[PATCH] color: allow colors to be prefixed with "reset"
From: Robert Estelle via GitGitGadget <hidden>
Date: 2021-10-26 01:03:52
Subsystem:
documentation, the rest · Maintainers:
Jonathan Corbet, Linus Torvalds
From: Robert Estelle <redacted>
"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 <redacted>
---
color: allow color specs to be prefixed by "reset"
The pseudo-attribute "reset", which was previously treated as a
standalone special color name, can now be combined with other color
properties.
This allows specification of an "entire" text style without implicitly
inheriting existing properties (colors, bold/italic/etc) nor requiring a
comprehensive clearing of each of them.
For example, "reset green" now renders \e[;32m, which is interpreted as
"default properties; then set foreground to green".
Previously, it was not possible to represent this in a single color due
to inability to clear the foreground or background (at best, they could
be overridden to a some explicit value). There is a complementary
proposed change (color: support "default" to restore fg/bg color,
https://lore.kernel.org/git/pull.1116.git.git.1635201156.gitgitgadget@gmail.com/ (local),
https://github.com/git/git/pull/1116) which introduces the "default"
color name to facilitate that, but even then, the above would still
require disabling each of the attributes explicitly: green default
no-bold no-dim no-italic no-ul no-blink no-reverse no-strike
This is useful in scenarios that the "reset" word or any of the "no-"
attribute modifiers might have been used before, e.g.
colors.diff-highlight.newReset.
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1117%2Frwe%2Freset-color-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1117/rwe/reset-color-v1
Pull-Request: https://github.com/git/git/pull/1117
Documentation/config.txt | 5 +++++
color.c | 18 +++++++++++-------
color.h | 1 +
t/t4026-color.sh | 4 ++++
4 files changed, 21 insertions(+), 7 deletions(-)
diff --git a/Documentation/config.txt b/Documentation/config.txt
index bf82766a6a2..b1423b6ce8b 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt@@ -280,6 +280,11 @@ The position of any attributes with respect to the colors be turned off by prefixing them with `no` or `no-` (e.g., `noreverse`, `no-ul`, etc). + +The pseudo-attribute `reset` resets all colors and attributes before +applying the specified coloring. For example, `reset green` will result +in a green foreground and default background without any active +attributes. ++ An empty color string produces no color effect at all. This can be used to avoid coloring specific elements without disabling color entirely. +
diff --git a/color.c b/color.c
index 64f52a4f93a..29ac83b2d6e 100644
--- a/color.c
+++ b/color.c@@ -234,6 +234,7 @@ 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 };
@@ -248,12 +249,7 @@ 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 };
@@ -270,6 +266,11 @@ 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;
@@ -295,13 +296,16 @@ 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))
diff --git a/color.h b/color.h
index 98894d6a175..684dbd3bceb 100644
--- a/color.h
+++ b/color.h@@ -6,6 +6,7 @@ struct strbuf; /* * The maximum length of ANSI color sequence we would generate: * - leading ESC '[' 2 + * - reset ';' .................1 * - attr + ';' 2 * num_attr (e.g. "1;") * - no-attr + ';' 3 * num_attr (e.g. "22;") * - fg color + ';' 17 (e.g. "38;2;255;255;255;")
diff --git a/t/t4026-color.sh b/t/t4026-color.sh
index c0b642c1ab0..5ef2ff28c48 100755
--- a/t/t4026-color.sh
+++ b/t/t4026-color.sh@@ -58,6 +58,10 @@ test_expect_success 'fg bg attr...' ' color "blue bold dim ul blink reverse" "[1;2;4;5;7;34m" ' +test_expect_success 'reset fg bg attr...' ' + color "reset blue bold dim ul blink reverse" "[;1;2;4;5;7;34m" +' + # note that nobold and nodim are the same code (22) test_expect_success 'attr negation' ' color "nobold nodim noul noblink noreverse" "[22;24;25;27m"
base-commit: 225bc32a989d7a22fa6addafd4ce7dcd04675dbf -- gitgitgadget