convert/gnuarch: parse continuation-of revisions in gnuarch source
In GNU Arch, continuation-of was often used for:
- tagging revisions
- continue working on a project in a new archive, because arch
was scaling poorly in revision numbers (cat-logs were slow
to be parsed and scanned through)
- very similar to the previous point, fork his own branch of
a project.
Parsing this header information will allow to 'follow' new history
because it often hints at older/forked/personal revision trees.
This patch however just implements the parsing of the
continuation-of header. A followup patch will implement the proper
use of this new information.
6:755d1e0d79e9
5:9ce2ce29723a 3:a3e00c7dbf11 4:bb4475edb621
4:bb4475edb621 1:5d953a1917d1
3:a3e00c7dbf11
2:befc7d89d081
1:5d953a1917d1
0:837088b6e1d9
should work with tag/branch/node/rev
tip^: 5
default^: 5
755d1e0d79e9^: 5
6^: 5
some random lookups
6^^: 3
6^^^: 2
6^^^^: 1
6^^^^^: 0
6^^^^^^: -1
6^1: 5
6^2: abort: unknown revision '6^2'!
6^^2: 4
6^1^2: 4
6^^3: abort: unknown revision '6^^3'!
6~: abort: unknown revision '6~'!
6~1: 5
6~2: 3
6~3: 2
6~4: 1
6~5: 0
6~42: -1
6~1^2: 4
6~1^2~2: 0
with a tag "6^" pointing to rev 1
6^: 1
6^1: 5
6~1: 5
6^^: 3
with a tag "foo^bar" pointing to rev 2
foo^bar: 2
foo^bar^: abort: unknown revision 'foo^bar^'!