Hi,
On Mon, 19 Jan 2009, Junio C Hamano wrote:
> Junio C Hamano <gitster@xxxxxxxxx> writes:
>
> > Well, I would rather be in favor of something like this.
> >
> > -- >8 --
> > Subject: interpret_nth_last_branch(): avoid traversing the reflog twice
> >
> > You can have quite a many reflog entries, but you typically won't recall
> > which branch you were on after switching branches for more than several
> > times.
> >
> > Instead of reading the reflog twice, this reads the branch switching event
> > and keeps the latest 16 (which is an arbitrary limitation that should be
> > plenty) such entry, to switch back to the branch we were recently on.
> >
> > Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
> > ---
> > sha1_name.c | 48 +++++++++++++++++++++------------------------
> > t/t2012-checkout-last.sh | 44 ++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 66 insertions(+), 26 deletions(-)
> >
> > diff --git a/sha1_name.c b/sha1_name.c
> > index 9e1538e..d6622f2 100644
> > --- a/sha1_name.c
> > +++ b/sha1_name.c
> > @@ -750,19 +746,19 @@ int interpret_nth_last_branch(const char *name, struct strbuf *buf)
> > nth = strtol(name+3, &num_end, 10);
> > if (num_end != brace)
> > return -1;
> > ...
> > - if (cb.nth < nth)
> > - return 0;
> > ...
> > + if (cb.cnt < nth)
> > + return -1;
>
> This should (obviously) be "return 0".
This, together with a removal of the hard-coded limit of 16 could be
squashed with this patch:
-- snipsnap --
diff --git a/sha1_name.c b/sha1_name.c
index 2c5461e..9e5f444 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -691,11 +691,9 @@ static int get_sha1_oneline(const char *prefix, unsigned char *sha1)
return retval;
}
-#define MAX_PREVIOUS_BRANCH 16
-
struct grab_nth_branch_switch_cbdata {
- long cnt;
- struct strbuf buf[MAX_PREVIOUS_BRANCH];
+ long cnt, alloc;
+ struct strbuf *buf;
};
static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
@@ -720,7 +718,7 @@ static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
if (target[len] == '\n' && !strncmp(match, target, len))
return 0;
- nth = cb->cnt++ % MAX_PREVIOUS_BRANCH;
+ nth = cb->cnt++ % cb->alloc;
strbuf_reset(&cb->buf[nth]);
strbuf_add(&cb->buf[nth], match, len);
return 0;
@@ -753,19 +751,22 @@ int interpret_nth_last_branch(const char *name, struct strbuf *buf)
nth = strtol(name+3, &num_end, 10);
if (num_end != brace)
return -1;
- if (nth <= 0 || MAX_PREVIOUS_BRANCH < nth)
+ if (nth <= 0)
return -1;
- for (i = 0; i < MAX_PREVIOUS_BRANCH; i++)
+ cb.alloc = nth;
+ cb.buf = xmalloc(nth * sizeof(struct strbuf));
+ for (i = 0; i < nth; i++)
strbuf_init(&cb.buf[i], 20);
cb.cnt = 0;
for_each_reflog_ent("HEAD", grab_nth_branch_switch, &cb);
if (cb.cnt < nth)
- return -1;
- i = (cb.cnt + MAX_PREVIOUS_BRANCH - nth) % MAX_PREVIOUS_BRANCH;
+ return 0;
+ i = cb.cnt % nth;
strbuf_reset(buf);
strbuf_add(buf, cb.buf[i].buf, cb.buf[i].len);
- for (i = 0; i < MAX_PREVIOUS_BRANCH; i++)
+ for (i = 0; i < nth; i++)
strbuf_release(&cb.buf[i]);
+ free(cb.buf);
return brace-name+1;
}
--
1.6.1.347.g7b62749
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