From 818c544d6be0daf399ad69222b196e75e6b54505 Mon Sep 17 00:00:00 2001
From: Morten Johan Sorvig <morten.sorvig@digia.com>
Date: Thu, 13 Dec 2012 14:54:47 +0100
Subject: Cache accessibility plugins.

Profiling shows that the cost of QAcccessible::
queryAccessibleInterface is dominated by plugin loading.
(json parsing etc.)

Cache QAccessiblePlugin per class. Also cache the fact
that no plugin is found for a certain class. This speeds
up the average queryAccessibleInterface call by a factor
of 10X

Change-Id: Iab6d052dec499a2203d1dcc4672a8a543b279239
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
---
 src/gui/accessible/qaccessible.cpp | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

(limited to 'src/gui')

diff --git a/src/gui/accessible/qaccessible.cpp b/src/gui/accessible/qaccessible.cpp
index f55037c37a..28a3afbbf0 100644
--- a/src/gui/accessible/qaccessible.cpp
+++ b/src/gui/accessible/qaccessible.cpp
@@ -51,6 +51,7 @@
 
 #include <QtCore/qdebug.h>
 #include <QtCore/qmetaobject.h>
+#include <QtCore/qhash.h>
 #include <private/qfactoryloader_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -430,6 +431,8 @@ Q_GLOBAL_STATIC_WITH_ARGS(QFactoryLoader, loader,
 #endif
 
 Q_GLOBAL_STATIC(QList<QAccessible::InterfaceFactory>, qAccessibleFactories)
+typedef QHash<QString, QAccessiblePlugin*> QAccessiblePluginsHash;
+Q_GLOBAL_STATIC(QAccessiblePluginsHash, qAccessiblePlugins);
 
 QAccessible::UpdateHandler QAccessible::updateHandler = 0;
 QAccessible::RootObjectHandler QAccessible::rootObjectHandler = 0;
@@ -580,9 +583,13 @@ QAccessibleInterface *QAccessible::queryAccessibleInterface(QObject *object)
     if (!object)
         return 0;
 
+    // Create a QAccessibleInterface for the object class. Start by the most
+    // derived class and walk up the class hierarchy.
     const QMetaObject *mo = object->metaObject();
     while (mo) {
         const QString cn = QLatin1String(mo->className());
+
+        // Check if the class has a InterfaceFactory installed.
         for (int i = qAccessibleFactories()->count(); i > 0; --i) {
             InterfaceFactory factory = qAccessibleFactories()->at(i - 1);
             if (QAccessibleInterface *iface = factory(cn, object))
@@ -590,8 +597,21 @@ QAccessibleInterface *QAccessible::queryAccessibleInterface(QObject *object)
         }
 #ifndef QT_NO_ACCESSIBILITY
 #ifndef QT_NO_LIBRARY
-        if (QAccessibleInterface * iface = qLoadPlugin1<QAccessibleInterface, QAccessiblePlugin>(loader(), cn, object))
-            return iface;
+        // Find a QAccessiblePlugin (factory) for the class name. If there's
+        // no entry in the cache try to create it using the plugin loader.
+        if (!qAccessiblePlugins()->contains(cn)) {
+            QAccessiblePlugin *factory = 0; // 0 means "no plugin found". This is cached as well.
+            const int index = loader()->indexOf(cn);
+            if (index != -1)
+                factory = qobject_cast<QAccessiblePlugin *>(loader()->instance(index));
+            qAccessiblePlugins()->insert(cn, factory);
+        }
+
+        // At this point the cache should contain a valid factory pointer or 0:
+        Q_ASSERT(qAccessiblePlugins()->contains(cn));
+        QAccessiblePlugin *factory = qAccessiblePlugins()->value(cn);
+        if (factory)
+            return factory->create(cn, object);
 #endif
 #endif
         mo = mo->superClass();
-- 
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