iOS: refactor usage of photos into optional plugin

Starting from iOS 10, apps that tries to access photos on the device
need to specify the reason for this up front by adding the key
'NSPhotoLibraryUsageDescription' into Info.plist. If the key is
missing, the app will be rejected from AppStore.

This causes problems for the iOS plugin as it stands since parts of it
already tries to access photos, e.g to show an image picker dialog
if a file dialog is set to open QStandardPaths::PicturesLocation.
This means that currently, all apps written with Qt will be rejected
from AppStore unless the developer adds this key, whether he tries
to access photos or not.

To solve this, we choose to split the plugin into two parts, one
that contains the core functionality, and one that contains
optional support. The latter will need to be enabled explicit
by the developer in the pro file, or in this case, indirectly
by adding the right key to the Info.plist.

This patch refactors the code in the plugin that gives access
to photos into a separate optional plugin called 'nsphotolibrarysupport'.

Change-Id: Ic4351eb0bbfffdf840fd88cd00bb29a25907798f
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Jake Petroules <jake.petroules@qt.io>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/plugins/platforms/ios/qiosintegration.mm b/src/plugins/platforms/ios/qiosintegration.mm
index 85b5c477cc..d33c8cf47c 100644
--- a/src/plugins/platforms/ios/qiosintegration.mm
+++ b/src/plugins/platforms/ios/qiosintegration.mm
@@ -43,6 +43,7 @@
 #include "qiosinputcontext.h"
 #include "qiostheme.h"
 #include "qiosservices.h"
+#include "qiosoptionalplugininterface.h"
 
 #include <QtGui/private/qguiapplication_p.h>
 
@@ -68,6 +69,7 @@ QIOSIntegration::QIOSIntegration()
     , m_inputContext(0)
     , m_platformServices(new QIOSServices)
     , m_accessibility(0)
+    , m_optionalPlugins(new QFactoryLoader(QIosOptionalPluginInterface_iid, QLatin1String("/platforms/darwin")))
     , m_debugWindowManagement(false)
 {
     if (![UIApplication sharedApplication]) {
@@ -112,6 +114,9 @@ QIOSIntegration::QIOSIntegration()
     m_touchDevice->setCapabilities(touchCapabilities);
     QWindowSystemInterface::registerTouchDevice(m_touchDevice);
     QMacInternalPasteboardMime::initializeMimeTypes();
+
+    for (int i = 0; i < m_optionalPlugins->metaData().size(); ++i)
+        qobject_cast<QIosOptionalPluginInterface *>(m_optionalPlugins->instance(i))->initPlugin();
 }
 
 QIOSIntegration::~QIOSIntegration()
@@ -134,6 +139,9 @@ QIOSIntegration::~QIOSIntegration()
 
     delete m_accessibility;
     m_accessibility = 0;
+
+    delete m_optionalPlugins;
+    m_optionalPlugins = 0;
 }
 
 bool QIOSIntegration::hasCapability(Capability cap) const