Merge branch 'master' into failhijackedrecv

1 files changed, 70 insertions, 8 deletions

diff --git a/include/grpcpp/impl/codegen/client_interceptor.h b/include/grpcpp/impl/codegen/client_interceptor.h
index f69c99ab22..7dfe2290a3 100644
--- a/include/grpcpp/impl/codegen/client_interceptor.h
+++ b/include/grpcpp/impl/codegen/client_interceptor.h
@@ -23,6 +23,7 @@
 #include <vector>
 
 #include <grpcpp/impl/codegen/interceptor.h>
+#include <grpcpp/impl/codegen/rpc_method.h>
 #include <grpcpp/impl/codegen/string_ref.h>
 
 namespace grpc {
@@ -37,9 +38,17 @@ class InterceptorBatchMethodsImpl;
 namespace experimental {
 class ClientRpcInfo;
 
+// A factory interface for creation of client interceptors. A vector of
+// factories can be provided at channel creation which will be used to create a
+// new vector of client interceptors per RPC. Client interceptor authors should
+// create a subclass of ClientInterceptorFactorInterface which creates objects
+// of their interceptors.
 class ClientInterceptorFactoryInterface {
  public:
   virtual ~ClientInterceptorFactoryInterface() {}
+  // 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* CreateClientInterceptor(ClientRpcInfo* info) = 0;
 };
 }  // namespace experimental
@@ -49,26 +58,74 @@ extern experimental::ClientInterceptorFactoryInterface*
     g_global_client_interceptor_factory;
 }
 
+/// ClientRpcInfo 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 CreateClientInterceptor method of the application's
+/// ClientInterceptorFactoryInterface implementation
 namespace experimental {
 class ClientRpcInfo {
  public:
-  ClientRpcInfo() {}
+  // TODO(yashykt): Stop default-constructing ClientRpcInfo and remove UNKNOWN
+  //                from the list of possible Types.
+  /// Type categorizes RPCs by unary or streaming type
+  enum class Type {
+    UNARY,
+    CLIENT_STREAMING,
+    SERVER_STREAMING,
+    BIDI_STREAMING,
+    UNKNOWN  // UNKNOWN is not API and will be removed later
+  };
 
   ~ClientRpcInfo(){};
 
+  // Delete copy constructor but allow default move constructor
   ClientRpcInfo(const ClientRpcInfo&) = delete;
   ClientRpcInfo(ClientRpcInfo&&) = default;
-  ClientRpcInfo& operator=(ClientRpcInfo&&) = default;
 
   // Getter methods
-  const char* method() { return method_; }
+
+  /// Return the fully-specified method name
+  const char* method() const { return method_; }
+
+  /// Return a pointer to the channel on which the RPC is being sent
   ChannelInterface* channel() { return channel_; }
+
+  /// Return a pointer to the underlying ClientContext structure associated
+  /// with the RPC to support features that apply to it
   grpc::ClientContext* client_context() { return ctx_; }
 
+  /// Return the type of the RPC (unary or a streaming flavor)
+  Type type() const { return type_; }
+
  private:
-  ClientRpcInfo(grpc::ClientContext* ctx, const char* method,
-                grpc::ChannelInterface* channel)
-      : ctx_(ctx), method_(method), channel_(channel) {}
+  static_assert(Type::UNARY ==
+                    static_cast<Type>(internal::RpcMethod::NORMAL_RPC),
+                "violated expectation about Type enum");
+  static_assert(Type::CLIENT_STREAMING ==
+                    static_cast<Type>(internal::RpcMethod::CLIENT_STREAMING),
+                "violated expectation about Type enum");
+  static_assert(Type::SERVER_STREAMING ==
+                    static_cast<Type>(internal::RpcMethod::SERVER_STREAMING),
+                "violated expectation about Type enum");
+  static_assert(Type::BIDI_STREAMING ==
+                    static_cast<Type>(internal::RpcMethod::BIDI_STREAMING),
+                "violated expectation about Type enum");
+
+  // Default constructor should only be used by ClientContext
+  ClientRpcInfo() = default;
+
+  // Constructor will only be called from ClientContext
+  ClientRpcInfo(grpc::ClientContext* ctx, internal::RpcMethod::RpcType type,
+                const char* method, grpc::ChannelInterface* channel)
+      : ctx_(ctx),
+        type_(static_cast<Type>(type)),
+        method_(method),
+        channel_(channel) {}
+
+  // Move assignment should only be used by ClientContext
+  // TODO(yashykt): Delete move assignment
+  ClientRpcInfo& operator=(ClientRpcInfo&&) = default;
+
   // Runs interceptor at pos \a pos.
   void RunInterceptor(
       experimental::InterceptorBatchMethods* interceptor_methods, size_t pos) {
@@ -86,8 +143,11 @@ class ClientRpcInfo {
     }
     for (auto it = creators.begin() + interceptor_pos; it != creators.end();
          ++it) {
-      interceptors_.push_back(std::unique_ptr<experimental::Interceptor>(
-          (*it)->CreateClientInterceptor(this)));
+      auto* interceptor = (*it)->CreateClientInterceptor(this);
+      if (interceptor != nullptr) {
+        interceptors_.push_back(
+            std::unique_ptr<experimental::Interceptor>(interceptor));
+      }
     }
     if (internal::g_global_client_interceptor_factory != nullptr) {
       interceptors_.push_back(std::unique_ptr<experimental::Interceptor>(
@@ -97,6 +157,8 @@ class ClientRpcInfo {
   }
 
   grpc::ClientContext* ctx_ = nullptr;
+  // TODO(yashykt): make type_ const once move-assignment is deleted
+  Type type_{Type::UNKNOWN};
   const char* method_ = nullptr;
   grpc::ChannelInterface* channel_ = nullptr;
   std::vector<std::unique_ptr<experimental::Interceptor>> interceptors_;