Introduce ahead-of-time registration of (method,host) pairs

1 files changed, 64 insertions, 17 deletions

diff --git a/src/core/surface/channel.c b/src/core/surface/channel.c
index e764a3b9af..adc339d479 100644
--- a/src/core/surface/channel.c
+++ b/src/core/surface/channel.c
@@ -43,6 +43,12 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
+typedef struct registered_call {
+  grpc_mdelem *path;
+  grpc_mdelem *authority;
+  struct registered_call *next;
+} registered_call;
+
 struct grpc_channel {
   int is_client;
   gpr_refcount refs;
@@ -51,6 +57,9 @@ struct grpc_channel {
   grpc_mdstr *grpc_message_string;
   grpc_mdstr *path_string;
   grpc_mdstr *authority_string;
+
+  gpr_mu registered_call_mu;
+  registered_call *registered_calls;
 };
 
 #define CHANNEL_STACK_FROM_CHANNEL(c) ((grpc_channel_stack *)((c)+1))
@@ -75,18 +84,17 @@ grpc_channel *grpc_channel_create_from_filters(
   channel->authority_string = grpc_mdstr_from_string(mdctx, ":authority");
   grpc_channel_stack_init(filters, num_filters, args, channel->metadata_context,
                           CHANNEL_STACK_FROM_CHANNEL(channel));
+  gpr_mu_init(&channel->registered_call_mu);
+  channel->registered_calls = NULL;
   return channel;
 }
 
 static void do_nothing(void *ignored, grpc_op_error error) {}
 
-grpc_call *grpc_channel_create_call(grpc_channel *channel,
-                                    grpc_completion_queue *cq,
-                                    const char *method, const char *host,
-                                    gpr_timespec absolute_deadline) {
+static grpc_call *grpc_channel_create_call_internal(
+    grpc_channel *channel, grpc_completion_queue *cq,
+    grpc_mdelem *path_mdelem, grpc_mdelem *authority_mdelem, gpr_timespec deadline) {
   grpc_call *call;
-  grpc_mdelem *path_mdelem;
-  grpc_mdelem *authority_mdelem;
   grpc_call_op op;
 
   if (!channel->is_client) {
@@ -97,11 +105,6 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
   call = grpc_call_create(channel, cq, NULL);
 
   /* Add :path and :authority headers. */
-  /* TODO(klempner): Consider optimizing this by stashing mdelems for common
-     values of method and host. */
-  path_mdelem = grpc_mdelem_from_metadata_strings(
-      channel->metadata_context, grpc_mdstr_ref(channel->path_string),
-      grpc_mdstr_from_string(channel->metadata_context, method));
   op.type = GRPC_SEND_METADATA;
   op.dir = GRPC_CALL_DOWN;
   op.flags = 0;
@@ -110,18 +113,14 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
   op.user_data = NULL;
   grpc_call_execute_op(call, &op);
 
-  grpc_mdstr_ref(channel->authority_string);
-  authority_mdelem = grpc_mdelem_from_metadata_strings(
-      channel->metadata_context, channel->authority_string,
-      grpc_mdstr_from_string(channel->metadata_context, host));
   op.data.metadata = authority_mdelem;
   grpc_call_execute_op(call, &op);
 
-  if (0 != gpr_time_cmp(absolute_deadline, gpr_inf_future)) {
+  if (0 != gpr_time_cmp(deadline, gpr_inf_future)) {
     op.type = GRPC_SEND_DEADLINE;
     op.dir = GRPC_CALL_DOWN;
     op.flags = 0;
-    op.data.deadline = absolute_deadline;
+    op.data.deadline = deadline;
     op.done_cb = do_nothing;
     op.user_data = NULL;
     grpc_call_execute_op(call, &op);
@@ -130,6 +129,22 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
   return call;
 }
 
+grpc_call *grpc_channel_create_call(grpc_channel *channel,
+                                    grpc_completion_queue *cq,
+                                    const char *method, const char *host,
+                                    gpr_timespec deadline) {
+  return grpc_channel_create_call_internal(
+      channel, 
+      cq,
+      grpc_mdelem_from_metadata_strings(
+          channel->metadata_context, grpc_mdstr_ref(channel->path_string),
+          grpc_mdstr_from_string(channel->metadata_context, method)),
+      grpc_mdelem_from_metadata_strings(
+          channel->metadata_context, grpc_mdstr_ref(channel->authority_string),
+          grpc_mdstr_from_string(channel->metadata_context, host)),
+      deadline);
+}
+
 grpc_call *grpc_channel_create_call_old(grpc_channel *channel,
                                         const char *method, const char *host,
                                         gpr_timespec absolute_deadline) {
@@ -137,6 +152,30 @@ grpc_call *grpc_channel_create_call_old(grpc_channel *channel,
                                   absolute_deadline);
 }
 
+void *grpc_channel_register_call(grpc_channel *channel, const char *method, 
+                                 const char *host) {
+  registered_call *rc = gpr_malloc(sizeof(registered_call));
+  rc->path = grpc_mdelem_from_metadata_strings(
+          channel->metadata_context, grpc_mdstr_ref(channel->path_string),
+          grpc_mdstr_from_string(channel->metadata_context, method));
+  rc->authority = grpc_mdelem_from_metadata_strings(
+          channel->metadata_context, grpc_mdstr_ref(channel->authority_string),
+          grpc_mdstr_from_string(channel->metadata_context, host));
+  gpr_mu_lock(&channel->registered_call_mu);
+  rc->next = channel->registered_calls;
+  channel->registered_calls = rc;
+  gpr_mu_unlock(&channel->registered_call_mu);
+  return rc;
+}
+
+grpc_call *grpc_channel_create_registered_call(grpc_channel *channel,
+                                               grpc_completion_queue *completion_queue,
+                                               void *registered_call_handle,
+                                               gpr_timespec deadline) {
+  registered_call *rc = registered_call_handle;
+  return grpc_channel_create_call_internal(channel, completion_queue, grpc_mdelem_ref(rc->path), grpc_mdelem_ref(rc->authority), deadline);
+}
+
 void grpc_channel_internal_ref(grpc_channel *channel) {
   gpr_ref(&channel->refs);
 }
@@ -148,7 +187,15 @@ static void destroy_channel(void *p, int ok) {
   grpc_mdstr_unref(channel->grpc_message_string);
   grpc_mdstr_unref(channel->path_string);
   grpc_mdstr_unref(channel->authority_string);
+  while (channel->registered_calls) {
+    registered_call *rc = channel->registered_calls;
+    channel->registered_calls = rc->next;
+    grpc_mdelem_unref(rc->path);
+    grpc_mdelem_unref(rc->authority);
+    gpr_free(rc);
+  }
   grpc_mdctx_unref(channel->metadata_context);
+  gpr_mu_destroy(&channel->registered_call_mu);
   gpr_free(channel);
 }