Bug 871, 752: Lock down enum color_mode and change option help to match.

The numbering of document.dump.color_mode and terminal._template_.colors
is now the same regardless of compile-time options, unlike in previous
versions.  Therefore this version of ELinks may interpret a configuration
file differently from previous versions even if compiled with the same
options.  This is unfortunate but the alternatives (keeping the numbering
dependent on configuration options; defining separate options that use
the new numbering; starting the numbers from 10 or so and recognizing the
previous ones only for compatibility) seem even worse.

src/config/options.inc

@@ -641,80 +641,20 @@ static struct option_info config_options_info[] = {
 		N_("Codepage used in dump output. 'System' stands for\n"
 		"a codepage determined by a selected locale.")),
 
-	/* The #if directives cannot be inside the argument list of
-	 * the INIT_OPT_INT macro; that wouldn't be standard C.
-	 * And they especially cannot be inside the argument list of N_;
-	 * xgettext (GNU gettext-tools) 0.14.3 wouldn't support that. */
-	 /* FIXME: It's totally brainless --witekfl */
-#if defined(CONFIG_88_COLORS) && defined(CONFIG_256_COLORS) && !defined(CONFIG_TRUE_COLOR)
 	INIT_OPT_INT("document.dump", N_("Color mode"),
-		"color_mode", 0, -1, 3, -1,
+		"color_mode", 0, -1, COLOR_MODES - 1, -1,
-		N_("Color mode for dumps:\n"
-		"-1 is standard dump mode\n"
-		"0 is mono mode\n"
-		"1 is 16 color mode\n"
-		"2 is 88 color mode\n"
-		"3 is 256 color mode")),
-#elif defined(CONFIG_88_COLORS) && !defined(CONFIG_256_COLORS) && !defined(CONFIG_TRUE_COLOR)
-	INIT_OPT_INT("document.dump", N_("Color mode"),
-		"color_mode", 0, -1, 2, -1,
-		N_("Color mode for dumps:\n"
-		"-1 is standard dump mode\n"
-		"0 is mono mode\n"
-		"1 is 16 color mode\n"
-		"2 is 88 color mode")),
-#elif defined(CONFIG_256_COLORS) && !defined(CONFIG_88_COLORS) && !defined(CONFIG_TRUE_COLOR)
-	INIT_OPT_INT("document.dump", N_("Color mode"),
-		"color_mode", 0, -1, 2, -1,
-		N_("Color mode for dumps:\n"
-		"-1 is standard dump mode\n"
-		"0 is mono mode\n"
-		"1 is 16 color mode\n"
-		"2 is 256 color mode")),
-#elif !defined(CONFIG_88_COLORS) && !defined(CONFIG_256_COLORS) && !defined(CONFIG_TRUE_COLOR)
-	INIT_OPT_INT("document.dump", N_("Color mode"),
-		"color_mode", 0, -1, 1, -1,
-		N_("Color mode for dumps:\n"
-		"-1 is standard dump mode\n"
-		"0 is mono mode\n"
-		"1 is 16 color mode")),
-#elif defined(CONFIG_88_COLORS) && defined(CONFIG_256_COLORS) && defined(CONFIG_TRUE_COLOR)
-	INIT_OPT_INT("document.dump", N_("Color mode"),
-		"color_mode", 0, -1, 4, -1,
 		N_("Color mode for dumps:\n"
 		"-1 is standard dump mode\n"
 		"0 is mono mode\n"
 		"1 is 16 color mode\n"
 		"2 is 88 color mode\n"
 		"3 is 256 color mode\n"
-		"4 is true color mode")),
+		"4 is true color mode\n"
-#elif defined(CONFIG_88_COLORS) && !defined(CONFIG_256_COLORS) && defined(CONFIG_TRUE_COLOR)
+		"Some of these may have been disabled at compile time. "
-	INIT_OPT_INT("document.dump", N_("Color mode"),
+		"The Setup -> Terminal options dialog lists the modes "
-		"color_mode", 0, -1, 3, -1,
+		"supported by this executable. If you select an "
-		N_("Color mode for dumps:\n"
+		"unsupported mode, ELinks uses 16 colors.")),
-		"-1 is standard dump mode\n"
+
-		"0 is mono mode\n"
-		"1 is 16 color mode\n"
-		"2 is 88 color mode\n"
-		"3 is true color mode")),
-#elif defined(CONFIG_256_COLORS) && !defined(CONFIG_88_COLORS) && defined(CONFIG_TRUE_COLOR)
-	INIT_OPT_INT("document.dump", N_("Color mode"),
-		"color_mode", 0, -1, 3, -1,
-		N_("Color mode for dumps:\n"
-		"-1 is standard dump mode\n"
-		"0 is mono mode\n"
-		"1 is 16 color mode\n"
-		"2 is 256 color mode\n"
-		"3 is true color mode")),
-#elif !defined(CONFIG_88_COLORS) && !defined(CONFIG_256_COLORS) && defined(CONFIG_TRUE_COLOR)
-	INIT_OPT_INT("document.dump", N_("Color mode"),
-		"color_mode", 0, -1, 2, -1,
-		N_("Color mode for dumps:\n"
-		"-1 is standard dump mode\n"
-		"0 is mono mode\n"
-		"1 is 16 color mode\n"
-		"2 is true color mode")),
-#endif /* !defined(CONFIG_88_COLORS) && !defined(CONFIG_256_COLORS) */
 	INIT_OPT_STRING("document.dump", N_("Footer"),
 		"footer", 0, "",
 		N_("Footer string used in dumps. %u is substituted by URL.")),
@@ -909,12 +849,17 @@ static struct option_info config_options_info[] = {
 
 	INIT_OPT_INT("terminal._template_", N_("Color mode"),
 		"colors", 0, 0, COLOR_MODES - 1, 0,
-		N_("The color mode controls what colors are used and how they are\n"
+		N_("The color mode controls what colors are used and how they are "
 		"output to the terminal. The color modes are:\n"
 		"0 is mono mode, only 2 colors are used\n"
 		"1 is 16 color mode, uses the common ANSI colors\n"
-		"2 is 256 color mode, uses XTerm RGB codes\n"
+		"2 is 88 color mode, uses XTerm RGB codes\n"
-		"3 is true color mode, uses konsole RGB codes.")),
+		"3 is 256 color mode, uses XTerm RGB codes\n"
+		"4 is true color mode, uses konsole RGB codes.\n"
+		"Some of these may have been disabled at compile time. "
+		"The Setup -> Terminal options dialog lists the modes "
+		"supported by this executable. If you select an "
+		"unsupported mode, ELinks uses 16 colors.")),
 
 	INIT_OPT_BOOL("terminal._template_", N_("Transparency"),
 		"transparency", 0, 0,

src/terminal/color.c

@@ -161,11 +161,22 @@ static const struct color_mode_info *const color_modes[] = {
 	/* COLOR_MODE_16 */	&color_mode_16,
 #ifdef CONFIG_88_COLORS
 	/* COLOR_MODE_88 */	&color_mode_88,
+#else
+	/* COLOR_MODE_88 */	&color_mode_16,
 #endif
 #ifdef CONFIG_256_COLORS
 	/* COLOR_MODE_256 */	&color_mode_256,
+#else
+	/* COLOR_MODE_256 */	&color_mode_16,
 #endif
+	/* @set_term_color reads @color_modes[COLOR_MODE_TRUE_COLOR]
+	 * only if CONFIG_TRUE_COLOR is not defined.  */
+	/* COLOR_MODE_TRUE_COLOR */ &color_mode_16,
 };
+/* Get a compile-time error if the array has the wrong size.  */
+typedef int assert_enough_color_modes[
+	(sizeof(color_modes) / sizeof(color_modes[0]) == COLOR_MODES)
+	? 1 : -1];
 
 /* Colors values used in the foreground color table:
  *

src/terminal/color.h

@@ -40,20 +40,26 @@ enum color_flags {
 	COLOR_ENSURE_INVERTED_CONTRAST = 16,
 };
 
+/* These numbers are used in the terminal._template_.colors and
+ * document.dump.color_mode options.  They should be kept stable so
+ * that configuration files are portable between ELinks versions.
+ * Any unsupported modes should be treated as COLOR_MODE_16.
+ * (Can't fall back to COLOR_MODE_88 from COLOR_MODE_256 because
+ * the palettes are incompatible.)  */
 enum color_mode {
 	COLOR_MODE_DUMP = -1,
-	COLOR_MODE_MONO,
+	COLOR_MODE_MONO = 0,
-	COLOR_MODE_16,
+	COLOR_MODE_16 = 1,
 #ifdef CONFIG_88_COLORS
-	COLOR_MODE_88,
+	COLOR_MODE_88 = 2,
 #endif
 #ifdef CONFIG_256_COLORS
-	COLOR_MODE_256,
+	COLOR_MODE_256 = 3,
 #endif
 #ifdef CONFIG_TRUE_COLOR
-	COLOR_MODE_TRUE_COLOR,
+	COLOR_MODE_TRUE_COLOR = 4,
 #endif
-	COLOR_MODES, /* XXX: Keep last */
+	COLOR_MODES = 5, /* XXX: Keep last */
 };
 
 inline void set_term_color16(struct screen_char *schar, enum color_flags flags,