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pickaxe -G: terminate early on matching lines 

Solve a long-standing item for "git log -Grx" of us e.g. finding "+
str" in the diff context and noting that we had a "hit", but xdiff
diligently continuing to generate and spew the rest of the diff at
us. This makes use of a new "early return" xdiff interface added by
preceding commits.

The TODO item (or, the NEEDSWORK comment) has been there since "git
log -G" was implemented. See f506b8e8b5 (git log/diff: add -G<regexp>
that greps in the patch text, 2010-08-23).

But now with the support added in the preceding changes to the
xdiff-interface we can return early. Let's assert the behavior of that
new early-return xdiff-interface by having a BUG() call here to die if
it ever starts handing us needless work again.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
maint
Ævar Arnfjörð Bjarmason 2021-04-12 19:15:26 +02:00 committed by Junio C Hamano
parent 9e20442298
commit fa59e7beb2
2 changed files with 23 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
diffcore-pickaxe.c
View File

@ -27,13 +27,12 @@ static int diffgrep_consume(void *priv, char *line, unsigned long len)
if (line[0] != '+' && line[0] != '-')
return 0;
if (data->hit)
/*
* NEEDSWORK: we should have a way to terminate the
* caller early.
*/
return 0;
data->hit = !regexec_buf(data->regexp, line + 1, len - 1, 1,
&regmatch, 0);
BUG("Already matched in diffgrep_consume! Broken xdiff_emit_line_fn?");
if (!regexec_buf(data->regexp, line + 1, len - 1, 1,
&regmatch, 0)) {
data->hit = 1;
return 1;
}
return 0;
}

@ -45,6 +44,7 @@ static int diff_grep(mmfile_t *one, mmfile_t *two,
struct diffgrep_cb ecbdata;
xpparam_t xpp;
xdemitconf_t xecfg;
int ret;

if (!one)
return !regexec_buf(regexp, two->ptr, two->size,
@ -63,10 +63,18 @@ static int diff_grep(mmfile_t *one, mmfile_t *two,
ecbdata.hit = 0;
xecfg.ctxlen = o->context;
xecfg.interhunkctxlen = o->interhunkcontext;
if (xdi_diff_outf(one, two, discard_hunk_line, diffgrep_consume,
&ecbdata, &xpp, &xecfg))
return 0;
return ecbdata.hit;

/*
* An xdiff error might be our "data->hit" from above. See the
* comment for xdiff_emit_line_fn in xdiff-interface.h
*/
ret = xdi_diff_outf(one, two, discard_hunk_line, diffgrep_consume,
&ecbdata, &xpp, &xecfg);
if (ecbdata.hit)
return 1;
if (ret)
return ret;
return 0;
}

static unsigned int contains(mmfile_t *mf, regex_t *regexp, kwset_t kws,

4
xdiff-interface.h
View File

@ -27,6 +27,10 @@
* doing so will currently make your early return indistinguishable
* from an error internal to xdiff, xdiff itself will see that
* non-zero return and translate it to -1.
*
* See "diff_grep" in diffcore-pickaxe.c for a trick to work around
* this, i.e. using the "consume_callback_data" to note the desired
* early return.
*/
typedef int (*xdiff_emit_line_fn)(void *, char *, unsigned long);
typedef void (*xdiff_emit_hunk_fn)(void *data,