C++ AsyncOp::timeOut_inlock方法代码示例

//.........这里部分代码省略.........
        }

        // We can't release the AsyncOp until we know we were not canceled.
        auto ownedOp = conn->releaseAsyncOp();
        op = ownedOp.get();

        // This AsyncOp may be recycled. We expect timeout and canceled to be clean.
        // If this op was most recently used to connect, its state transitions won't have been
        // reset, so we do that here.
        MONGO_ASIO_INVARIANT_INLOCK(!op->canceled(), "AsyncOp has dirty canceled flag", op);
        MONGO_ASIO_INVARIANT_INLOCK(!op->timedOut(), "AsyncOp has dirty timeout flag", op);
        op->clearStateTransitions();

        // Now that we're inProgress, an external cancel can touch our op, but
        // not until we release the inProgressMutex.
        _inProgress.emplace(op, std::move(ownedOp));

        op->_cbHandle = std::move(cbHandle);
        op->_request = std::move(request);
        op->_onFinish = std::move(onFinish);
        op->_connectionPoolHandle = std::move(swConn.getValue());
        op->startProgress(getConnectionStartTime);

        // This ditches the lock and gets us onto the strand (so we're
        // threadsafe)
        op->_strand.post([this, op, getConnectionStartTime] {
            const auto timeout = op->_request.timeout;

            // Set timeout now that we have the correct request object
            if (timeout != RemoteCommandRequest::kNoTimeout) {
                // Subtract the time it took to get the connection from the pool from the request
                // timeout.
                auto getConnectionDuration = now() - getConnectionStartTime;
                if (getConnectionDuration >= timeout) {
                    // We only assume that the request timer is guaranteed to fire *after* the
                    // timeout duration - but make no stronger assumption. It is thus possible that
                    // we have already exceeded the timeout. In this case we timeout the operation
                    // manually.
                    std::stringstream msg;
                    msg << "Remote command timed out while waiting to get a connection from the "
                        << "pool, took " << getConnectionDuration << ", timeout was set to "
                        << timeout;
                    auto rs = ResponseStatus(ErrorCodes::NetworkInterfaceExceededTimeLimit,
                                             msg.str(),
                                             getConnectionDuration);
                    return _completeOperation(op, rs);
                }

                // The above conditional guarantees that the adjusted timeout will never underflow.
                MONGO_ASIO_INVARIANT(timeout > getConnectionDuration, "timeout underflowed", op);
                const auto adjustedTimeout = timeout - getConnectionDuration;
                const auto requestId = op->_request.id;

                try {
                    op->_timeoutAlarm =
                        op->_owner->_timerFactory->make(&op->_strand, adjustedTimeout);
                } catch (std::system_error& e) {
                    severe() << "Failed to construct timer for AsyncOp: " << e.what();
                    fassertFailed(40334);
                }

                std::shared_ptr<AsyncOp::AccessControl> access;
                std::size_t generation;
                {
                    stdx::lock_guard<stdx::mutex> lk(op->_access->mutex);
                    access = op->_access;
                    generation = access->id;
                }

                op->_timeoutAlarm->asyncWait(
                    [this, op, access, generation, requestId, adjustedTimeout](std::error_code ec) {
                        // We must pass a check for safe access before using op inside the
                        // callback or we may attempt access on an invalid pointer.
                        stdx::lock_guard<stdx::mutex> lk(access->mutex);
                        if (generation != access->id) {
                            // The operation has been cleaned up, do not access.
                            return;
                        }

                        if (!ec) {
                            LOG(2) << "Request " << requestId << " timed out"
                                   << ", adjusted timeout after getting connection from pool was "
                                   << adjustedTimeout << ", op was " << redact(op->toString());

                            op->timeOut_inlock();
                        } else {
                            LOG(2) << "Failed to time request " << requestId
                                   << "out: " << ec.message() << ", op was "
                                   << redact(op->toString());
                        }
                    });
            }

            _beginCommunication(op);
        });
    };

    _connectionPool.get(request.target, request.timeout, nextStep);
    return Status::OK();
}