Issue #6816: expose the zipfile and directory execution mechanism to Python code via the runpy module. Also consolidated some script execution functionality in the test harness into a helper module and removed some implementation details from the runpy module documentation.

This commit is contained in:
Nick Coghlan 2009-11-15 07:30:34 +00:00
parent 51200277b2
commit 49868cb686
8 changed files with 563 additions and 241 deletions

View file

@ -11,15 +11,53 @@ importers when locating support scripts as well as when importing modules.
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_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,
@ -38,26 +76,10 @@ 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"""
# Set up the top level namespace dictionary
temp_module = imp.new_module(mod_name)
mod_globals = temp_module.__dict__
# Modify sys.argv[0] and sys.module[mod_name]
saved_argv0 = sys.argv[0]
restore_module = mod_name in sys.modules
if restore_module:
saved_module = sys.modules[mod_name]
sys.argv[0] = mod_fname
sys.modules[mod_name] = temp_module
try:
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)
finally:
sys.argv[0] = saved_argv0
if restore_module:
sys.modules[mod_name] = saved_module
else:
del sys.modules[mod_name]
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()
@ -95,10 +117,22 @@ def _get_module_details(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 _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
# This function is the actual implementation of the -m switch and direct
# execution of zipfiles and directories and is deliberately kept private.
# This avoids a repeat of the situation where 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
@ -113,18 +147,12 @@ def _run_module_as_main(mod_name, alter_argv=True):
__package__
"""
try:
mod_name, loader, code, fname = _get_module_details(mod_name)
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__.py' in %r" % sys.argv[0]
msg = "%s: %s" % (sys.executable, info)
msg = "%s: %s" % (sys.executable, str(exc))
sys.exit(msg)
pkg_name = mod_name.rpartition('.')[0]
main_globals = sys.modules["__main__"].__dict__
@ -152,6 +180,95 @@ def run_module(mod_name, init_globals=None,
fname, loader, pkg_name)
# 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 throws 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, "rU") 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>"
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)
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
pkg_name = ""
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)
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: