Simplify server ready for async path

2 files changed, 44 insertions, 43 deletions

diff --git a/include/grpc++/server.h b/include/grpc++/server.h
index 670ffa7815..eefd4457f9 100644
--- a/include/grpc++/server.h
+++ b/include/grpc++/server.h
@@ -35,7 +35,7 @@
 #define __GRPCPP_SERVER_H__
 
 #include <condition_variable>
-#include <map>
+#include <list>
 #include <memory>
 #include <mutex>
 
@@ -69,6 +69,25 @@ class Server {
  private:
   friend class ServerBuilder;
 
+  class MethodRequestData {
+   public:
+    MethodRequestData(RpcServiceMethod* method, void* tag) : method_(method), tag_(tag) {}
+    static MethodRequestData *Wait(CompletionQueue *cq);
+
+    void Request(CompletionQueue* cq);
+
+    class CallData {
+     public:
+      explicit CallData(MethodRequestData *mrd);
+
+      void Run();
+    };
+
+   private:
+    RpcServiceMethod *const method_;
+    void *const tag_;
+  };
+
   // ServerBuilder use only
   Server(ThreadPoolInterface* thread_pool, bool thread_pool_owned, ServerCredentials* creds);
   Server();
@@ -85,7 +104,8 @@ class Server {
   void ScheduleCallback();
 
   // Completion queue.
-  CompletionQueue cq_;
+  std::unique_ptr<CompletionQueue> cq_sync_;
+  std::unique_ptr<CompletionQueue> cq_async_;
 
   // Sever status
   std::mutex mu_;
@@ -95,12 +115,11 @@ class Server {
   int num_running_cb_;
   std::condition_variable callback_cv_;
 
+  std::list<MethodRequestData> methods_;
+
   // Pointer to the c grpc server.
   grpc_server* server_;
 
-  // A map for all method information.
-  std::map<grpc::string, RpcServiceMethod*> method_map_;
-
   ThreadPoolInterface* thread_pool_;
   // Whether the thread pool is created and owned by the server.
   bool thread_pool_owned_;
diff --git a/src/cpp/server/server.cc b/src/cpp/server/server.cc
index 44c5276b54..f5bbfdc6f7 100644
--- a/src/cpp/server/server.cc
+++ b/src/cpp/server/server.cc
@@ -54,9 +54,9 @@ Server::Server(ThreadPoolInterface *thread_pool, bool thread_pool_owned, ServerC
       secure_(creds != nullptr) {
   if (creds) {
     server_ =
-        grpc_secure_server_create(creds->GetRawCreds(), cq_.cq(), nullptr);
+        grpc_secure_server_create(creds->GetRawCreds(), nullptr, nullptr);
   } else {
-    server_ = grpc_server_create(cq_.cq(), nullptr);
+    server_ = grpc_server_create(nullptr, nullptr);
   }
 }
 
@@ -80,13 +80,17 @@ Server::~Server() {
 }
 
 bool Server::RegisterService(RpcService *service) {
+  if (!cq_sync_) {
+    cq_sync_.reset(new CompletionQueue);
+  }
   for (int i = 0; i < service->GetMethodCount(); ++i) {
     RpcServiceMethod *method = service->GetMethod(i);
-    if (method_map_.find(method->name()) != method_map_.end()) {
+    void *tag = grpc_server_register_method(server_, method->name(), nullptr);
+    if (!tag) {
       gpr_log(GPR_DEBUG, "Attempt to register %s multiple times", method->name());
       return false;
     }
-    method_map_.insert(std::make_pair(method->name(), method));
+    methods_.emplace_back(method, tag);
   }
   return true;
 }
@@ -106,7 +110,11 @@ bool Server::Start() {
   grpc_server_start(server_);
 
   // Start processing rpcs.
-  if (thread_pool_) {
+  if (cq_sync_) {
+    for (auto& m : methods_) {
+      m.Request(cq_sync_.get());
+    }
+
     ScheduleCallback();
   }
 
@@ -126,12 +134,6 @@ void Server::Shutdown() {
       }
     }
   }
-
-  // Shutdown the completion queue.
-  cq_.Shutdown();
-  void *tag = nullptr;
-  bool ok = false;
-  GPR_ASSERT(false == cq_.Next(&tag, &ok));
 }
 
 void Server::ScheduleCallback() {
@@ -144,35 +146,15 @@ void Server::ScheduleCallback() {
 
 void Server::RunRpc() {
   // Wait for one more incoming rpc.
-  void *tag = nullptr;
-  GPR_ASSERT(started_);
-  grpc_call *c_call = NULL;
-  grpc_call_details call_details;
-  grpc_call_details_init(&call_details);
-  grpc_metadata_array initial_metadata;
-  grpc_metadata_array_init(&initial_metadata);
-  CompletionQueue cq;
-  grpc_call_error err = grpc_server_request_call(server_, &c_call, &call_details, &initial_metadata, cq.cq(), cq.cq(), nullptr);
-  GPR_ASSERT(err == GRPC_CALL_OK);
-  bool ok = false;
-  GPR_ASSERT(cq_.Next(&tag, &ok));
-  if (ok) {
-    ServerContext context;
-    Call call(c_call, nullptr, &cq);
+  auto* mrd = MethodRequestData::Wait(cq_sync_.get());
+  if (mrd) {
+    MethodRequestData::CallData cd(mrd);
+
+    mrd->Request(cq_sync_.get());
     ScheduleCallback();
-    RpcServiceMethod *method = nullptr;
-    auto iter = method_map_.find(call_details.method);
-    if (iter != method_map_.end()) {
-      method = iter->second;
-    }
-    // TODO(ctiller): allocate only if necessary
-    std::unique_ptr<google::protobuf::Message> request(method->AllocateRequestProto());
-    std::unique_ptr<google::protobuf::Message> response(method->AllocateResponseProto());
-    method->handler()->RunHandler(MethodHandler::HandlerParameter(
-      &call, &context, request.get(), response.get()));
+
+    cd.Run();
   }
-  grpc_call_details_destroy(&call_details);
-  grpc_metadata_array_destroy(&initial_metadata);
 
   {
     std::unique_lock<std::mutex> lock(mu_);