QDBusMetaTypeId: don't cache the result of qMetaTypeId<>() in static ints

There's not much point in caching the result of qMetaTypeId<>,
because it's already internally memoised.

In addition, the code that initialised the static int caches wasn't
protected against concurrent access under the assumption that the
operations performed were thread-safe.

That is true for most of them, but not for the stores to the static ints,
which race against each other:

   // Thread A               // Thread B
   r1 = initialized /*=false*/
                             r1 = initialized /*=false*/
   r2 = qMetaTypeId<...>();
                             r2 = qMetaTypeId<...>();
   message = r2;             message = r2; // race, ditto for all other ints

To fix, turn the ints into inline functions that just call the respective
qMetaTypeId<>() function.

Change-Id: I5aa80c624872c3867232abc26ffdcde70cd54022
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/dbus/qdbusmarshaller.cpp b/src/dbus/qdbusmarshaller.cpp
index 00ef7fd9d8..0a91a7c38e 100644
--- a/src/dbus/qdbusmarshaller.cpp
+++ b/src/dbus/qdbusmarshaller.cpp
@@ -185,7 +185,7 @@ inline bool QDBusMarshaller::append(const QDBusVariant &arg)
 
     QByteArray tmpSignature;
     const char *signature = 0;
-    if (id == QDBusMetaTypeId::argument) {
+    if (id == QDBusMetaTypeId::argument()) {
         // take the signature from the QDBusArgument object we're marshalling
         tmpSignature =
             qvariant_cast<QDBusArgument>(value).currentSignature().toLatin1();
@@ -372,7 +372,7 @@ bool QDBusMarshaller::appendVariantInternal(const QVariant &arg)
     }
 
     // intercept QDBusArgument parameters here
-    if (id == QDBusMetaTypeId::argument) {
+    if (id == QDBusMetaTypeId::argument()) {
         QDBusArgument dbusargument = qvariant_cast<QDBusArgument>(arg);
         QDBusArgumentPrivate *d = QDBusArgumentPrivate::d(dbusargument);
         if (!d->message)