Let us clean a few things before getting started

3 files changed, 50 insertions, 71 deletions

diff --git a/include/grpcpp/impl/codegen/call_op_set.h b/include/grpcpp/impl/codegen/call_op_set.h
index 785688e67f..826a5972a0 100644
--- a/include/grpcpp/impl/codegen/call_op_set.h
+++ b/include/grpcpp/impl/codegen/call_op_set.h
@@ -214,11 +214,10 @@ class CallNoOp {
   void AddOp(grpc_op* ops, size_t* nops) {}
   void FinishOp(bool* status) {}
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {}
+      InterceptorBatchMethodsImpl* interceptor_methods) {}
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {}
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
-  }
+      InterceptorBatchMethodsImpl* interceptor_methods) {}
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {}
 };
 
 class CallOpSendInitialMetadata {
@@ -265,7 +264,7 @@ class CallOpSendInitialMetadata {
   }
 
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     if (!send_) return;
     interceptor_methods->AddInterceptionHookPoint(
         experimental::InterceptionHookPoints::PRE_SEND_INITIAL_METADATA);
@@ -273,9 +272,9 @@ class CallOpSendInitialMetadata {
   }
 
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {}
+      InterceptorBatchMethodsImpl* interceptor_methods) {}
 
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {
     hijacked_ = true;
   }
 
@@ -318,7 +317,7 @@ class CallOpSendMessage {
   void FinishOp(bool* status) { send_buf_.Clear(); }
 
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     if (!send_buf_.Valid()) return;
     interceptor_methods->AddInterceptionHookPoint(
         experimental::InterceptionHookPoints::PRE_SEND_MESSAGE);
@@ -326,9 +325,9 @@ class CallOpSendMessage {
   }
 
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {}
+      InterceptorBatchMethodsImpl* interceptor_methods) {}
 
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {
     hijacked_ = true;
   }
 
@@ -406,17 +405,17 @@ class CallOpRecvMessage {
   }
 
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     interceptor_methods->SetRecvMessage(message_);
   }
 
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     if (!got_message) return;
     interceptor_methods->AddInterceptionHookPoint(
         experimental::InterceptionHookPoints::POST_RECV_MESSAGE);
   }
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {
     hijacked_ = true;
     if (message_ == nullptr) return;
     interceptor_methods->AddInterceptionHookPoint(
@@ -501,17 +500,17 @@ class CallOpGenericRecvMessage {
   }
 
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     interceptor_methods->SetRecvMessage(message_);
   }
 
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     if (!got_message) return;
     interceptor_methods->AddInterceptionHookPoint(
         experimental::InterceptionHookPoints::POST_RECV_MESSAGE);
   }
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {
     hijacked_ = true;
     if (!deserialize_) return;
     interceptor_methods->AddInterceptionHookPoint(
@@ -543,16 +542,16 @@ class CallOpClientSendClose {
   void FinishOp(bool* status) { send_ = false; }
 
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     if (!send_) return;
     interceptor_methods->AddInterceptionHookPoint(
         experimental::InterceptionHookPoints::PRE_SEND_CLOSE);
   }
 
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {}
+      InterceptorBatchMethodsImpl* interceptor_methods) {}
 
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {
     hijacked_ = true;
   }
 
@@ -600,7 +599,7 @@ class CallOpServerSendStatus {
   }
 
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     if (!send_status_available_) return;
     interceptor_methods->AddInterceptionHookPoint(
         experimental::InterceptionHookPoints::PRE_SEND_STATUS);
@@ -610,9 +609,9 @@ class CallOpServerSendStatus {
   }
 
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {}
+      InterceptorBatchMethodsImpl* interceptor_methods) {}
 
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {
     hijacked_ = true;
   }
 
@@ -652,19 +651,19 @@ class CallOpRecvInitialMetadata {
   }
 
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     interceptor_methods->SetRecvInitialMetadata(metadata_map_);
   }
 
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     if (metadata_map_ == nullptr) return;
     interceptor_methods->AddInterceptionHookPoint(
         experimental::InterceptionHookPoints::POST_RECV_INITIAL_METADATA);
     metadata_map_ = nullptr;
   }
 
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {
     hijacked_ = true;
     if (metadata_map_ == nullptr) return;
     interceptor_methods->AddInterceptionHookPoint(
@@ -720,20 +719,20 @@ class CallOpClientRecvStatus {
   }
 
   void SetInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     interceptor_methods->SetRecvStatus(recv_status_);
     interceptor_methods->SetRecvTrailingMetadata(metadata_map_);
   }
 
   void SetFinishInterceptionHookPoint(
-      InternalInterceptorBatchMethods* interceptor_methods) {
+      InterceptorBatchMethodsImpl* interceptor_methods) {
     if (recv_status_ == nullptr) return;
     interceptor_methods->AddInterceptionHookPoint(
         experimental::InterceptionHookPoints::POST_RECV_STATUS);
     recv_status_ = nullptr;
   }
 
-  void SetHijackingState(InternalInterceptorBatchMethods* interceptor_methods) {
+  void SetHijackingState(InterceptorBatchMethodsImpl* interceptor_methods) {
     hijacked_ = true;
     if (recv_status_ == nullptr) return;
     interceptor_methods->AddInterceptionHookPoint(
diff --git a/include/grpcpp/impl/codegen/interceptor.h b/include/grpcpp/impl/codegen/interceptor.h
index 15cab711e5..4fb322aa8e 100644
--- a/include/grpcpp/impl/codegen/interceptor.h
+++ b/include/grpcpp/impl/codegen/interceptor.h
@@ -56,6 +56,9 @@ enum class InterceptionHookPoints {
   POST_RECV_MESSAGE,
   POST_RECV_STATUS /* client only */,
   POST_RECV_CLOSE /* server only */,
+  /* This is a special hook point available to both clients and servers. It is
+     illegal for an interceptor to block/delay this operation */
+  PRE_SEND_CANCEL,
   NUM_INTERCEPTION_HOOKS
 };
 
@@ -66,7 +69,9 @@ class InterceptorBatchMethods {
   // of type \a type
   virtual bool QueryInterceptionHookPoint(InterceptionHookPoints type) = 0;
   // Calling this will signal that the interceptor is done intercepting the
-  // current batch of the RPC
+  // current batch of the RPC.
+  // Proceed is a no-op if the batch contains PRE_SEND_CANCEL. Simply returning
+  // from the Intercept method does the job of continuing the RPC.
   virtual void Proceed() = 0;
   // Calling this indicates that the interceptor has hijacked the RPC (only
   // valid if the batch contains send_initial_metadata on the client side)
diff --git a/include/grpcpp/impl/codegen/interceptor_common.h b/include/grpcpp/impl/codegen/interceptor_common.h
index cf564977f6..d47e28d615 100644
--- a/include/grpcpp/impl/codegen/interceptor_common.h
+++ b/include/grpcpp/impl/codegen/interceptor_common.h
@@ -19,7 +19,12 @@
 #ifndef GRPCPP_IMPL_CODEGEN_INTERCEPTOR_COMMON_H
 #define GRPCPP_IMPL_CODEGEN_INTERCEPTOR_COMMON_H
 
+#include <functional>
+
+#include <grpcpp/impl/codegen/call.h>
+#include <grpcpp/impl/codegen/call_op_set_interface.h>
 #include <grpcpp/impl/codegen/client_interceptor.h>
+#include <grpcpp/impl/codegen/intercepted_channel.h>
 #include <grpcpp/impl/codegen/server_interceptor.h>
 
 #include <grpc/impl/codegen/grpc_types.h>
@@ -27,38 +32,9 @@
 namespace grpc {
 namespace internal {
 
-/// Internal methods for setting the state
-class InternalInterceptorBatchMethods
+class InterceptorBatchMethodsImpl
     : public experimental::InterceptorBatchMethods {
  public:
-  virtual ~InternalInterceptorBatchMethods() {}
-
-  virtual void AddInterceptionHookPoint(
-      experimental::InterceptionHookPoints type) = 0;
-
-  virtual void SetSendMessage(ByteBuffer* buf) = 0;
-
-  virtual void SetSendInitialMetadata(
-      std::multimap<grpc::string, grpc::string>* metadata) = 0;
-
-  virtual void SetSendStatus(grpc_status_code* code,
-                             grpc::string* error_details,
-                             grpc::string* error_message) = 0;
-
-  virtual void SetSendTrailingMetadata(
-      std::multimap<grpc::string, grpc::string>* metadata) = 0;
-
-  virtual void SetRecvMessage(void* message) = 0;
-
-  virtual void SetRecvInitialMetadata(MetadataMap* map) = 0;
-
-  virtual void SetRecvStatus(Status* status) = 0;
-
-  virtual void SetRecvTrailingMetadata(MetadataMap* map) = 0;
-};
-
-class InterceptorBatchMethodsImpl : public InternalInterceptorBatchMethods {
- public:
   InterceptorBatchMethodsImpl() {
     for (auto i = static_cast<experimental::InterceptionHookPoints>(0);
          i < experimental::InterceptionHookPoints::NUM_INTERCEPTION_HOOKS;
@@ -75,7 +51,7 @@ class InterceptorBatchMethodsImpl : public InternalInterceptorBatchMethods {
     return hooks_[static_cast<size_t>(type)];
   }
 
-  void Proceed() override { /* fill this */
+  void Proceed() override {
     if (call_->client_rpc_info() != nullptr) {
       return ProceedClient();
     }
@@ -98,8 +74,7 @@ class InterceptorBatchMethodsImpl : public InternalInterceptorBatchMethods {
     rpc_info->RunInterceptor(this, current_interceptor_index_);
   }
 
-  void AddInterceptionHookPoint(
-      experimental::InterceptionHookPoints type) override {
+  void AddInterceptionHookPoint(experimental::InterceptionHookPoints type) {
     hooks_[static_cast<size_t>(type)] = true;
   }
 
@@ -139,38 +114,38 @@ class InterceptorBatchMethodsImpl : public InternalInterceptorBatchMethods {
     return recv_trailing_metadata_->map();
   }
 
-  void SetSendMessage(ByteBuffer* buf) override { send_message_ = buf; }
+  void SetSendMessage(ByteBuffer* buf) { send_message_ = buf; }
 
   void SetSendInitialMetadata(
-      std::multimap<grpc::string, grpc::string>* metadata) override {
+      std::multimap<grpc::string, grpc::string>* metadata) {
     send_initial_metadata_ = metadata;
   }
 
   void SetSendStatus(grpc_status_code* code, grpc::string* error_details,
-                     grpc::string* error_message) override {
+                     grpc::string* error_message) {
     code_ = code;
     error_details_ = error_details;
     error_message_ = error_message;
   }
 
   void SetSendTrailingMetadata(
-      std::multimap<grpc::string, grpc::string>* metadata) override {
+      std::multimap<grpc::string, grpc::string>* metadata) {
     send_trailing_metadata_ = metadata;
   }
 
-  void SetRecvMessage(void* message) override { recv_message_ = message; }
+  void SetRecvMessage(void* message) { recv_message_ = message; }
 
-  void SetRecvInitialMetadata(MetadataMap* map) override {
+  void SetRecvInitialMetadata(MetadataMap* map) {
     recv_initial_metadata_ = map;
   }
 
-  void SetRecvStatus(Status* status) override { recv_status_ = status; }
+  void SetRecvStatus(Status* status) { recv_status_ = status; }
 
-  void SetRecvTrailingMetadata(MetadataMap* map) override {
+  void SetRecvTrailingMetadata(MetadataMap* map) {
     recv_trailing_metadata_ = map;
   }
 
-  std::unique_ptr<ChannelInterface> GetInterceptedChannel() override {
+  std::unique_ptr<ChannelInterface> GetInterceptedChannel() {
     auto* info = call_->client_rpc_info();
     if (info == nullptr) {
       return std::unique_ptr<ChannelInterface>(nullptr);