Add API to allow creation of widgets for customising a layer's source

This adds api in the provider gui to allow a provider to create a custom
widget which exposes options to customise and change the layer's source.

E.g. a file based layer provider could expose a widget for selecting
a new file path, and an online one could expose widgets for changing
the host, authentication, etc.

python/gui/auto_generated/qgsgui.sip.in

@@ -122,6 +122,13 @@ Returns the registry of GUI-related components of data providers
 %Docstring
 Returns the registry of subset string editors of data providers
 
+.. versionadded:: 3.18
+%End
+
+    static QgsProviderSourceWidgetProviderRegistry *sourceWidgetProviderRegistry() /KeepReference/;
+%Docstring
+Returns the registry of provider source widget providers.
+
 .. versionadded:: 3.18
 %End
 

python/gui/auto_generated/qgsproviderguimetadata.sip.in

@@ -70,7 +70,18 @@ Returns subset string editor providers
 
 .. note::
 
-   Ownership of created  providers is passed to the caller.
+   Ownership of created providers is passed to the caller.
+
+.. versionadded:: 3.18
+%End
+
+    virtual QList<QgsProviderSourceWidgetProvider *> sourceWidgetProviders() /Factory/;
+%Docstring
+Returns source widget providers
+
+.. note::
+
+   Ownership of created providers is passed to the caller.
 
 .. versionadded:: 3.18
 %End

python/gui/auto_generated/qgsproviderguiregistry.sip.in

@@ -85,6 +85,17 @@ Returns all project storage gui providers registered in provider with ``provider
 %Docstring
 Returns all subset string editor providers registered in provider with ``providerKey``
 
+.. note::
+
+   Ownership of providers is passed to the caller.
+
+.. versionadded:: 3.18
+%End
+
+    virtual QList<QgsProviderSourceWidgetProvider *> sourceWidgetProviders( const QString &providerKey ) /Factory/;
+%Docstring
+Returns all source widget providers registered in provider with ``providerKey``
+
 .. note::
 
    Ownership of providers is passed to the caller.

python/gui/auto_generated/qgsprovidersourcewidget.sip.in

@@ -0,0 +1,50 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsprovidersourcewidget.h                                    *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+class QgsProviderSourceWidget : QWidget
+{
+%Docstring
+Base class for widgets which allow customisation of a provider's source URI.
+
+.. versionadded:: 3.18
+%End
+
+%TypeHeaderCode
+#include "qgsprovidersourcewidget.h"
+%End
+  public:
+
+    QgsProviderSourceWidget( QWidget *parent /TransferThis/ = 0 );
+%Docstring
+Constructor for QgsProviderSourceWidget with the specified ``parent`` widget.
+%End
+
+    virtual void setSourceUri( const QString &uri ) = 0;
+%Docstring
+Sets the source ``uri`` to show in the widget.
+
+.. seealso:: :py:func:`sourceUri`
+%End
+
+    virtual QString sourceUri() const = 0;
+%Docstring
+Returns the source URI as currently defined by the widget.
+
+.. seealso:: :py:func:`setSourceUri`
+%End
+
+};
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsprovidersourcewidget.h                                    *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/gui/auto_generated/qgsprovidersourcewidgetprovider.sip.in

@@ -0,0 +1,61 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsprovidersourcewidgetprovider.h                            *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+class QgsProviderSourceWidgetProvider
+{
+%Docstring
+
+An interface for providers of widgets designed to configure a data provider's source.
+
+.. versionadded:: 3.18
+%End
+
+%TypeHeaderCode
+#include "qgsprovidersourcewidgetprovider.h"
+%End
+  public:
+
+    virtual ~QgsProviderSourceWidgetProvider();
+
+    virtual QString providerKey() const = 0;
+%Docstring
+Provider key
+%End
+
+    virtual QString name() const;
+%Docstring
+Source widget provider name, this is useful to retrieve
+a particular source widget provider in case the provider has more
+than one, it should be unique among all providers.
+
+The default implementation returns the :py:func:`~QgsProviderSourceWidgetProvider.providerKey`
+%End
+
+    virtual bool canHandleLayer( QgsMapLayer *layer ) const = 0;
+%Docstring
+Returns ``True`` if the provider can handle the specified ``layer``.
+%End
+
+    virtual QgsProviderSourceWidget *createWidget( QgsMapLayer *layer, QWidget *parent /TransferThis/ = 0 ) = 0 /Factory/;
+%Docstring
+Creates a new widget to configure the source of the specified ``layer``.
+It may return ``None`` if it cannot handle the layer.
+The returned object must be destroyed by the caller.
+%End
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsprovidersourcewidgetprovider.h                            *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/gui/auto_generated/qgsprovidersourcewidgetproviderregistry.sip.in

@@ -0,0 +1,83 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsprovidersourcewidgetproviderregistry.h                    *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+
+class QgsProviderSourceWidgetProviderRegistry
+{
+%Docstring
+This class keeps a list of provider source widget providers.
+
+QgsProviderSourceWidgetProviderRegistry is not usually directly created, but rather accessed through
+QgsGui.QgsProviderSourceWidgetProviderRegistry().
+
+.. versionadded:: 3.18
+%End
+
+%TypeHeaderCode
+#include "qgsprovidersourcewidgetproviderregistry.h"
+%End
+  public:
+
+    QgsProviderSourceWidgetProviderRegistry();
+    ~QgsProviderSourceWidgetProviderRegistry();
+
+
+    QList< QgsProviderSourceWidgetProvider *> providers();
+%Docstring
+Gets list of available providers
+%End
+
+    void addProvider( QgsProviderSourceWidgetProvider *provider /Transfer/ );
+%Docstring
+Add a ``provider`` implementation. Takes ownership of the object.
+%End
+
+    bool removeProvider( QgsProviderSourceWidgetProvider *provider /Transfer/ );
+%Docstring
+Remove ``provider`` implementation from the list (``provider`` object is deleted)
+
+:return: ``True`` if the provider was actually removed and deleted
+%End
+
+    void initializeFromProviderGuiRegistry( QgsProviderGuiRegistry *providerGuiRegistry );
+%Docstring
+Initializes the registry. The registry needs to be passed explicitly
+(instead of using singleton) because this gets called from QgsGui constructor.
+%End
+
+    QgsProviderSourceWidgetProvider *providerByName( const QString &name );
+%Docstring
+Returns a provider by ``name`` or ``None`` if not found
+%End
+
+    QList<QgsProviderSourceWidgetProvider *> providersByKey( const QString &providerKey );
+%Docstring
+Returns a (possibly empty) list of providers by data ``providerkey``
+%End
+
+    QgsProviderSourceWidget *createWidget( QgsMapLayer *layer, QWidget *parent /TransferThis/ = 0 ) /TransferBack/;
+%Docstring
+Creates a new widget to configure the source of the specified ``layer``.
+It may return ``None`` if no provider was found.
+The returned object must be destroyed by the caller.
+%End
+
+  private:
+    QgsProviderSourceWidgetProviderRegistry( const QgsProviderSourceWidgetProviderRegistry &rh );
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/qgsprovidersourcewidgetproviderregistry.h                    *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/gui/gui_auto.sip

@@ -170,6 +170,9 @@
 %Include auto_generated/qgsproviderconnectioncombobox.sip
 %Include auto_generated/qgsproviderguimetadata.sip
 %Include auto_generated/qgsproviderguiregistry.sip
+%Include auto_generated/qgsprovidersourcewidget.sip
+%Include auto_generated/qgsprovidersourcewidgetprovider.sip
+%Include auto_generated/qgsprovidersourcewidgetproviderregistry.sip
 %Include auto_generated/qgsproxystyle.sip
 %Include auto_generated/qgsquerybuilder.sip
 %Include auto_generated/qgsrangeslider.sip

src/gui/CMakeLists.txt

@@ -552,6 +552,9 @@ set(QGIS_GUI_SRCS
   qgspropertyoverridebutton.cpp
   qgsproviderguiregistry.cpp
   qgsproviderguimetadata.cpp
+  qgsprovidersourcewidget.cpp
+  qgsprovidersourcewidgetprovider.cpp
+  qgsprovidersourcewidgetproviderregistry.cpp
   qgsprojectstorageguiregistry.cpp
   qgsproviderconnectioncombobox.cpp
   qgsproxystyle.cpp
@@ -796,6 +799,9 @@ set(QGIS_GUI_HDRS
   qgsproviderconnectioncombobox.h
   qgsproviderguimetadata.h
   qgsproviderguiregistry.h
+  qgsprovidersourcewidget.h
+  qgsprovidersourcewidgetprovider.h
+  qgsprovidersourcewidgetproviderregistry.h
   qgsproxystyle.h
   qgsquerybuilder.h
   qgsrangeslider.h

src/gui/qgsgui.cpp

@@ -59,6 +59,7 @@
 #include "qgsnumericformatguiregistry.h"
 #include "qgscodeeditorcolorschemeregistry.h"
 #include "qgssubsetstringeditorproviderregistry.h"
+#include "qgsprovidersourcewidgetproviderregistry.h"
 
 QgsGui *QgsGui::instance()
 {
@@ -86,6 +87,11 @@ QgsSubsetStringEditorProviderRegistry *QgsGui::subsetStringEditorProviderRegistr
   return instance()->mSubsetStringEditorProviderRegistry;
 }
 
+QgsProviderSourceWidgetProviderRegistry *QgsGui::sourceWidgetProviderRegistry()
+{
+  return instance()->mProviderSourceWidgetProviderRegistry;
+}
+
 QgsShortcutsManager *QgsGui::shortcutsManager()
 {
   return instance()->mShortcutsManager;
@@ -191,6 +197,7 @@ QgsGui::~QgsGui()
   delete mProviderGuiRegistry;
   delete mCodeEditorColorSchemeRegistry;
   delete mSubsetStringEditorProviderRegistry;
+  delete mProviderSourceWidgetProviderRegistry;
 }
 
 QColor QgsGui::sampleColor( QPoint point )
@@ -245,11 +252,13 @@ QgsGui::QgsGui()
   mSourceSelectProviderRegistry = new QgsSourceSelectProviderRegistry();
   mNumericFormatGuiRegistry = new QgsNumericFormatGuiRegistry();
   mSubsetStringEditorProviderRegistry = new QgsSubsetStringEditorProviderRegistry();
+  mProviderSourceWidgetProviderRegistry = new QgsProviderSourceWidgetProviderRegistry();
 
   mProjectStorageGuiRegistry->initializeFromProviderGuiRegistry( mProviderGuiRegistry );
   mDataItemGuiProviderRegistry->initializeFromProviderGuiRegistry( mProviderGuiRegistry );
   mSourceSelectProviderRegistry->initializeFromProviderGuiRegistry( mProviderGuiRegistry );
   mSubsetStringEditorProviderRegistry->initializeFromProviderGuiRegistry( mProviderGuiRegistry );
+  mProviderSourceWidgetProviderRegistry->initializeFromProviderGuiRegistry( mProviderGuiRegistry );
 
   mEditorWidgetRegistry = new QgsEditorWidgetRegistry();
   mShortcutsManager = new QgsShortcutsManager();

src/gui/qgsgui.h

@@ -41,6 +41,7 @@ class QgsNumericFormatGuiRegistry;
 class QgsCodeEditorColorSchemeRegistry;
 class QgsMessageBar;
 class QgsSubsetStringEditorProviderRegistry;
+class QgsProviderSourceWidgetProviderRegistry;
 
 /**
  * \ingroup gui
@@ -161,6 +162,12 @@ class GUI_EXPORT QgsGui : public QObject
      */
     static QgsSubsetStringEditorProviderRegistry *subsetStringEditorProviderRegistry() SIP_KEEPREFERENCE;
 
+    /**
+     * Returns the registry of provider source widget providers.
+     * \since QGIS 3.18
+     */
+    static QgsProviderSourceWidgetProviderRegistry *sourceWidgetProviderRegistry() SIP_KEEPREFERENCE;
+
     /**
      * Register the widget to allow its position to be automatically saved and restored when open and closed.
      * Use this to avoid needing to call saveGeometry() and restoreGeometry() on your widget.
@@ -263,6 +270,7 @@ class GUI_EXPORT QgsGui : public QObject
     QgsCodeEditorColorSchemeRegistry *mCodeEditorColorSchemeRegistry = nullptr;
     QgsProjectStorageGuiRegistry *mProjectStorageGuiRegistry = nullptr;
     QgsSubsetStringEditorProviderRegistry *mSubsetStringEditorProviderRegistry = nullptr;
+    QgsProviderSourceWidgetProviderRegistry *mProviderSourceWidgetProviderRegistry = nullptr;
     std::unique_ptr< QgsWindowManagerInterface > mWindowManager;
 
 #ifdef SIP_RUN

src/gui/qgsproviderguimetadata.cpp

@@ -47,6 +47,11 @@ QList<QgsSubsetStringEditorProvider *> QgsProviderGuiMetadata::subsetStringEdito
   return QList<QgsSubsetStringEditorProvider *>();
 }
 
+QList<QgsProviderSourceWidgetProvider *> QgsProviderGuiMetadata::sourceWidgetProviders()
+{
+  return QList<QgsProviderSourceWidgetProvider *>();
+}
+
 QString QgsProviderGuiMetadata::key() const
 {
   return mKey;

src/gui/qgsproviderguimetadata.h

@@ -28,6 +28,7 @@ class QgsDataItemGuiProvider;
 class QgsSourceSelectProvider;
 class QgsProjectStorageGuiProvider;
 class QgsSubsetStringEditorProvider;
+class QgsProviderSourceWidgetProvider;
 
 /**
  * \ingroup gui
@@ -72,11 +73,18 @@ class GUI_EXPORT QgsProviderGuiMetadata
 
     /**
      * Returns subset string editor providers
-     * \note Ownership of created  providers is passed to the caller.
+     * \note Ownership of created providers is passed to the caller.
      * \since QGIS 3.18
      */
     virtual QList<QgsSubsetStringEditorProvider *> subsetStringEditorProviders() SIP_FACTORY;
 
+    /**
+     * Returns source widget providers
+     * \note Ownership of created providers is passed to the caller.
+     * \since QGIS 3.18
+     */
+    virtual QList<QgsProviderSourceWidgetProvider *> sourceWidgetProviders() SIP_FACTORY;
+
     //! Returns unique provider key
     QString key() const;