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Import hooks; when installed with the install() function, these hooks
allow importing .pyx files as if they were Python modules.
If you want the hook installed every time you run Python
you can add it to your Python version by adding these lines to (which you can create from scratch in site-packages
if it doesn't exist there or somewhere else on your python path)::
import pyximport
For instance on the Mac with a non-system Python 2.3, you could create with only those two lines at
/usr/local/lib/python2.3/site-packages/ .
Since Cython 0.11, the :mod:`pyximport` module also has experimental
compilation support for normal Python modules. This allows you to
automatically run Cython on every .pyx and .py module that Python
imports, including parts of the standard library and installed
packages. Cython will still fail to compile a lot of Python modules,
in which case the import mechanism will fall back to loading the
Python source modules instead. The .py import mechanism is installed
like this::
pyximport.install(pyimport = True)
Running this module as a top-level script will run a test and then print
the documentation.
This code is based on the Py2.3+ import protocol as described in PEP 302.
import sys
import os
import glob
import imp
import pyxbuild
from distutils.dep_util import newer
from distutils.extension import Extension
import hashlib
except ImportError:
import md5 as hashlib
mod_name = "pyximport"
assert sys.hexversion >= 0x2030000, "need Python 2.3 or later"
PYX_EXT = ".pyx"
PYXDEP_EXT = ".pyxdep"
PYXBLD_EXT = ".pyxbld"
# Performance problem: for every PYX file that is imported, we will
# invoke the whole distutils infrastructure even if the module is
# already built. It might be more efficient to only do it when the
# mod time of the .pyx is newer than the mod time of the .so but
# the question is how to get distutils to tell me the name of the .so
# before it builds it. Maybe it is easy...but maybe the peformance
# issue isn't real.
def _load_pyrex(name, filename):
"Load a pyrex file given a name and filename."
def get_distutils_extension(modname, pyxfilename):
extra = "_" + hashlib.md5(open(pyxfilename).read()).hexdigest()
# modname = modname + extra
extension_mod = handle_special_build(modname, pyxfilename)
if not extension_mod:
extension_mod = Extension(name = modname, sources=[pyxfilename])
return extension_mod
def handle_special_build(modname, pyxfilename):
special_build = os.path.splitext(pyxfilename)[0] + PYXBLD_EXT
if not os.path.exists(special_build):
ext = None
globls = {}
locs = {}
# execfile(special_build, globls, locs)
# ext = locs["make_ext"](modname, pyxfilename)
mod = imp.load_source("XXXX", special_build, open(special_build))
ext = mod.make_ext(modname, pyxfilename)
assert ext and ext.sources, ("make_ext in %s did not return Extension"
% special_build)
ext.sources = [os.path.join(os.path.dirname(special_build), source)
for source in ext.sources]
return ext
def handle_dependencies(pyxfilename):
dependfile = os.path.splitext(pyxfilename)[0] + PYXDEP_EXT
# by default let distutils decide whether to rebuild on its own
# (it has a better idea of what the output file will be)
# but we know more about dependencies so force a rebuild if
# some of the dependencies are newer than the pyxfile.
if os.path.exists(dependfile):
depends = open(dependfile).readlines()
depends = [depend.strip() for depend in depends]
# gather dependencies in the "files" variable
# the dependency file is itself a dependency
files = [dependfile]
for depend in depends:
fullpath = os.path.join(os.path.dirname(dependfile),
# only for unit testing to see we did the right thing
_test_files[:] = []
# if any file that the pyxfile depends upon is newer than
# the pyx file, 'touch' the pyx file so that distutils will
# be tricked into rebuilding it.
for file in files:
if newer(file, pyxfilename):
print("Rebuilding because of ", file)
filetime = os.path.getmtime(file)
os.utime(pyxfilename, (filetime, filetime))
def build_module(name, pyxfilename, pyxbuild_dir=None):
assert os.path.exists(pyxfilename), (
"Path does not exist: %s" % pyxfilename)
extension_mod = get_distutils_extension(name, pyxfilename)
so_path = pyxbuild.pyx_to_dll(pyxfilename, extension_mod,
assert os.path.exists(so_path), "Cannot find: %s" % so_path
junkpath = os.path.join(os.path.dirname(so_path), name+"_*")
junkstuff = glob.glob(junkpath)
for path in junkstuff:
if path!=so_path:
except IOError:
print("Couldn't remove ", path)
return so_path
def load_module(name, pyxfilename, pyxbuild_dir=None):
so_path = build_module(name, pyxfilename, pyxbuild_dir)
mod = imp.load_dynamic(name, so_path)
assert mod.__file__ == so_path, (mod.__file__, so_path)
except Exception, e:
raise ImportError("Building module failed: %s" % e)
return mod
# import hooks
class PyxImporter(object):
"""A meta-path importer for .pyx files.
def __init__(self, extension=PYX_EXT, pyxbuild_dir=None):
self.extension = extension
self.pyxbuild_dir = pyxbuild_dir
def find_module(self, fullname, package_path=None):
if fullname in sys.modules:
return None
print("SEARCHING", fullname, package_path)
if '.' in fullname:
mod_parts = fullname.split('.')
package = '.'.join(mod_parts[:-1])
module_name = mod_parts[-1]
package = None
module_name = fullname
pyx_module_name = module_name + self.extension
# this may work, but it returns the file content, not its path
#import pkgutil
#pyx_source = pkgutil.get_data(package, pyx_module_name)
if package_path:
paths = package_path
paths = sys.path
join_path = os.path.join
is_file = os.path.isfile
is_dir = os.path.isdir
for path in paths:
if not is_dir(path):
if not path:
path = os.getcwd()
for filename in os.listdir(path):
if filename == pyx_module_name:
return PyxLoader(fullname, join_path(path, filename),
elif filename == module_name:
package_path = join_path(path, filename)
init_path = join_path(package_path,
'__init__' + self.extension)
if is_file(init_path):
return PyxLoader(fullname, package_path, init_path,
# not found, normal package, not a .pyx file, none of our business
return None
class PyImporter(PyxImporter):
"""A meta-path importer for normal .py files.
def __init__(self, pyxbuild_dir=None):
self.super = super(PyImporter, self)
self.super.__init__(extension='.py', pyxbuild_dir=pyxbuild_dir)
self.uncompilable_modules = {}
self.blocked_modules = ['Cython']
def find_module(self, fullname, package_path=None):
if fullname in sys.modules:
return None
if fullname.startswith('Cython.'):
return None
if fullname in self.blocked_modules:
# prevent infinite recursion
return None
print("trying import of module", fullname)
if fullname in self.uncompilable_modules:
path, last_modified = self.uncompilable_modules[fullname]
new_last_modified = os.stat(path).st_mtime
if new_last_modified > last_modified:
# import would fail again
return None
except OSError:
# module is no longer where we found it, retry the import
importer = self.super.find_module(fullname, package_path)
if importer is not None:
print("importer found")
if importer.init_path:
path = importer.init_path
path = importer.path
build_module(fullname, path,
except Exception, e:
import traceback
# build failed, not a compilable Python module
last_modified = os.stat(path).st_mtime
except OSError:
last_modified = 0
self.uncompilable_modules[fullname] = (path, last_modified)
importer = None
return importer
class PyxLoader(object):
def __init__(self, fullname, path, init_path=None, pyxbuild_dir=None):
self.fullname = fullname
self.path, self.init_path = path, init_path
self.pyxbuild_dir = pyxbuild_dir
def load_module(self, fullname):
assert self.fullname == fullname, (
"invalid module, expected %s, got %s" % (
self.fullname, fullname))
if self.init_path:
# package
#print "PACKAGE", fullname
module = load_module(fullname, self.init_path,
module.__path__ = [self.path]
#print "MODULE", fullname
module = load_module(fullname, self.path,
return module
def install(pyximport=True, pyimport=False, build_dir=None):
"""Main entry point. Call this to install the .pyx import hook in
your meta-path for a single Python process. If you want it to be
installed whenever you use Python, add it to your sitecustomize
(as described above).
You can pass ``pyimport=True`` to also install the .py import hook
in your meta-path. Note, however, that it is highly experimental,
will not work for most .py files, and will therefore only slow
down your imports. Use at your own risk.
By default, compiled modules will end up in a ``.pyxbld``
directory in the user's home directory. Passing a different path
as ``build_dir`` will override this.
if not build_dir:
build_dir = os.path.expanduser('~/.pyxbld')
has_py_importer = False
has_pyx_importer = False
for importer in sys.meta_path:
if isinstance(importer, PyxImporter):
if isinstance(importer, PyImporter):
has_py_importer = True
has_pyx_importer = True
if pyimport and not has_py_importer:
importer = PyImporter(pyxbuild_dir=build_dir)
sys.meta_path.insert(0, importer)
if pyximport and not has_pyx_importer:
importer = PyxImporter(pyxbuild_dir=build_dir)
def show_docs():
import __main__
__main__.__name__ = mod_name
for name in dir(__main__):
item = getattr(__main__, name)
setattr(item, "__module__", mod_name)
except (AttributeError, TypeError):
if __name__ == '__main__':
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