Add cancellation notification

1 files changed, 99 insertions, 0 deletions

diff --git a/include/grpcpp/impl/codegen/interceptor_common.h b/include/grpcpp/impl/codegen/interceptor_common.h
index d47e28d615..f520e7905a 100644
--- a/include/grpcpp/impl/codegen/interceptor_common.h
+++ b/include/grpcpp/impl/codegen/interceptor_common.h
@@ -352,6 +352,105 @@ class InterceptorBatchMethodsImpl
   MetadataMap* recv_trailing_metadata_ = nullptr;
 };
 
+// A special implementation of InterceptorBatchMethods to send a Cancel
+// notification down the interceptor stack
+class CancelInterceptorBatchMethods
+    : public experimental::InterceptorBatchMethods {
+ public:
+  bool QueryInterceptionHookPoint(
+      experimental::InterceptionHookPoints type) override {
+    if (type == experimental::InterceptionHookPoints::PRE_SEND_CANCEL) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  void Proceed() override {
+    // This is a no-op. For actual continuation of the RPC simply needs to
+    // return from the Intercept method
+  }
+
+  void Hijack() override {
+    // Only the client can hijack when sending down initial metadata
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call Hijack on a method which has a "
+                       "Cancel notification");
+  }
+
+  ByteBuffer* GetSendMessage() override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetSendMessage on a method which "
+                       "has a Cancel notification");
+    return nullptr;
+  }
+
+  std::multimap<grpc::string, grpc::string>* GetSendInitialMetadata() override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetSendInitialMetadata on a "
+                       "method which has a Cancel notification");
+    return nullptr;
+  }
+
+  Status GetSendStatus() override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetSendStatus on a method which "
+                       "has a Cancel notification");
+    return Status();
+  }
+
+  void ModifySendStatus(const Status& status) override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call ModifySendStatus on a method "
+                       "which has a Cancel notification");
+    return;
+  }
+
+  std::multimap<grpc::string, grpc::string>* GetSendTrailingMetadata()
+      override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetSendTrailingMetadata on a "
+                       "method which has a Cancel notification");
+    return nullptr;
+  }
+
+  void* GetRecvMessage() override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetRecvMessage on a method which "
+                       "has a Cancel notification");
+    return nullptr;
+  }
+
+  std::multimap<grpc::string_ref, grpc::string_ref>* GetRecvInitialMetadata()
+      override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetRecvInitialMetadata on a "
+                       "method which has a Cancel notification");
+    return nullptr;
+  }
+
+  Status* GetRecvStatus() override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetRecvStatus on a method which "
+                       "has a Cancel notification");
+    return nullptr;
+  }
+
+  std::multimap<grpc::string_ref, grpc::string_ref>* GetRecvTrailingMetadata()
+      override {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetRecvTrailingMetadata on a "
+                       "method which has a Cancel notification");
+    return nullptr;
+  }
+
+  std::unique_ptr<ChannelInterface> GetInterceptedChannel() {
+    GPR_CODEGEN_ASSERT(false &&
+                       "It is illegal to call GetInterceptedChannel on a "
+                       "method which has a Cancel notification");
+    return std::unique_ptr<ChannelInterface>(nullptr);
+  }
+};
 }  // namespace internal
 }  // namespace grpc