Decouple filter selection from channel construction

Allow plugins to extend the set of filters used by gRPC core:
- plugins at construction time can register against the 'channel_init' system to be allowed to mutate a new channel_stack_builder type
- channel_stack_builder provides a central and rather dynamic place to construct the list of filters required by a channel stack
- ultimately we construct the channel stack in the fashion we always have

This is also a prerequisite step to allowing filters to be implemented from wrapped languages.

1 files changed, 7 insertions, 7 deletions

diff --git a/src/core/surface/lame_client.c b/src/core/surface/lame_client.c
index 537069e984..58f89946d2 100644
--- a/src/core/surface/lame_client.c
+++ b/src/core/surface/lame_client.c
@@ -31,6 +31,8 @@
  *
  */
 
+#include "src/core/surface/lame_client.h"
+
 #include <grpc/grpc.h>
 
 #include <string.h>
@@ -115,7 +117,7 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                  grpc_channel_element *elem) {}
 
-static const grpc_channel_filter lame_filter = {
+const grpc_channel_filter grpc_lame_filter = {
     lame_start_transport_stream_op, lame_start_transport_op, sizeof(call_data),
     init_call_elem, grpc_call_stack_ignore_set_pollset, destroy_call_elem,
     sizeof(channel_data), init_channel_elem, destroy_channel_elem,
@@ -127,19 +129,17 @@ static const grpc_channel_filter lame_filter = {
 grpc_channel *grpc_lame_client_channel_create(const char *target,
                                               grpc_status_code error_code,
                                               const char *error_message) {
-  grpc_channel *channel;
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_channel_element *elem;
   channel_data *chand;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  static const grpc_channel_filter *filters[] = {&lame_filter};
-  channel =
-      grpc_channel_create_from_filters(&exec_ctx, target, filters, 1, NULL, 1);
+  grpc_channel *channel = grpc_channel_create(&exec_ctx, target, NULL,
+                                              GRPC_CLIENT_LAME_CHANNEL, NULL);
   elem = grpc_channel_stack_element(grpc_channel_get_channel_stack(channel), 0);
   GRPC_API_TRACE(
       "grpc_lame_client_channel_create(target=%s, error_code=%d, "
       "error_message=%s)",
       3, (target, (int)error_code, error_message));
-  GPR_ASSERT(elem->filter == &lame_filter);
+  GPR_ASSERT(elem->filter == &grpc_lame_filter);
   chand = (channel_data *)elem->channel_data;
   chand->error_code = error_code;
   chand->error_message = error_message;