Use QSocketNotifier instead of sleeping in an endless loop

Event driven listening for navigator events, basically a backport of
the respective QPA plugin code in Qt5/qtbase

Change-Id: I120a755af614d35a9e5a0e755c521bbf8bf0d13d
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>

2 files changed, 51 insertions, 35 deletions

diff --git a/src/plugins/platforms/blackberry/qbbnavigatorthread.cpp b/src/plugins/platforms/blackberry/qbbnavigatorthread.cpp
index 97d50a9..675e812 100644
--- a/src/plugins/platforms/blackberry/qbbnavigatorthread.cpp
+++ b/src/plugins/platforms/blackberry/qbbnavigatorthread.cpp
@@ -43,12 +43,14 @@
 #include "qbbnavigatorthread.h"
 #include "qbbscreen.h"
 
+#include <QtCore/private/qcore_unix_p.h>
 #include <QtGui/QApplication>
 #include <QtGui/QWidget>
 #include <QtGui/QWindowSystemInterface>
 #include <QByteArray>
 #include <QList>
 #include <QDebug>
+#include <QSocketNotifier>
 
 #include <errno.h>
 #include <fcntl.h>
@@ -62,7 +64,7 @@
 QBBNavigatorThread::QBBNavigatorThread(QBBScreen& primaryScreen)
     : mPrimaryScreen(primaryScreen),
       mFd(-1),
-      mQuit(false)
+      mReadNotifier(0)
 {
 }
 
@@ -70,6 +72,8 @@ QBBNavigatorThread::~QBBNavigatorThread()
 {
     // block until thread terminates
     shutdown();
+
+    delete mReadNotifier;
 }
 
 void QBBNavigatorThread::run()
@@ -86,37 +90,11 @@ void QBBNavigatorThread::run()
         return;
     }
 
-    // allocate buffer for pps data
-    char buffer[PPS_BUFFER_SIZE];
-
-    // loop indefinitely
-    while (!mQuit) {
-
-        // attempt to read pps data
-        errno = 0;
-        int bytes = read(mFd, buffer, PPS_BUFFER_SIZE - 1);
-        if (bytes == -1) {
-            qFatal("QBB: failed to read navigator pps, errno=%d", errno);
-        }
-
-        // check if pps data was received
-        if (bytes > 0) {
-
-            // ensure data is null terminated
-            buffer[bytes] = '\0';
+    mReadNotifier = new QSocketNotifier(mFd, QSocketNotifier::Read);
+    // using direct connection to get the slot called in this thread's context
+    connect(mReadNotifier, SIGNAL(activated(int)), this, SLOT(readData()), Qt::DirectConnection);
 
-            // process received message
-            QByteArray ppsData(buffer);
-            QByteArray msg;
-            QByteArray dat;
-            QByteArray id;
-            parsePPS(ppsData, msg, dat, id);
-            handleMessage(msg, dat, id);
-        }
-
-        // yield
-        msleep(5);
-    }
+    exec();
 
     // close connection to navigator
     close(mFd);
@@ -128,13 +106,13 @@ void QBBNavigatorThread::run()
 
 void QBBNavigatorThread::shutdown()
 {
-    // signal thread to terminate
-    mQuit = true;
-
 #if defined(QBBNAVIGATORTHREAD_DEBUG)
     qDebug() << "QBB: navigator thread shutdown begin";
 #endif
 
+    // signal thread to terminate
+    quit();
+
     // block until thread terminates
     wait();
 
@@ -269,3 +247,36 @@ void QBBNavigatorThread::handleMessage(const QByteArray &msg, const QByteArray &
         QApplication::quit();
     }
 }
+
+void QBBNavigatorThread::readData()
+{
+#if defined(QBBNAVIGATORTHREAD_DEBUG)
+    qDebug() << "QBB: reading navigator data";
+#endif
+
+    // allocate buffer for pps data
+    char buffer[PPS_BUFFER_SIZE];
+
+    // attempt to read pps data
+    errno = 0;
+    int bytes = qt_safe_read(mFd, buffer, PPS_BUFFER_SIZE - 1);
+    if (bytes == -1) {
+        qFatal("QBB: failed to read navigator pps, errno=%d", errno);
+    }
+
+    // check if pps data was received
+    if (bytes > 0) {
+
+        // ensure data is null terminated
+        buffer[bytes] = '\0';
+
+        // process received message
+        QByteArray ppsData(buffer);
+        QByteArray msg;
+        QByteArray dat;
+        QByteArray id;
+        parsePPS(ppsData, msg, dat, id);
+        handleMessage(msg, dat, id);
+    }
+
+}
diff --git a/src/plugins/platforms/blackberry/qbbnavigatorthread.h b/src/plugins/platforms/blackberry/qbbnavigatorthread.h
index fa7e8ae..a4dd23a 100644
--- a/src/plugins/platforms/blackberry/qbbnavigatorthread.h
+++ b/src/plugins/platforms/blackberry/qbbnavigatorthread.h
@@ -45,9 +45,11 @@
 QT_BEGIN_NAMESPACE
 
 class QBBScreen;
+class QSocketNotifier;
 
 class QBBNavigatorThread : public QThread
 {
+    Q_OBJECT
 public:
     QBBNavigatorThread(QBBScreen& primaryScreen);
     virtual ~QBBNavigatorThread();
@@ -55,10 +57,13 @@ public:
 protected:
     virtual void run();
 
+private Q_SLOTS:
+    void readData();
+
 private:
     QBBScreen& mPrimaryScreen;
     int mFd;
-    bool mQuit;
+    QSocketNotifier *mReadNotifier;
 
     void shutdown();
     void parsePPS(const QByteArray &ppsData, QByteArray &msg, QByteArray &dat, QByteArray &id);