Maintenance refactor of the GDAL (OGR) ctypes interface. Changes include: (f1ada999) · Commits · Dom Sekotill / django

django/contrib/gis/gdal/LICENSE

+1 −1

Original line number	Diff line number	Diff line
		Copyright (c) 2007, Justin Bronn
		Copyright (c) 2007-2009, Justin Bronn
		All rights reserved.

		Redistribution and use in source and binary forms, with or without modification,

django/contrib/gis/gdal/base.py

0 → 100644

+35 −0

Original line number	Diff line number	Diff line
		from ctypes import c_void_p
		from types import NoneType
		from django.contrib.gis.gdal.error import GDALException

		class GDALBase(object):
		"""
		Base object for GDAL objects that has a pointer access property
		that controls access to the underlying C pointer.
		"""
		# Initially the pointer is NULL.
		_ptr = None

		# Default allowed pointer type.
		ptr_type = c_void_p

		# Pointer access property.
		def _get_ptr(self):
		# Raise an exception if the pointer isn't valid don't
		# want to be passing NULL pointers to routines --
		# that's very bad.
		if self._ptr: return self._ptr
		else: raise GDALException('GDAL %s pointer no longer valid.' % self.__class__.__name__)

		def _set_ptr(self, ptr):
		# Only allow the pointer to be set with pointers of the
		# compatible type or None (NULL).
		if isinstance(ptr, int):
		self._ptr = self.ptr_type(ptr)
		elif isinstance(ptr, (self.ptr_type, NoneType)):
		self._ptr = ptr
		else:
		raise TypeError('Incompatible pointer type')

		ptr = property(_get_ptr, _set_ptr)

django/contrib/gis/gdal/datasource.py

+15 −25

Original line number	Diff line number	Diff line
		@@ -37,28 +37,23 @@
		from ctypes import byref, c_void_p

		# The GDAL C library, OGR exceptions, and the Layer object.
		from django.contrib.gis.gdal.base import GDALBase
		from django.contrib.gis.gdal.driver import Driver
		from django.contrib.gis.gdal.error import OGRException, OGRIndexError
		from django.contrib.gis.gdal.layer import Layer

		# Getting the ctypes prototypes for the DataSource.
		from django.contrib.gis.gdal.prototypes.ds import \
		destroy_ds, get_driver_count, register_all, open_ds, release_ds, \
		get_ds_name, get_layer, get_layer_count, get_layer_by_name
		from django.contrib.gis.gdal.prototypes import ds as capi

		# For more information, see the OGR C API source code:
		# http://www.gdal.org/ogr/ogr__api_8h.html
		#
		# The OGR_DS_* routines are relevant here.
		class DataSource(object):
		class DataSource(GDALBase):
		"Wraps an OGR Data Source object."

		#### Python 'magic' routines ####
		def __init__(self, ds_input, ds_driver=False, write=False):

		# DataSource pointer is initially NULL.
		self._ptr = None

		# The write flag.
		if write:
		self._write = 1
		@@ -67,33 +62,34 @@ class DataSource(object):

		# Registering all the drivers, this needs to be done
		# _before_ we try to open up a data source.
		if not get_driver_count(): register_all()
		if not capi.get_driver_count():
		capi.register_all()

		if isinstance(ds_input, basestring):
		# The data source driver is a void pointer.
		ds_driver = c_void_p()
		ds_driver = Driver.ptr_type()
		try:
		# OGROpen will auto-detect the data source type.
		ds = open_ds(ds_input, self._write, byref(ds_driver))
		ds = capi.open_ds(ds_input, self._write, byref(ds_driver))
		except OGRException:
		# Making the error message more clear rather than something
		# like "Invalid pointer returned from OGROpen".
		raise OGRException('Could not open the datasource at "%s"' % ds_input)
		elif isinstance(ds_input, c_void_p) and isinstance(ds_driver, c_void_p):
		elif isinstance(ds_input, self.ptr_type) and isinstance(ds_driver, Driver.ptr_type):
		ds = ds_input
		else:
		raise OGRException('Invalid data source input type: %s' % type(ds_input))

		if bool(ds):
		self._ptr = ds
		self._driver = Driver(ds_driver)
		self.ptr = ds
		self.driver = Driver(ds_driver)
		else:
		# Raise an exception if the returned pointer is NULL
		raise OGRException('Invalid data source file "%s"' % ds_input)

		def __del__(self):
		"Destroys this DataStructure object."
		if self._ptr: destroy_ds(self._ptr)
		if self._ptr: capi.destroy_ds(self._ptr)

		def __iter__(self):
		"Allows for iteration over the layers in a data source."
		@@ -103,12 +99,12 @@ class DataSource(object):
		def __getitem__(self, index):
		"Allows use of the index [] operator to get a layer at the index."
		if isinstance(index, basestring):
		l = get_layer_by_name(self._ptr, index)
		l = capi.get_layer_by_name(self.ptr, index)
		if not l: raise OGRIndexError('invalid OGR Layer name given: "%s"' % index)
		elif isinstance(index, int):
		if index < 0 or index >= self.layer_count:
		raise OGRIndexError('index out of range')
		l = get_layer(self._ptr, index)
		l = capi.get_layer(self._ptr, index)
		else:
		raise TypeError('Invalid index type: %s' % type(index))
		return Layer(l, self)
		@@ -121,18 +117,12 @@ class DataSource(object):
		"Returns OGR GetName and Driver for the Data Source."
		return '%s (%s)' % (self.name, str(self.driver))

		#### DataSource Properties ####
		@property
		def driver(self):
		"Returns the Driver object for this Data Source."
		return self._driver

		@property
		def layer_count(self):
		"Returns the number of layers in the data source."
		return get_layer_count(self._ptr)
		return capi.get_layer_count(self._ptr)

		@property
		def name(self):
		"Returns the name of the data source."
		return get_ds_name(self._ptr)
		return capi.get_ds_name(self._ptr)

django/contrib/gis/gdal/driver.py

+9 −10

Original line number	Diff line number	Diff line
		# prerequisites imports
		from ctypes import c_void_p
		from django.contrib.gis.gdal.base import GDALBase
		from django.contrib.gis.gdal.error import OGRException
		from django.contrib.gis.gdal.prototypes.ds import \
		get_driver, get_driver_by_name, get_driver_count, get_driver_name, register_all
		from django.contrib.gis.gdal.prototypes import ds as capi

		# For more information, see the OGR C API source code:
		# http://www.gdal.org/ogr/ogr__api_8h.html
		#
		# The OGR_Dr_* routines are relevant here.
		class Driver(object):
		class Driver(GDALBase):
		"Wraps an OGR Data Source Driver."

		# Case-insensitive aliases for OGR Drivers.
		@@ -24,7 +24,6 @@ class Driver(object):

		if isinstance(dr_input, basestring):
		# If a string name of the driver was passed in
		self._ptr = None # Initially NULL
		self._register()

		# Checking the alias dictionary (case-insensitive) to see if an alias
		@@ -35,10 +34,10 @@ class Driver(object):
		name = dr_input

		# Attempting to get the OGR driver by the string name.
		dr = get_driver_by_name(name)
		dr = capi.get_driver_by_name(name)
		elif isinstance(dr_input, int):
		self._register()
		dr = get_driver(dr_input)
		dr = capi.get_driver(dr_input)
		elif isinstance(dr_input, c_void_p):
		dr = dr_input
		else:
		@@ -47,20 +46,20 @@ class Driver(object):
		# Making sure we get a valid pointer to the OGR Driver
		if not dr:
		raise OGRException('Could not initialize OGR Driver on input: %s' % str(dr_input))
		self._ptr = dr
		self.ptr = dr

		def __str__(self):
		"Returns the string name of the OGR Driver."
		return get_driver_name(self._ptr)
		return capi.get_driver_name(self.ptr)

		def _register(self):
		"Attempts to register all the data source drivers."
		# Only register all if the driver count is 0 (or else all drivers
		# will be registered over and over again)
		if not self.driver_count: register_all()
		if not self.driver_count: capi.register_all()

		# Driver properties
		@property
		def driver_count(self):
		"Returns the number of OGR data source drivers registered."
		return get_driver_count()
		return capi.get_driver_count()

django/contrib/gis/gdal/envelope.py

+48 −7

Original line number	Diff line number	Diff line
		@@ -11,7 +11,6 @@
		Lower left (min_x, min_y) o----------+
		"""
		from ctypes import Structure, c_double
		from types import TupleType, ListType
		from django.contrib.gis.gdal.error import OGRException

		# The OGR definition of an Envelope is a C structure containing four doubles.
		@@ -42,7 +41,7 @@ class Envelope(object):
		if isinstance(args[0], OGREnvelope):
		# OGREnvelope (a ctypes Structure) was passed in.
		self._envelope = args[0]
		elif isinstance(args[0], (TupleType, ListType)):
		elif isinstance(args[0], (tuple, list)):
		# A tuple was passed in.
		if len(args[0]) != 4:
		raise OGRException('Incorrect number of tuple elements (%d).' % len(args[0]))
		@@ -58,10 +57,10 @@ class Envelope(object):
		raise OGRException('Incorrect number (%d) of arguments.' % len(args))

		# Checking the x,y coordinates
		if self.min_x >= self.max_x:
		raise OGRException('Envelope minimum X >= maximum X.')
		if self.min_y >= self.max_y:
		raise OGRException('Envelope minimum Y >= maximum Y.')
		if self.min_x > self.max_x:
		raise OGRException('Envelope minimum X > maximum X.')
		if self.min_y > self.max_y:
		raise OGRException('Envelope minimum Y > maximum Y.')

		def __eq__(self, other):
		"""
		@@ -71,7 +70,7 @@ class Envelope(object):
		if isinstance(other, Envelope):
		return (self.min_x == other.min_x) and (self.min_y == other.min_y) and \
		(self.max_x == other.max_x) and (self.max_y == other.max_y)
		elif isinstance(other, TupleType) and len(other) == 4:
		elif isinstance(other, tuple) and len(other) == 4:
		return (self.min_x == other[0]) and (self.min_y == other[1]) and \
		(self.max_x == other[2]) and (self.max_y == other[3])
		else:
		@@ -89,6 +88,48 @@ class Envelope(object):
		self._envelope.MaxX = seq[2]
		self._envelope.MaxY = seq[3]

		def expand_to_include(self, *args):
		"""
		Modifies the envelope to expand to include the boundaries of
		the passed-in 2-tuple (a point), 4-tuple (an extent) or
		envelope.
		"""
		# We provide a number of different signatures for this method,
		# and the logic here is all about converting them into a
		# 4-tuple single parameter which does the actual work of
		# expanding the envelope.
		if len(args) == 1:
		if isinstance(args[0], Envelope):
		return self.expand_to_include(args[0].tuple)
		elif hasattr(args[0], 'x') and hasattr(args[0], 'y'):
		return self.expand_to_include(args[0].x, args[0].y, args[0].x, args[0].y)
		elif isinstance(args[0], (tuple, list)):
		# A tuple was passed in.
		if len(args[0]) == 2:
		return self.expand_to_include((args[0][0], args[0][1], args[0][0], args[0][1]))
		elif len(args[0]) == 4:
		(minx, miny, maxx, maxy) = args[0]
		if minx < self._envelope.MinX:
		self._envelope.MinX = minx
		if miny < self._envelope.MinY:
		self._envelope.MinY = miny
		if maxx > self._envelope.MaxX:
		self._envelope.MaxX = maxx
		if maxy > self._envelope.MaxY:
		self._envelope.MaxY = maxy
		else:
		raise OGRException('Incorrect number of tuple elements (%d).' % len(args[0]))
		else:
		raise TypeError('Incorrect type of argument: %s' % str(type(args[0])))
		elif len(args) == 2:
		# An x and an y parameter were passed in
		return self.expand_to_include((args[0], args[1], args[0], args[1]))
		elif len(args) == 4:
		# Individiual parameters passed in.
		return self.expand_to_include(args)
		else:
		raise OGRException('Incorrect number (%d) of arguments.' % len(args[0]))

		@property
		def min_x(self):
		"Returns the value of the minimum X coordinate."