Merge pull request #13647 from y-zeng/send_ping

Add on_initiate callback for the send_ping tranport op

4 files changed, 17 insertions, 6 deletions

diff --git a/src/core/lib/surface/channel_ping.cc b/src/core/lib/surface/channel_ping.cc
index e8f47f01cf..7b1964fd55 100644
--- a/src/core/lib/surface/channel_ping.cc
+++ b/src/core/lib/surface/channel_ping.cc
@@ -57,7 +57,7 @@ void grpc_channel_ping(grpc_channel* channel, grpc_completion_queue* cq,
   pr->tag = tag;
   pr->cq = cq;
   GRPC_CLOSURE_INIT(&pr->closure, ping_done, pr, grpc_schedule_on_exec_ctx);
-  op->send_ping = &pr->closure;
+  op->send_ping.on_ack = &pr->closure;
   op->bind_pollset = grpc_cq_pollset(cq);
   GPR_ASSERT(grpc_cq_begin_op(cq, tag));
   top_elem->filter->start_transport_op(&exec_ctx, top_elem, op);
diff --git a/src/core/lib/surface/lame_client.cc b/src/core/lib/surface/lame_client.cc
index c32c9af50e..559d7af43e 100644
--- a/src/core/lib/surface/lame_client.cc
+++ b/src/core/lib/surface/lame_client.cc
@@ -104,9 +104,14 @@ static void lame_start_transport_op(grpc_exec_ctx* exec_ctx,
     GRPC_CLOSURE_SCHED(exec_ctx, op->on_connectivity_state_change,
                        GRPC_ERROR_NONE);
   }
-  if (op->send_ping != nullptr) {
+  if (op->send_ping.on_initiate != nullptr) {
     GRPC_CLOSURE_SCHED(
-        exec_ctx, op->send_ping,
+        exec_ctx, op->send_ping.on_initiate,
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("lame client channel"));
+  }
+  if (op->send_ping.on_ack != nullptr) {
+    GRPC_CLOSURE_SCHED(
+        exec_ctx, op->send_ping.on_ack,
         GRPC_ERROR_CREATE_FROM_STATIC_STRING("lame client channel"));
   }
   GRPC_ERROR_UNREF(op->disconnect_with_error);
diff --git a/src/core/lib/transport/transport.h b/src/core/lib/transport/transport.h
index b3cf04c22d..73264142d9 100644
--- a/src/core/lib/transport/transport.h
+++ b/src/core/lib/transport/transport.h
@@ -245,8 +245,14 @@ typedef struct grpc_transport_op {
   grpc_pollset* bind_pollset;
   /** add this transport to a pollset_set */
   grpc_pollset_set* bind_pollset_set;
-  /** send a ping, call this back if not NULL */
-  grpc_closure* send_ping;
+  /** send a ping, if either on_initiate or on_ack is not NULL */
+  struct {
+    /** Ping may be delayed by the transport, on_initiate callback will be
+        called when the ping is actually being sent. */
+    grpc_closure* on_initiate;
+    /** Called when the ping ack is received */
+    grpc_closure* on_ack;
+  } send_ping;
 
   /***************************************************************************
    * remaining fields are initialized and used at the discretion of the
diff --git a/src/core/lib/transport/transport_op_string.cc b/src/core/lib/transport/transport_op_string.cc
index e69ab02570..c0f82fea0d 100644
--- a/src/core/lib/transport/transport_op_string.cc
+++ b/src/core/lib/transport/transport_op_string.cc
@@ -187,7 +187,7 @@ char* grpc_transport_op_string(grpc_transport_op* op) {
     gpr_strvec_add(&b, gpr_strdup("BIND_POLLSET_SET"));
   }
 
-  if (op->send_ping != nullptr) {
+  if (op->send_ping.on_initiate != nullptr || op->send_ping.on_ack != nullptr) {
     if (!first) gpr_strvec_add(&b, gpr_strdup(" "));
     // first = false;
     gpr_strvec_add(&b, gpr_strdup("SEND_PING"));