Restructure heirarchy

10 files changed, 40 insertions, 75 deletions

diff --git a/src/core/ext/filters/client_channel/client_channel.cc b/src/core/ext/filters/client_channel/client_channel.cc
index 13a0b95511..683cb0e01d 100644
--- a/src/core/ext/filters/client_channel/client_channel.cc
+++ b/src/core/ext/filters/client_channel/client_channel.cc
@@ -3094,7 +3094,6 @@ static grpc_error* cc_init_call_elem(grpc_call_element* elem,
   calld->arena = args->arena;
   calld->owning_call = args->call_stack;
   calld->call_combiner = args->call_combiner;
-  calld->call = args->call;
   if (GPR_LIKELY(chand->deadline_checking_enabled)) {
     grpc_deadline_state_init(elem, args->call_stack, args->call_combiner,
                              calld->deadline);
diff --git a/src/core/ext/filters/client_channel/client_channel_channelz.cc b/src/core/ext/filters/client_channel/client_channel_channelz.cc
index 996a871f38..b209acc2ea 100644
--- a/src/core/ext/filters/client_channel/client_channel_channelz.cc
+++ b/src/core/ext/filters/client_channel/client_channel_channelz.cc
@@ -124,8 +124,8 @@ grpc_json* ClientChannelNode::RenderJson() {
   grpc_json_create_child(nullptr, json, "target", target_view(),
                          GRPC_JSON_STRING, false);
   // as CallCountingAndTracingNode to populate trace and call count data.
-  PopulateTrace(json);
-  PopulateCallData(json);
+  counter_and_tracer()->PopulateTrace(json);
+  counter_and_tracer()->PopulateCallData(json);
   // reset to the top level
   json = top_level_json;
   PopulateChildRefs(json);
@@ -148,11 +148,11 @@ RefCountedPtr<ChannelNode> ClientChannelNode::MakeClientChannelNode(
 
 SubchannelNode::SubchannelNode(grpc_subchannel* subchannel,
                                size_t channel_tracer_max_nodes)
-    : CallCountingAndTracingNode(EntityType::kSubchannel,
-                                 channel_tracer_max_nodes),
+    : BaseNode(EntityType::kSubchannel),
       subchannel_(subchannel),
-      target_(UniquePtr<char>(
-          gpr_strdup(grpc_subchannel_get_target(subchannel_)))) {}
+      target_(
+          UniquePtr<char>(gpr_strdup(grpc_subchannel_get_target(subchannel_)))),
+      counter_and_tracer_(channel_tracer_max_nodes) {}
 
 SubchannelNode::~SubchannelNode() {}
 
@@ -192,8 +192,8 @@ grpc_json* SubchannelNode::RenderJson() {
   GPR_ASSERT(target_.get() != nullptr);
   grpc_json_create_child(nullptr, json, "target", target_.get(),
                          GRPC_JSON_STRING, false);
-  PopulateTrace(json);
-  PopulateCallData(json);
+  counter_and_tracer_.PopulateTrace(json);
+  counter_and_tracer_.PopulateCallData(json);
   return top_level_json;
 }
 
diff --git a/src/core/ext/filters/client_channel/client_channel_channelz.h b/src/core/ext/filters/client_channel/client_channel_channelz.h
index 1bc555448c..f5344c049e 100644
--- a/src/core/ext/filters/client_channel/client_channel_channelz.h
+++ b/src/core/ext/filters/client_channel/client_channel_channelz.h
@@ -64,7 +64,7 @@ class ClientChannelNode : public ChannelNode {
 };
 
 // Handles channelz bookkeeping for sockets
-class SubchannelNode : public CallCountingAndTracingNode {
+class SubchannelNode : public BaseNode {
  public:
   SubchannelNode(grpc_subchannel* subchannel, size_t channel_tracer_max_nodes);
   ~SubchannelNode() override;
@@ -76,9 +76,14 @@ class SubchannelNode : public CallCountingAndTracingNode {
 
   grpc_json* RenderJson() override;
 
+  CallCountingAndTracingNode* counter_and_tracer() {
+    return &counter_and_tracer_;
+  }
+
  private:
   grpc_subchannel* subchannel_;
   UniquePtr<char> target_;
+  CallCountingAndTracingNode counter_and_tracer_;
 
   void PopulateConnectivityState(grpc_json* json);
 };
diff --git a/src/core/ext/filters/client_channel/subchannel.cc b/src/core/ext/filters/client_channel/subchannel.cc
index a15cfd43c3..5894d52e6b 100644
--- a/src/core/ext/filters/client_channel/subchannel.cc
+++ b/src/core/ext/filters/client_channel/subchannel.cc
@@ -183,7 +183,7 @@ static void connection_destroy(void* arg, grpc_error* error) {
 static void subchannel_destroy(void* arg, grpc_error* error) {
   grpc_subchannel* c = static_cast<grpc_subchannel*>(arg);
   if (c->channelz_subchannel != nullptr) {
-    c->channelz_subchannel->trace()->AddTraceEvent(
+    c->channelz_subchannel->counter_and_tracer()->trace()->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Subchannel destroyed"));
     c->channelz_subchannel->MarkSubchannelDestroyed();
@@ -397,7 +397,7 @@ grpc_subchannel* grpc_subchannel_create(grpc_connector* connector,
     c->channelz_subchannel =
         grpc_core::MakeRefCounted<grpc_core::channelz::SubchannelNode>(
             c, channel_tracer_max_nodes);
-    c->channelz_subchannel->trace()->AddTraceEvent(
+    c->channelz_subchannel->counter_and_tracer()->trace()->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Subchannel created"));
   }
@@ -857,7 +857,6 @@ grpc_error* ConnectedSubchannel::CreateCall(const CallArgs& args,
       args.deadline,      /* deadline */
       args.arena,         /* arena */
       args.call_combiner, /* call_combiner */
-      args.call           /* call */
   };
   grpc_error* error = grpc_call_stack_init(
       channel_stack_, 1, subchannel_call_destroy, *call, &call_args);
@@ -866,10 +865,6 @@ grpc_error* ConnectedSubchannel::CreateCall(const CallArgs& args,
     gpr_log(GPR_ERROR, "error: %s", error_string);
     return error;
   }
-  if (channelz_subchannel_ != nullptr) {
-    channelz_subchannel_->RecordCallStarted();
-    grpc_call_set_channelz_subchannel(args.call, channelz_subchannel_);
-  }
   grpc_call_stack_set_pollset_or_pollset_set(callstk, args.pollent);
   return GRPC_ERROR_NONE;
 }
diff --git a/src/core/lib/channel/channel_stack.h b/src/core/lib/channel/channel_stack.h
index 727f36a6f8..7581f937b6 100644
--- a/src/core/lib/channel/channel_stack.h
+++ b/src/core/lib/channel/channel_stack.h
@@ -71,7 +71,6 @@ typedef struct {
   grpc_millis deadline;
   gpr_arena* arena;
   grpc_call_combiner* call_combiner;
-  grpc_call* call;
 } grpc_call_element_args;
 
 typedef struct {
diff --git a/src/core/lib/channel/channelz.cc b/src/core/lib/channel/channelz.cc
index 4fbc441c0a..ee1717ce9f 100644
--- a/src/core/lib/channel/channelz.cc
+++ b/src/core/lib/channel/channelz.cc
@@ -54,8 +54,7 @@ char* BaseNode::RenderJsonString() {
 }
 
 CallCountingAndTracingNode::CallCountingAndTracingNode(
-    EntityType type, size_t channel_tracer_max_nodes)
-    : BaseNode(type) {
+    size_t channel_tracer_max_nodes) {
   trace_.Init(channel_tracer_max_nodes);
   gpr_atm_no_barrier_store(&last_call_started_millis_,
                            (gpr_atm)ExecCtx::Get()->Now());
@@ -103,12 +102,11 @@ void CallCountingAndTracingNode::PopulateCallData(grpc_json* json) {
 
 ChannelNode::ChannelNode(grpc_channel* channel, size_t channel_tracer_max_nodes,
                          bool is_top_level_channel)
-    : CallCountingAndTracingNode(is_top_level_channel
-                                     ? EntityType::kTopLevelChannel
-                                     : EntityType::kInternalChannel,
-                                 channel_tracer_max_nodes),
+    : BaseNode(is_top_level_channel ? EntityType::kTopLevelChannel
+                                    : EntityType::kInternalChannel),
       channel_(channel),
-      target_(UniquePtr<char>(grpc_channel_get_target(channel_))) {}
+      target_(UniquePtr<char>(grpc_channel_get_target(channel_))),
+      counter_and_tracer_(channel_tracer_max_nodes) {}
 
 ChannelNode::~ChannelNode() {}
 
@@ -137,8 +135,8 @@ grpc_json* ChannelNode::RenderJson() {
   grpc_json_create_child(nullptr, json, "target", target_.get(),
                          GRPC_JSON_STRING, false);
   // as CallCountingAndTracingNode to populate trace and call count data.
-  PopulateTrace(json);
-  PopulateCallData(json);
+  counter_and_tracer_.PopulateTrace(json);
+  counter_and_tracer_.PopulateCallData(json);
   return top_level_json;
 }
 
diff --git a/src/core/lib/channel/channelz.h b/src/core/lib/channel/channelz.h
index 5496163fb9..7bc4567ad2 100644
--- a/src/core/lib/channel/channelz.h
+++ b/src/core/lib/channel/channelz.h
@@ -86,10 +86,10 @@ class BaseNode : public RefCounted<BaseNode> {
 //   - track last_call_started_timestamp
 //   - hold the channel trace.
 //   - perform common rendering.
-class CallCountingAndTracingNode : public BaseNode {
+class CallCountingAndTracingNode {
  public:
-  CallCountingAndTracingNode(EntityType type, size_t channel_tracer_max_nodes);
-  ~CallCountingAndTracingNode() override;
+  CallCountingAndTracingNode(size_t channel_tracer_max_nodes);
+  ~CallCountingAndTracingNode();
 
   void RecordCallStarted();
   void RecordCallFailed() {
@@ -118,7 +118,7 @@ class CallCountingAndTracingNode : public BaseNode {
 };
 
 // Handles channelz bookkeeping for channels
-class ChannelNode : public CallCountingAndTracingNode {
+class ChannelNode : public BaseNode {
  public:
   static RefCountedPtr<ChannelNode> MakeChannelNode(
       grpc_channel* channel, size_t channel_tracer_max_nodes,
@@ -137,6 +137,10 @@ class ChannelNode : public CallCountingAndTracingNode {
 
   bool ChannelIsDestroyed() { return channel_ == nullptr; }
 
+  CallCountingAndTracingNode* counter_and_tracer() {
+    return &counter_and_tracer_;
+  }
+
  protected:
   // provides view of target for child.
   char* target_view() { return target_.get(); }
@@ -144,15 +148,14 @@ class ChannelNode : public CallCountingAndTracingNode {
  private:
   grpc_channel* channel_ = nullptr;
   UniquePtr<char> target_;
+  CallCountingAndTracingNode counter_and_tracer_;
 };
 
 // Handles channelz bookkeeping for servers
 // TODO(ncteisen): implement in subsequent PR.
-class ServerNode : public CallCountingAndTracingNode {
+class ServerNode : public BaseNode {
  public:
-  ServerNode(size_t channel_tracer_max_nodes)
-      : CallCountingAndTracingNode(EntityType::kServer,
-                                   channel_tracer_max_nodes) {}
+  ServerNode(size_t channel_tracer_max_nodes) : BaseNode(EntityType::kServer) {}
   ~ServerNode() override {}
 };
 
@@ -162,8 +165,6 @@ class SocketNode : public BaseNode {
  public:
   SocketNode() : BaseNode(EntityType::kSocket) {}
   ~SocketNode() override {}
-
- private:
 };
 
 // Creation functions
diff --git a/src/core/lib/surface/call.cc b/src/core/lib/surface/call.cc
index 6545af8f72..b86ff048cf 100644
--- a/src/core/lib/surface/call.cc
+++ b/src/core/lib/surface/call.cc
@@ -170,11 +170,6 @@ struct grpc_call {
   /* parent_call* */ gpr_atm parent_call_atm;
   child_call* child;
 
-  // the call holds onto this so that once the call knows if the RPC was
-  // a success or failure, it can update the channelz bookkeeping for the
-  // subchannel that sent it.
-  grpc_core::channelz::CallCountingAndTracingNode* channelz_subchannel_;
-
   /* client or server call */
   bool is_client;
   /** has grpc_call_unref been called */
@@ -274,11 +269,6 @@ struct grpc_call {
   gpr_atm recv_state;
 };
 
-void grpc_call_set_channelz_subchannel(
-    grpc_call* call, grpc_core::channelz::CallCountingAndTracingNode* node) {
-  call->channelz_subchannel_ = node;
-}
-
 grpc_core::TraceFlag grpc_call_error_trace(false, "call_error");
 grpc_core::TraceFlag grpc_compression_trace(false, "compression");
 
@@ -454,8 +444,7 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
                                       call->start_time,
                                       send_deadline,
                                       call->arena,
-                                      &call->call_combiner,
-                                      call};
+                                      &call->call_combiner};
   add_init_error(&error, grpc_call_stack_init(channel_stack, 1, destroy_call,
                                               call, &call_args));
   // Publish this call to parent only after the call stack has been initialized.
@@ -500,7 +489,7 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
   grpc_core::channelz::ChannelNode* channelz_channel =
       grpc_channel_get_channelz_node(call->channel);
   if (channelz_channel != nullptr) {
-    channelz_channel->RecordCallStarted();
+    channelz_channel->counter_and_tracer()->RecordCallStarted();
   }
 
   grpc_slice_unref_internal(path);
@@ -1279,17 +1268,9 @@ static void post_batch_completion(batch_control* bctl) {
         grpc_channel_get_channelz_node(call->channel);
     if (channelz_channel != nullptr) {
       if (*call->final_op.client.status != GRPC_STATUS_OK) {
-        channelz_channel->RecordCallFailed();
-      } else {
-        channelz_channel->RecordCallSucceeded();
-      }
-    }
-    // Record channelz data for the subchannel.
-    if (call->channelz_subchannel_ != nullptr) {
-      if (*call->final_op.client.status != GRPC_STATUS_OK) {
-        call->channelz_subchannel_->RecordCallFailed();
+        channelz_channel->counter_and_tracer()->RecordCallFailed();
       } else {
-        call->channelz_subchannel_->RecordCallSucceeded();
+        channelz_channel->counter_and_tracer()->RecordCallSucceeded();
       }
     }
     GRPC_ERROR_UNREF(error);
diff --git a/src/core/lib/surface/call.h b/src/core/lib/surface/call.h
index 200c840c61..b3b06059d4 100644
--- a/src/core/lib/surface/call.h
+++ b/src/core/lib/surface/call.h
@@ -110,19 +110,6 @@ size_t grpc_call_get_initial_size_estimate();
 grpc_compression_algorithm grpc_call_compression_for_level(
     grpc_call* call, grpc_compression_level level);
 
-namespace grpc_core {
-namespace channelz {
-class CallCountingAndTracingNode;
-}  // namespace channelz
-}  // namespace grpc_core
-
-// We need this so that a subchannel selected for a call can add itself to
-// the call's data structure. This allows the call to trigger the correct
-// channelz bookkeeping on the subchannel once the call knows if the RPC was
-// successful or not.
-void grpc_call_set_channelz_subchannel(
-    grpc_call* call, grpc_core::channelz::CallCountingAndTracingNode* node);
-
 extern grpc_core::TraceFlag grpc_call_error_trace;
 extern grpc_core::TraceFlag grpc_compression_trace;
 
diff --git a/src/core/lib/surface/channel.cc b/src/core/lib/surface/channel.cc
index 01caadaaba..16d3322a9d 100644
--- a/src/core/lib/surface/channel.cc
+++ b/src/core/lib/surface/channel.cc
@@ -170,7 +170,7 @@ grpc_channel* grpc_channel_create_with_builder(
     bool is_top_level_channel = channel->is_client && !internal_channel;
     channel->channelz_channel = channel_node_create_func(
         channel, channel_tracer_max_nodes, is_top_level_channel);
-    channel->channelz_channel->trace()->AddTraceEvent(
+    channel->channelz_channel->counter_and_tracer()->trace()->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Channel created"));
   }
@@ -417,7 +417,7 @@ void grpc_channel_internal_unref(grpc_channel* c REF_ARG) {
 static void destroy_channel(void* arg, grpc_error* error) {
   grpc_channel* channel = static_cast<grpc_channel*>(arg);
   if (channel->channelz_channel != nullptr) {
-    channel->channelz_channel->trace()->AddTraceEvent(
+    channel->channelz_channel->counter_and_tracer()->trace()->AddTraceEvent(
         grpc_core::channelz::ChannelTrace::Severity::Info,
         grpc_slice_from_static_string("Channel destroyed"));
     channel->channelz_channel->MarkChannelDestroyed();