Stub out PGPPacket._parse_signature_packet

The first octet of each signature packet is it's version number.  That
means we can parse the first octet of the signature packet and use its
value to determine which version we're parsing.  From RFC 4880 [1]:

  The body of a version 3 Signature Packet contains:

  - One-octet version number (3).
  - ...

And in the next section [2]:

  The body of a version 4 Signature Packet contains:

  - One-octet version number (4).
  - ...

[1]: http://tools.ietf.org/search/rfc4880#section-5.2.2
[2]: http://tools.ietf.org/search/rfc4880#section-5.2.3

diff --git a/gpg-migrate.py b/gpg-migrate.py
index 7b51b724278e3b9e59dd29fd44236d1ff5d69ebb..48429b4f3ec7ac227a2d478fc0afe8905ed9ba8f 100755 (executable)
--- a/gpg-migrate.py
+++ b/gpg-migrate.py
@@ -351,6 +351,13 @@ class PGPPacket (dict):
         if key_end:
             self['secret-key-checksum'] = data[key_end:]
 
+    def _parse_signature_packet(self, data):
+        self['signature-version'] = data[0]
+        offset = 1
+        raise NotImplementedError(
+            'signature packet version {}'.format(
+                self['signature-version']))
+
     def to_bytes(self):
         pass