server_context.h

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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_SERVER_CONTEXT_H
#define GRPCPP_SERVER_CONTEXT_H
 
#include <grpc/grpc.h>
#include <grpc/impl/call.h>
#include <grpc/impl/compression_types.h>
#include <grpc/support/port_platform.h>
#include <grpcpp/impl/call.h>
#include <grpcpp/impl/call_op_set.h>
#include <grpcpp/impl/codegen/create_auth_context.h>
#include <grpcpp/impl/codegen/metadata_map.h>
#include <grpcpp/impl/completion_queue_tag.h>
#include <grpcpp/impl/metadata_map.h>
#include <grpcpp/impl/rpc_service_method.h>
#include <grpcpp/impl/sync.h>
#include <grpcpp/security/auth_context.h>
#include <grpcpp/support/callback_common.h>
#include <grpcpp/support/config.h>
#include <grpcpp/support/message_allocator.h>
#include <grpcpp/support/server_callback.h>
#include <grpcpp/support/server_interceptor.h>
#include <grpcpp/support/status.h>
#include <grpcpp/support/string_ref.h>
#include <grpcpp/support/time.h>
 
#include <atomic>
#include <cassert>
#include <cstdint>
#include <map>
#include <memory>
#include <type_traits>
#include <vector>
 
struct grpc_metadata;
struct grpc_call;
struct census_context;
 
namespace grpc {
template <class W, class R>
class ServerAsyncReader;
template <class W>
class ServerAsyncWriter;
template <class W>
class ServerAsyncResponseWriter;
template <class W, class R>
class ServerAsyncReaderWriter;
template <class R>
class ServerReader;
template <class W>
class ServerWriter;
 
namespace internal {
template <class ServiceType, class RequestType, class ResponseType>
class BidiStreamingHandler;
template <class RequestType, class ResponseType>
class CallbackUnaryHandler;
template <class RequestType, class ResponseType>
class CallbackClientStreamingHandler;
template <class RequestType, class ResponseType>
class CallbackServerStreamingHandler;
template <class RequestType, class ResponseType>
class CallbackBidiHandler;
template <class ServiceType, class RequestType, class ResponseType>
class ClientStreamingHandler;
template <class ResponseType>
void UnaryRunHandlerHelper(const MethodHandler::HandlerParameter&,
                           ResponseType*, Status&);
template <class ServiceType, class RequestType, class ResponseType,
          class BaseRequestType, class BaseResponseType>
class RpcMethodHandler;
template <class Base>
class FinishOnlyReactor;
template <class W, class R>
class ServerReaderWriterBody;
template <class ServiceType, class RequestType, class ResponseType>
class ServerStreamingHandler;
class ServerReactor;
template <class Streamer, bool WriteNeeded>
class TemplatedBidiStreamingHandler;
template <grpc::StatusCode code>
class ErrorMethodHandler;
}  // namespace internal
 
class ClientContext;
class CompletionQueue;
class GenericServerContext;
class Server;
class ServerInterface;
class ContextAllocator;
class GenericCallbackServerContext;
 
namespace internal {
class Call;
 
void ServerContextSetSessionContext(grpc_call* call, uint16_t id, void* ptr);
void* ServerContextGetSessionContext(grpc_call* call, uint16_t id);
uint16_t ServerContextRegisterSessionContext(void (*destroy)(void*));
 
template <typename T>
struct SessionContextType {
  static uint16_t id() {
    static const uint16_t id =
        ServerContextRegisterSessionContext([](void* element) {
          delete static_cast<std::shared_ptr<T>*>(element);
        });
    return id;
  }
 
  static void* Wrap(std::shared_ptr<T> context) {
    return new std::shared_ptr<T>(std::move(context));
  }
 
  static std::shared_ptr<T> Unwrap(void* ptr) {
    return ptr != nullptr ? *static_cast<std::shared_ptr<T>*>(ptr) : nullptr;
  }
};
}  // namespace internal
 
namespace testing {
class InteropServerContextInspector;
class ServerContextTestSpouse;
class DefaultReactorTestPeer;
}  // namespace testing
 
class ServerContextBase;
 
namespace experimental {
template <typename T>
void SetSessionContext(ServerContextBase* context,
                       std::shared_ptr<T> session_context);
 
template <typename T>
std::shared_ptr<T> GetSessionContext(const ServerContextBase* context);
 
class CallMetricRecorder;
class ServerMetricRecorder;
namespace internal {
template <class RequestType>
class CallbackSessionHandler;
}  // namespace internal
}  // namespace experimental
 
class ServerContextBase {
 public:
  virtual ~ServerContextBase();
 
  std::chrono::system_clock::time_point deadline() const {
    return grpc::Timespec2Timepoint(deadline_);
  }
 
  gpr_timespec raw_deadline() const { return deadline_; }
 
  void AddInitialMetadata(const std::string& key, const std::string& value);
 
  void AddTrailingMetadata(const std::string& key, const std::string& value);
 
  bool IsCancelled() const;
 
  void TryCancel() const;
 
  const std::multimap<grpc::string_ref, grpc::string_ref>& client_metadata()
      const {
    return *client_metadata_.map();
  }
 
  grpc_compression_level compression_level() const {
    return compression_level_;
  }
 
  void set_compression_level(grpc_compression_level level) {
    compression_level_set_ = true;
    compression_level_ = level;
  }
 
  bool compression_level_set() const { return compression_level_set_; }
 
  grpc_compression_algorithm compression_algorithm() const {
    return compression_algorithm_;
  }
  void set_compression_algorithm(grpc_compression_algorithm algorithm);
 
  void SetLoadReportingCosts(const std::vector<std::string>& cost_data);
 
  std::shared_ptr<const grpc::AuthContext> auth_context() const {
    if (auth_context_ == nullptr) {
      auth_context_ = grpc::CreateAuthContext(call_.call);
    }
    return auth_context_;
  }
 
  std::string peer() const;
 
  const struct census_context* census_context() const;
 
  grpc_call* c_call() { return call_.call; }
 
  experimental::CallMetricRecorder* ExperimentalGetCallMetricRecorder() {
    return call_metric_recorder_;
  }
 
  grpc_event_engine::experimental::MemoryAllocator* memory_allocator() {
    return memory_allocator_;
  }
 
  grpc::string_ref ExperimentalGetAuthority() const;
 
 protected:
  void AsyncNotifyWhenDone(void* tag) {
    has_notify_when_done_tag_ = true;
    async_notify_when_done_tag_ = tag;
  }
 
  RpcAllocatorState* GetRpcAllocatorState() { return message_allocator_state_; }
 
  grpc::ServerUnaryReactor* DefaultReactor() {
    // Short-circuit the case where a default reactor was already set up by
    // the TestPeer.
    if (test_unary_ != nullptr) {
      return reinterpret_cast<Reactor*>(&default_reactor_);
    }
    new (&default_reactor_) Reactor;
#ifndef NDEBUG
    bool old = false;
    assert(default_reactor_used_.compare_exchange_strong(
        old, true, std::memory_order_relaxed));
#else
    default_reactor_used_.store(true, std::memory_order_relaxed);
#endif
    return reinterpret_cast<Reactor*>(&default_reactor_);
  }
 
  void MarkInitialMetadataSent() {
    // Lock prevents the session from transitioning to the lock-free read phase
    // while a concurrent call to SetSessionContext is currently executing.
    grpc::internal::MutexLock lock(&metadata_mu_);
    // Release-store synchronizes with the acquire-loads in
    // Set/GetSessionContext to guarantee that all context writes made before
    // initial metadata is sent are fully visible to subsequent read operations.
    sent_initial_metadata_.store(true, std::memory_order_release);
  }
 
  ServerContextBase();
  ServerContextBase(gpr_timespec deadline, grpc_metadata_array* arr);
 
  void set_context_allocator(ContextAllocator* context_allocator) {
    context_allocator_ = context_allocator;
  }
 
  ContextAllocator* context_allocator() const { return context_allocator_; }
 
 private:
  friend class grpc::testing::InteropServerContextInspector;
  friend class grpc::testing::ServerContextTestSpouse;
  friend class grpc::testing::DefaultReactorTestPeer;
  friend class grpc::ServerInterface;
  friend class grpc::Server;
  template <class W, class R>
  friend class grpc::ServerAsyncReader;
  template <class W>
  friend class grpc::ServerAsyncWriter;
  template <class W>
  friend class grpc::ServerAsyncResponseWriter;
  template <class W, class R>
  friend class grpc::ServerAsyncReaderWriter;
  template <class R>
  friend class grpc::ServerReader;
  template <class W>
  friend class grpc::ServerWriter;
  template <class W, class R>
  friend class grpc::internal::ServerReaderWriterBody;
  template <class ResponseType>
  friend void grpc::internal::UnaryRunHandlerHelper(
      const internal::MethodHandler::HandlerParameter& param, ResponseType* rsp,
      Status& status);
  template <class ServiceType, class RequestType, class ResponseType,
            class BaseRequestType, class BaseResponseType>
  friend class grpc::internal::RpcMethodHandler;
  template <class ServiceType, class RequestType, class ResponseType>
  friend class grpc::internal::ClientStreamingHandler;
  template <class ServiceType, class RequestType, class ResponseType>
  friend class grpc::internal::ServerStreamingHandler;
  template <class Streamer, bool WriteNeeded>
  friend class grpc::internal::TemplatedBidiStreamingHandler;
  template <class RequestType, class ResponseType>
  friend class grpc::internal::CallbackUnaryHandler;
  template <class RequestType, class ResponseType>
  friend class grpc::internal::CallbackClientStreamingHandler;
  template <class RequestType, class ResponseType>
  friend class grpc::internal::CallbackServerStreamingHandler;
  template <class RequestType, class ResponseType>
  friend class grpc::internal::CallbackBidiHandler;
  template <class RequestType>
  friend class grpc::experimental::internal::CallbackSessionHandler;
  template <grpc::StatusCode code>
  friend class grpc::internal::ErrorMethodHandler;
  template <class Base>
  friend class grpc::internal::FinishOnlyReactor;
  friend class grpc::ClientContext;
  friend class grpc::GenericServerContext;
  friend class grpc::GenericCallbackServerContext;
 
  template <typename T>
  friend void experimental::SetSessionContext(
      ServerContextBase* context, std::shared_ptr<T> session_context);
  template <typename T>
  friend std::shared_ptr<T> experimental::GetSessionContext(
      const ServerContextBase* context);
 
  template <typename T>
  void SetSessionContext(std::shared_ptr<T> context) {
    if (!sent_initial_metadata_.load(std::memory_order_acquire)) {
      grpc::internal::MutexLock lock(&metadata_mu_);
      if (!sent_initial_metadata_.load(std::memory_order_acquire)) {
        internal::ServerContextSetSessionContext(
            call_.call, internal::SessionContextType<T>::id(),
            internal::SessionContextType<T>::Wrap(std::move(context)));
      }
    }
  }
 
  template <typename T>
  std::shared_ptr<T> GetSessionContext() const {
    if (sent_initial_metadata_.load(std::memory_order_acquire)) {
      return internal::SessionContextType<T>::Unwrap(
          internal::ServerContextGetSessionContext(
              call_.call, internal::SessionContextType<T>::id()));
    } else {
      grpc::internal::MutexLock lock(&metadata_mu_);
      return internal::SessionContextType<T>::Unwrap(
          internal::ServerContextGetSessionContext(
              call_.call, internal::SessionContextType<T>::id()));
    }
  }
 
  ServerContextBase(const ServerContextBase&);
  ServerContextBase& operator=(const ServerContextBase&);
 
  class CompletionOp;
 
  void BeginCompletionOp(
      grpc::internal::Call* call, std::function<void(bool)> callback,
      grpc::internal::ServerCallbackCall* callback_controller);
  grpc::internal::CompletionQueueTag* GetCompletionOpTag();
 
  void set_call(
      grpc_call* call, bool call_metric_recording_enabled,
      experimental::ServerMetricRecorder* server_metric_recorder,
      grpc_event_engine::experimental::MemoryAllocator* memory_allocator) {
    call_.call = call;
    if (call_metric_recording_enabled) {
      CreateCallMetricRecorder(server_metric_recorder);
    }
    memory_allocator_ = memory_allocator;
  }
 
  void BindDeadlineAndMetadata(gpr_timespec deadline, grpc_metadata_array* arr);
 
  uint32_t initial_metadata_flags() const { return 0; }
 
  grpc::experimental::ServerRpcInfo* set_server_rpc_info(
      const char* method, grpc::internal::RpcMethod::RpcType type,
      const std::vector<std::unique_ptr<
          grpc::experimental::ServerInterceptorFactoryInterface>>& creators) {
    if (!creators.empty()) {
      rpc_info_ = new grpc::experimental::ServerRpcInfo(this, method, type);
      rpc_info_->RegisterInterceptors(creators);
    }
    return rpc_info_;
  }
 
  void set_message_allocator_state(RpcAllocatorState* allocator_state) {
    message_allocator_state_ = allocator_state;
  }
 
  void MaybeMarkCancelledOnRead() {
    if (grpc_call_failed_before_recv_message(call_.call)) {
      marked_cancelled_.store(true, std::memory_order_release);
    }
  }
 
  // This should be called only once and only when call metric recording is
  // enabled.
  void CreateCallMetricRecorder(
      experimental::ServerMetricRecorder* server_metric_recorder = nullptr);
 
  struct CallWrapper {
    ~CallWrapper();
 
    grpc_call* call = nullptr;
  };
 
  // NOTE: call_ must be the first data member of this object so that its
  //       destructor is the last to be called, since its destructor may unref
  //       the underlying core call which holds the arena that may be used to
  //       hold this object.
  CallWrapper call_;
 
  CompletionOp* completion_op_ = nullptr;
  bool has_notify_when_done_tag_ = false;
  void* async_notify_when_done_tag_ = nullptr;
  grpc::internal::CallbackWithSuccessTag completion_tag_;
 
  gpr_timespec deadline_;
  grpc::CompletionQueue* cq_ = nullptr;
  std::atomic<bool> sent_initial_metadata_{false};
  mutable grpc::internal::Mutex metadata_mu_;
  mutable std::shared_ptr<const grpc::AuthContext> auth_context_;
  mutable grpc::internal::MetadataMap client_metadata_;
  std::multimap<std::string, std::string> initial_metadata_;
  std::multimap<std::string, std::string> trailing_metadata_;
 
  bool compression_level_set_ = false;
  grpc_compression_level compression_level_;
  grpc_compression_algorithm compression_algorithm_;
 
  grpc::internal::CallOpSet<grpc::internal::CallOpSendInitialMetadata,
                            grpc::internal::CallOpSendMessage>
      pending_ops_;
  bool has_pending_ops_ = false;
 
  grpc::experimental::ServerRpcInfo* rpc_info_ = nullptr;
  RpcAllocatorState* message_allocator_state_ = nullptr;
  ContextAllocator* context_allocator_ = nullptr;
  experimental::CallMetricRecorder* call_metric_recorder_ = nullptr;
  grpc_event_engine::experimental::MemoryAllocator* memory_allocator_ = nullptr;
 
  class Reactor : public grpc::ServerUnaryReactor {
   public:
    void OnCancel() override {}
    void OnDone() override {}
    // Override InternalInlineable for this class since its reactions are
    // trivial and thus do not need to be run from the EventEngine (potentially
    // triggering a thread hop). This should only be used by internal reactors
    // (thus the name) and not by user application code.
    bool InternalInlineable() override { return true; }
  };
 
  void SetupTestDefaultReactor(std::function<void(grpc::Status)> func) {
    // NOLINTNEXTLINE(modernize-make-unique)
    test_unary_.reset(new TestServerCallbackUnary(this, std::move(func)));
  }
  bool test_status_set() const {
    return (test_unary_ != nullptr) && test_unary_->status_set();
  }
  grpc::Status test_status() const { return test_unary_->status(); }
 
  class TestServerCallbackUnary : public grpc::ServerCallbackUnary {
   public:
    TestServerCallbackUnary(ServerContextBase* ctx,
                            std::function<void(grpc::Status)> func)
        : reactor_(ctx->DefaultReactor()),
          func_(std::move(func)),
          call_(ctx->c_call()) {
      this->BindReactor(reactor_);
    }
    void Finish(grpc::Status s) override {
      status_ = s;
      func_(std::move(s));
      status_set_.store(true, std::memory_order_release);
    }
    void SendInitialMetadata() override {}
 
    bool status_set() const {
      return status_set_.load(std::memory_order_acquire);
    }
    grpc::Status status() const { return status_; }
 
   private:
    void CallOnDone() override {}
 
    grpc_call* call() override { return call_; }
 
    grpc::internal::ServerReactor* reactor() override { return reactor_; }
 
    grpc::ServerUnaryReactor* const reactor_;
    std::atomic_bool status_set_{false};
    grpc::Status status_;
    const std::function<void(grpc::Status s)> func_;
    grpc_call* call_;
  };
 
  alignas(Reactor) char default_reactor_[sizeof(Reactor)];
  std::atomic_bool default_reactor_used_{false};
 
  std::atomic_bool marked_cancelled_{false};
 
  std::unique_ptr<TestServerCallbackUnary> test_unary_;
};
 
class ServerContext : public ServerContextBase {
 public:
  ServerContext() {}  // for async calls
 
  using ServerContextBase::AddInitialMetadata;
  using ServerContextBase::AddTrailingMetadata;
  using ServerContextBase::auth_context;
  using ServerContextBase::c_call;
  using ServerContextBase::census_context;
  using ServerContextBase::client_metadata;
  using ServerContextBase::compression_algorithm;
  using ServerContextBase::compression_level;
  using ServerContextBase::compression_level_set;
  using ServerContextBase::deadline;
  using ServerContextBase::IsCancelled;
  using ServerContextBase::peer;
  using ServerContextBase::raw_deadline;
  using ServerContextBase::set_compression_algorithm;
  using ServerContextBase::set_compression_level;
  using ServerContextBase::SetLoadReportingCosts;
  using ServerContextBase::TryCancel;
 
  // Sync/CQ-based Async ServerContext only
  using ServerContextBase::AsyncNotifyWhenDone;
 
 private:
  // Constructor for internal use by server only
  friend class grpc::Server;
  ServerContext(gpr_timespec deadline, grpc_metadata_array* arr)
      : ServerContextBase(deadline, arr) {}
 
  // CallbackServerContext only
  using ServerContextBase::DefaultReactor;
  using ServerContextBase::GetRpcAllocatorState;
 
  ServerContext(const ServerContext&) = delete;
  ServerContext& operator=(const ServerContext&) = delete;
};
 
class CallbackServerContext : public ServerContextBase {
 public:
  CallbackServerContext() {}
 
  using ServerContextBase::AddInitialMetadata;
  using ServerContextBase::AddTrailingMetadata;
  using ServerContextBase::auth_context;
  using ServerContextBase::c_call;
  using ServerContextBase::census_context;
  using ServerContextBase::client_metadata;
  using ServerContextBase::compression_algorithm;
  using ServerContextBase::compression_level;
  using ServerContextBase::compression_level_set;
  using ServerContextBase::context_allocator;
  using ServerContextBase::deadline;
  using ServerContextBase::IsCancelled;
  using ServerContextBase::peer;
  using ServerContextBase::raw_deadline;
  using ServerContextBase::set_compression_algorithm;
  using ServerContextBase::set_compression_level;
  using ServerContextBase::set_context_allocator;
  using ServerContextBase::SetLoadReportingCosts;
  using ServerContextBase::TryCancel;
 
  // CallbackServerContext only
  using ServerContextBase::DefaultReactor;
  using ServerContextBase::GetRpcAllocatorState;
 
 private:
  // Sync/CQ-based Async ServerContext only
  using ServerContextBase::AsyncNotifyWhenDone;
 
  CallbackServerContext(const CallbackServerContext&) = delete;
  CallbackServerContext& operator=(const CallbackServerContext&) = delete;
};
 
class ContextAllocator {
 public:
  virtual ~ContextAllocator() {}
 
  virtual CallbackServerContext* NewCallbackServerContext() { return nullptr; }
 
  virtual GenericCallbackServerContext* NewGenericCallbackServerContext() {
    return nullptr;
  }
 
  virtual void Release(CallbackServerContext*) {}
 
  virtual void Release(GenericCallbackServerContext*) {}
};
 
namespace experimental {
 
template <typename T>
inline void SetSessionContext(ServerContextBase* context,
                              std::shared_ptr<T> session_context) {
  context->SetSessionContext(std::move(session_context));
}
 
template <typename T>
inline std::shared_ptr<T> GetSessionContext(const ServerContextBase* context) {
  return context->GetSessionContext<T>();
}
 
}  // namespace experimental
 
}  // namespace grpc
 
static_assert(
    std::is_base_of<grpc::ServerContextBase, grpc::ServerContext>::value,
    "improper base class");
static_assert(std::is_base_of<grpc::ServerContextBase,
                              grpc::CallbackServerContext>::value,
              "improper base class");
static_assert(sizeof(grpc::ServerContextBase) == sizeof(grpc::ServerContext),
              "wrong size");
static_assert(sizeof(grpc::ServerContextBase) ==
                  sizeof(grpc::CallbackServerContext),
              "wrong size");
 
#endif  // GRPCPP_SERVER_CONTEXT_H