Tweak diff colors

This patch does:

 - always reset the color _before_ printing out the newline.

   This is actually important. You (and Johannes) didn't see it, because
   it only matters if you set the background, but if you don't do this,
   you get some random and funky behaviour if you pick a color with a
   non-default background (which still potentially has problems with tabs
   etc, but less so).

 - allow people to have a different color for the "file headers"
   (DIFF_METAINFO) and for the "fragment header" (DIFF_FRAGINFO). Also,
   make a difference between "normal color" and "reset colors"

 - default to red/green for old/new lines. That's the norm, I'd think.

 - instead of that eye-popping (and eye-ball-with-a-fondue-fork-popping)
   purple color for metadata, use bold-face for file headers, and cyan for
   the frag headers. I actually prefer the "gray background" for that, but
   it only works well in xterms, so COLOR_CYAN it is..

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff.c

@@ -26,17 +26,41 @@ int git_diff_config(const char *var, const char *value)
 }
 
 enum color_diff {
-	DIFF_PLAIN = 0,
-	DIFF_METAINFO = 1,
-	DIFF_FILE_OLD = 2,
-	DIFF_FILE_NEW = 3,
+	DIFF_RESET = 0,
+	DIFF_PLAIN = 1,
+	DIFF_METAINFO = 2,
+	DIFF_FRAGINFO = 3,
+	DIFF_FILE_OLD = 4,
+	DIFF_FILE_NEW = 5,
 };
 
+#define COLOR_NORMAL  ""
+#define COLOR_BOLD    "\033[1m"
+#define COLOR_DIM     "\033[2m"
+#define COLOR_UL      "\033[4m"
+#define COLOR_BLINK   "\033[5m"
+#define COLOR_REVERSE "\033[7m"
+#define COLOR_RESET   "\033[m"
+
+#define COLOR_BLACK   "\033[30m"
+#define COLOR_RED     "\033[31m"
+#define COLOR_GREEN   "\033[32m"
+#define COLOR_YELLOW  "\033[33m"
+#define COLOR_BLUE    "\033[34m"
+#define COLOR_MAGENTA "\033[35m"
+#define COLOR_CYAN    "\033[36m"
+#define COLOR_WHITE   "\033[37m"
+
+#define COLOR_CYANBG  "\033[46m"
+#define COLOR_GRAYBG  "\033[47m"	// Good for xterm
+
 static const char *diff_colors[] = {
-	"\033[0;0m",
-	"\033[1;35m",
-	"\033[1;31m",
-	"\033[1;34m",
+	[DIFF_RESET]    = COLOR_RESET,
+	[DIFF_PLAIN]    = COLOR_NORMAL,
+	[DIFF_METAINFO] = COLOR_BOLD,
+	[DIFF_FRAGINFO] = COLOR_CYAN,
+	[DIFF_FILE_OLD] = COLOR_RED,
+	[DIFF_FILE_NEW] = COLOR_GREEN,
 };
 
 static char *quote_one(const char *str)
@@ -196,22 +220,23 @@ struct emit_callback {
 	const char **label_path;
 };
 
-static inline void color_diff(int diff_use_color, enum color_diff ix)
+static inline const char *get_color(int diff_use_color, enum color_diff ix)
 {
 	if (diff_use_color)
-		fputs(diff_colors[ix], stdout);
+		return diff_colors[ix];
+	return "";
 }
 
 static void fn_out_consume(void *priv, char *line, unsigned long len)
 {
 	int i;
 	struct emit_callback *ecbdata = priv;
+	const char *set = get_color(ecbdata->color_diff, DIFF_METAINFO);
+	const char *reset = get_color(ecbdata->color_diff, DIFF_RESET);
 
 	if (ecbdata->label_path[0]) {
-		color_diff(ecbdata->color_diff, DIFF_METAINFO);
-		printf("--- %s\n", ecbdata->label_path[0]);
-		color_diff(ecbdata->color_diff, DIFF_METAINFO);
-		printf("+++ %s\n", ecbdata->label_path[1]);
+		printf("%s--- %s%s\n", set, ecbdata->label_path[0], reset);
+		printf("%s+++ %s%s\n", set, ecbdata->label_path[1], reset);
 		ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 	}
 
@@ -222,10 +247,10 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 		;
 	if (2 <= i && i < len && line[i] == ' ') {
 		ecbdata->nparents = i - 1;
-		color_diff(ecbdata->color_diff, DIFF_METAINFO);
+		set = get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 	}
 	else if (len < ecbdata->nparents)
-		color_diff(ecbdata->color_diff, DIFF_PLAIN);
+		set = reset;
 	else {
 		int nparents = ecbdata->nparents;
 		int color = DIFF_PLAIN;
@@ -235,10 +260,11 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 			else if (line[i] == '+')
 				color = DIFF_FILE_NEW;
 		}
-		color_diff(ecbdata->color_diff, color);
+		set = get_color(ecbdata->color_diff, color);
 	}
-	fwrite(line, len, 1, stdout);
-	color_diff(ecbdata->color_diff, DIFF_PLAIN);
+	if (len > 0 && line[len-1] == '\n')
+		len--;
+	printf("%s%.*s%s\n", set, (int) len, line, reset);
 }
 
 static char *pprint_rename(const char *a, const char *b)
@@ -589,40 +615,32 @@ static void builtin_diff(const char *name_a,
 	mmfile_t mf1, mf2;
 	const char *lbl[2];
 	char *a_one, *b_two;
+	const char *set = get_color(o->color_diff, DIFF_METAINFO);
+	const char *reset = get_color(o->color_diff, DIFF_PLAIN);
 
 	a_one = quote_two("a/", name_a);
 	b_two = quote_two("b/", name_b);
 	lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
 	lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
-	color_diff(o->color_diff, DIFF_METAINFO);
-	printf("diff --git %s %s\n", a_one, b_two);
+	printf("%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
 	if (lbl[0][0] == '/') {
 		/* /dev/null */
-		color_diff(o->color_diff, DIFF_METAINFO);
-		printf("new file mode %06o\n", two->mode);
-		if (xfrm_msg && xfrm_msg[0]) {
-			color_diff(o->color_diff, DIFF_METAINFO);
-			puts(xfrm_msg);
-		}
+		printf("%snew file mode %06o%s\n", set, two->mode, reset);
+		if (xfrm_msg && xfrm_msg[0])
+			printf("%s%s%s\n", set, xfrm_msg, reset);
 	}
 	else if (lbl[1][0] == '/') {
-		printf("deleted file mode %06o\n", one->mode);
-		if (xfrm_msg && xfrm_msg[0]) {
-			color_diff(o->color_diff, DIFF_METAINFO);
-			puts(xfrm_msg);
-		}
+		printf("%sdeleted file mode %06o%s\n", set, one->mode, reset);
+		if (xfrm_msg && xfrm_msg[0])
+			printf("%s%s%s\n", set, xfrm_msg, reset);
 	}
 	else {
 		if (one->mode != two->mode) {
-			color_diff(o->color_diff, DIFF_METAINFO);
-			printf("old mode %06o\n", one->mode);
-			color_diff(o->color_diff, DIFF_METAINFO);
-			printf("new mode %06o\n", two->mode);
-		}
-		if (xfrm_msg && xfrm_msg[0]) {
-			color_diff(o->color_diff, DIFF_METAINFO);
-			puts(xfrm_msg);
+			printf("%sold mode %06o%s\n", set, one->mode, reset);
+			printf("%snew mode %06o%s\n", set, two->mode, reset);
 		}
+		if (xfrm_msg && xfrm_msg[0])
+			printf("%s%s%s\n", set, xfrm_msg, reset);
 		/*
 		 * we do not run diff between different kind
 		 * of objects.
@@ -630,7 +648,6 @@ static void builtin_diff(const char *name_a,
 		if ((one->mode ^ two->mode) & S_IFMT)
 			goto free_ab_and_return;
 		if (complete_rewrite) {
-			color_diff(o->color_diff, DIFF_PLAIN);
 			emit_rewrite_diff(name_a, name_b, one, two);
 			goto free_ab_and_return;
 		}