| 1 | """runpy.py - locating and running Python code using the module namespace
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| 2 |
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| 3 | Provides support for locating and running Python scripts using the Python
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| 4 | module namespace instead of the native filesystem.
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| 5 |
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| 6 | This allows Python code to play nicely with non-filesystem based PEP 302
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| 7 | importers when locating support scripts as well as when importing modules.
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| 8 | """
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| 9 | # Written by Nick Coghlan <ncoghlan at gmail.com>
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| 10 | # to implement PEP 338 (Executing Modules as Scripts)
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| 11 |
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| 12 | import sys
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| 13 | import imp
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| 14 | try:
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| 15 | from imp import get_loader
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| 16 | except ImportError:
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| 17 | from pkgutil import get_loader
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| 18 |
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| 19 | __all__ = [
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| 20 | "run_module",
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| 21 | ]
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| 22 |
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| 23 |
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| 24 | def _run_code(code, run_globals, init_globals,
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| 25 | mod_name, mod_fname, mod_loader):
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| 26 | """Helper for _run_module_code"""
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| 27 | if init_globals is not None:
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| 28 | run_globals.update(init_globals)
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| 29 | run_globals.update(__name__ = mod_name,
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| 30 | __file__ = mod_fname,
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| 31 | __loader__ = mod_loader)
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| 32 | exec code in run_globals
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| 33 | return run_globals
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| 34 |
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| 35 | def _run_module_code(code, init_globals=None,
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| 36 | mod_name=None, mod_fname=None,
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| 37 | mod_loader=None, alter_sys=False):
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| 38 | """Helper for run_module"""
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| 39 | # Set up the top level namespace dictionary
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| 40 | if alter_sys:
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| 41 | # Modify sys.argv[0] and sys.module[mod_name]
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| 42 | temp_module = imp.new_module(mod_name)
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| 43 | mod_globals = temp_module.__dict__
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| 44 | saved_argv0 = sys.argv[0]
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| 45 | restore_module = mod_name in sys.modules
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| 46 | if restore_module:
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| 47 | saved_module = sys.modules[mod_name]
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| 48 | sys.argv[0] = mod_fname
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| 49 | sys.modules[mod_name] = temp_module
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| 50 | try:
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| 51 | _run_code(code, mod_globals, init_globals,
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| 52 | mod_name, mod_fname, mod_loader)
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| 53 | finally:
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| 54 | sys.argv[0] = saved_argv0
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| 55 | if restore_module:
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| 56 | sys.modules[mod_name] = saved_module
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| 57 | else:
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| 58 | del sys.modules[mod_name]
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| 59 | # Copy the globals of the temporary module, as they
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| 60 | # may be cleared when the temporary module goes away
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| 61 | return mod_globals.copy()
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| 62 | else:
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| 63 | # Leave the sys module alone
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| 64 | return _run_code(code, {}, init_globals,
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| 65 | mod_name, mod_fname, mod_loader)
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| 66 |
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| 67 |
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| 68 | # This helper is needed due to a missing component in the PEP 302
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| 69 | # loader protocol (specifically, "get_filename" is non-standard)
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| 70 | def _get_filename(loader, mod_name):
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| 71 | try:
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| 72 | get_filename = loader.get_filename
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| 73 | except AttributeError:
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| 74 | return None
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| 75 | else:
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| 76 | return get_filename(mod_name)
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| 77 |
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| 78 |
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| 79 | def run_module(mod_name, init_globals=None,
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| 80 | run_name=None, alter_sys=False):
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| 81 | """Execute a module's code without importing it
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| 82 |
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| 83 | Returns the resulting top level namespace dictionary
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| 84 | """
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| 85 | loader = get_loader(mod_name)
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| 86 | if loader is None:
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| 87 | raise ImportError("No module named " + mod_name)
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| 88 | code = loader.get_code(mod_name)
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| 89 | if code is None:
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| 90 | raise ImportError("No code object available for " + mod_name)
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| 91 | filename = _get_filename(loader, mod_name)
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| 92 | if run_name is None:
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| 93 | run_name = mod_name
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| 94 | return _run_module_code(code, init_globals, run_name,
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| 95 | filename, loader, alter_sys)
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| 96 |
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| 97 |
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| 98 | if __name__ == "__main__":
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| 99 | # Run the module specified as the next command line argument
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| 100 | if len(sys.argv) < 2:
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| 101 | print >> sys.stderr, "No module specified for execution"
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| 102 | else:
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| 103 | del sys.argv[0] # Make the requested module sys.argv[0]
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| 104 | run_module(sys.argv[0], run_name="__main__", alter_sys=True)
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