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/*
*
* Copyright 2015 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#ifndef GRPCPP_SUPPORT_SERVER_INTERCEPTOR_H
#define GRPCPP_SUPPORT_SERVER_INTERCEPTOR_H
#include <atomic>
#include <vector>
#include <grpcpp/impl/rpc_method.h>
#include <grpcpp/support/interceptor.h>
#include <grpcpp/support/string_ref.h>
namespace grpc {
class ServerContextBase;
namespace internal {
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
ServerContextBase* server_context() { return ctx_; }
private:
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");
ServerRpcInfo(ServerContextBase* ctx, const char* method,
internal::RpcMethod::RpcType type)
: ctx_(ctx), method_(method), type_(static_cast<Type>(type)) {}
// Runs interceptor at pos \a pos.
void RunInterceptor(
experimental::InterceptorBatchMethods* interceptor_methods, size_t pos) {
GPR_CODEGEN_ASSERT(pos < interceptors_.size());
interceptors_[pos]->Intercept(interceptor_methods);
}
void RegisterInterceptors(
const std::vector<
std::unique_ptr<experimental::ServerInterceptorFactoryInterface>>&
creators) {
for (const auto& creator : creators) {
auto* interceptor = creator->CreateServerInterceptor(this);
if (interceptor != nullptr) {
interceptors_.push_back(
std::unique_ptr<experimental::Interceptor>(interceptor));
}
}
}
void Ref() { ref_.fetch_add(1, std::memory_order_relaxed); }
void Unref() {
if (GPR_UNLIKELY(ref_.fetch_sub(1, std::memory_order_acq_rel) == 1)) {
delete this;
}
}
ServerContextBase* ctx_ = nullptr;
const char* method_ = nullptr;
const Type type_;
std::atomic<intptr_t> ref_{1};
std::vector<std::unique_ptr<experimental::Interceptor>> interceptors_;
friend class internal::InterceptorBatchMethodsImpl;
friend class grpc::ServerContextBase;
};
} // namespace experimental
} // namespace grpc
#endif // GRPCPP_SUPPORT_SERVER_INTERCEPTOR_H
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