Commit e4ea2e12 authored by Justin Bronn's avatar Justin Bronn
Browse files

Fixed #9448 -- `Layer` objects now carry a reference to their parent... 

Fixed #9448 -- `Layer` objects now carry a reference to their parent `DataSource`.  Thanks, Matthew D. Hancher for the bug report.

Backport of r9284 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9285 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent 3517f8a5

django/contrib/gis/gdal/datasource.py

+1 −1
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ class DataSource(object): 
            l = get_layer(self._ptr, index)

        else:

            raise TypeError('Invalid index type: %s' % type(index))

        return Layer(l)

        return Layer(l, self)

        

    def __len__(self):

        "Returns the number of layers within the data source."

django/contrib/gis/gdal/layer.py

+8 −2
Original line number Diff line number Diff line
@@ -25,12 +25,18 @@ class Layer(object): 
    "A class that wraps an OGR Layer, needs to be instantiated from a DataSource object."



    #### Python 'magic' routines ####

    def __init__(self, layer_ptr):

        "Needs a C pointer (Python/ctypes integer) in order to initialize."

    def __init__(self, layer_ptr, ds):

        """

        Initializes on an OGR C pointer to the Layer and the `DataSource` object

        that owns this layer.  The `DataSource` object is required so that a 

        reference to it is kept with this Layer.  This prevents garbage 

        collection of the `DataSource` while this Layer is still active.

        """

        self._ptr = None # Initially NULL

        if not layer_ptr:

            raise OGRException('Cannot create Layer, invalid pointer given')

        self._ptr = layer_ptr

        self._ds = ds

        self._ldefn = get_layer_defn(self._ptr)

        # Does the Layer support random reading?

        self._random_read = self.test_capability('RandomRead')

django/contrib/gis/tests/test_gdal_ds.py

+17 −0
Original line number Diff line number Diff line
@@ -130,6 +130,23 @@ class DataSourceTest(unittest.TestCase): 
            control_vals = source.field_values[fld_name][sl]

            self.assertEqual(control_vals, test_vals)



    def test03c_layer_references(self):

        "Test to make sure Layer access is still available without the DataSource."

        source = ds_list[0]



        # See ticket #9448.

        def get_layer():

            # This DataSource object is not accessible outside this

            # scope.  However, a reference should still be kept alive

            # on the `Layer` returned.

            ds = DataSource(source.ds)

            return ds[0]



        # Making sure we can call OGR routines on the Layer returned.

        lyr = get_layer()

        self.assertEqual(source.nfeat, len(lyr))

        self.assertEqual(source.gtype, lyr.geom_type.num)        



    def test04_features(self):

        "Testing Data Source Features."

        for source in ds_list: