path: root/contrib/libs/grpc/src/cpp/server/server_context.cc

/*
 *
 * 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.
 *
 */

#include <grpcpp/impl/codegen/server_context.h>

#include <algorithm>
#include <utility>

#include <grpc/compression.h>
#include <grpc/grpc.h>
#include <grpc/load_reporting.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpcpp/impl/call.h>
#include <grpcpp/impl/codegen/completion_queue.h>
#include <grpcpp/support/server_callback.h>
#include <grpcpp/support/time.h>

#include "src/core/lib/gprpp/ref_counted.h"
#include "src/core/lib/gprpp/sync.h"
#include "src/core/lib/surface/call.h"

namespace grpc {

// CompletionOp

class ServerContextBase::CompletionOp final
    : public internal::CallOpSetInterface {
 public:
  // initial refs: one in the server context, one in the cq
  // must ref the call before calling constructor and after deleting this 
  CompletionOp(internal::Call* call,
               ::grpc::internal::ServerCallbackCall* callback_controller)
      : call_(*call), 
        callback_controller_(callback_controller),
        has_tag_(false), 
        tag_(nullptr),
        core_cq_tag_(this), 
        refs_(2),
        finalized_(false),
        cancelled_(0), 
        done_intercepting_(false) {} 

  // CompletionOp isn't copyable or movable 
  CompletionOp(const CompletionOp&) = delete; 
  CompletionOp& operator=(const CompletionOp&) = delete; 
  CompletionOp(CompletionOp&&) = delete; 
  CompletionOp& operator=(CompletionOp&&) = delete; 
 
  ~CompletionOp() { 
    if (call_.server_rpc_info()) { 
      call_.server_rpc_info()->Unref(); 
    } 
  } 
 
  void FillOps(internal::Call* call) override;
 
  // This should always be arena allocated in the call, so override delete. 
  // But this class is not trivially destructible, so must actually call delete 
  // before allowing the arena to be freed 
  static void operator delete(void* /*ptr*/, std::size_t size) {
    // Use size to avoid unused-parameter warning since assert seems to be
    // compiled out and treated as unused in some gcc optimized versions.
    (void)size;
    assert(size == sizeof(CompletionOp)); 
  } 
 
  // This operator should never be called as the memory should be freed as part 
  // of the arena destruction. It only exists to provide a matching operator 
  // delete to the operator new so that some compilers will not complain (see 
  // https://github.com/grpc/grpc/issues/11301) Note at the time of adding this 
  // there are no tests catching the compiler warning. 
  static void operator delete(void*, void*) { assert(0); } 
 
  bool FinalizeResult(void** tag, bool* status) override;

  bool CheckCancelled(CompletionQueue* cq) {
    cq->TryPluck(this);
    return CheckCancelledNoPluck();
  }
  bool CheckCancelledAsync() { return CheckCancelledNoPluck(); }

  void set_tag(void* tag) {
    has_tag_ = true;
    tag_ = tag;
  }

  void set_core_cq_tag(void* core_cq_tag) { core_cq_tag_ = core_cq_tag; } 
 
  void* core_cq_tag() override { return core_cq_tag_; } 
 
  void Unref();

  // This will be called while interceptors are run if the RPC is a hijacked 
  // RPC. This should set hijacking state for each of the ops. 
  void SetHijackingState() override { 
    /* Servers don't allow hijacking */ 
    GPR_ASSERT(false);
  } 
 
  /* Should be called after interceptors are done running */ 
  void ContinueFillOpsAfterInterception() override {} 
 
  /* Should be called after interceptors are done running on the finalize result 
   * path */ 
  void ContinueFinalizeResultAfterInterception() override { 
    done_intercepting_ = true; 
    if (!has_tag_) { 
      /* We don't have a tag to return. */ 
      Unref();
      return; 
    } 
    /* Start a dummy op so that we can return the tag */ 
    GPR_ASSERT(grpc_call_start_batch(call_.call(), nullptr, 0, core_cq_tag_,
                                     nullptr) == GRPC_CALL_OK);
  } 
 
 private:
  bool CheckCancelledNoPluck() {
    grpc_core::MutexLock lock(&mu_);
    return finalized_ ? (cancelled_ != 0) : false;
  }

  internal::Call call_;
  ::grpc::internal::ServerCallbackCall* const callback_controller_;
  bool has_tag_;
  void* tag_;
  void* core_cq_tag_; 
  grpc_core::RefCount refs_;
  grpc_core::Mutex mu_;
  bool finalized_;
  int cancelled_;  // This is an int (not bool) because it is passed to core 
  bool done_intercepting_; 
  internal::InterceptorBatchMethodsImpl interceptor_methods_;
};

void ServerContextBase::CompletionOp::Unref() {
  if (refs_.Unref()) {
    grpc_call* call = call_.call(); 
    delete this;
    grpc_call_unref(call); 
  }
}

void ServerContextBase::CompletionOp::FillOps(internal::Call* call) {
  grpc_op ops; 
  ops.op = GRPC_OP_RECV_CLOSE_ON_SERVER; 
  ops.data.recv_close_on_server.cancelled = &cancelled_; 
  ops.flags = 0; 
  ops.reserved = nullptr; 
  interceptor_methods_.SetCall(&call_); 
  interceptor_methods_.SetReverse(); 
  interceptor_methods_.SetCallOpSetInterface(this); 
  // The following call_start_batch is internally-generated so no need for an
  // explanatory log on failure.
  GPR_ASSERT(grpc_call_start_batch(call->call(), &ops, 1, core_cq_tag_,
                                   nullptr) == GRPC_CALL_OK);
  /* No interceptors to run here */ 
}

bool ServerContextBase::CompletionOp::FinalizeResult(void** tag, bool* status) {
  // Decide whether to call the cancel callback within the lock
  bool call_cancel;

  {
    grpc_core::MutexLock lock(&mu_);
    if (done_intercepting_) {
      // We are done intercepting.
      bool has_tag = has_tag_;
      if (has_tag) {
        *tag = tag_;
      }
      Unref();
      return has_tag;
    } 
    finalized_ = true;
 
    // If for some reason the incoming status is false, mark that as a
    // cancellation.
    // TODO(vjpai): does this ever happen?
    if (!*status) {
      cancelled_ = 1;
    }

    call_cancel = (cancelled_ != 0);
    // Release the lock since we may call a callback and interceptors.
  }
 
  if (call_cancel && callback_controller_ != nullptr) {
    callback_controller_->MaybeCallOnCancel();
  }
  /* Add interception point and run through interceptors */ 
  interceptor_methods_.AddInterceptionHookPoint( 
      experimental::InterceptionHookPoints::POST_RECV_CLOSE);
  if (interceptor_methods_.RunInterceptors()) { 
    // No interceptors were run
    bool has_tag = has_tag_;
    if (has_tag) {
      *tag = tag_; 
    } 
    Unref();
    return has_tag;
  } 
  // There are interceptors to be run. Return false for now.
  return false; 
}

// ServerContextBase body

ServerContextBase::ServerContextBase()
    : deadline_(gpr_inf_future(GPR_CLOCK_REALTIME)) {}

ServerContextBase::ServerContextBase(gpr_timespec deadline,
                                     grpc_metadata_array* arr)
    : deadline_(deadline) {
  std::swap(*client_metadata_.arr(), *arr);
}

void ServerContextBase::BindDeadlineAndMetadata(gpr_timespec deadline,
                                                grpc_metadata_array* arr) {
  deadline_ = deadline; 
  std::swap(*client_metadata_.arr(), *arr); 
} 
 
ServerContextBase::~ServerContextBase() {
  if (completion_op_) {
    completion_op_->Unref();
  }
  if (rpc_info_) { 
    rpc_info_->Unref(); 
  } 
  if (default_reactor_used_.load(std::memory_order_relaxed)) {
    reinterpret_cast<Reactor*>(&default_reactor_)->~Reactor();
  }
}

ServerContextBase::CallWrapper::~CallWrapper() {
  if (call) {
    // If the ServerContext is part of the call's arena, this could free the
    // object itself.
    grpc_call_unref(call);
  }
}

void ServerContextBase::BeginCompletionOp(
    internal::Call* call, std::function<void(bool)> callback,
    ::grpc::internal::ServerCallbackCall* callback_controller) {
  GPR_ASSERT(!completion_op_);
  if (rpc_info_) { 
    rpc_info_->Ref(); 
  } 
  grpc_call_ref(call->call()); 
  completion_op_ = 
      new (grpc_call_arena_alloc(call->call(), sizeof(CompletionOp))) 
          CompletionOp(call, callback_controller);
  if (callback_controller != nullptr) {
    completion_tag_.Set(call->call(), std::move(callback), completion_op_,
                        true);
    completion_op_->set_core_cq_tag(&completion_tag_); 
    completion_op_->set_tag(completion_op_); 
  } else if (has_notify_when_done_tag_) { 
    completion_op_->set_tag(async_notify_when_done_tag_);
  }
  call->PerformOps(completion_op_);
}

internal::CompletionQueueTag* ServerContextBase::GetCompletionOpTag() {
  return static_cast<internal::CompletionQueueTag*>(completion_op_);
}

void ServerContextBase::AddInitialMetadata(const TString& key,
                                           const TString& value) {
  initial_metadata_.insert(std::make_pair(key, value));
}

void ServerContextBase::AddTrailingMetadata(const TString& key,
                                            const TString& value) {
  trailing_metadata_.insert(std::make_pair(key, value));
}

void ServerContextBase::TryCancel() const {
  internal::CancelInterceptorBatchMethods cancel_methods;
  if (rpc_info_) { 
    for (size_t i = 0; i < rpc_info_->interceptors_.size(); i++) { 
      rpc_info_->RunInterceptor(&cancel_methods, i); 
    } 
  } 
  grpc_call_error err =
      grpc_call_cancel_with_status(call_.call, GRPC_STATUS_CANCELLED,
                                   "Cancelled on the server side", nullptr);
  if (err != GRPC_CALL_OK) {
    gpr_log(GPR_ERROR, "TryCancel failed with: %d", err);
  }
}

bool ServerContextBase::IsCancelled() const {
  if (completion_tag_) { 
    // When using callback API, this result is always valid. 
    return completion_op_->CheckCancelledAsync(); 
  } else if (has_notify_when_done_tag_) { 
    // When using async API, the result is only valid 
    // if the tag has already been delivered at the completion queue
    return completion_op_ && completion_op_->CheckCancelledAsync();
  } else {
    // when using sync API, the result is always valid 
    return completion_op_ && completion_op_->CheckCancelled(cq_);
  }
}

void ServerContextBase::set_compression_algorithm(
    grpc_compression_algorithm algorithm) {
  compression_algorithm_ = algorithm;
  const char* algorithm_name = nullptr;
  if (!grpc_compression_algorithm_name(algorithm, &algorithm_name)) {
    gpr_log(GPR_ERROR, "Name for compression algorithm '%d' unknown.",
            algorithm);
    abort();
  }
  GPR_ASSERT(algorithm_name != nullptr);
  AddInitialMetadata(GRPC_COMPRESSION_REQUEST_ALGORITHM_MD_KEY, algorithm_name);
}

TString ServerContextBase::peer() const {
  TString peer;
  if (call_.call) {
    char* c_peer = grpc_call_get_peer(call_.call);
    peer = c_peer;
    gpr_free(c_peer);
  }
  return peer;
}

const struct census_context* ServerContextBase::census_context() const {
  return call_.call == nullptr ? nullptr
                               : grpc_census_call_get_context(call_.call);
}

void ServerContextBase::SetLoadReportingCosts(
    const std::vector<TString>& cost_data) {
  if (call_.call == nullptr) return;
  for (const auto& cost_datum : cost_data) {
    AddTrailingMetadata(GRPC_LB_COST_MD_KEY, cost_datum);
  }
}

}  // namespace grpc