Merge pull request #2442 from yang-g/authcontext_lazy_create_at_server

Create server side auth context lazily

include/grpc++/server_context.h

@@ -99,9 +99,7 @@ class ServerContext {
     return client_metadata_;
   }
 
-  std::shared_ptr<const AuthContext> auth_context() const {
+  std::shared_ptr<const AuthContext> auth_context() const;
-    return auth_context_;
-  }
 
  private:
   friend class ::grpc::Server;
@@ -147,7 +145,7 @@ class ServerContext {
   grpc_call* call_;
   CompletionQueue* cq_;
   bool sent_initial_metadata_;
-  std::shared_ptr<const AuthContext> auth_context_;
+  mutable std::shared_ptr<const AuthContext> auth_context_;
   std::multimap<grpc::string, grpc::string> client_metadata_;
   std::multimap<grpc::string, grpc::string> initial_metadata_;
   std::multimap<grpc::string, grpc::string> trailing_metadata_;

src/cpp/server/server_context.cc

@@ -153,4 +153,11 @@ void ServerContext::set_call(grpc_call* call) {
   auth_context_ = CreateAuthContext(call);
 }
 
+std::shared_ptr<const AuthContext> ServerContext::auth_context() const {
+  if (auth_context_.get() == nullptr) {
+    auth_context_ = CreateAuthContext(call_);
+  }
+  return auth_context_;
+}
+
 }  // namespace grpc