grpc/src/cpp/common/completion_queue.cc

/*
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#include <grpc++/completion_queue.h>

#include <memory>

#include <grpc/grpc.h>
#include <grpc/support/log.h>
#include <grpc++/time.h>

namespace grpc {

CompletionQueue::CompletionQueue() {
  cq_ = grpc_completion_queue_create(nullptr);
}

CompletionQueue::CompletionQueue(grpc_completion_queue* take) : cq_(take) {}

CompletionQueue::~CompletionQueue() { grpc_completion_queue_destroy(cq_); }

void CompletionQueue::Shutdown() { grpc_completion_queue_shutdown(cq_); }

CompletionQueue::NextStatus CompletionQueue::AsyncNextInternal(
    void** tag, bool* ok, gpr_timespec deadline) {
  for (;;) {
    auto ev = grpc_completion_queue_next(cq_, deadline, nullptr);
    switch (ev.type) {
      case GRPC_QUEUE_TIMEOUT:
        return TIMEOUT;
      case GRPC_QUEUE_SHUTDOWN:
        return SHUTDOWN;
      case GRPC_OP_COMPLETE:
        auto cq_tag = static_cast<CompletionQueueTag*>(ev.tag);
        *ok = ev.success != 0;
        *tag = cq_tag;
        if (cq_tag->FinalizeResult(tag, ok)) {
          return GOT_EVENT;
        }
        break;
    }
  }
}

bool CompletionQueue::Pluck(CompletionQueueTag* tag) {
  auto deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
  auto ev = grpc_completion_queue_pluck(cq_, tag, deadline, nullptr);
  bool ok = ev.success != 0;
  void* ignored = tag;
  GPR_ASSERT(tag->FinalizeResult(&ignored, &ok));
  GPR_ASSERT(ignored == tag);
  // Ignore mutations by FinalizeResult: Pluck returns the C API status
  return ev.success != 0;
}

void CompletionQueue::TryPluck(CompletionQueueTag* tag) {
  auto deadline = gpr_time_0(GPR_CLOCK_REALTIME);
  auto ev = grpc_completion_queue_pluck(cq_, tag, deadline, nullptr);
  if (ev.type == GRPC_QUEUE_TIMEOUT) return;
  bool ok = ev.success != 0;
  void* ignored = tag;
  // the tag must be swallowed if using TryPluck
  GPR_ASSERT(!tag->FinalizeResult(&ignored, &ok));
}

}  // namespace grpc