175 lines
4.9 KiB
Python
175 lines
4.9 KiB
Python
"""
|
|
This module houses the ctypes initialization procedures, as well
|
|
as the notice and error handler function callbacks (get called
|
|
when an error occurs in GEOS).
|
|
|
|
This module also houses GEOS Pointer utilities, including
|
|
get_pointer_arr(), and GEOM_PTR.
|
|
"""
|
|
import logging
|
|
import os
|
|
from ctypes import CDLL, CFUNCTYPE, POINTER, Structure, c_char_p
|
|
from ctypes.util import find_library
|
|
|
|
from django.core.exceptions import ImproperlyConfigured
|
|
from django.utils.functional import SimpleLazyObject, cached_property
|
|
from django.utils.version import get_version_tuple
|
|
|
|
logger = logging.getLogger("django.contrib.gis")
|
|
|
|
|
|
def load_geos():
|
|
# Custom library path set?
|
|
try:
|
|
from django.conf import settings
|
|
|
|
lib_path = settings.GEOS_LIBRARY_PATH
|
|
except (AttributeError, ImportError, ImproperlyConfigured, OSError):
|
|
lib_path = None
|
|
|
|
# Setting the appropriate names for the GEOS-C library.
|
|
if lib_path:
|
|
lib_names = None
|
|
elif os.name == "nt":
|
|
# Windows NT libraries
|
|
lib_names = ["geos_c", "libgeos_c-1"]
|
|
elif os.name == "posix":
|
|
# *NIX libraries
|
|
lib_names = ["geos_c", "GEOS"]
|
|
else:
|
|
raise ImportError('Unsupported OS "%s"' % os.name)
|
|
|
|
# Using the ctypes `find_library` utility to find the path to the GEOS
|
|
# shared library. This is better than manually specifying each library name
|
|
# and extension (e.g., libgeos_c.[so|so.1|dylib].).
|
|
if lib_names:
|
|
for lib_name in lib_names:
|
|
lib_path = find_library(lib_name)
|
|
if lib_path is not None:
|
|
break
|
|
|
|
# No GEOS library could be found.
|
|
if lib_path is None:
|
|
raise ImportError(
|
|
'Could not find the GEOS library (tried "%s"). '
|
|
"Try setting GEOS_LIBRARY_PATH in your settings." % '", "'.join(lib_names)
|
|
)
|
|
# Getting the GEOS C library. The C interface (CDLL) is used for
|
|
# both *NIX and Windows.
|
|
# See the GEOS C API source code for more details on the library function calls:
|
|
# https://libgeos.org/doxygen/geos__c_8h_source.html
|
|
_lgeos = CDLL(lib_path)
|
|
# Here we set up the prototypes for the initGEOS_r and finishGEOS_r
|
|
# routines. These functions aren't actually called until they are
|
|
# attached to a GEOS context handle -- this actually occurs in
|
|
# geos/prototypes/threadsafe.py.
|
|
_lgeos.initGEOS_r.restype = CONTEXT_PTR
|
|
_lgeos.finishGEOS_r.argtypes = [CONTEXT_PTR]
|
|
# Set restype for compatibility across 32 and 64-bit platforms.
|
|
_lgeos.GEOSversion.restype = c_char_p
|
|
return _lgeos
|
|
|
|
|
|
# The notice and error handler C function callback definitions.
|
|
# Supposed to mimic the GEOS message handler (C below):
|
|
# typedef void (*GEOSMessageHandler)(const char *fmt, ...);
|
|
NOTICEFUNC = CFUNCTYPE(None, c_char_p, c_char_p)
|
|
|
|
|
|
def notice_h(fmt, lst):
|
|
fmt, lst = fmt.decode(), lst.decode()
|
|
try:
|
|
warn_msg = fmt % lst
|
|
except TypeError:
|
|
warn_msg = fmt
|
|
logger.warning("GEOS_NOTICE: %s\n", warn_msg)
|
|
|
|
|
|
notice_h = NOTICEFUNC(notice_h)
|
|
|
|
ERRORFUNC = CFUNCTYPE(None, c_char_p, c_char_p)
|
|
|
|
|
|
def error_h(fmt, lst):
|
|
fmt, lst = fmt.decode(), lst.decode()
|
|
try:
|
|
err_msg = fmt % lst
|
|
except TypeError:
|
|
err_msg = fmt
|
|
logger.error("GEOS_ERROR: %s\n", err_msg)
|
|
|
|
|
|
error_h = ERRORFUNC(error_h)
|
|
|
|
# #### GEOS Geometry C data structures, and utility functions. ####
|
|
|
|
|
|
# Opaque GEOS geometry structures, used for GEOM_PTR and CS_PTR
|
|
class GEOSGeom_t(Structure):
|
|
pass
|
|
|
|
|
|
class GEOSPrepGeom_t(Structure):
|
|
pass
|
|
|
|
|
|
class GEOSCoordSeq_t(Structure):
|
|
pass
|
|
|
|
|
|
class GEOSContextHandle_t(Structure):
|
|
pass
|
|
|
|
|
|
# Pointers to opaque GEOS geometry structures.
|
|
GEOM_PTR = POINTER(GEOSGeom_t)
|
|
PREPGEOM_PTR = POINTER(GEOSPrepGeom_t)
|
|
CS_PTR = POINTER(GEOSCoordSeq_t)
|
|
CONTEXT_PTR = POINTER(GEOSContextHandle_t)
|
|
|
|
|
|
lgeos = SimpleLazyObject(load_geos)
|
|
|
|
|
|
class GEOSFuncFactory:
|
|
"""
|
|
Lazy loading of GEOS functions.
|
|
"""
|
|
|
|
argtypes = None
|
|
restype = None
|
|
errcheck = None
|
|
|
|
def __init__(self, func_name, *, restype=None, errcheck=None, argtypes=None):
|
|
self.func_name = func_name
|
|
if restype is not None:
|
|
self.restype = restype
|
|
if errcheck is not None:
|
|
self.errcheck = errcheck
|
|
if argtypes is not None:
|
|
self.argtypes = argtypes
|
|
|
|
def __call__(self, *args):
|
|
return self.func(*args)
|
|
|
|
@cached_property
|
|
def func(self):
|
|
from django.contrib.gis.geos.prototypes.threadsafe import GEOSFunc
|
|
|
|
func = GEOSFunc(self.func_name)
|
|
func.argtypes = self.argtypes or []
|
|
func.restype = self.restype
|
|
if self.errcheck:
|
|
func.errcheck = self.errcheck
|
|
return func
|
|
|
|
|
|
def geos_version():
|
|
"""Return the string version of the GEOS library."""
|
|
return lgeos.GEOSversion()
|
|
|
|
|
|
def geos_version_tuple():
|
|
"""Return the GEOS version as a tuple (major, minor, subminor)."""
|
|
return get_version_tuple(geos_version().decode())
|