+                  call, effective_compression_level);
-                            .compression_level);
           char *calgo_name;
           grpc_compression_algorithm_name(calgo, &calgo_name);
           compression_md.key = GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY;