color: allow colors to be prefixed with "reset"

"reset" was previously treated as a standalone special color name
representing `\e[m`. Now, it can apply to other color properties,
allowing exact specifications without implicit attribute inheritance.

For example, "reset green" now renders `\e[;32m`, which is interpreted
as "reset everything; then set foreground to green". This means the
background and other attributes are also reset to their defaults.

Previously, this was impossible to represent in a single color:
"reset" could be specified alone, or a color with attributes, but some
thing like clearing a background color were impossible.

There is a separate change that introduces the "default" color name to
assist with that, but even then, the above could only to be represented
by explicitly disabling each of the attributes:
  green default no-bold no-dim no-italic no-ul no-blink no-reverse no-strike

Signed-off-by: Robert Estelle <robertestelle@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Robert Estelle
2021-10-26 01:03:47 +00:00
committed by Junio C Hamano
parent 05f1f41c9b
commit de658515ae
4 changed files with 21 additions and 7 deletions

18
color.c
View File

@@ -255,6 +255,7 @@ int color_parse_mem(const char *value, int value_len, char *dst)
const char *ptr = value;
int len = value_len;
char *end = dst + COLOR_MAXLEN;
unsigned int has_reset = 0;
unsigned int attr = 0;
struct color fg = { COLOR_UNSPECIFIED };
struct color bg = { COLOR_UNSPECIFIED };
@@ -269,12 +270,7 @@ int color_parse_mem(const char *value, int value_len, char *dst)
return 0;
}
if (!strncasecmp(ptr, "reset", len)) {
xsnprintf(dst, end - dst, GIT_COLOR_RESET);
return 0;
}
/* [fg [bg]] [attr]... */
/* [reset] [fg [bg]] [attr]... */
while (len > 0) {
const char *word = ptr;
struct color c = { COLOR_UNSPECIFIED };
@@ -291,6 +287,11 @@ int color_parse_mem(const char *value, int value_len, char *dst)
len--;
}
if (match_word(word, wordlen, "reset")) {
has_reset = 1;
continue;
}
if (!parse_color(&c, word, wordlen)) {
if (fg.type == COLOR_UNSPECIFIED) {
fg = c;
@@ -316,13 +317,16 @@ int color_parse_mem(const char *value, int value_len, char *dst)
*dst++ = (x); \
} while(0)
if (attr || !color_empty(&fg) || !color_empty(&bg)) {
if (has_reset || attr || !color_empty(&fg) || !color_empty(&bg)) {
int sep = 0;
int i;
OUT('\033');
OUT('[');
if (has_reset)
sep++;
for (i = 0; attr; i++) {
unsigned bit = (1 << i);
if (!(attr & bit))