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/*
* Copyright (C) 2018 Max Kellermann <max.kellermann@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef ODBUS_ASYNC_REQUEST_HXX
#define ODBUS_ASYNC_REQUEST_HXX
#include "PendingCall.hxx"
#include "Message.hxx"
#include <functional>
#include <assert.h>
namespace ODBus {
/**
* Helper class which makes sending messages and receiving the
* response asynchronously easy.
*
* Remember to always cancel pending operations before destructing
* this class.
*/
class AsyncRequest {
PendingCall pending_call;
std::function<void(Message) noexcept> callback;
public:
operator bool() const noexcept {
return pending_call;
}
/**
* Send a message on the specified connection and invoke the
* given callback upon completion (or error).
*
* The callback should invoke Message::CheckThrowError() to
* check for errors.
*
* This object must be kept around until the operation
* completes. It can only be reused after completion.
*/
template<typename F>
void Send(DBusConnection &connection,
DBusMessage &message,
int timeout_milliseconds,
F &&_callback) {
assert(!pending_call);
callback = std::forward<F>(_callback);
pending_call = PendingCall::SendWithReply(&connection,
&message,
timeout_milliseconds);
pending_call.SetNotify(Notify, this);
}
template<typename F>
void Send(DBusConnection &connection,
DBusMessage &message,
F &&_callback) {
Send(connection, message, -1, std::forward<F>(_callback));
}
void Cancel() {
pending_call.Cancel();
}
private:
void Notify(DBusPendingCall *pending) noexcept {
assert(pending_call.Get() == pending);
pending_call = {};
std::exchange(callback, {})(Message::StealReply(*pending));
}
static void Notify(DBusPendingCall *pending,
void *user_data) noexcept {
auto &ar = *(AsyncRequest *)user_data;
ar.Notify(pending);
}
};
} /* namespace ODBus */
#endif