File indexing completed on 2024-04-28 16:51:32

 /*
     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.count();
     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);
 }