[processing] New c++ QgsProcessingRegistry class

Intended as a registry for the various processing components,
including providers, algorithms and various parameters and outputs.

Currently handles only registration of providers, as a step toward
removing processing's algList (this requires first porting
the algorithm class to c++)

A QgsProcessingRegistry instance is attached to QgsApplication,
and is retrieved by QgsApplication::processingRegistry()

python/core/core.sip

@@ -260,6 +260,7 @@
 %Include layertree/qgslayertreeutils.sip
 
 %Include processing/qgsprocessingprovider.sip
+%Include processing/qgsprocessingregistry.sip
 
 %Include raster/qgsbilinearrasterresampler.sip
 %Include raster/qgsbrightnesscontrastfilter.sip

python/core/processing/qgsprocessingregistry.sip

@@ -0,0 +1,72 @@
+/**
+ * \class QgsProcessingRegistry
+ * \ingroup core
+ * Registry for various processing components, including providers, algorithms
+ * and various parameters and outputs.
+ *
+ * QgsProcessingRegistry is not usually directly created, but rather accessed through
+ * QgsApplication::processingRegistry().
+ * \note added in QGIS 3.0
+ */
+class QgsProcessingRegistry : QObject
+{
+%TypeHeaderCode
+#include <qgsprocessingregistry.h>
+%End
+
+  public:
+
+    /**
+     * Constructor for QgsProcessingRegistry.
+     */
+    QgsProcessingRegistry( QObject* parent /TransferThis/ = nullptr );
+
+    ~QgsProcessingRegistry();
+
+    /**
+     * Get list of available providers.
+     */
+    QList<QgsProcessingProvider*> providers() const;
+
+    /**
+     * Add a processing provider to the registry. Ownership of the provider is transferred to the registry.
+     * Returns false if the provider could not be added (eg if a provider with a duplicate ID already exists
+     * in the registry).
+     * @see removeProvider()
+     */
+    bool addProvider( QgsProcessingProvider* provider /Transfer/ );
+
+    /**
+     * Removes a provider implementation from the registry (the provider object is deleted).
+     * Returns false if the provider could not be removed (eg provider does not exist in the registry).
+     * @see addProvider()
+     */
+    bool removeProvider( QgsProcessingProvider* provider );
+
+    /**
+     * Removes a provider implementation from the registry (the provider object is deleted).
+     * Returns false if the provider could not be removed (eg provider does not exist in the registry).
+     * @see addProvider()
+     */
+    bool removeProvider( const QString& providerId );
+
+    /**
+     * Returns a matching provider by provider ID.
+     */
+    QgsProcessingProvider* providerById( const QString& id );
+
+  signals:
+
+    //! Emitted when a provider has been added to the registry.
+    void providerAdded( const QString& id );
+
+    //! Emitted when a provider is removed from the registry
+    void providerRemoved( const QString& id );
+
+  private:
+
+    //! Registry cannot be copied
+    QgsProcessingRegistry( const QgsProcessingRegistry& other );
+    //! Registry cannot be copied
+    //QgsProcessingRegistry& operator=( const QgsProcessingRegistry& other );
+};

python/core/qgsapplication.sip

@@ -442,6 +442,13 @@ static void qtgui_UpdatePyArgv(PyObject *argvlist, int argc, char **argv)
      */
     static QgsMessageLog* messageLog();
 
+    /**
+     * Returns the application's processing registry, used for managing processing providers,
+     * algorithms, and various parameters and outputs.
+     * @note added in QGIS 3.0
+     */
+    static QgsProcessingRegistry* processingRegistry();
+
 %If(ANDROID)
     //dummy method to workaround sip generation issue issue
     bool x11EventFilter ( XEvent * event );

python/plugins/processing/core/Processing.py

@@ -38,7 +38,8 @@ from qgis.PyQt.QtWidgets import QApplication
 from qgis.PyQt.QtGui import QCursor
 
 from qgis.utils import iface
-from qgis.core import QgsMessageLog
+from qgis.core import (QgsMessageLog,
+                       QgsApplication)
 
 import processing
 from processing.core.AlgorithmProvider import AlgorithmProvider
@@ -87,7 +88,7 @@ class Processing(object):
         """Use this method to add algorithms from external providers.
         """
 
-        if provider.id() in [p.id() for p in algList.providers]:
+        if provider.id() in [p.id() for p in QgsApplication.processingRegistry().providers()]:
             return
         try:
             provider.initializeSettings()
@@ -128,11 +129,6 @@ class Processing(object):
             # before I find out how to properly avoid that.
             pass
 
-    @staticmethod
-    def providerById(id):
-        """Returns the provider with the given id."""
-        return algList.providerById(id)
-
     @staticmethod
     def activateProvider(providerOrName, activate=True):
         provider_id = providerOrName.id() if isinstance(providerOrName, AlgorithmProvider) else providerOrName
@@ -155,7 +151,7 @@ class Processing(object):
     @staticmethod
     def addScripts(folder):
         Processing.initialize()
-        provider = Processing.providerById("qgis")
+        provider = QgsApplication.processingRegistry().providerById("qgis")
         scripts = ScriptUtils.loadFromFolder(folder)
         # fix_print_with_import
         print(scripts)
@@ -168,7 +164,7 @@ class Processing(object):
 
     @staticmethod
     def removeScripts(folder):
-        provider = Processing.providerById("qgis")
+        provider = QgsApplication.processingRegistry().providerById("qgis")
         for alg in provider.externalAlgs[::-1]:
             path = os.path.dirname(alg.descriptionFile)
             if path == folder:

python/plugins/processing/core/alglist.py

@@ -25,13 +25,13 @@ __copyright__ = '(C) 2016, Victor Olaya'
 
 __revision__ = '$Format:%H$'
 
+from qgis.core import (QgsApplication,
+                       QgsProcessingRegistry)
 from qgis.PyQt.QtCore import QObject, pyqtSignal
 
 
 class AlgorithmList(QObject):
 
-    providerAdded = pyqtSignal(str)
-    providerRemoved = pyqtSignal(str)
     providerUpdated = pyqtSignal(str)
 
     # A dictionary of algorithms. Keys are names of providers
@@ -41,13 +41,10 @@ class AlgorithmList(QObject):
     providers = []
 
     def removeProvider(self, provider_id):
-        for p in self.providers:
-            if p.id() == provider_id:
-                self.providers.remove(p)
-                break
         if provider_id in self.algs:
             del self.algs[provider_id]
-        self.providerRemoved.emit(provider_id)
+
+        QgsApplication.processingRegistry().removeProvider(provider_id)
 
     def reloadProvider(self, provider_id):
         for p in self.providers:
@@ -58,14 +55,8 @@ class AlgorithmList(QObject):
                 break
 
     def addProvider(self, provider):
-        self.providers.append(provider)
-        self.algs[provider.id()] = {a.commandLineName(): a for a in provider.algs}
-        self.providerAdded.emit(provider.id())
-
-    def providerById(self, id):
-        for provider in self.providers:
-            if provider.id() == id:
-                return provider
+        if QgsApplication.processingRegistry().addProvider(provider):
+            self.algs[provider.id()] = {a.commandLineName(): a for a in provider.algs}
 
     def getAlgorithm(self, name):
         for provider in list(self.algs.values()):

python/plugins/processing/gui/ProcessingToolbox.py

@@ -33,6 +33,8 @@ from qgis.PyQt import uic
 from qgis.PyQt.QtCore import Qt, QCoreApplication
 from qgis.PyQt.QtWidgets import QMenu, QAction, QTreeWidgetItem, QLabel, QMessageBox
 from qgis.utils import iface
+from qgis.core import (QgsApplication,
+                       QgsProcessingRegistry)
 
 from processing.gui.Postprocessing import handleAlgorithmResults
 from processing.core.Processing import Processing
@@ -82,8 +84,8 @@ class ProcessingToolbox(BASE, WIDGET):
 
         self.fillTree()
 
-        algList.providerRemoved.connect(self.removeProvider)
-        algList.providerAdded.connect(self.addProvider)
+        QgsApplication.processingRegistry().providerRemoved.connect(self.removeProvider)
+        QgsApplication.processingRegistry().providerAdded.connect(self.addProvider)
         algList.providerUpdated.connect(self.updateProvider)
         settingsWatcher.settingsChanged.connect(self.fillTree)
 
@@ -159,7 +161,7 @@ class ProcessingToolbox(BASE, WIDGET):
         self.fillTree()
         self.textChanged()
         self.showDisabled()
-        provider = Processing.providerById(id)
+        provider = QgsApplication.processingRegistry().providerById(id)
         if not provider.canBeActivated():
             QMessageBox.warning(self, "Activate provider",
                                 "The provider has been activated, but it might need additional configuration.")
@@ -376,7 +378,7 @@ class TreeProviderItem(QTreeWidgetItem):
         self.tree = tree
         self.toolbox = toolbox
         self.provider_id = provider_id
-        self.provider = Processing.providerById(provider_id)
+        self.provider = QgsApplication.processingRegistry().providerById(provider_id)
         self.setIcon(0, self.provider.icon())
         self.populate()
 

python/plugins/processing/gui/ScriptEditorDialog.py

@@ -43,7 +43,6 @@ from qgis.PyQt.QtWidgets import (QMenu,
 from qgis.core import QgsApplication
 from qgis.utils import iface
 
-from processing.core.alglist import algList
 from processing.gui.AlgorithmDialog import AlgorithmDialog
 from processing.gui.HelpEditionDialog import HelpEditionDialog
 from processing.algs.r.RAlgorithm import RAlgorithm
@@ -279,10 +278,10 @@ class ScriptEditorDialog(BASE, WIDGET):
     def runAlgorithm(self):
         if self.algType == self.SCRIPT_PYTHON:
             alg = ScriptAlgorithm(None, self.editor.text())
-            alg.provider = algList.providerById('script')
+            alg.provider = QgsApplication.processingRegistry().providerById('script')
         if self.algType == self.SCRIPT_R:
             alg = RAlgorithm(None, self.editor.text())
-            alg.provider = algList.providerById('r')
+            alg.provider = QgsApplication.processingRegistry().providerById('r')
 
         dlg = alg.getCustomParametersDialog()
         if not dlg:

python/plugins/processing/gui/menus.py

@@ -8,6 +8,7 @@ from processing.core.ProcessingConfig import ProcessingConfig, Setting
 from processing.gui.MessageDialog import MessageDialog
 from processing.gui.AlgorithmDialog import AlgorithmDialog
 from qgis.utils import iface
+from qgis.core import QgsApplication
 from processing.gui.MessageBarProgress import MessageBarProgress
 from processing.gui.AlgorithmExecutor import runalg
 from processing.gui.Postprocessing import handleAlgorithmResults
@@ -111,7 +112,7 @@ defaultMenuEntries.update({'gdal:buildvirtualraster': miscMenu,
 
 
 def initializeMenus():
-    for provider in algList.providers:
+    for provider in QgsApplication.processingRegistry().providers():
         for alg in provider.algs:
             d = defaultMenuEntries.get(alg.commandLineName(), "")
             setting = Setting(menusSettingsGroup, "MENU_" + alg.commandLineName(),

python/plugins/processing/modeler/ModelerDialog.py

@@ -272,7 +272,7 @@ class ModelerDialog(BASE, WIDGET):
     def editHelp(self):
         if self.alg.provider is None:
             # Might happen if model is opened from modeler dialog
-            self.alg.provider = algList.providerById('model')
+            self.alg.provider = QgsApplication.processingRegistry().providerById('model')
         alg = self.alg.getCopy()
         dlg = HelpEditionDialog(alg)
         dlg.exec_()
@@ -287,7 +287,7 @@ class ModelerDialog(BASE, WIDGET):
 
         if self.alg.provider is None:
             # Might happen if model is opened from modeler dialog
-            self.alg.provider = algList.providerById('model')
+            self.alg.provider = QgsApplication.processingRegistry().providerById('model')
         alg = self.alg.getCopy()
         dlg = AlgorithmDialog(alg)
         dlg.exec_()
@@ -640,7 +640,7 @@ class ModelerDialog(BASE, WIDGET):
 
             if len(groups) > 0:
                 providerItem = QTreeWidgetItem()
-                provider = algList.providerById(provider_id)
+                provider = QgsApplication.processingRegistry().providerById(provider_id)
                 providerItem.setText(0, provider.name())
                 providerItem.setToolTip(0, provider.name())
                 providerItem.setIcon(0, provider.icon())

python/plugins/processing/script/ScriptSelector.py

@@ -31,7 +31,7 @@ from qgis.PyQt import uic
 from qgis.PyQt.QtCore import Qt
 from qgis.PyQt.QtWidgets import QTreeWidgetItem, QFileDialog
 
-from processing.core.alglist import algList
+from qgis.core import QgsApplication
 
 pluginPath = os.path.split(os.path.dirname(__file__))[0]
 WIDGET, BASE = uic.loadUiType(
@@ -47,7 +47,7 @@ class ScriptSelector(BASE, WIDGET):
         self.scripts = None
 
         allScripts = defaultdict(list)
-        alglist = algList.providerById("script").algs
+        alglist = QgsApplication.processingRegistry().providerById("script").algs
         for script in alglist:
             allScripts[script.group].append(script)
 

src/core/CMakeLists.txt

@@ -79,6 +79,7 @@ SET(QGIS_CORE_SRCS
   auth/qgsauthmethodregistry.cpp
 
   processing/qgsprocessingprovider.cpp
+  processing/qgsprocessingregistry.cpp
 
   qgis.cpp
   qgsapplication.cpp
@@ -562,6 +563,8 @@ SET(QGIS_CORE_MOC_HDRS
   composer/qgsgroupungroupitemscommand.h
   composer/qgspaperitem.h
 
+  processing/qgsprocessingregistry.h
+
   raster/qgsrasterlayer.h
   raster/qgsrasterdataprovider.h
 

src/core/processing/qgsprocessingregistry.cpp

@@ -0,0 +1,71 @@
+/***************************************************************************
+                         qgsprocessingregistry.cpp
+                         --------------------------
+    begin                : December 2016
+    copyright            : (C) 2016 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsprocessingregistry.h"
+
+QgsProcessingRegistry::QgsProcessingRegistry( QObject* parent )
+    : QObject( parent )
+{
+
+}
+
+QgsProcessingRegistry::~QgsProcessingRegistry()
+{
+  Q_FOREACH ( QgsProcessingProvider* p, mProviders )
+  {
+    removeProvider( p );
+  }
+}
+
+bool QgsProcessingRegistry::addProvider( QgsProcessingProvider* provider )
+{
+  if ( !provider )
+    return false;
+
+  if ( mProviders.contains( provider->id() ) )
+    return false;
+
+  mProviders[ provider->id()] = provider;
+  emit providerAdded( provider->id() );
+  return true;
+}
+
+bool QgsProcessingRegistry::removeProvider( QgsProcessingProvider* provider )
+{
+  if ( !provider )
+    return false;
+
+  QString id = provider->id();
+
+  if ( !mProviders.contains( id ) )
+    return false;
+
+  delete mProviders.take( id );
+  emit providerRemoved( id );
+  return true;
+}
+
+bool QgsProcessingRegistry::removeProvider( const QString& providerId )
+{
+  QgsProcessingProvider* p = providerById( providerId );
+  return removeProvider( p );
+}
+
+QgsProcessingProvider* QgsProcessingRegistry::providerById( const QString& id )
+{
+  return mProviders.value( id, nullptr );
+}

src/core/processing/qgsprocessingregistry.h

@@ -0,0 +1,101 @@
+/***************************************************************************
+                         qgsprocessingregistry.h
+                         ------------------------
+    begin                : December 2016
+    copyright            : (C) 2016 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSPROCESSINGREGISTRY_H
+#define QGSPROCESSINGREGISTRY_H
+
+#include "qgis_core.h"
+#include "qgsprocessingprovider.h"
+#include <QMap>
+
+/**
+ * \class QgsProcessingRegistry
+ * \ingroup core
+ * Registry for various processing components, including providers, algorithms
+ * and various parameters and outputs.
+ *
+ * QgsProcessingRegistry is not usually directly created, but rather accessed through
+ * QgsApplication::processingRegistry().
+ * \note added in QGIS 3.0
+ */
+class CORE_EXPORT QgsProcessingRegistry : public QObject
+{
+    Q_OBJECT
+
+  public:
+
+    /**
+     * Constructor for QgsProcessingRegistry.
+     */
+    QgsProcessingRegistry( QObject* parent = nullptr );
+
+    ~QgsProcessingRegistry();
+
+    //! Registry cannot be copied
+    QgsProcessingRegistry( const QgsProcessingRegistry& other ) = delete;
+    //! Registry cannot be copied
+    QgsProcessingRegistry& operator=( const QgsProcessingRegistry& other ) = delete;
+
+    /**
+     * Get list of available providers.
+     */
+    QList<QgsProcessingProvider*> providers() const { return mProviders.values(); }
+
+    /**
+     * Add a processing provider to the registry. Ownership of the provider is transferred to the registry.
+     * Returns false if the provider could not be added (eg if a provider with a duplicate ID already exists
+     * in the registry).
+     * @see removeProvider()
+     */
+    bool addProvider( QgsProcessingProvider* provider );
+
+    /**
+     * Removes a provider implementation from the registry (the provider object is deleted).
+     * Returns false if the provider could not be removed (eg provider does not exist in the registry).
+     * @see addProvider()
+     */
+    bool removeProvider( QgsProcessingProvider* provider );
+
+    /**
+     * Removes a provider implementation from the registry (the provider object is deleted).
+     * Returns false if the provider could not be removed (eg provider does not exist in the registry).
+     * @see addProvider()
+     */
+    bool removeProvider( const QString& providerId );
+
+    /**
+     * Returns a matching provider by provider ID.
+     */
+    QgsProcessingProvider* providerById( const QString& id );
+
+  signals:
+
+    //! Emitted when a provider has been added to the registry.
+    void providerAdded( const QString& id );
+
+    //! Emitted when a provider is removed from the registry
+    void providerRemoved( const QString& id );
+
+  private:
+
+    //! Map of available providers by id. This class owns the pointers
+    QMap<QString, QgsProcessingProvider*> mProviders;
+};
+
+#endif // QGSPROCESSINGREGISTRY_H
+
+

src/core/qgsapplication.cpp

@@ -36,6 +36,7 @@
 #include "gps/qgsgpsconnectionregistry.h"
 #include "qgspluginlayerregistry.h"
 #include "qgsmessagelog.h"
+#include "processing/qgsprocessingregistry.h"
 
 #include <QDir>
 #include <QFile>
@@ -114,20 +115,6 @@ const char* QgsApplication::QGIS_APPLICATION_NAME = "QGIS3";
 */
 QgsApplication::QgsApplication( int & argc, char ** argv, bool GUIenabled, const QString& customConfigPath, const QString& platformName )
     : QApplication( argc, argv, GUIenabled )
-    , mActionScopeRegistry( nullptr )
-    , mProfiler( nullptr )
-    , mTaskManager( nullptr )
-    , mFieldFormatterRegistry( nullptr )
-    , mColorSchemeRegistry( nullptr )
-    , mPaintEffectRegistry( nullptr )
-    , mRendererRegistry( nullptr )
-    , mSvgCache( nullptr )
-    , mSymbolLayerRegistry( nullptr )
-    , mRasterRendererRegistry( nullptr )
-    , mGpsConnectionRegistry( nullptr )
-    , mDataItemProviderRegistry( nullptr )
-    , mPluginLayerRegistry( nullptr )
-    , mMessageLog( nullptr )
 {
   sPlatformName = platformName;
 
@@ -147,6 +134,7 @@ QgsApplication::QgsApplication( int & argc, char ** argv, bool GUIenabled, const
   mRasterRendererRegistry = new QgsRasterRendererRegistry();
   mGpsConnectionRegistry = new QgsGPSConnectionRegistry();
   mPluginLayerRegistry = new QgsPluginLayerRegistry();
+  mProcessingRegistry = new QgsProcessingRegistry();
 
   init( customConfigPath ); // init can also be called directly by e.g. unit tests that don't inherit QApplication.
 }
@@ -278,6 +266,7 @@ void QgsApplication::init( QString customConfigPath )
 
 QgsApplication::~QgsApplication()
 {
+  delete mProcessingRegistry;
   delete mActionScopeRegistry;
   delete mTaskManager;
   delete mFieldFormatterRegistry;
@@ -1608,6 +1597,11 @@ QgsMessageLog* QgsApplication::messageLog()
   return instance()->mMessageLog;
 }
 
+QgsProcessingRegistry*QgsApplication::processingRegistry()
+{
+  return instance()->mProcessingRegistry;
+}
+
 QgsFieldFormatterRegistry* QgsApplication::fieldFormatterRegistry()
 {
   return instance()->mFieldFormatterRegistry;

src/core/qgsapplication.h

@@ -37,6 +37,7 @@ class QgsGPSConnectionRegistry;
 class QgsDataItemProviderRegistry;
 class QgsPluginLayerRegistry;
 class QgsMessageLog;
+class QgsProcessingRegistry;
 
 /** \ingroup core
  * Extends QApplication to provide access to QGIS specific resources such
@@ -454,6 +455,13 @@ class CORE_EXPORT QgsApplication : public QApplication
      */
     static QgsMessageLog* messageLog();
 
+    /**
+     * Returns the application's processing registry, used for managing processing providers,
+     * algorithms, and various parameters and outputs.
+     * @note added in QGIS 3.0
+     */
+    static QgsProcessingRegistry* processingRegistry();
+
 #ifdef ANDROID
     //dummy method to workaround sip generation issue issue
     bool x11EventFilter( XEvent * event )
@@ -584,20 +592,21 @@ class CORE_EXPORT QgsApplication : public QApplication
 
     QMap<QString, QIcon> mIconCache;
 
-    QgsActionScopeRegistry* mActionScopeRegistry;
-    QgsRuntimeProfiler* mProfiler;
-    QgsTaskManager* mTaskManager;
-    QgsFieldFormatterRegistry* mFieldFormatterRegistry;
-    QgsColorSchemeRegistry* mColorSchemeRegistry;
-    QgsPaintEffectRegistry* mPaintEffectRegistry;
-    QgsRendererRegistry* mRendererRegistry;
-    QgsSvgCache* mSvgCache;
-    QgsSymbolLayerRegistry* mSymbolLayerRegistry;
-    QgsRasterRendererRegistry* mRasterRendererRegistry;
-    QgsGPSConnectionRegistry* mGpsConnectionRegistry;
-    QgsDataItemProviderRegistry* mDataItemProviderRegistry;
-    QgsPluginLayerRegistry* mPluginLayerRegistry;
-    QgsMessageLog* mMessageLog;
+    QgsActionScopeRegistry* mActionScopeRegistry = nullptr;
+    QgsRuntimeProfiler* mProfiler = nullptr;
+    QgsTaskManager* mTaskManager = nullptr;
+    QgsFieldFormatterRegistry* mFieldFormatterRegistry = nullptr;
+    QgsColorSchemeRegistry* mColorSchemeRegistry = nullptr;
+    QgsPaintEffectRegistry* mPaintEffectRegistry = nullptr;
+    QgsRendererRegistry* mRendererRegistry = nullptr;
+    QgsSvgCache* mSvgCache = nullptr;
+    QgsSymbolLayerRegistry* mSymbolLayerRegistry = nullptr;
+    QgsRasterRendererRegistry* mRasterRendererRegistry = nullptr;
+    QgsGPSConnectionRegistry* mGpsConnectionRegistry = nullptr;
+    QgsDataItemProviderRegistry* mDataItemProviderRegistry = nullptr;
+    QgsPluginLayerRegistry* mPluginLayerRegistry = nullptr;
+    QgsMessageLog* mMessageLog = nullptr;
+    QgsProcessingRegistry* mProcessingRegistry = nullptr;
     QString mNullRepresentation;
 };