1 files changed, 27 insertions, 2 deletions

diff --git a/include/grpcpp/impl/codegen/server_interceptor.h b/include/grpcpp/impl/codegen/server_interceptor.h
index afc3c198cc..3e71b3fc55 100644
--- a/include/grpcpp/impl/codegen/server_interceptor.h
+++ b/include/grpcpp/impl/codegen/server_interceptor.h
@@ -37,25 +37,47 @@ class InterceptorBatchMethodsImpl;
 namespace experimental {
 class ServerRpcInfo;
 
+// A factory interface for creation of server interceptors. A vector of
+// factories can be provided to ServerBuilder which will be used to create a new
+// vector of server interceptors per RPC. Server interceptor authors should
+// create a subclass of ServerInterceptorFactorInterface which creates objects
+// of their interceptors.
 class ServerInterceptorFactoryInterface {
  public:
   virtual ~ServerInterceptorFactoryInterface() {}
+  // Returns a pointer to an Interceptor object on successful creation, nullptr
+  // otherwise. If nullptr is returned, this server interceptor factory is
+  // ignored for the purposes of that RPC.
   virtual Interceptor* CreateServerInterceptor(ServerRpcInfo* info) = 0;
 };
 
+/// ServerRpcInfo represents the state of a particular RPC as it
+/// appears to an interceptor. It is created and owned by the library and
+/// passed to the CreateServerInterceptor method of the application's
+/// ServerInterceptorFactoryInterface implementation
 class ServerRpcInfo {
  public:
+  /// Type categorizes RPCs by unary or streaming type
   enum class Type { UNARY, CLIENT_STREAMING, SERVER_STREAMING, BIDI_STREAMING };
 
   ~ServerRpcInfo(){};
 
+  // Delete all copy and move constructors and assignments
   ServerRpcInfo(const ServerRpcInfo&) = delete;
+  ServerRpcInfo& operator=(const ServerRpcInfo&) = delete;
   ServerRpcInfo(ServerRpcInfo&&) = delete;
   ServerRpcInfo& operator=(ServerRpcInfo&&) = delete;
 
   // Getter methods
+
+  /// Return the fully-specified method name
   const char* method() const { return method_; }
+
+  /// Return the type of the RPC (unary or a streaming flavor)
   Type type() const { return type_; }
+
+  /// Return a pointer to the underlying ServerContext structure associated
+  /// with the RPC to support features that apply to it
   grpc::ServerContext* server_context() { return ctx_; }
 
  private:
@@ -90,8 +112,11 @@ class ServerRpcInfo {
           std::unique_ptr<experimental::ServerInterceptorFactoryInterface>>&
           creators) {
     for (const auto& creator : creators) {
-      interceptors_.push_back(std::unique_ptr<experimental::Interceptor>(
-          creator->CreateServerInterceptor(this)));
+      auto* interceptor = creator->CreateServerInterceptor(this);
+      if (interceptor != nullptr) {
+        interceptors_.push_back(
+            std::unique_ptr<experimental::Interceptor>(interceptor));
+      }
     }
   }