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/*
SPDX-FileCopyrightText: 2017 Kai Uwe Broulik <kde@privat.broulik.de>
SPDX-FileCopyrightText: 2017 David Edmundson <davidedmundson@kde.org>
SPDX-License-Identifier: MIT
*/
#include "connection.h"
#include <QCoreApplication>
#include <QJsonDocument>
#include <QSocketNotifier>
#include <QDebug>
#include <poll.h>
#include <unistd.h>
Connection::Connection()
: QObject()
{
// Make really sure no one but us, who uses the correct format, prints to stdout
int newStdout = dup(STDOUT_FILENO);
// redirect it to stderr so it's not just swallowed
dup2(STDERR_FILENO, STDOUT_FILENO);
m_stdOut.open(newStdout, QIODevice::WriteOnly);
m_stdIn.open(STDIN_FILENO, QIODevice::ReadOnly | QIODevice::Unbuffered);
auto notifier = new QSocketNotifier(STDIN_FILENO, QSocketNotifier::Read, this);
connect(notifier, &QSocketNotifier::activated, this, &Connection::readData);
}
void Connection::sendData(const QJsonObject &data)
{
const QByteArray rawData = QJsonDocument(data).toJson(QJsonDocument::Compact);
// note, don't use QDataStream as we need to control the binary format used
quint32 len = rawData.length();
m_stdOut.write((char *)&len, sizeof(len));
m_stdOut.write(rawData);
m_stdOut.flush();
}
Connection *Connection::self()
{
static Connection *s = nullptr;
if (!s) {
s = new Connection();
}
return s;
}
void Connection::readData()
{
/* Qt does not recognize POLLHUP as an error and
* as that flag never gets cleared, we enter an
* infinite busy loop polling STDIN.
* So we need to check for this condition ourselves
* and exit. */
struct pollfd poll_stdin = {};
poll_stdin.fd = STDIN_FILENO;
poll_stdin.events = POLLHUP;
poll_stdin.revents = 0;
if (poll(&poll_stdin, 1, 0) != 0) {
// STDIN has HUP/ERR/NVAL condition
qApp->exit(0);
return;
}
m_stdIn.startTransaction();
quint32 length = 0;
auto rc = m_stdIn.read((char *)(&length), sizeof(quint32));
if (rc == -1) {
m_stdIn.rollbackTransaction();
return;
}
QByteArray data = m_stdIn.read(length);
if (data.length() != int(length)) {
m_stdIn.rollbackTransaction();
return;
}
if (data.isEmpty()) {
m_stdIn.rollbackTransaction();
return;
}
m_stdIn.commitTransaction();
const QJsonObject json = QJsonDocument::fromJson(data).object();
Q_EMIT dataReceived(json);
}
#include "moc_connection.cpp"
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