mirror of https://github.com/python/cpython
291 lines
11 KiB
Python
291 lines
11 KiB
Python
"""runpy.py - locating and running Python code using the module namespace
|
|
|
|
Provides support for locating and running Python scripts using the Python
|
|
module namespace instead of the native filesystem.
|
|
|
|
This allows Python code to play nicely with non-filesystem based PEP 302
|
|
importers when locating support scripts as well as when importing modules.
|
|
"""
|
|
# Written by Nick Coghlan <ncoghlan at gmail.com>
|
|
# to implement PEP 338 (Executing Modules as Scripts)
|
|
|
|
import sys
|
|
import imp
|
|
from pkgutil import read_code
|
|
try:
|
|
from imp import get_loader
|
|
except ImportError:
|
|
from pkgutil import get_loader
|
|
|
|
__all__ = [
|
|
"run_module", "run_path",
|
|
]
|
|
|
|
class _TempModule(object):
|
|
"""Temporarily replace a module in sys.modules with an empty namespace"""
|
|
def __init__(self, mod_name):
|
|
self.mod_name = mod_name
|
|
self.module = imp.new_module(mod_name)
|
|
self._saved_module = []
|
|
|
|
def __enter__(self):
|
|
mod_name = self.mod_name
|
|
try:
|
|
self._saved_module.append(sys.modules[mod_name])
|
|
except KeyError:
|
|
pass
|
|
sys.modules[mod_name] = self.module
|
|
return self
|
|
|
|
def __exit__(self, *args):
|
|
if self._saved_module:
|
|
sys.modules[self.mod_name] = self._saved_module[0]
|
|
else:
|
|
del sys.modules[self.mod_name]
|
|
self._saved_module = []
|
|
|
|
class _ModifiedArgv0(object):
|
|
def __init__(self, value):
|
|
self.value = value
|
|
self._saved_value = self._sentinel = object()
|
|
|
|
def __enter__(self):
|
|
if self._saved_value is not self._sentinel:
|
|
raise RuntimeError("Already preserving saved value")
|
|
self._saved_value = sys.argv[0]
|
|
sys.argv[0] = self.value
|
|
|
|
def __exit__(self, *args):
|
|
self.value = self._sentinel
|
|
sys.argv[0] = self._saved_value
|
|
|
|
def _run_code(code, run_globals, init_globals=None,
|
|
mod_name=None, mod_fname=None,
|
|
mod_loader=None, pkg_name=None):
|
|
"""Helper to run code in nominated namespace"""
|
|
if init_globals is not None:
|
|
run_globals.update(init_globals)
|
|
run_globals.update(__name__ = mod_name,
|
|
__file__ = mod_fname,
|
|
__cached__ = None,
|
|
__doc__ = None,
|
|
__loader__ = mod_loader,
|
|
__package__ = pkg_name)
|
|
exec(code, run_globals)
|
|
return run_globals
|
|
|
|
def _run_module_code(code, init_globals=None,
|
|
mod_name=None, mod_fname=None,
|
|
mod_loader=None, pkg_name=None):
|
|
"""Helper to run code in new namespace with sys modified"""
|
|
with _TempModule(mod_name) as temp_module, _ModifiedArgv0(mod_fname):
|
|
mod_globals = temp_module.module.__dict__
|
|
_run_code(code, mod_globals, init_globals,
|
|
mod_name, mod_fname, mod_loader, pkg_name)
|
|
# Copy the globals of the temporary module, as they
|
|
# may be cleared when the temporary module goes away
|
|
return mod_globals.copy()
|
|
|
|
|
|
# This helper is needed due to a missing component in the PEP 302
|
|
# loader protocol (specifically, "get_filename" is non-standard)
|
|
# Since we can't introduce new features in maintenance releases,
|
|
# support was added to zipimporter under the name '_get_filename'
|
|
def _get_filename(loader, mod_name):
|
|
for attr in ("get_filename", "_get_filename"):
|
|
meth = getattr(loader, attr, None)
|
|
if meth is not None:
|
|
return meth(mod_name)
|
|
return None
|
|
|
|
# Helper to get the loader, code and filename for a module
|
|
def _get_module_details(mod_name):
|
|
loader = get_loader(mod_name)
|
|
if loader is None:
|
|
raise ImportError("No module named %s" % mod_name)
|
|
if loader.is_package(mod_name):
|
|
if mod_name == "__main__" or mod_name.endswith(".__main__"):
|
|
raise ImportError("Cannot use package as __main__ module")
|
|
try:
|
|
pkg_main_name = mod_name + ".__main__"
|
|
return _get_module_details(pkg_main_name)
|
|
except ImportError as e:
|
|
raise ImportError(("%s; %r is a package and cannot " +
|
|
"be directly executed") %(e, mod_name))
|
|
code = loader.get_code(mod_name)
|
|
if code is None:
|
|
raise ImportError("No code object available for %s" % mod_name)
|
|
filename = _get_filename(loader, mod_name)
|
|
return mod_name, loader, code, filename
|
|
|
|
# XXX ncoghlan: Should this be documented and made public?
|
|
# (Current thoughts: don't repeat the mistake that lead to its
|
|
# creation when run_module() no longer met the needs of
|
|
# mainmodule.c, but couldn't be changed because it was public)
|
|
def _run_module_as_main(mod_name, alter_argv=True):
|
|
"""Runs the designated module in the __main__ namespace
|
|
|
|
Note that the executed module will have full access to the
|
|
__main__ namespace. If this is not desirable, the run_module()
|
|
function should be used to run the module code in a fresh namespace.
|
|
|
|
At the very least, these variables in __main__ will be overwritten:
|
|
__name__
|
|
__file__
|
|
__cached__
|
|
__loader__
|
|
__package__
|
|
"""
|
|
try:
|
|
if alter_argv or mod_name != "__main__": # i.e. -m switch
|
|
mod_name, loader, code, fname = _get_module_details(mod_name)
|
|
else: # i.e. directory or zipfile execution
|
|
mod_name, loader, code, fname = _get_main_module_details()
|
|
except ImportError as exc:
|
|
# Try to provide a good error message
|
|
# for directories, zip files and the -m switch
|
|
if alter_argv:
|
|
# For -m switch, just display the exception
|
|
info = str(exc)
|
|
else:
|
|
# For directories/zipfiles, let the user
|
|
# know what the code was looking for
|
|
info = "can't find '__main__' module in %r" % sys.argv[0]
|
|
msg = "%s: %s" % (sys.executable, info)
|
|
sys.exit(msg)
|
|
pkg_name = mod_name.rpartition('.')[0]
|
|
main_globals = sys.modules["__main__"].__dict__
|
|
if alter_argv:
|
|
sys.argv[0] = fname
|
|
return _run_code(code, main_globals, None,
|
|
"__main__", fname, loader, pkg_name)
|
|
|
|
def run_module(mod_name, init_globals=None,
|
|
run_name=None, alter_sys=False):
|
|
"""Execute a module's code without importing it
|
|
|
|
Returns the resulting top level namespace dictionary
|
|
"""
|
|
mod_name, loader, code, fname = _get_module_details(mod_name)
|
|
if run_name is None:
|
|
run_name = mod_name
|
|
pkg_name = mod_name.rpartition('.')[0]
|
|
if alter_sys:
|
|
return _run_module_code(code, init_globals, run_name,
|
|
fname, loader, pkg_name)
|
|
else:
|
|
# Leave the sys module alone
|
|
return _run_code(code, {}, init_globals, run_name,
|
|
fname, loader, pkg_name)
|
|
|
|
def _get_main_module_details():
|
|
# Helper that gives a nicer error message when attempting to
|
|
# execute a zipfile or directory by invoking __main__.py
|
|
main_name = "__main__"
|
|
try:
|
|
return _get_module_details(main_name)
|
|
except ImportError as exc:
|
|
if main_name in str(exc):
|
|
raise ImportError("can't find %r module in %r" %
|
|
(main_name, sys.path[0]))
|
|
raise
|
|
|
|
|
|
# XXX (ncoghlan): Perhaps expose the C API function
|
|
# as imp.get_importer instead of reimplementing it in Python?
|
|
def _get_importer(path_name):
|
|
"""Python version of PyImport_GetImporter C API function"""
|
|
cache = sys.path_importer_cache
|
|
try:
|
|
importer = cache[path_name]
|
|
except KeyError:
|
|
# Not yet cached. Flag as using the
|
|
# standard machinery until we finish
|
|
# checking the hooks
|
|
cache[path_name] = None
|
|
for hook in sys.path_hooks:
|
|
try:
|
|
importer = hook(path_name)
|
|
break
|
|
except ImportError:
|
|
pass
|
|
else:
|
|
# The following check looks a bit odd. The trick is that
|
|
# NullImporter raises ImportError if the supplied path is a
|
|
# *valid* directory entry (and hence able to be handled
|
|
# by the standard import machinery)
|
|
try:
|
|
importer = imp.NullImporter(path_name)
|
|
except ImportError:
|
|
return None
|
|
cache[path_name] = importer
|
|
return importer
|
|
|
|
def _get_code_from_file(fname):
|
|
# Check for a compiled file first
|
|
with open(fname, "rb") as f:
|
|
code = read_code(f)
|
|
if code is None:
|
|
# That didn't work, so try it as normal source code
|
|
with open(fname, "rb") as f:
|
|
code = compile(f.read(), fname, 'exec')
|
|
return code
|
|
|
|
def run_path(path_name, init_globals=None, run_name=None):
|
|
"""Execute code located at the specified filesystem location
|
|
|
|
Returns the resulting top level namespace dictionary
|
|
|
|
The file path may refer directly to a Python script (i.e.
|
|
one that could be directly executed with execfile) or else
|
|
it may refer to a zipfile or directory containing a top
|
|
level __main__.py script.
|
|
"""
|
|
if run_name is None:
|
|
run_name = "<run_path>"
|
|
pkg_name = run_name.rpartition(".")[0]
|
|
importer = _get_importer(path_name)
|
|
if isinstance(importer, imp.NullImporter):
|
|
# Not a valid sys.path entry, so run the code directly
|
|
# execfile() doesn't help as we want to allow compiled files
|
|
code = _get_code_from_file(path_name)
|
|
return _run_module_code(code, init_globals, run_name, path_name,
|
|
pkg_name=pkg_name)
|
|
else:
|
|
# Importer is defined for path, so add it to
|
|
# the start of sys.path
|
|
sys.path.insert(0, path_name)
|
|
try:
|
|
# Here's where things are a little different from the run_module
|
|
# case. There, we only had to replace the module in sys while the
|
|
# code was running and doing so was somewhat optional. Here, we
|
|
# have no choice and we have to remove it even while we read the
|
|
# code. If we don't do this, a __loader__ attribute in the
|
|
# existing __main__ module may prevent location of the new module.
|
|
main_name = "__main__"
|
|
saved_main = sys.modules[main_name]
|
|
del sys.modules[main_name]
|
|
try:
|
|
mod_name, loader, code, fname = _get_main_module_details()
|
|
finally:
|
|
sys.modules[main_name] = saved_main
|
|
with _TempModule(run_name) as temp_module, \
|
|
_ModifiedArgv0(path_name):
|
|
mod_globals = temp_module.module.__dict__
|
|
return _run_code(code, mod_globals, init_globals,
|
|
run_name, fname, loader, pkg_name).copy()
|
|
finally:
|
|
try:
|
|
sys.path.remove(path_name)
|
|
except ValueError:
|
|
pass
|
|
|
|
|
|
if __name__ == "__main__":
|
|
# Run the module specified as the next command line argument
|
|
if len(sys.argv) < 2:
|
|
print("No module specified for execution", file=sys.stderr)
|
|
else:
|
|
del sys.argv[0] # Make the requested module sys.argv[0]
|
|
_run_module_as_main(sys.argv[0])
|