Qt now really unloads plugins and libraries when exiting an app

It also means that when creating a QPluginLoader or a QLibrary for a dynamic
lib already loaded, isLoaded will return true immediately after the creation of
the instance of QPluginLoader or QLibrary.

Reviewed-By: Jan-Arve Saether

9 files changed, 97 insertions, 70 deletions

diff --git a/src/corelib/plugin/qlibrary.cpp b/src/corelib/plugin/qlibrary.cpp
index ccde2b0..f6ae038 100644
--- a/src/corelib/plugin/qlibrary.cpp
+++ b/src/corelib/plugin/qlibrary.cpp
@@ -426,10 +426,14 @@ struct LibraryData {
     LibraryData() : settings(0) { }
     ~LibraryData() {
         delete settings;
+        foreach(QLibraryPrivate *lib, loadedLibs) {
+            lib->unload();
+        }
     }
 
     QSettings *settings;
     LibraryMap libraryMap;
+    QSet<QLibraryPrivate*> loadedLibs;
 };
 
 Q_GLOBAL_STATIC(LibraryData, libraryData)
@@ -481,7 +485,18 @@ bool QLibraryPrivate::load()
         return true;
     if (fileName.isEmpty())
         return false;
-    return load_sys();
+
+    bool ret = load_sys();
+    if (ret) {
+        //when loading a library we add a reference to it so that the QLibraryPrivate won't get deleted
+        //this allows to unload the library at a later time
+        if (LibraryData *lib = libraryData()) {
+            lib->loadedLibs += this;
+            libraryRefCount.ref();
+        }
+    }
+
+    return ret;
 }
 
 bool QLibraryPrivate::unload()
@@ -489,10 +504,16 @@ bool QLibraryPrivate::unload()
     if (!pHnd)
         return false;
     if (!libraryUnloadCount.deref()) { // only unload if ALL QLibrary instance wanted to
-        if (instance)
-            delete instance();
+        delete inst.data();
         if  (unload_sys()) {
-            instance = 0;
+            if (qt_debug_component())
+                qWarning() << "QLibraryPrivate::unload succeeded on" << fileName;
+            //when the library is unloaded, we release the reference on it so that 'this'
+            //can get deleted
+            if (LibraryData *lib = libraryData()) {
+                if (lib->loadedLibs.remove(this))
+                    libraryRefCount.deref();
+            }
             pHnd = 0;
         }
     }
@@ -1126,7 +1147,7 @@ void QLibrary::setFileNameAndVersion(const QString &fileName, const QString &ver
 */
 void *QLibrary::resolve(const char *symbol)
 {
-    if (!load())
+    if (!isLoaded() && !load())
         return 0;
     return d->resolve(symbol);
 }
diff --git a/src/corelib/plugin/qlibrary_p.h b/src/corelib/plugin/qlibrary_p.h
index 02dc523..b73fce5 100644
--- a/src/corelib/plugin/qlibrary_p.h
+++ b/src/corelib/plugin/qlibrary_p.h
@@ -60,6 +60,7 @@
 #include "QtCore/qpointer.h"
 #include "QtCore/qstringlist.h"
 #include "QtCore/qplugin.h"
+#include "QtCore/qsharedpointer.h"
 
 #ifndef QT_NO_LIBRARY
 
@@ -90,6 +91,7 @@ public:
 
     static QLibraryPrivate *findOrCreate(const QString &fileName, const QString &version = QString());
 
+    QWeakPointer<QObject> inst;
     QtPluginInstanceFunction instance;
     uint qt_version;
     QString lastModified;
diff --git a/src/corelib/plugin/qpluginloader.cpp b/src/corelib/plugin/qpluginloader.cpp
index b1d1ecc..9f322df 100644
--- a/src/corelib/plugin/qpluginloader.cpp
+++ b/src/corelib/plugin/qpluginloader.cpp
@@ -198,11 +198,11 @@ QPluginLoader::~QPluginLoader()
 */
 QObject *QPluginLoader::instance()
 {
-    if (!load())
+    if (!isLoaded() && !load())
         return 0;
-    if (d->instance)
-        return d->instance();
-    return 0;
+    if (!d->inst && d->instance)
+        d->inst = d->instance();
+    return d->inst.data();
 }
 
 /*!
diff --git a/src/gui/kernel/qapplication_win.cpp b/src/gui/kernel/qapplication_win.cpp
index 60fc5e1..d2ce5ff 100644
--- a/src/gui/kernel/qapplication_win.cpp
+++ b/src/gui/kernel/qapplication_win.cpp
@@ -206,8 +206,6 @@ static void resolveAygLibs()
     if (!aygResolved) {
         aygResolved = true;
         QLibrary ayglib(QLatin1String("aygshell"));
-        if (!ayglib.load())
-            return;
         ptrRecognizeGesture = (AygRecognizeGesture) ayglib.resolve("SHRecognizeGesture");
     }
 }
@@ -3642,13 +3640,11 @@ static void initWinTabFunctions()
         return;
 
     QLibrary library(QLatin1String("wintab32"));
-    if (library.load()) {
-        ptrWTInfo = (PtrWTInfo)library.resolve("WTInfoW");
-        ptrWTGet = (PtrWTGet)library.resolve("WTGetW");
-        ptrWTEnable = (PtrWTEnable)library.resolve("WTEnable");
-        ptrWTOverlap = (PtrWTEnable)library.resolve("WTOverlap");
-        ptrWTPacketsGet = (PtrWTPacketsGet)library.resolve("WTPacketsGet");
-    }
+    ptrWTInfo = (PtrWTInfo)library.resolve("WTInfoW");
+    ptrWTGet = (PtrWTGet)library.resolve("WTGetW");
+    ptrWTEnable = (PtrWTEnable)library.resolve("WTEnable");
+    ptrWTOverlap = (PtrWTEnable)library.resolve("WTOverlap");
+    ptrWTPacketsGet = (PtrWTPacketsGet)library.resolve("WTPacketsGet");
 #endif // Q_OS_WINCE
 }
 #endif // QT_NO_TABLETEVENT
diff --git a/src/gui/kernel/qapplication_x11.cpp b/src/gui/kernel/qapplication_x11.cpp
index 78fc704..b2dc638 100644
--- a/src/gui/kernel/qapplication_x11.cpp
+++ b/src/gui/kernel/qapplication_x11.cpp
@@ -456,11 +456,9 @@ static void* qt_load_library_runtime(const char *library, int vernum,
     Q_FOREACH(int version, versions) {
         QLatin1String libName(library);
         QLibrary xfixesLib(libName, version);
-        if (xfixesLib.load()) {
-            void *ptr = xfixesLib.resolve(symbol);
-            if (ptr)
-                return ptr;
-        }
+        void *ptr = xfixesLib.resolve(symbol);
+        if (ptr)
+            return ptr;
     }
     return 0;
 }
@@ -2557,22 +2555,20 @@ void qt_init(QApplicationPrivate *priv, int,
 
 #if !defined (Q_OS_IRIX) && !defined (QT_NO_TABLET)
     QLibrary wacom(QString::fromLatin1("wacomcfg"), 0); // version 0 is the latest release at time of writing this.
-    if (wacom.load()) {
-        // NOTE: C casts instead of reinterpret_cast for GCC 3.3.x
-        ptrWacomConfigInit = (PtrWacomConfigInit)wacom.resolve("WacomConfigInit");
-        ptrWacomConfigOpenDevice = (PtrWacomConfigOpenDevice)wacom.resolve("WacomConfigOpenDevice");
-        ptrWacomConfigGetRawParam  = (PtrWacomConfigGetRawParam)wacom.resolve("WacomConfigGetRawParam");
-        ptrWacomConfigCloseDevice = (PtrWacomConfigCloseDevice)wacom.resolve("WacomConfigCloseDevice");
-        ptrWacomConfigTerm = (PtrWacomConfigTerm)wacom.resolve("WacomConfigTerm");
-
-        if (ptrWacomConfigInit == 0 || ptrWacomConfigOpenDevice == 0 || ptrWacomConfigGetRawParam == 0
-                || ptrWacomConfigCloseDevice == 0 || ptrWacomConfigTerm == 0) { // either we have all, or we have none.
+    // NOTE: C casts instead of reinterpret_cast for GCC 3.3.x
+    ptrWacomConfigInit = (PtrWacomConfigInit)wacom.resolve("WacomConfigInit");
+    ptrWacomConfigOpenDevice = (PtrWacomConfigOpenDevice)wacom.resolve("WacomConfigOpenDevice");
+    ptrWacomConfigGetRawParam  = (PtrWacomConfigGetRawParam)wacom.resolve("WacomConfigGetRawParam");
+    ptrWacomConfigCloseDevice = (PtrWacomConfigCloseDevice)wacom.resolve("WacomConfigCloseDevice");
+    ptrWacomConfigTerm = (PtrWacomConfigTerm)wacom.resolve("WacomConfigTerm");
+
+    if (ptrWacomConfigInit == 0 || ptrWacomConfigOpenDevice == 0 || ptrWacomConfigGetRawParam == 0
+        || ptrWacomConfigCloseDevice == 0 || ptrWacomConfigTerm == 0) { // either we have all, or we have none.
             ptrWacomConfigInit = 0;
             ptrWacomConfigOpenDevice = 0;
             ptrWacomConfigGetRawParam  = 0;
             ptrWacomConfigCloseDevice = 0;
             ptrWacomConfigTerm = 0;
-        }
     }
 #endif
 }
diff --git a/src/gui/kernel/qdesktopwidget_win.cpp b/src/gui/kernel/qdesktopwidget_win.cpp
index 07dbc24..5aa206c 100644
--- a/src/gui/kernel/qdesktopwidget_win.cpp
+++ b/src/gui/kernel/qdesktopwidget_win.cpp
@@ -156,10 +156,8 @@ void QDesktopWidgetPrivate::init(QDesktopWidget *that)
 
 #ifndef Q_OS_WINCE
     QLibrary user32Lib(QLatin1String("user32"));
-    if (user32Lib.load()) {
-        enumDisplayMonitors = (EnumFunc)user32Lib.resolve("EnumDisplayMonitors");
-        getMonitorInfo = (InfoFunc)user32Lib.resolve("GetMonitorInfoW");
-    }
+    enumDisplayMonitors = (EnumFunc)user32Lib.resolve("EnumDisplayMonitors");
+    getMonitorInfo = (InfoFunc)user32Lib.resolve("GetMonitorInfoW");
 
     if (!enumDisplayMonitors || !getMonitorInfo) {
         screenCount = GetSystemMetrics(80);  // SM_CMONITORS
@@ -174,11 +172,9 @@ void QDesktopWidgetPrivate::init(QDesktopWidget *that)
     getMonitorInfo = 0;
 #else
     QLibrary coreLib(QLatin1String("coredll"));
-    if (coreLib.load()) {
-        // CE >= 4.0 case
-        enumDisplayMonitors = (EnumFunc)coreLib.resolve("EnumDisplayMonitors");
-        getMonitorInfo = (InfoFunc)coreLib.resolve("GetMonitorInfo");
-    }
+    // CE >= 4.0 case
+    enumDisplayMonitors = (EnumFunc)coreLib.resolve("EnumDisplayMonitors");
+    getMonitorInfo = (InfoFunc)coreLib.resolve("GetMonitorInfo");
 
     if ((!enumDisplayMonitors || !getMonitorInfo)) {
         screenCount = GetSystemMetrics(SM_CMONITORS);
diff --git a/src/gui/kernel/qguifunctions_wince.cpp b/src/gui/kernel/qguifunctions_wince.cpp
index f5004b0..cc98d43 100644
--- a/src/gui/kernel/qguifunctions_wince.cpp
+++ b/src/gui/kernel/qguifunctions_wince.cpp
@@ -123,8 +123,6 @@ static void resolveAygLibs()
     if (!aygResolved) {
         aygResolved = true;
         QLibrary ayglib(QLatin1String("aygshell"));
-        if (!ayglib.load())
-            return;
         ptrAygInitDialog = (AygInitDialog) ayglib.resolve("SHInitDialog");
         ptrAygFullScreen = (AygFullScreen) ayglib.resolve("SHFullScreen");
         ptrAygSHSipInfo  = (AygSHSipInfo)  ayglib.resolve("SHSipInfo");
diff --git a/src/gui/widgets/qmenu_wince.cpp b/src/gui/widgets/qmenu_wince.cpp
index e088db6..15d0116 100644
--- a/src/gui/widgets/qmenu_wince.cpp
+++ b/src/gui/widgets/qmenu_wince.cpp
@@ -113,8 +113,6 @@ static void resolveAygLibs()
     if (!aygResolved) {
         aygResolved = true;
         QLibrary aygLib(QLatin1String("aygshell"));
-        if (!aygLib.load())
-            return;
         ptrCreateMenuBar = (AygCreateMenuBar) aygLib.resolve("SHCreateMenuBar");
         ptrEnableSoftKey = (AygEnableSoftKey) aygLib.resolve("SHEnableSoftkey");
     }
diff --git a/tests/auto/qlibrary/tst_qlibrary.cpp b/tests/auto/qlibrary/tst_qlibrary.cpp
index 3d26e0b..99e6de3 100644
--- a/tests/auto/qlibrary/tst_qlibrary.cpp
+++ b/tests/auto/qlibrary/tst_qlibrary.cpp
@@ -203,6 +203,7 @@ void tst_QLibrary::version()
     VersionFunction fnVersion = (VersionFunction)library.resolve("mylibversion");
     QVERIFY(fnVersion);
     QCOMPARE(fnVersion(), resultversion);
+	QVERIFY(library.unload());
 #else
     Q_UNUSED(lib);
     Q_UNUSED(loadversion);
@@ -249,6 +250,7 @@ void tst_QLibrary::load()
     bool ok = library.load();
     if ( result ) {
 	QVERIFY( ok );
+	QVERIFY(library.unload());
     } else {
 	QVERIFY( !ok );
     }
@@ -338,6 +340,7 @@ void tst_QLibrary::resolve()
     } else {
 	QVERIFY( func == 0 );
     }
+	library.unload();
 }
 
 void tst_QLibrary::library_data()
@@ -469,7 +472,9 @@ void tst_QLibrary::errorString()
             break;
     }
     QRegExp re(errorString);
-    QVERIFY2(re.exactMatch(lib.errorString()), qPrintable(lib.errorString()));
+	QString libErrorString = lib.errorString();
+    QVERIFY(!lib.isLoaded() || lib.unload());
+    QVERIFY2(re.exactMatch(libErrorString), qPrintable(libErrorString));
     QCOMPARE(ok, success);
 }
 
@@ -525,6 +530,7 @@ void tst_QLibrary::loadHints()
     bool ok = library.load();
     if ( result ) {
         QVERIFY( ok );
+		QVERIFY(library.unload());
     } else {
         QVERIFY( !ok );
     }
@@ -565,6 +571,7 @@ void tst_QLibrary::fileName()
 #else
     QCOMPARE(lib.fileName(), expectedFilename);
 #endif
+    QVERIFY(lib.unload());
 
 }
 
@@ -576,29 +583,42 @@ void tst_QLibrary::multipleInstancesForOneLibrary()
     QString lib = QDir::currentPath() + "/mylib";
 #endif
 
-    QLibrary lib1(lib);
-    QLibrary lib2(lib);
-    QCOMPARE(lib1.isLoaded(), false);
-    QCOMPARE(lib2.isLoaded(), false);
-    lib1.load();
-    QCOMPARE(lib1.isLoaded(), true);
-    QCOMPARE(lib2.isLoaded(), true);
-    QCOMPARE(lib1.unload(), true);
-    QCOMPARE(lib1.isLoaded(), false);
-    QCOMPARE(lib2.isLoaded(), false);
-    lib1.load();
-    lib2.load();
-    QCOMPARE(lib1.isLoaded(), true);
-    QCOMPARE(lib2.isLoaded(), true);
-    QCOMPARE(lib1.unload(), false);
-    QCOMPARE(lib1.isLoaded(), true);
-    QCOMPARE(lib2.isLoaded(), true);
-    QCOMPARE(lib2.unload(), true);
-    QCOMPARE(lib1.isLoaded(), false);
-    QCOMPARE(lib2.isLoaded(), false);
+    {
+		QLibrary lib1(lib);
+		QLibrary lib2(lib);
+		QCOMPARE(lib1.isLoaded(), false);
+		QCOMPARE(lib2.isLoaded(), false);
+		lib1.load();
+		QCOMPARE(lib1.isLoaded(), true);
+		QCOMPARE(lib2.isLoaded(), true);
+		QCOMPARE(lib1.unload(), true);
+		QCOMPARE(lib1.isLoaded(), false);
+		QCOMPARE(lib2.isLoaded(), false);
+		lib1.load();
+		lib2.load();
+		QCOMPARE(lib1.isLoaded(), true);
+		QCOMPARE(lib2.isLoaded(), true);
+		QCOMPARE(lib1.unload(), false);
+		QCOMPARE(lib1.isLoaded(), true);
+		QCOMPARE(lib2.isLoaded(), true);
+		QCOMPARE(lib2.unload(), true);
+		QCOMPARE(lib1.isLoaded(), false);
+		QCOMPARE(lib2.isLoaded(), false);
+
+		// Finally; unload on that is already unloaded
+		QCOMPARE(lib1.unload(), false);
+    }
 
-    // Finally; unload on that is already unloaded
-    QCOMPARE(lib1.unload(), false);
+    //now let's try with a 3rd one that will go out of scope
+    {
+        QLibrary lib1(lib);
+        QCOMPARE(lib1.isLoaded(), false);
+        lib1.load();
+        QCOMPARE(lib1.isLoaded(), true);
+	}
+	QLibrary lib2(lib);
+	//lib2 should be loaded because lib1 was loaded and never unloaded
+    QCOMPARE(lib2.isLoaded(), true);
 
 /*
     lib1.setLoadHints(QLibrary::ResolveAllSymbolsHint);