Move provider algorithm handling to QgsProcessingProvider

Author: nyalldawson

python/core/processing/qgsprocessingalgorithm.sip

@@ -9,6 +9,7 @@
 
 
 
+
 class QgsProcessingAlgorithm
 {
 %Docstring
@@ -85,6 +86,11 @@ class QgsProcessingAlgorithm
  Returns the flags indicating how and when the algorithm operates and should be exposed to users.
 %End
 
+    QgsProcessingProvider *provider() const;
+%Docstring
+ Returns the provider to which this algorithm belongs.
+%End
+
 };
 QFlags<QgsProcessingAlgorithm::Flag> operator|(QgsProcessingAlgorithm::Flag f1, QFlags<QgsProcessingAlgorithm::Flag> f2);
 

python/core/processing/qgsprocessingprovider.sip

@@ -95,6 +95,53 @@ class QgsProcessingProvider
  \see supportedOutputVectorLayerExtensions()
 %End
 
+    virtual bool load();
+%Docstring
+ Loads the provider. This will be called when the plugin is being loaded, and any general
+ setup actions should occur in an overridden version of this method.
+ Subclasses should not load any algorithms in their load() implementations, as that must
+ occur within the loadAlgorithms() method.
+ \returns true if provider could be successfully loaded
+ \see unload()
+%End
+
+    virtual void unload();
+%Docstring
+ Unloads the provider. Any tear-down steps required by the provider should be implemented here.
+ \see load()
+%End
+
+    void refreshAlgorithms();
+%Docstring
+ Refreshes the algorithms available from the provider, causing it to re-populate with all associated algorithms.
+%End
+
+    QList< QgsProcessingAlgorithm * > algorithms() const;
+%Docstring
+ Returns a list of algorithms supplied by this provider.
+ \see algorithm()
+%End
+
+    QgsProcessingAlgorithm *algorithm( const QString &name ) const;
+%Docstring
+ Returns the matching algorithm by name, or a nullptr if no matching
+ algorithm is contained by this provider.
+ \see algorithms()
+%End
+
+  protected:
+
+    virtual void loadAlgorithms() = 0;
+%Docstring
+ Loads all algorithms belonging to this provider. Subclasses should implement this, calling
+ addAlgorithm() to register all their associated algorithms.
+%End
+
+    bool addAlgorithm( QgsProcessingAlgorithm *algorithm /Transfer/ );
+%Docstring
+ Adds an algorithm to the provider. Ownership of the algorithm is transferred to the provider.
+%End
+
   private:
     QgsProcessingProvider( const QgsProcessingProvider &other );
 };

python/plugins/processing/algs/exampleprovider/ExampleAlgorithmProvider.py

@@ -40,23 +40,19 @@ def __init__(self):
         # Deactivate provider by default
         self.activate = False
 
-        # Load algorithms
-        self.alglist = [ExampleAlgorithm()]
-        for alg in self.alglist:
-            alg.provider = self
-
-    def initializeSettings(self):
+    def load(self):
         """In this method we add settings needed to configure our
         provider.
 
         Do not forget to call the parent method, since it takes care
         or automatically adding a setting for activating or
         deactivating the algorithms in the provider.
         """
-        AlgorithmProvider.initializeSettings(self)
+        AlgorithmProvider.load(self)
         ProcessingConfig.addSetting(Setting('Example algorithms',
                                             ExampleAlgorithmProvider.MY_DUMMY_SETTING,
                                             'Example setting', 'Default value'))
+        return True
 
     def unload(self):
         """Setting should be removed here, so they do not appear anymore
@@ -84,7 +80,7 @@ def icon(self):
         """
         return AlgorithmProvider.icon(self)
 
-    def _loadAlgorithms(self):
+    def loadAlgorithms(self):
         """Here we fill the list of algorithms in self.algs.
 
         This method is called whenever the list of algorithms should
@@ -98,4 +94,5 @@ def _loadAlgorithms(self):
         even if the list does not change, since the self.algs list is
         cleared before calling this method.
         """
-        self.algs = self.alglist
+        for alg in [ExampleAlgorithm()]:
+            self.addAlgorithm(alg)

python/plugins/processing/algs/gdal/GdalAlgorithmProvider.py

@@ -98,15 +98,15 @@ class GdalAlgorithmProvider(AlgorithmProvider):
 
     def __init__(self):
         super().__init__()
-        self.createAlgsList()
 
-    def initializeSettings(self):
-        AlgorithmProvider.initializeSettings(self)
+    def load(self):
+        AlgorithmProvider.load(self)
         ProcessingConfig.addSetting(Setting(
             self.name(),
             GdalUtils.GDAL_HELP_PATH,
             self.tr('Location of GDAL docs'),
             GdalUtils.gdalHelpPath()))
+        return True
 
     def unload(self):
         AlgorithmProvider.unload(self)
@@ -125,27 +125,23 @@ def icon(self):
     def svgIconPath(self):
         return QgsApplication.iconPath("providerGdal.svg")
 
-    def _loadAlgorithms(self):
-        self.algs = self.preloadedAlgs
-
-    def createAlgsList(self):
-        # First we populate the list of algorithms with those created
-        # extending GeoAlgorithm directly (those that execute GDAL
-        # using the console)
-        self.preloadedAlgs = [nearblack(), information(), warp(), translate(),
-                              rgb2pct(), pct2rgb(), merge(), buildvrt(), polygonize(), gdaladdo(),
-                              ClipByExtent(), ClipByMask(), contour(), rasterize(), proximity(),
-                              sieve(), fillnodata(), ExtractProjection(), gdal2xyz(),
-                              hillshade(), slope(), aspect(), tri(), tpi(), roughness(),
-                              ColorRelief(), GridInvDist(), GridAverage(), GridNearest(),
-                              GridDataMetrics(), gdaltindex(), gdalcalc(), rasterize_over(),
-                              retile(), gdal2tiles(), AssignProjection(),
-                              # ----- OGR tools -----
-                              OgrInfo(), Ogr2Ogr(), Ogr2OgrClip(), Ogr2OgrClipExtent(),
-                              Ogr2OgrToPostGis(), Ogr2OgrToPostGisList(), Ogr2OgrPointsOnLines(),
-                              Ogr2OgrBuffer(), Ogr2OgrDissolve(), OneSideBuffer(),
-                              OffsetCurve(), Ogr2OgrTableToPostGisList(), OgrSql(),
-                              ]
+    def loadAlgorithms(self):
+        algs = [nearblack(), information(), warp(), translate(),
+                rgb2pct(), pct2rgb(), merge(), buildvrt(), polygonize(), gdaladdo(),
+                ClipByExtent(), ClipByMask(), contour(), rasterize(), proximity(),
+                sieve(), fillnodata(), ExtractProjection(), gdal2xyz(),
+                hillshade(), slope(), aspect(), tri(), tpi(), roughness(),
+                ColorRelief(), GridInvDist(), GridAverage(), GridNearest(),
+                GridDataMetrics(), gdaltindex(), gdalcalc(), rasterize_over(),
+                retile(), gdal2tiles(), AssignProjection(),
+                # ----- OGR tools -----
+                OgrInfo(), Ogr2Ogr(), Ogr2OgrClip(), Ogr2OgrClipExtent(),
+                Ogr2OgrToPostGis(), Ogr2OgrToPostGisList(), Ogr2OgrPointsOnLines(),
+                Ogr2OgrBuffer(), Ogr2OgrDissolve(), OneSideBuffer(),
+                OffsetCurve(), Ogr2OgrTableToPostGisList(), OgrSql(),
+                ]
+        for a in algs:
+            self.addAlgorithm(a)
 
     def supportedOutputRasterLayerExtensions(self):
         return GdalUtils.getSupportedRasterExtensions()

python/plugins/processing/algs/grass7/Grass7Algorithm.py

@@ -98,7 +98,6 @@ def __init__(self, descriptionfile):
 
     def getCopy(self):
         newone = Grass7Algorithm(self.descriptionFile)
-        newone.provider = self.provider
         return newone
 
     def name(self):

python/plugins/processing/algs/grass7/Grass7AlgorithmProvider.py

@@ -44,10 +44,9 @@ class Grass7AlgorithmProvider(AlgorithmProvider):
 
     def __init__(self):
         super().__init__()
-        self.createAlgsList()
 
-    def initializeSettings(self):
-        AlgorithmProvider.initializeSettings(self)
+    def load(self):
+        AlgorithmProvider.load(self)
         if isWindows() or isMac():
             ProcessingConfig.addSetting(Setting(
                 self.name(),
@@ -66,6 +65,7 @@ def initializeSettings(self):
             Grass7Utils.GRASS_HELP_PATH,
             self.tr('Location of GRASS docs'),
             Grass7Utils.grassHelpPath()))
+        return True
 
     def unload(self):
         AlgorithmProvider.unload(self)
@@ -76,14 +76,14 @@ def unload(self):
         ProcessingConfig.removeSetting(Grass7Utils.GRASS_HELP_PATH)
 
     def createAlgsList(self):
-        self.preloadedAlgs = []
+        algs = []
         folder = Grass7Utils.grassDescriptionPath()
         for descriptionFile in os.listdir(folder):
             if descriptionFile.endswith('txt'):
                 try:
                     alg = Grass7Algorithm(os.path.join(folder, descriptionFile))
                     if alg.name().strip() != '':
-                        self.preloadedAlgs.append(alg)
+                        algs.append(alg)
                     else:
                         ProcessingLog.addToLog(
                             ProcessingLog.LOG_ERROR,
@@ -92,10 +92,12 @@ def createAlgsList(self):
                     ProcessingLog.addToLog(
                         ProcessingLog.LOG_ERROR,
                         self.tr('Could not open GRASS GIS 7 algorithm: {0}\n{1}').format(descriptionFile, str(e)))
-        self.preloadedAlgs.append(nviz7())
+        algs.append(nviz7())
+        return algs
 
-    def _loadAlgorithms(self):
-        self.algs = self.preloadedAlgs
+    def loadAlgorithms(self):
+        for a in self.createAlgsList():
+            self.addAlgorithm(a)
 
     def name(self):
         version = Grass7Utils.installedVersion()

python/plugins/processing/algs/grass7/ext/r_texture.py

@@ -53,7 +53,7 @@ def processOutputs(alg):
     else:
         angles = ['']
 
-    ext = alg.provider.supportedOutputRasterLayerExtensions()[0]
+    ext = alg.provider().getSupportedOutputRasterLayerExtensions()[0]
     for method in methodList:
         out = alg.getOutputValue(u'output')
         for angle in angles: