[PATCH v2 4/6] extractor: Re-add 'main' method

[Stephen Finucane]

This was removed in '3c2ee2d'. Re-add it, so it can be used by scripts
found in 'tools'. Unlike the original version, this returns error codes
if a patch is not found, and it uses argparse as optparse is deprecated.

Signed-off-by: Stephen Finucane <stephen at that.guru>
Cc: Paul Jakma <paul at jakma.org>
Cc: Tom Rini <trini at konsulko.com>
---
 patchwork/extractor.py | 53 +++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/patchwork/extractor.py b/patchwork/extractor.py
index 74fe4ab..f6c3c7d 100644
--- a/patchwork/extractor.py
+++ b/patchwork/extractor.py
@@ -21,11 +21,21 @@
 
 """Extract comments and (optional) diffs from mbox files."""
 
+import argparse
 import codecs
+import email
 import hashlib
 import re
+import sys
 
-from django.utils import six
+try:
+    # Python 2
+    text_type = unicode
+    PY2 = True
+except NameError:
+    # Python 3
+    text_type = str
+    PY2 = False
 
 HUNK_RE = re.compile(r'^\@\@ -\d+(?:,(\d+))? \+\d+(?:,(\d+))? \@\@')
 FILENAME_RE = re.compile(r'^(---|\+\+\+) (\S+)')
@@ -208,7 +218,7 @@ def find_content(mail):
         payload = part.get_payload(decode=True)
         subtype = part.get_content_subtype()
 
-        if not isinstance(payload, six.text_type):
+        if not isinstance(payload, text_type):
             charset = part.get_content_charset()
 
             # Check that we have a charset that we understand. Otherwise,
@@ -228,7 +238,7 @@ def find_content(mail):
 
             for cset in try_charsets:
                 try:
-                    payload = six.text_type(payload, cset)
+                    payload = text_type(payload, cset)
                     break
                 except UnicodeDecodeError:
                     payload = None
@@ -296,3 +306,40 @@ def hash_diff(diff):
         hash.update((line + '\n').encode('utf-8'))
 
     return hash
+
+
+def main(args):
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-p', '--patch', action='store_true',
+                        dest='print_patch', help='print parsed patch')
+    parser.add_argument('-c', '--comment', action='store_true',
+                        dest='print_comment', help='print parsed comment')
+    parser.add_argument('-#', '--hash', action='store_true',
+                        dest='print_hash', help='print patch hash')
+
+    args = parser.parse_args()
+
+    if PY2:
+        mail = email.message_from_file(sys.stdin)
+    else:
+        mail = email.message_from_binary_file(sys.stdin.buffer)
+
+    patch, comment = find_content(mail)
+
+    if args.print_hash and patch:
+        print(hash_diff(patch).hexdigest())
+        return 0
+
+    if args.print_patch and patch:
+        print(patch)
+        return 0
+
+    if args.print_comment and comment:
+        print(comment)
+        return 0
+
+    return -1
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))
-- 
2.9.3