Merge pull request #16167 from markdroth/ping_api

Eliminate PingOneLocked() from LB policy API.

1 files changed, 10 insertions, 16 deletions

diff --git a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
index d217dc0e63..46acbf628b 100644
--- a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
@@ -46,7 +46,7 @@ class PickFirst : public LoadBalancingPolicy {
   explicit PickFirst(const Args& args);
 
   void UpdateLocked(const grpc_channel_args& args) override;
-  bool PickLocked(PickState* pick) override;
+  bool PickLocked(PickState* pick, grpc_error** error) override;
   void CancelPickLocked(PickState* pick, grpc_error* error) override;
   void CancelMatchingPicksLocked(uint32_t initial_metadata_flags_mask,
                                  uint32_t initial_metadata_flags_eq,
@@ -56,7 +56,6 @@ class PickFirst : public LoadBalancingPolicy {
   grpc_connectivity_state CheckConnectivityLocked(
       grpc_error** connectivity_error) override;
   void HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) override;
-  void PingOneLocked(grpc_closure* on_initiate, grpc_closure* on_ack) override;
   void ExitIdleLocked() override;
   void FillChildRefsForChannelz(ChildRefsList* child_subchannels,
                                 ChildRefsList* ignored) override;
@@ -173,9 +172,10 @@ void PickFirst::HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) {
   PickState* pick;
   while ((pick = pending_picks_) != nullptr) {
     pending_picks_ = pick->next;
-    if (new_policy->PickLocked(pick)) {
+    grpc_error* error = GRPC_ERROR_NONE;
+    if (new_policy->PickLocked(pick, &error)) {
       // Synchronous return, schedule closure.
-      GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_NONE);
+      GRPC_CLOSURE_SCHED(pick->on_complete, error);
     }
   }
 }
@@ -259,13 +259,18 @@ void PickFirst::ExitIdleLocked() {
   }
 }
 
-bool PickFirst::PickLocked(PickState* pick) {
+bool PickFirst::PickLocked(PickState* pick, grpc_error** error) {
   // If we have a selected subchannel already, return synchronously.
   if (selected_ != nullptr) {
     pick->connected_subchannel = selected_->connected_subchannel()->Ref();
     return true;
   }
   // No subchannel selected yet, so handle asynchronously.
+  if (pick->on_complete == nullptr) {
+    *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "No pick result available but synchronous result required.");
+    return true;
+  }
   if (!started_picking_) {
     StartPickingLocked();
   }
@@ -293,17 +298,6 @@ void PickFirst::NotifyOnStateChangeLocked(grpc_connectivity_state* current,
                                                  notify);
 }
 
-void PickFirst::PingOneLocked(grpc_closure* on_initiate, grpc_closure* on_ack) {
-  if (selected_ != nullptr) {
-    selected_->connected_subchannel()->Ping(on_initiate, on_ack);
-  } else {
-    GRPC_CLOSURE_SCHED(on_initiate,
-                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
-    GRPC_CLOSURE_SCHED(on_ack,
-                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
-  }
-}
-
 void PickFirst::FillChildRefsForChannelz(
     ChildRefsList* child_subchannels_to_fill, ChildRefsList* ignored) {
   mu_guard guard(&child_refs_mu_);