From: Bo Yang <struggleyb.nku@gmail.com>
Date: Tue, 23 Mar 2010 10:38:42 GMT
Subject: Re: GSoC draft proposal: Line-level history browser
Message-ID: <41f08ee11003230338y5cf70a13xa649e67071bc2a72@mail.gmail.com>
In-Reply-To: <m38w9jjqqd.fsf@localhost.localdomain>

Hi,

>
> Errr... how the first line in preimage differs from first line in
> postimage?  The look as if they are the same:
>
>  -       for (i = 0; i < extra_hdr_nr; i++) {
>  +       for (i = 0; i < extra_hdr.nr; i++) {
>

Maybe some space... :)
>
> The problem is when you are asking about tracking a subset of lines
> that appear in postimage of a patch.  For example if we ask for
> history of
>
>                  strbuf_addstr(&buf, extra_hdr.items[i].string);
>
> line, should we track history of
>
>          for (i = 0; i < extra_hdr.nr; i++) {
>
> line which appears in relevant diff chunk?  If not, how we should
> detect which line in preimage (if any) corresponds to given line in
> postimage?

If I understand correctly, that is as following.

@@ -1008,29 +1000,29 @@ int cmd_format_patch(int argc, const char
**argv, const char *prefix)
               add_signoff = xmemdupz(committer, endpos - committer + 1);
       }

-       for (i = 0; i < extra_hdr_nr; i++) {
-               strbuf_addstr(&buf, extra_hdr[i]);
+       for (i = 0; i < extra_hdr.nr; i++) {
+               strbuf_addstr(&buf, extra_hdr.items[i].string);
               strbuf_addch(&buf, '\n');
       }

Here, the user only ask for tracking the strbuf_addstr line. And we
find the above diff hunk. I think we can then find what the line would
be in the preimage using @@ -1008,29 +1000,29 @@.  The strbuf_addstr
is located at
1000(the postimage start line number)
+3(the context number)
+1(the number of lines '+' before this line) in the postimage,
and we can calculate its line number in the preimage by the same way
1008
+3
+1(the number of lines with '-' before this line).

How do you think about this method?

Regards!
Bo