grep.c: display column number of first match

To prepare for 'git grep' learning '--column', teach grep.c's
show_line() how to show the column of the first match on non-context
lines.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/grep.c b/grep.c
index c885101017f6a4505a2525fa83975d1b1e86936d..83fe32a6a08009d510c8a2e432902414be03a332 100644 (file)
--- a/grep.c
+++ b/grep.c
@@ -1405,7 +1405,7 @@ static int next_match(struct grep_opt *opt, char *bol, char *eol,
 }
 
 static void show_line(struct grep_opt *opt, char *bol, char *eol,
-                     const char *name, unsigned lno, char sign)
+                     const char *name, unsigned lno, ssize_t cno, char sign)
 {
        int rest = eol - bol;
        const char *match_color, *line_color = NULL;
@@ -1440,6 +1440,17 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
                output_color(opt, buf, strlen(buf), opt->color_lineno);
                output_sep(opt, sign);
        }
+       /*
+        * Treat 'cno' as the 1-indexed offset from the start of a non-context
+        * line to its first match. Otherwise, 'cno' is 0 indicating that we are
+        * being called with a context line.
+        */
+       if (opt->columnnum && cno) {
+               char buf[32];
+               xsnprintf(buf, sizeof(buf), "%"PRIuMAX, (uintmax_t)cno);
+               output_color(opt, buf, strlen(buf), opt->color_columnno);
+               output_sep(opt, sign);
+       }
        if (opt->color) {
                regmatch_t match;
                enum grep_context ctx = GREP_CONTEXT_BODY;
@@ -1545,7 +1556,7 @@ static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
                        break;
 
                if (match_funcname(opt, gs, bol, eol)) {
-                       show_line(opt, bol, eol, gs->name, lno, '=');
+                       show_line(opt, bol, eol, gs->name, lno, 0, '=');
                        break;
                }
        }
@@ -1610,7 +1621,7 @@ static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
 
                while (*eol != '\n')
                        eol++;
-               show_line(opt, bol, eol, gs->name, cur, sign);
+               show_line(opt, bol, eol, gs->name, cur, 0, sign);
                bol = eol + 1;
                cur++;
        }
@@ -1809,6 +1820,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
        while (left) {
                char *eol, ch;
                int hit;
+               ssize_t cno;
                ssize_t col = -1, icol = -1;
 
                /*
@@ -1874,7 +1886,18 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
                                show_pre_context(opt, gs, bol, eol, lno);
                        else if (opt->funcname)
                                show_funcname_line(opt, gs, bol, lno);
-                       show_line(opt, bol, eol, gs->name, lno, ':');
+                       cno = opt->invert ? icol : col;
+                       if (cno < 0) {
+                               /*
+                                * A negative cno indicates that there was no
+                                * match on the line. We are thus inverted and
+                                * being asked to show all lines that _don't_
+                                * match a given expression. Therefore, set cno
+                                * to 0 to suggest the whole line matches.
+                                */
+                               cno = 0;
+                       }
+                       show_line(opt, bol, eol, gs->name, lno, cno + 1, ':');
                        last_hit = lno;
                        if (opt->funcbody)
                                show_function = 1;
@@ -1903,7 +1926,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
                        /* If the last hit is within the post context,
                         * we need to show this line.
                         */
-                       show_line(opt, bol, eol, gs->name, lno, '-');
+                       show_line(opt, bol, eol, gs->name, lno, col + 1, '-');
                }
 
        next_line: