ref: 834a4a1040b80e89b2a2b06fe5de199635824f0c
dir: /sys/src/cmd/python/Tools/scripts/findnocoding.py/
#!/usr/bin/env python
"""List all those Python files that require a coding directive
Usage: nocoding.py dir1 [dir2...]
"""
__author__ = "Oleg Broytmann, Georg Brandl"
import sys, os, re, getopt
# our pysource module finds Python source files
try:
    import pysource
except:
    # emulate the module with a simple os.walk
    class pysource:
        has_python_ext = looks_like_python = can_be_compiled = None
        def walk_python_files(self, paths, *args, **kwargs):
            for path in paths:
                if os.path.isfile(path):
                    yield path.endswith(".py")
                elif os.path.isdir(path):
                    for root, dirs, files in os.walk(path):
                        for filename in files:
                            if filename.endswith(".py"):
                                yield os.path.join(root, filename)
    pysource = pysource()
    print >>sys.stderr, ("The pysource module is not available; "
                         "no sophisticated Python source file search will be done.")
decl_re = re.compile(r"coding[=:]\s*([-\w.]+)")
def get_declaration(line):
    match = decl_re.search(line)
    if match:
        return match.group(1)
    return ''
def has_correct_encoding(text, codec):
    try:
        unicode(text, codec)
    except UnicodeDecodeError:
        return False
    else:
        return True
def needs_declaration(fullpath):
    try:
        infile = open(fullpath, 'rU')
    except IOError: # Oops, the file was removed - ignore it
        return None
    line1 = infile.readline()
    line2 = infile.readline()
    if get_declaration(line1) or get_declaration(line2):
        # the file does have an encoding declaration, so trust it
        infile.close()
        return False
    # check the whole file for non-ASCII characters
    rest = infile.read()
    infile.close()
    if has_correct_encoding(line1+line2+rest, "ascii"):
        return False
    return True
usage = """Usage: %s [-cd] paths...
    -c: recognize Python source files trying to compile them
    -d: debug output""" % sys.argv[0]
try:
    opts, args = getopt.getopt(sys.argv[1:], 'cd')
except getopt.error, msg:
    print >>sys.stderr, msg
    print >>sys.stderr, usage
    sys.exit(1)
is_python = pysource.looks_like_python
debug = False
for o, a in opts:
    if o == '-c':
        is_python = pysource.can_be_compiled
    elif o == '-d':
        debug = True
if not args:
    print >>sys.stderr, usage
    sys.exit(1)
for fullpath in pysource.walk_python_files(args, is_python):
    if debug:
        print "Testing for coding: %s" % fullpath
    result = needs_declaration(fullpath)
    if result:
        print fullpath