Don't use QSettings to "cache" plugin information

The main rationale of the cache was to examine the plugin's build-key
before loading it. Now that the build-key has been removed, the cache
has lost its usefulness.

This is part of a larger push to not use QSettings for Qt specific
settings or caches.

See also:
http://lists.qt.nokia.com/pipermail/qt5-feedback/2011-August/000892.html
http://lists.qt.nokia.com/pipermail/qt5-feedback/2011-August/000960.html
http://lists.qt.nokia.com/pipermail/qt5-feedback/2011-August/000907.html
http://lists.qt.nokia.com/pipermail/qt5-feedback/2011-August/000904.html

Change-Id: I96e84aa25983c8e06e027ff70cef109444c362a2
Reviewed-on: http://codereview.qt.nokia.com/3978
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

1 files changed, 18 insertions, 39 deletions

diff --git a/src/corelib/plugin/qfactoryloader.cpp b/src/corelib/plugin/qfactoryloader.cpp
index c8831e5ae5..c175dcfe1b 100644
--- a/src/corelib/plugin/qfactoryloader.cpp
+++ b/src/corelib/plugin/qfactoryloader.cpp
@@ -45,7 +45,6 @@
 #include "qfactoryinterface.h"
 #include "qmap.h"
 #include <qdir.h>
-#include <qsettings.h>
 #include <qdebug.h>
 #include "qmutex.h"
 #include "qplugin.h"
@@ -107,7 +106,6 @@ void QFactoryLoader::update()
 #ifdef QT_SHARED
     Q_D(QFactoryLoader);
     QStringList paths = QCoreApplication::libraryPaths();
-    QSettings settings(QSettings::UserScope, QLatin1String("Trolltech"));
     for (int i = 0; i < paths.count(); ++i) {
         const QString &pluginDir = paths.at(i);
         // Already loaded, skip it...
@@ -127,7 +125,7 @@ void QFactoryLoader::update()
                 qDebug() << "QFactoryLoader::QFactoryLoader() looking at" << fileName;
             }
             library = QLibraryPrivate::findOrCreate(QFileInfo(fileName).canonicalFilePath());
-            if (!library->isPlugin(&settings)) {
+            if (!library->isPlugin()) {
                 if (qt_debug_component()) {
                     qDebug() << library->errorString;
                     qDebug() << "         not a plugin";
@@ -135,45 +133,26 @@ void QFactoryLoader::update()
                 library->release();
                 continue;
             }
-            QString regkey = QString::fromLatin1("Qt Factory Cache %1.%2/%3:/%4")
-                             .arg((QT_VERSION & 0xff0000) >> 16)
-                             .arg((QT_VERSION & 0xff00) >> 8)
-                             .arg(QLatin1String(d->iid))
-                             .arg(fileName);
-            QStringList reg, keys;
-            reg = settings.value(regkey).toStringList();
-            if (reg.count() && library->lastModified == reg[0]) {
-                keys = reg;
-                keys.removeFirst();
-            } else {
-                if (!library->loadPlugin()) {
-                    if (qt_debug_component()) {
-                        qDebug() << library->errorString;
-                        qDebug() << "           could not load";
-                    }
-                    library->release();
-                    continue;
-                }
-                QObject *instance = library->instance();
-                if (!instance) {
-                    library->release();
-                    // ignore plugins that have a valid signature but cannot be loaded.
-                    continue;
+            QStringList keys;
+            if (!library->loadPlugin()) {
+                if (qt_debug_component()) {
+                    qDebug() << library->errorString;
+                    qDebug() << "           could not load";
                 }
-                QFactoryInterface *factory = qobject_cast<QFactoryInterface*>(instance);
-                if (instance && factory && instance->qt_metacast(d->iid))
-                    keys = factory->keys();
-                if (keys.isEmpty())
-                    library->unload();
-                reg.clear();
-                reg << library->lastModified;
-                reg += keys;
-                settings.setValue(regkey, reg);
+                library->release();
+                continue;
             }
-            if (qt_debug_component()) {
-                qDebug() << "keys" << keys;
+            QObject *instance = library->instance();
+            if (!instance) {
+                library->release();
+                // ignore plugins that have a valid signature but cannot be loaded.
+                continue;
             }
-
+            QFactoryInterface *factory = qobject_cast<QFactoryInterface*>(instance);
+            if (instance && factory && instance->qt_metacast(d->iid))
+                keys = factory->keys();
+            if (keys.isEmpty())
+                library->unload();
             if (keys.isEmpty()) {
                 library->release();
                 continue;