Reduce unnecessary QtCore DLL loads during Symbian app thread creation

The Symbain fast allocator integration in Qt 4.7 loads QtCore.DLL to
check availablility. This load has been causing a crash in the Nokia
Store app when a different version of QtCore 4.7 is installed. The new
DLL is loaded and it's static data tries to initialise before the
allocator is set up.

This change stores the allocator setup function so that extra DLL loads
are not required. Now the same allocator setup function is used for the
lifetime of the app.

Reviewed-by: Shane Kearns

1 files changed, 26 insertions, 14 deletions

diff --git a/src/s60main/newallocator_hook.cpp b/src/s60main/newallocator_hook.cpp
index 7e0b344..4cec214 100644
--- a/src/s60main/newallocator_hook.cpp
+++ b/src/s60main/newallocator_hook.cpp
@@ -109,26 +109,38 @@ struct SStdEpocThreadCreateInfo : public SThreadCreateInfo
  * startup. On return, there is some kind of heap allocator installed on the
  * thread.
 */
+typedef int (*TSetupThreadHeapFunc)(TBool aNotFirst, SStdEpocThreadCreateInfo& aInfo);
+// keep the SetupThreadHeap() pointer so that we don't reload QtCore.dll after the first time
+static TSetupThreadHeapFunc gp_qt_symbian_SetupThreadHeap = 0;
+static bool gp_qt_symbian_SetupThreadHeap_set = false;
+
 TInt UserHeap::SetupThreadHeap(TBool aNotFirst, SStdEpocThreadCreateInfo& aInfo)
 {
     TInt r = KErrNone;
 
 #ifndef __WINS__
-    // attempt to create the fast allocator through a known export ordinal in qtcore.dll
-    RLibrary qtcore;
-    if (qtcore.Load(QtCoreLibName) == KErrNone)
-    {
-        const int qt_symbian_SetupThreadHeap_eabi_ordinal = 3713;
-        TLibraryFunction libFunc = qtcore.Lookup(qt_symbian_SetupThreadHeap_eabi_ordinal);
-        if (libFunc)
-        {
-            typedef int (*TSetupThreadHeapFunc)(TBool aNotFirst, SStdEpocThreadCreateInfo& aInfo);
-            TSetupThreadHeapFunc p_qt_symbian_SetupThreadHeap = TSetupThreadHeapFunc(libFunc);
-            r = (*p_qt_symbian_SetupThreadHeap)(aNotFirst, aInfo);
+    // on first call, aNotFirst will be false.
+    // on second call, gp_qt_symbian_SetupThreadHeap_set will be false(!) because WSD is zeroed after the first call
+    // on subsequent calls, both will be true and we can use the stored SetupThreadHeap() pointer
+    if (aNotFirst && gp_qt_symbian_SetupThreadHeap_set) {
+        if (gp_qt_symbian_SetupThreadHeap)
+            return (*gp_qt_symbian_SetupThreadHeap)(aNotFirst, aInfo);
+    } else {
+        // attempt to create the fast allocator through a known export ordinal in qtcore.dll
+        RLibrary qtcore;
+        gp_qt_symbian_SetupThreadHeap_set = true;
+        if (qtcore.Load(QtCoreLibName) == KErrNone) {
+            const int qt_symbian_SetupThreadHeap_eabi_ordinal = 3713;
+            TLibraryFunction libFunc = qtcore.Lookup(qt_symbian_SetupThreadHeap_eabi_ordinal);
+            if (libFunc) {
+                TSetupThreadHeapFunc p_qt_symbian_SetupThreadHeap = TSetupThreadHeapFunc(libFunc);
+                gp_qt_symbian_SetupThreadHeap = p_qt_symbian_SetupThreadHeap;
+                r = (*p_qt_symbian_SetupThreadHeap)(aNotFirst, aInfo);
+            }
+            qtcore.Close();
+            if (libFunc)
+                return r;
         }
-        qtcore.Close();
-        if (libFunc)
-            return r;
     }
 #endif