QDeclarativeImageProvider: Do not keep the global declarative mutex locked when processing.

The point is to be able to process images in a thread. If the mutex
is locked, this is useless.

Use case is a slow QDeclarativeImageProvider that generates thumbmails
from large files. Even with the asynchronous attribute set to true, the
gui thread would be blocked by the mutex.

By using QSharedPointer, I also fix the leak of the providers (which
were not deleted)

Reviewed-by: Martin Jones

3 files changed, 13 insertions, 8 deletions

diff --git a/src/declarative/qml/qdeclarativeengine.cpp b/src/declarative/qml/qdeclarativeengine.cpp
index 513fc65..bc7468f 100644
--- a/src/declarative/qml/qdeclarativeengine.cpp
+++ b/src/declarative/qml/qdeclarativeengine.cpp
@@ -674,7 +674,7 @@ void QDeclarativeEngine::addImageProvider(const QString &providerId, QDeclarativ
 {
     Q_D(QDeclarativeEngine);
     QMutexLocker locker(&d->mutex);
-    d->imageProviders.insert(providerId, provider);
+    d->imageProviders.insert(providerId, QSharedPointer<QDeclarativeImageProvider>(provider));
 }
 
 /*!
@@ -684,7 +684,7 @@ QDeclarativeImageProvider *QDeclarativeEngine::imageProvider(const QString &prov
 {
     Q_D(const QDeclarativeEngine);
     QMutexLocker locker(&d->mutex);
-    return d->imageProviders.value(providerId);
+    return d->imageProviders.value(providerId).data();
 }
 
 /*!
@@ -698,13 +698,14 @@ void QDeclarativeEngine::removeImageProvider(const QString &providerId)
 {
     Q_D(QDeclarativeEngine);
     QMutexLocker locker(&d->mutex);
-    delete d->imageProviders.take(providerId);
+    d->imageProviders.take(providerId);
 }
 
 QDeclarativeImageProvider::ImageType QDeclarativeEnginePrivate::getImageProviderType(const QUrl &url)
 {
     QMutexLocker locker(&mutex);
-    QDeclarativeImageProvider *provider = imageProviders.value(url.host());
+    QSharedPointer<QDeclarativeImageProvider> provider = imageProviders.value(url.host());
+    locker.unlock();
     if (provider)
         return provider->imageType();
     return static_cast<QDeclarativeImageProvider::ImageType>(-1);
@@ -714,7 +715,8 @@ QImage QDeclarativeEnginePrivate::getImageFromProvider(const QUrl &url, QSize *s
 {
     QMutexLocker locker(&mutex);
     QImage image;
-    QDeclarativeImageProvider *provider = imageProviders.value(url.host());
+    QSharedPointer<QDeclarativeImageProvider> provider = imageProviders.value(url.host());
+    locker.unlock();
     if (provider)
         image = provider->requestImage(url.path().mid(1), size, req_size);
     return image;
@@ -724,7 +726,8 @@ QPixmap QDeclarativeEnginePrivate::getPixmapFromProvider(const QUrl &url, QSize
 {
     QMutexLocker locker(&mutex);
     QPixmap pixmap;
-    QDeclarativeImageProvider *provider = imageProviders.value(url.host());
+    QSharedPointer<QDeclarativeImageProvider> provider = imageProviders.value(url.host());
+    locker.unlock();
     if (provider)
         pixmap = provider->requestPixmap(url.path().mid(1), size, req_size);
     return pixmap;
diff --git a/src/declarative/qml/qdeclarativeengine_p.h b/src/declarative/qml/qdeclarativeengine_p.h
index 3b5dd5a..db2db35 100644
--- a/src/declarative/qml/qdeclarativeengine_p.h
+++ b/src/declarative/qml/qdeclarativeengine_p.h
@@ -232,7 +232,7 @@ public:
     mutable QNetworkAccessManager *networkAccessManager;
     mutable QDeclarativeNetworkAccessManagerFactory *networkAccessManagerFactory;
 
-    QHash<QString,QDeclarativeImageProvider*> imageProviders;
+    QHash<QString,QSharedPointer<QDeclarativeImageProvider> > imageProviders;
     QDeclarativeImageProvider::ImageType getImageProviderType(const QUrl &url);
     QImage getImageFromProvider(const QUrl &url, QSize *size, const QSize& req_size);
     QPixmap getPixmapFromProvider(const QUrl &url, QSize *size, const QSize& req_size);
diff --git a/src/declarative/qml/qdeclarativeimageprovider.cpp b/src/declarative/qml/qdeclarativeimageprovider.cpp
index ea68327..ef31be7 100644
--- a/src/declarative/qml/qdeclarativeimageprovider.cpp
+++ b/src/declarative/qml/qdeclarativeimageprovider.cpp
@@ -161,7 +161,9 @@ QDeclarativeImageProvider::QDeclarativeImageProvider(ImageType type)
 }
 
 /*!
-   \internal
+    Destroys the QDeclarativeImageProvider
+
+    \note The destructor of your derived class need to be thread safe.
 */
 QDeclarativeImageProvider::~QDeclarativeImageProvider()
 {