#! /opt/alt/python33/bin/python3.3
"""\
List python source files.
There are three functions to check whether a file is a Python source, listed
here with increasing complexity:
- has_python_ext() checks whether a file name ends in '.py[w]'.
- look_like_python() checks whether the file is not binary and either has
the '.py[w]' extension or the first line contains the word 'python'.
- can_be_compiled() checks whether the file can be compiled by compile().
The file also must be of appropriate size - not bigger than a megabyte.
walk_python_files() recursively lists all Python files under the given directories.
"""
__author__ = "Oleg Broytmann, Georg Brandl"
__all__ = ["has_python_ext", "looks_like_python", "can_be_compiled", "walk_python_files"]
import os, re
binary_re = re.compile(br'[\x00-\x08\x0E-\x1F\x7F]')
debug = False
def print_debug(msg):
if debug: print(msg)
def _open(fullpath):
try:
size = os.stat(fullpath).st_size
except OSError as err: # Permission denied - ignore the file
print_debug("%s: permission denied: %s" % (fullpath, err))
return None
if size > 1024*1024: # too big
print_debug("%s: the file is too big: %d bytes" % (fullpath, size))
return None
try:
return open(fullpath, "rb")
except IOError as err: # Access denied, or a special file - ignore it
print_debug("%s: access denied: %s" % (fullpath, err))
return None
def has_python_ext(fullpath):
return fullpath.endswith(".py") or fullpath.endswith(".pyw")
def looks_like_python(fullpath):
infile = _open(fullpath)
if infile is None:
return False
with infile:
line = infile.readline()
if binary_re.search(line):
# file appears to be binary
print_debug("%s: appears to be binary" % fullpath)
return False
if fullpath.endswith(".py") or fullpath.endswith(".pyw"):
return True
elif b"python" in line:
# disguised Python script (e.g. CGI)
return True
return False
def can_be_compiled(fullpath):
infile = _open(fullpath)
if infile is None:
return False
with infile:
code = infile.read()
try:
compile(code, fullpath, "exec")
except Exception as err:
print_debug("%s: cannot compile: %s" % (fullpath, err))
return False
return True
def walk_python_files(paths, is_python=looks_like_python, exclude_dirs=None):
"""\
Recursively yield all Python source files below the given paths.
paths: a list of files and/or directories to be checked.
is_python: a function that takes a file name and checks whether it is a
Python source file
exclude_dirs: a list of directory base names that should be excluded in
the search
"""
if exclude_dirs is None:
exclude_dirs=[]
for path in paths:
print_debug("testing: %s" % path)
if os.path.isfile(path):
if is_python(path):
yield path
elif os.path.isdir(path):
print_debug(" it is a directory")
for dirpath, dirnames, filenames in os.walk(path):
for exclude in exclude_dirs:
if exclude in dirnames:
dirnames.remove(exclude)
for filename in filenames:
fullpath = os.path.join(dirpath, filename)
print_debug("testing: %s" % fullpath)
if is_python(fullpath):
yield fullpath
else:
print_debug(" unknown type")
if __name__ == "__main__":
# Two simple examples/tests
for fullpath in walk_python_files(['.']):
print(fullpath)
print("----------")
for fullpath in walk_python_files(['.'], is_python=can_be_compiled):
print(fullpath)
