QEvdevKeyboardHandler: use RAII in create()/ctor

Coverity somewhat rightfully complained that the FD may be leaked in
certain cases, e.g. when the new-expression throws. Yes, the plugin
is compiled with exceptions disabled, but the code is still a bug
waiting to happen, because it's too easy to just add an early return
to the function and leak the FD that way.

Fix by writing a small RAII class for FDs (can't use QSharedPointer,
since it's not a pointer we're dealing with). It's quite generically
named, in anticipation that it might come in handy elsewhere, too.

Coverity-Id: 89046
Change-Id: I83d1ed3f11219065d2248c129ed191a651f617c7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/src/platformsupport/input/evdevkeyboard/qevdevkeyboardhandler_p.h b/src/platformsupport/input/evdevkeyboard/qevdevkeyboardhandler_p.h
index 84c251c3c2..b08f30b6ee 100644
--- a/src/platformsupport/input/evdevkeyboard/qevdevkeyboardhandler_p.h
+++ b/src/platformsupport/input/evdevkeyboard/qevdevkeyboardhandler_p.h
@@ -123,12 +123,25 @@ inline QDataStream &operator<<(QDataStream &ds, const QEvdevKeyboardMap::Composi
     return ds << c.first << c.second << c.result;
 }
 
+class QFdContainer
+{
+    int m_fd;
+    Q_DISABLE_COPY(QFdContainer);
+public:
+    explicit QFdContainer(int fd = -1) Q_DECL_NOTHROW : m_fd(fd) {}
+    ~QFdContainer() { reset(); }
+
+    int get() const Q_DECL_NOTHROW { return m_fd; }
+
+    int release() Q_DECL_NOTHROW { int result = m_fd; m_fd = -1; return result; }
+    void reset() Q_DECL_NOTHROW;
+};
 
 class QEvdevKeyboardHandler : public QObject
 {
     Q_OBJECT
 public:
-    QEvdevKeyboardHandler(const QString &device, int fd, bool disableZap, bool enableCompose, const QString &keymapFile);
+    QEvdevKeyboardHandler(const QString &device, QFdContainer &fd, bool disableZap, bool enableCompose, const QString &keymapFile);
     ~QEvdevKeyboardHandler();
 
     enum KeycodeAction {
@@ -181,7 +194,7 @@ private:
     void switchLed(int, bool);
 
     QString m_device;
-    int m_fd;
+    QFdContainer m_fd;
     QSocketNotifier *m_notify;
 
     // keymap handling