Qt: Move the MIME init thread to WiresharkApplication.

The Qt 4.8 "Starting a Thread" document at
http://doc.qt.io/qt-4.8/threads-starting.html says,

"Note that you must create the QApplication (or QCoreApplication) object
 before you can create a QThread."

It looks like this changed some time around Qt 5.5 or 5.6, e.g.
https://codereview.qt-project.org/#/c/120793/, but just to be safe move
the MIME database initialization thread to WiresharkApplication. We
start reading the database later than I'd like, but it's still early
enough to make a difference here.

QMimeDatabase was added in Qt 5.0. Add version checks.

Change-Id: Ic80ebb8692e93b1e4aea7a8670f4fcf45e385b29
Reviewed-on: https://code.wireshark.org/review/24512
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Gerald Combs <gerald@wireshark.org>

1 files changed, 0 insertions, 18 deletions

diff --git a/wireshark-qt.cpp b/wireshark-qt.cpp
index 73c5153ca7..a4341e5835 100644
--- a/wireshark-qt.cpp
+++ b/wireshark-qt.cpp
@@ -96,8 +96,6 @@
 #include "caputils/capture-pcap-util.h"
 
 #include <QMessageBox>
-#include <QMimeDatabase>
-#include <QThreadPool>
 
 #ifdef _WIN32
 #  include "caputils/capture-wpcap.h"
@@ -140,19 +138,6 @@
 */
 #define DEBUG_STARTUP_TIME_LOGLEVEL 252
 
-// QMimeDatabase can be slow to initialize. Do so in a worker thread
-// as early as possible.
-// https://github.com/lxde/pcmanfm-qt/issues/415
-class MimeDatabaseInitThread : public QRunnable
-{
-private:
-    void run()
-    {
-        QMimeDatabase mime_db;
-        mime_db.mimeTypeForData(QByteArray());
-    }
-};
-
 /* update the main window */
 void main_window_update(void)
 {
@@ -395,9 +380,6 @@ int main(int argc, char *qt_argv[])
     QTextCodec::setCodecForTr(utf8codec);
 #endif
 
-    MimeDatabaseInitThread *mime_db_init_thread = new(MimeDatabaseInitThread);
-    QThreadPool::globalInstance()->start(mime_db_init_thread);
-
     /* Set the C-language locale to the native environment. */
     setlocale(LC_ALL, "");