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grep.c: expose {,inverted} match column in match_line() 

When calling match_line(), callers presently cannot determine the
relative offset of the match because match_line() discards the
'regmatch_t' that contains this information.

Instead, teach match_line() to take in two 'ssize_t's. Fill the first
with the offset of the match produced by the given expression. If
extended, fill the later with the offset of the match produced as if
--invert were given.

For instance, matching "--not -e x" on this line produces a columnar
offset of 0, (i.e., the whole line does not contain an x), but "--invert
--not -e -x" will fill the later ssize_t of the column containing an
"x", because this expression is semantically equivalent to "-e x".

To determine the column for the inverted and non-inverted case, do the
following:

  - If matching an atom, the non-inverted column is as given from
    match_one_pattern(), and the inverted column is unset.

  - If matching a --not, the inverted column and non-inverted column
    swap.

  - If matching an --and, or --or, the non-inverted column is the
    minimum of the two children.

Presently, the existing short-circuiting logic for AND and OR applies as
before. This will change in the following commit when we add options to
configure the --column flag. Taken together, this and the forthcoming
change will always yield the earlier column on a given line.

This patch will become useful when we later pick between the two new
results in order to display the column number of the first match on a
line with --column.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
maint
Taylor Blau 2018-06-22 10:49:35 -05:00 committed by Junio C Hamano
parent f8a0c6e799
commit 68d686e6af
1 changed files with 39 additions and 19 deletions
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58
grep.c
View File

@ -1248,11 +1248,11 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
return hit;
}

static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
enum grep_context ctx, int collect_hits)
static int match_expr_eval(struct grep_opt *opt, struct grep_expr *x, char *bol,
char *eol, enum grep_context ctx, ssize_t *col,
ssize_t *icol, int collect_hits)
{
int h = 0;
regmatch_t match;

if (!x)
die("Not a valid grep expression");
@ -1261,25 +1261,39 @@ static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
h = 1;
break;
case GREP_NODE_ATOM:
h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
{
regmatch_t tmp;
h = match_one_pattern(x->u.atom, bol, eol, ctx,
&tmp, 0);
if (h && (*col < 0 || tmp.rm_so < *col))
*col = tmp.rm_so;
}
break;
case GREP_NODE_NOT:
h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
/*
* Upon visiting a GREP_NODE_NOT, col and icol become swapped.
*/
h = !match_expr_eval(opt, x->u.unary, bol, eol, ctx, icol, col,
0);
break;
case GREP_NODE_AND:
if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
if (!match_expr_eval(opt, x->u.binary.left, bol, eol, ctx, col,
icol, 0))
return 0;
h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
h = match_expr_eval(opt, x->u.binary.right, bol, eol, ctx, col,
icol, 0);
break;
case GREP_NODE_OR:
if (!collect_hits)
return (match_expr_eval(x->u.binary.left,
bol, eol, ctx, 0) ||
match_expr_eval(x->u.binary.right,
bol, eol, ctx, 0));
h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
return (match_expr_eval(opt, x->u.binary.left, bol, eol,
ctx, col, icol, 0) ||
match_expr_eval(opt, x->u.binary.right, bol,
eol, ctx, col, icol, 0));
h = match_expr_eval(opt, x->u.binary.left, bol, eol, ctx, col,
icol, 0);
x->u.binary.left->hit |= h;
h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
h |= match_expr_eval(opt, x->u.binary.right, bol, eol, ctx, col,
icol, 1);
break;
default:
die("Unexpected node type (internal error) %d", x->node);
@ -1290,25 +1304,30 @@ static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
}

static int match_expr(struct grep_opt *opt, char *bol, char *eol,
enum grep_context ctx, int collect_hits)
enum grep_context ctx, ssize_t *col,
ssize_t *icol, int collect_hits)
{
struct grep_expr *x = opt->pattern_expression;
return match_expr_eval(x, bol, eol, ctx, collect_hits);
return match_expr_eval(opt, x, bol, eol, ctx, col, icol, collect_hits);
}

static int match_line(struct grep_opt *opt, char *bol, char *eol,
ssize_t *col, ssize_t *icol,
enum grep_context ctx, int collect_hits)
{
struct grep_pat *p;
regmatch_t match;

if (opt->extended)
return match_expr(opt, bol, eol, ctx, collect_hits);
return match_expr(opt, bol, eol, ctx, col, icol,
collect_hits);

/* we do not call with collect_hits without being extended */
for (p = opt->pattern_list; p; p = p->next) {
if (match_one_pattern(p, bol, eol, ctx, &match, 0))
regmatch_t tmp;
if (match_one_pattern(p, bol, eol, ctx, &tmp, 0)) {
*col = tmp.rm_so;
return 1;
}
}
return 0;
}
@ -1763,6 +1782,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
while (left) {
char *eol, ch;
int hit;
ssize_t col = -1, icol = -1;

/*
* look_ahead() skips quickly to the line that possibly
@ -1786,7 +1806,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
ctx = GREP_CONTEXT_BODY;

hit = match_line(opt, bol, eol, ctx, collect_hits);
hit = match_line(opt, bol, eol, &col, &icol, ctx, collect_hits);
*eol = ch;

if (collect_hits)