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, 4 insertions, 4 deletions

diff --git a/src/dbus/qdbusinterface.cpp b/src/dbus/qdbusinterface.cpp
index 47b5b7b173..29d00077ae 100644
--- a/src/dbus/qdbusinterface.cpp
+++ b/src/dbus/qdbusinterface.cpp
@@ -106,13 +106,13 @@ static void copyArgument(void *to, int id, const QVariant &arg)
             return;
         }
 
-        if (id == QDBusMetaTypeId::variant) {
+        if (id == QDBusMetaTypeId::variant()) {
             *reinterpret_cast<QDBusVariant *>(to) = arg.value<QDBusVariant>();
             return;
-        } else if (id == QDBusMetaTypeId::objectpath) {
+        } else if (id == QDBusMetaTypeId::objectpath()) {
             *reinterpret_cast<QDBusObjectPath *>(to) = arg.value<QDBusObjectPath>();
             return;
-        } else if (id == QDBusMetaTypeId::signature) {
+        } else if (id == QDBusMetaTypeId::signature()) {
             *reinterpret_cast<QDBusSignature *>(to) = arg.value<QDBusSignature>();
             return;
         }
@@ -123,7 +123,7 @@ static void copyArgument(void *to, int id, const QVariant &arg)
     }
 
     // if we got here, it's either an un-dermarshalled type or a mismatch
-    if (arg.userType() != QDBusMetaTypeId::argument) {
+    if (arg.userType() != QDBusMetaTypeId::argument()) {
         // it's a mismatch
         //qWarning?
         return;