add wrapper vector writer class

git-svn-id: http://sextante.googlecode.com/svn/trunk/soft/bindings/qgis-plugin@349 881b9c09-3ef8-f3c2-ec3d-21d735c97f4d

Author: alexander.bruy@gmail.com

src/sextante/core/SextanteVectorWriter.py

@@ -0,0 +1,49 @@
+from PyQt4.QtCore import *
+
+from qgis.core import *
+
+class SextanteVectorWriter:
+
+    MEMORY_LAYER_PREFIX = "memory:"
+
+    TYPE_MAP = {QGis.WKBPoint : "Point",
+                QGis.WKBLineString : "LineString",
+                QGis.WKBPolygon : "Polygon",
+                QGis.WKBMultiPoint : "MultiPoint",
+                QGis.WKBMultiLineString : "MultiLineString",
+                QGis.WKBMultiPolygon : "MultiPolygon"
+               }
+
+    def __init__(self, fileName, encoding, fields, geometryType, crs, options=None):
+        self.fileName = fileName
+        self.isMemory = False
+        self.memLayer = None
+        self.writer = None
+
+        if self.fileName.startswith(self.MEMORY_LAYER_PREFIX):
+            self.isMemory = True
+
+            uri = self.TYPE_MAP[geometryType]
+            if crs.isValid():
+              uri += "?crs=" + crs.authid()
+            self.memLayer = QgsVectorLayer(uri, self.fileName, "memory")
+            self.writer = self.memLayer.dataProvider()
+            self.writer.addAttributes(fields.values())
+            self.memLayer.updateFieldMap()
+        else:
+            formats = QgsVectorFileWriter.supportedFiltersAndFormats()
+            OGRCodes = {}
+            for key, value in formats.items():
+                extension = str(key)
+                extension = extension[extension.find('*.') + 2:]
+                extension = extension[:extension.find(" ")]
+                OGRCodes[extension] = value
+
+            extension = self.fileName[self.fileName.find(".") + 1:]
+            self.writer = QgsVectorFileWriter(self.fileName, encoding, fields, geometryType, crs, OGRCodes[extension])
+
+    def addFeature(self, feature):
+        if self.isMemory:
+            self.writer.addFeatures([feature])
+        else:
+            self.writer.addFeature(feature)

src/sextante/gui/SextantePostprocessing.py

@@ -22,9 +22,6 @@ def handleAlgorithmResults(alg, showResults = True):
                 try:
                     if out.value.startswith("memory:"):
                         layer = out.memoryLayer
-                        layer.updateFieldMap()
-                        layer.commitChanges()
-                        layer.updateExtents()
                         QgsMapLayerRegistry.instance().addMapLayer(layer)
                     else:
                         if SextanteConfig.getSetting(SextanteConfig.USE_FILENAME_AS_LAYER_NAME):

src/sextante/outputs/OutputVector.py

@@ -1,11 +1,9 @@
-from sextante.outputs.Output import Output
-from qgis.core import *
 from PyQt4.QtCore import *
-from sextante.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
 
-class OutputVector(Output):
+from sextante.outputs.Output import Output
+from sextante.core.SextanteVectorWriter import SextanteVectorWriter
 
-    MEMORY_LAYER_PREFIX = "memory:"
+class OutputVector(Output):
 
     def getFileFilter(self,alg):
         exts = alg.provider.getSupportedOutputVectorLayerExtensions()
@@ -17,50 +15,26 @@ def getDefaultFileExtension(self, alg):
         return alg.provider.getSupportedOutputVectorLayerExtensions()[0]
 
     def getVectorWriter(self, fields, geomType, crs, options=None):
-        '''Returns a suitable writer to which features can be added as a result of the algorithm.
-        Use this to transparently handle output values instead of creating your own method.
-        Parameters:
-        -field: an array with the fields of the attributes table or dict of int-QgsField
-        -geomType: A suitable geometry type, as it would be passed to a QgsVectorFileWriter constructor
-        -crs: the crs of the layer to create.
-        Executing this method might modify the object, adding additional information to it, so the writer
-        can be later accessed and processed within QGIS.
-        It should be called just once, since a new call might result in previous data being replaced,
-        thus rendering a previously obtained writer useless'''
+        '''Returns a suitable writer to which features can be added as a
+        result of the algorithm. Use this to transparently handle output
+        values instead of creating your own method.
+
+        Executing this method might modify the object, adding additional
+        information to it, so the writer can be later accessed and processed
+        within QGIS. It should be called just once, since a new call might
+        result in previous data being replaced, thus rendering a previously
+        obtained writer useless
+
+        @param fields   a dict of int-QgsField
+        @param geomType a suitable geometry type, as it would be passed
+                        to a QgsVectorFileWriter constructor
+        @param crs      the crs of the layer to create
+
+        @return writer  instance of the vectoe writer class
+        '''
 
-        if self.value.startswith(self.MEMORY_LAYER_PREFIX):
-            if isinstance(fields, dict):
-                fields = fields.values()
-            types = { QGis.WKBPoint : "Point", QGis.WKBLineString : "Point", QGis.WKBPolygon : "Polygon",
-                     QGis.WKBMultiPoint : "MultiPoint", QGis.WKBMultiLineString : "MultiLineString", QGis.WKBMultiPolygon : "MultiPolygon",}
-            v = QgsVectorLayer(types[geomType], self.description, "memory")
-            pr = v.dataProvider()
-            pr.addAttributes(fields)
-            v.startEditing()
-            self.memoryLayer = v #keep a reference to the writer
-            return v
-        else: #outputChannel is a file path
-            #TODO: Add support for encodings
-            check = QFile(self.value)
-            if check.exists():
-                if not QgsVectorFileWriter.deleteShapeFile(self.value):
-                    raise GeoAlgorithmExecutionException("Could not delete existing output file")
-            formats = QgsVectorFileWriter.supportedFiltersAndFormats()
-            OGRCodes = {}
-            for key,value in formats.items():
-                extension = str(key)
-                extension = extension[extension.find('*.') + 2:]
-                extension = extension[:extension.find(" ")]
-                OGRCodes[extension] = value
-            if isinstance(fields, dict):
-                fieldsDict = fields
-            else:
-                fieldsDict = {}
-                i = 0
-                for field in fields:
-                    fieldsDict[i] = field
-                    i += 1
-            settings = QSettings()
-            systemEncoding = settings.value( "/UI/encoding", "System" ).toString()
-            extension = self.value[self.value.find(".")+1:]
-            return QgsVectorFileWriter(self.value, systemEncoding,  fieldsDict, geomType, crs, OGRCodes[extension] )
+        settings = QSettings()
+        encoding = settings.value( "/UI/encoding", "System" ).toString()
+        w = SextanteVectorWriter(self.value, encoding, fields, geomType, crs, options)
+        self.memoryLayer = w.memLayer
+        return w