color: add color_parse_gently()

When parsing colors, a failed parse leads to an error message due to the
result returning error(). To allow for quiet parsing, create
color_parse_gently().

To accomplish this, convert the implementation of color_parse_mem() into
a static color_parse_mem_1() helper that adds a 'gently' parameter. The
color_parse_gently() method can then use this. Since it is a near
equivalent to color_parse(), move that method down in the file so they
can be nearby while also appearing after color_parse_mem_1().

Signed-off-by: Derrick Stolee <stolee@gmail.com>

Author: derrickstolee

color.c

@@ -223,11 +223,6 @@ static int parse_attr(const char *name, size_t len)
 	return -1;
 }
 
-int color_parse(const char *value, char *dst)
-{
-	return color_parse_mem(value, strlen(value), dst);
-}
-
 /*
  * Write the ANSI color codes for "c" to "out"; the string should
  * already have the ANSI escape code in it. "out" should have enough
@@ -264,7 +259,8 @@ static int color_empty(const struct color *c)
 	return c->type <= COLOR_NORMAL;
 }
 
-int color_parse_mem(const char *value, int value_len, char *dst)
+static int color_parse_mem_1(const char *value, int value_len,
+			     char *dst, int gently)
 {
 	const char *ptr = value;
 	int len = value_len;
@@ -365,10 +361,25 @@ int color_parse_mem(const char *value, int value_len, char *dst)
 	OUT(0);
 	return 0;
 bad:
-	return error(_("invalid color value: %.*s"), value_len, value);
+	return gently ? -1 : error(_("invalid color value: %.*s"), value_len, value);
 #undef OUT
 }
 
+int color_parse_mem(const char *value, int value_len, char *dst)
+{
+	return color_parse_mem_1(value, value_len, dst, 0);
+}
+
+int color_parse(const char *value, char *dst)
+{
+	return color_parse_mem(value, strlen(value), dst);
+}
+
+int color_parse_gently(const char *value, char *dst)
+{
+	return color_parse_mem_1(value, strlen(value), dst, 1);
+}
+
 enum git_colorbool git_config_colorbool(const char *var, const char *value)
 {
 	if (value) {

color.h

@@ -118,6 +118,7 @@ bool want_color_fd(int fd, enum git_colorbool var);
  * terminal.
  */
 int color_parse(const char *value, char *dst);
+int color_parse_gently(const char *value, char *dst);
 int color_parse_mem(const char *value, int len, char *dst);
 
 /*