common: introduce struct bt_common_color_codes and function bt_common_color_get_codes

The behavior of the color functions is currently initialized at startup.
If we detect that colors should be enabled, we set the
bt_common_color_code_* variables once and for all.

The following patches will introduce string formatting functions that
optionally use color, based on a parameter with three values:

 - always: always use colors, regardless of what we detected at startup
 - never: never use colors, regardless of what we detected at startup
 - auto: use colors based on what we detected at startup

One option would be to add some color functions that take a parameter,
so you could do:

  bt_common_color_bg_cyan_opt(BT_COMMON_COLOR_WHEN_ALWAYS)
  bt_common_color_bg_cyan_opt(BT_COMMON_COLOR_WHEN_NEVER)
  bt_common_color_bg_cyan_opt(BT_COMMON_COLOR_WHEN_AUTO)

However, I find this very verbose, so not very practical.

This patch introduces a new structure type bt_common_color_codes that
holds the color codes for the current terminal, or empty strings.  It
also introduces a function bt_common_color_get_codes that accepts an
always/never/auto parameter.  It initializes a bt_common_color_codes
structure with the color codes (or empty strings) to use.

This will allow the string formatting function to conditionally use
colors without being too verbose:

  struct bt_common_color_codes codes;
  bt_common_color_get_codes(&codes, use_colors);
  printf("%sHello%s\n", codes.fg_cyan, codes.reset);

Change-Id: I887e736291e9e1fe54156a81ce4011b3906d6f3c
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/2431
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>

diff --git a/src/common/common.c b/src/common/common.c
index 86c703411497d96518dd586723844ee54f88a3d4..1a7d57cc2bb420520508336968ef155d6631b6bf 100644 (file)
--- a/src/common/common.c
+++ b/src/common/common.c
@@ -79,14 +79,107 @@ static const char *bt_common_color_code_bg_magenta = "";
 static const char *bt_common_color_code_bg_cyan = "";
 static const char *bt_common_color_code_bg_light_gray = "";
 
+/*
+ * A color codes structure always filled with the proper color codes for the
+ * terminal.
+ */
+static struct bt_common_color_codes color_codes;
+
+/*
+ * A color codes structure always filled with empty strings, for when we want no
+ * colors.
+ */
+static struct bt_common_color_codes no_color_codes = {
+       "", "", "", "", "", "", "", "", "", "",
+       "", "", "", "", "", "", "", "", "", "",
+       "", "", "", "", "",
+};
+
 static
 void __attribute__((constructor)) bt_common_color_ctor(void)
 {
-       if (bt_common_colors_supported()) {
-               const char *term_env_var;
-               const char *bright_means_bold_env_var;
-               bool bright_means_bold = true;
+       const char *term_env_var;
+       const char *bright_means_bold_env_var;
+       bool bright_means_bold = true;
+       const char *code_fg_bright_red;
+       const char *code_fg_bright_green;
+       const char *code_fg_bright_yellow;
+       const char *code_fg_bright_blue;
+       const char *code_fg_bright_magenta;
+       const char *code_fg_bright_cyan;
+       const char *code_fg_bright_light_gray;
+
+       /*
+        * Check whether or not the terminal supports having
+        * bold foreground colors which do _not_ become bright
+        * colors, that is, the lines
+        *
+        *     $ echo -e "\033[31mTHIS\n\033[1mTHAT\033[0m"
+        *
+        * have the _same_ color, but `THAT` uses a bold font.
+        *
+        * This is the case of the kitty terminal emulator.
+        *
+        * It's also possible with GNOME Terminal since 3.27.2
+        * and xfce4-terminal since 0.8.7 (and GNOME VTE since
+        * 0.51.2), but it's user-configurable. Since we don't
+        * have this configuration value here, assume it's not
+        * the case to support old versions of GNOME Terminal.
+        *
+        * Any user can set the
+        * `BABELTRACE_TERM_COLOR_BRIGHT_MEANS_BOLD` environment
+        * variable to `0` to use the bright foreground color
+        * codes instead of making the normal foreground color
+        * codes bold.
+        *
+        * Summary:
+        *
+        * With kitty or when
+        * `BABELTRACE_TERM_COLOR_BRIGHT_MEANS_BOLD` is `0`:
+        *     Output bright colors using dedicated SGR codes
+        *     90 to 97.
+        *
+        * Otherwise:
+        *     Output bright colors with bold + SGR codes 30 to
+        *     37.
+        */
+       term_env_var = getenv("TERM");
+
+       if (term_env_var && strcmp(term_env_var, "xterm-kitty") == 0) {
+               /*
+                * The kitty terminal emulator supports
+                * non-bright bold foreground colors.
+                */
+               bright_means_bold = false;
+       }
+
+       bright_means_bold_env_var =
+               getenv("BABELTRACE_TERM_COLOR_BRIGHT_MEANS_BOLD");
+
+       if (bright_means_bold_env_var) {
+               bright_means_bold =
+                       !(strcmp(bright_means_bold_env_var, "0") == 0);
+       }
 
+       if (bright_means_bold) {
+               code_fg_bright_red = BT_COMMON_COLOR_FG_BOLD_RED;
+               code_fg_bright_green = BT_COMMON_COLOR_FG_BOLD_GREEN;
+               code_fg_bright_yellow = BT_COMMON_COLOR_FG_BOLD_YELLOW;
+               code_fg_bright_blue = BT_COMMON_COLOR_FG_BOLD_BLUE;
+               code_fg_bright_magenta = BT_COMMON_COLOR_FG_BOLD_MAGENTA;
+               code_fg_bright_cyan = BT_COMMON_COLOR_FG_BOLD_CYAN;
+               code_fg_bright_light_gray = BT_COMMON_COLOR_FG_BOLD_LIGHT_GRAY;
+       } else {
+               code_fg_bright_red = BT_COMMON_COLOR_FG_BRIGHT_RED;
+               code_fg_bright_green = BT_COMMON_COLOR_FG_BRIGHT_GREEN;
+               code_fg_bright_yellow = BT_COMMON_COLOR_FG_BRIGHT_YELLOW;
+               code_fg_bright_blue = BT_COMMON_COLOR_FG_BRIGHT_BLUE;
+               code_fg_bright_magenta = BT_COMMON_COLOR_FG_BRIGHT_MAGENTA;
+               code_fg_bright_cyan = BT_COMMON_COLOR_FG_BRIGHT_CYAN;
+               code_fg_bright_light_gray = BT_COMMON_COLOR_FG_BRIGHT_LIGHT_GRAY;
+       }
+
+       if (bt_common_colors_supported()) {
                bt_common_color_code_reset = BT_COMMON_COLOR_RESET;
                bt_common_color_code_bold = BT_COMMON_COLOR_BOLD;
                bt_common_color_code_fg_default = BT_COMMON_COLOR_FG_DEFAULT;
@@ -98,76 +191,13 @@ void __attribute__((constructor)) bt_common_color_ctor(void)
                bt_common_color_code_fg_cyan = BT_COMMON_COLOR_FG_CYAN;
                bt_common_color_code_fg_light_gray = BT_COMMON_COLOR_FG_LIGHT_GRAY;
 
-               /*
-                * Check whether or not the terminal supports having
-                * bold foreground colors which do _not_ become bright
-                * colors, that is, the lines
-                *
-                *     $ echo -e "\033[31mTHIS\n\033[1mTHAT\033[0m"
-                *
-                * have the _same_ color, but `THAT` uses a bold font.
-                *
-                * This is the case of the kitty terminal emulator.
-                *
-                * It's also possible with GNOME Terminal since 3.27.2
-                * and xfce4-terminal since 0.8.7 (and GNOME VTE since
-                * 0.51.2), but it's user-configurable. Since we don't
-                * have this configuration value here, assume it's not
-                * the case to support old versions of GNOME Terminal.
-                *
-                * Any user can set the
-                * `BABELTRACE_TERM_COLOR_BRIGHT_MEANS_BOLD` environment
-                * variable to `0` to use the bright foreground color
-                * codes instead of making the normal foreground color
-                * codes bold.
-                *
-                * Summary:
-                *
-                * With kitty or when
-                * `BABELTRACE_TERM_COLOR_BRIGHT_MEANS_BOLD` is `0`:
-                *     Output bright colors using dedicated SGR codes
-                *     90 to 97.
-                *
-                * Otherwise:
-                *     Output bright colors with bold + SGR codes 30 to
-                *     37.
-                */
-               term_env_var = getenv("TERM");
-               BT_ASSERT(term_env_var);
-
-               if (strcmp(term_env_var, "xterm-kitty") == 0) {
-                       /*
-                        * The kitty terminal emulator supports
-                        * non-bright bold foreground colors.
-                        */
-                       bright_means_bold = false;
-               }
-
-               bright_means_bold_env_var =
-                       getenv("BABELTRACE_TERM_COLOR_BRIGHT_MEANS_BOLD");
-
-               if (bright_means_bold_env_var) {
-                       bright_means_bold =
-                               !(strcmp(bright_means_bold_env_var, "0") == 0);
-               }
-
-               if (bright_means_bold) {
-                       bt_common_color_code_fg_bright_red = BT_COMMON_COLOR_FG_BOLD_RED;
-                       bt_common_color_code_fg_bright_green = BT_COMMON_COLOR_FG_BOLD_GREEN;
-                       bt_common_color_code_fg_bright_yellow = BT_COMMON_COLOR_FG_BOLD_YELLOW;
-                       bt_common_color_code_fg_bright_blue = BT_COMMON_COLOR_FG_BOLD_BLUE;
-                       bt_common_color_code_fg_bright_magenta = BT_COMMON_COLOR_FG_BOLD_MAGENTA;
-                       bt_common_color_code_fg_bright_cyan = BT_COMMON_COLOR_FG_BOLD_CYAN;
-                       bt_common_color_code_fg_bright_light_gray = BT_COMMON_COLOR_FG_BOLD_LIGHT_GRAY;
-               } else {
-                       bt_common_color_code_fg_bright_red = BT_COMMON_COLOR_FG_BRIGHT_RED;
-                       bt_common_color_code_fg_bright_green = BT_COMMON_COLOR_FG_BRIGHT_GREEN;
-                       bt_common_color_code_fg_bright_yellow = BT_COMMON_COLOR_FG_BRIGHT_YELLOW;
-                       bt_common_color_code_fg_bright_blue = BT_COMMON_COLOR_FG_BRIGHT_BLUE;
-                       bt_common_color_code_fg_bright_magenta = BT_COMMON_COLOR_FG_BRIGHT_MAGENTA;
-                       bt_common_color_code_fg_bright_cyan = BT_COMMON_COLOR_FG_BRIGHT_CYAN;
-                       bt_common_color_code_fg_bright_light_gray = BT_COMMON_COLOR_FG_BRIGHT_LIGHT_GRAY;
-               }
+               bt_common_color_code_fg_bright_red = code_fg_bright_red;
+               bt_common_color_code_fg_bright_green = code_fg_bright_green;
+               bt_common_color_code_fg_bright_yellow = code_fg_bright_yellow;
+               bt_common_color_code_fg_bright_blue = code_fg_bright_blue;
+               bt_common_color_code_fg_bright_magenta = code_fg_bright_magenta;
+               bt_common_color_code_fg_bright_cyan = code_fg_bright_cyan;
+               bt_common_color_code_fg_bright_light_gray = code_fg_bright_light_gray;
 
                bt_common_color_code_bg_default = BT_COMMON_COLOR_BG_DEFAULT;
                bt_common_color_code_bg_red = BT_COMMON_COLOR_BG_RED;
@@ -178,6 +208,32 @@ void __attribute__((constructor)) bt_common_color_ctor(void)
                bt_common_color_code_bg_cyan = BT_COMMON_COLOR_BG_CYAN;
                bt_common_color_code_bg_light_gray = BT_COMMON_COLOR_BG_LIGHT_GRAY;
        }
+
+       color_codes.reset = BT_COMMON_COLOR_RESET;
+       color_codes.bold = BT_COMMON_COLOR_BOLD;
+       color_codes.fg_default = BT_COMMON_COLOR_FG_DEFAULT;
+       color_codes.fg_red = BT_COMMON_COLOR_FG_RED;
+       color_codes.fg_green = BT_COMMON_COLOR_FG_GREEN;
+       color_codes.fg_yellow = BT_COMMON_COLOR_FG_YELLOW;
+       color_codes.fg_blue = BT_COMMON_COLOR_FG_BLUE;
+       color_codes.fg_magenta = BT_COMMON_COLOR_FG_MAGENTA;
+       color_codes.fg_cyan = BT_COMMON_COLOR_FG_CYAN;
+       color_codes.fg_light_gray = BT_COMMON_COLOR_FG_LIGHT_GRAY;
+       color_codes.fg_bright_red = code_fg_bright_red;
+       color_codes.fg_bright_green = code_fg_bright_green;
+       color_codes.fg_bright_yellow = code_fg_bright_yellow;
+       color_codes.fg_bright_blue = code_fg_bright_blue;
+       color_codes.fg_bright_magenta = code_fg_bright_magenta;
+       color_codes.fg_bright_cyan = code_fg_bright_cyan;
+       color_codes.fg_bright_light_gray = code_fg_bright_light_gray;
+       color_codes.bg_default = BT_COMMON_COLOR_BG_DEFAULT;
+       color_codes.bg_red = BT_COMMON_COLOR_BG_RED;
+       color_codes.bg_green = BT_COMMON_COLOR_BG_GREEN;
+       color_codes.bg_yellow = BT_COMMON_COLOR_BG_YELLOW;
+       color_codes.bg_blue = BT_COMMON_COLOR_BG_BLUE;
+       color_codes.bg_magenta = BT_COMMON_COLOR_BG_MAGENTA;
+       color_codes.bg_cyan = BT_COMMON_COLOR_BG_CYAN;
+       color_codes.bg_light_gray = BT_COMMON_COLOR_BG_LIGHT_GRAY;
 }
 
 BT_HIDDEN
@@ -561,6 +617,25 @@ const char *bt_common_color_bg_light_gray(void)
        return bt_common_color_code_bg_light_gray;
 }
 
+BT_HIDDEN
+void bt_common_color_get_codes(struct bt_common_color_codes *codes,
+               enum bt_common_color_when use_colors)
+{
+       if (use_colors == BT_COMMON_COLOR_WHEN_ALWAYS) {
+               *codes = color_codes;
+       } else if (use_colors == BT_COMMON_COLOR_WHEN_NEVER) {
+               *codes = no_color_codes;
+       } else {
+               BT_ASSERT(use_colors == BT_COMMON_COLOR_WHEN_AUTO);
+
+               if (bt_common_colors_supported()) {
+                       *codes = color_codes;
+               } else {
+                       *codes = no_color_codes;
+               }
+       }
+}
+
 BT_HIDDEN
 GString *bt_common_string_until(const char *input, const char *escapable_chars,
                const char *end_chars, size_t *end_pos)

diff --git a/src/common/common.h b/src/common/common.h
index e931e2d10047aa188c439853bc634849ffcd4723..b5990a885395036a853288d3b7fe330f203e94bb 100644 (file)
--- a/src/common/common.h
+++ b/src/common/common.h
@@ -77,6 +77,40 @@
 #define BT_COMMON_COLOR_BG_CYAN                        "\033[46m"
 #define BT_COMMON_COLOR_BG_LIGHT_GRAY          "\033[47m"
 
+enum bt_common_color_when {
+       BT_COMMON_COLOR_WHEN_AUTO,
+       BT_COMMON_COLOR_WHEN_ALWAYS,
+       BT_COMMON_COLOR_WHEN_NEVER,
+};
+
+struct bt_common_color_codes {
+       const char *reset;
+       const char *bold;
+       const char *fg_default;
+       const char *fg_red;
+       const char *fg_green;
+       const char *fg_yellow;
+       const char *fg_blue;
+       const char *fg_magenta;
+       const char *fg_cyan;
+       const char *fg_light_gray;
+       const char *fg_bright_red;
+       const char *fg_bright_green;
+       const char *fg_bright_yellow;
+       const char *fg_bright_blue;
+       const char *fg_bright_magenta;
+       const char *fg_bright_cyan;
+       const char *fg_bright_light_gray;
+       const char *bg_default;
+       const char *bg_red;
+       const char *bg_green;
+       const char *bg_yellow;
+       const char *bg_blue;
+       const char *bg_magenta;
+       const char *bg_cyan;
+       const char *bg_light_gray;
+};
+
 struct bt_common_lttng_live_url_parts {
        GString *proto;
        GString *hostname;
@@ -199,6 +233,10 @@ const char *bt_common_color_bg_cyan(void);
 BT_HIDDEN
 const char *bt_common_color_bg_light_gray(void);
 
+BT_HIDDEN
+void bt_common_color_get_codes(struct bt_common_color_codes *codes,
+               enum bt_common_color_when use_colors);
+
 /*
  * Returns the substring from `input` to the first character found
  * in the list of characters `end_chars`, unescaping any character