[processing] allow selection parameters with option populated from data source

Author: volaya

python/plugins/processing/core/parameters.py

@@ -17,6 +17,7 @@
 *                                                                         *
 ***************************************************************************
 """
+from processing.tools.vector import resolveFieldIndex, features
 
 __author__ = 'Victor Olaya'
 __date__ = 'August 2012'
@@ -536,10 +537,21 @@ def getFileFilter(self):
 
 class ParameterSelection(Parameter):
 
-    def __init__(self, name='', description='', options=[], default=0):
+    def __init__(self, name='', description='', options=[], default=0, isSource = False):
         Parameter.__init__(self, name, description)
         self.options = options
-        if isinstance(self.options, basestring):
+        if isSource:
+            self.options = []
+            layer = QgsVectorLayer(options[0], "layer", "ogr")
+            if layer.isValid():
+                try:
+                    index = resolveFieldIndex(layer, options[1])
+                    feats = features(layer)
+                    for feature in feats:
+                        self.options.append(unicode(feature.attributes()[index]))  
+                except ValueError:
+                    pass
+        elif isinstance(self.options, basestring):
             self.options = self.options.split(";")
         self.value = None
         self.default = int(default)

python/plugins/processing/script/ScriptAlgorithm.py

@@ -169,6 +169,9 @@ def processParameterLine(self, line):
             param = ParameterMultipleInput(tokens[0], desc,
                     ParameterMultipleInput.TYPE_VECTOR_ANY)
             param.optional = False
+        elif tokens[1].lower().strip().startswith('selectionfromfile'):
+            options = tokens[1].strip()[len('selectionfromfile '):].split(';')
+            param = ParameterSelection(tokens[0], desc, options, isSource=True)
         elif tokens[1].lower().strip().startswith('selection'):
             options = tokens[1].strip()[len('selection '):].split(';')
             param = ParameterSelection(tokens[0], desc, options)