pager.c: replace git_config() with git_config_get_value()

Use `git_config_get_value()` instead of `git_config()` to take advantage of
the config-set API which provides a cleaner control flow.

Signed-off-by: Tanay Abhra <tanayabh@gmail.com>
Reviewed-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pager.c

@@ -6,12 +6,6 @@
 #define DEFAULT_PAGER "less"
 #endif
 
-struct pager_config {
-	const char *cmd;
-	int want;
-	char *value;
-};
-
 /*
  * This is split up from the rest of git so that we can do
  * something different on Windows.
@@ -155,30 +149,22 @@ int decimal_width(int number)
 	return width;
 }
 
-static int pager_command_config(const char *var, const char *value, void *data)
+/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
+int check_pager_config(const char *cmd)
 {
-	struct pager_config *c = data;
-	if (starts_with(var, "pager.") && !strcmp(var + 6, c->cmd)) {
-		int b = git_config_maybe_bool(var, value);
+	int want = -1;
+	struct strbuf key = STRBUF_INIT;
+	const char *value = NULL;
+	strbuf_addf(&key, "pager.%s", cmd);
+	if (!git_config_get_value(key.buf, &value)) {
+		int b = git_config_maybe_bool(key.buf, value);
 		if (b >= 0)
-			c->want = b;
+			want = b;
 		else {
-			c->want = 1;
-			c->value = xstrdup(value);
+			want = 1;
+			pager_program = xstrdup(value);
 		}
 	}
-	return 0;
-}
-
-/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
-int check_pager_config(const char *cmd)
-{
-	struct pager_config c;
-	c.cmd = cmd;
-	c.want = -1;
-	c.value = NULL;
-	git_config(pager_command_config, &c);
-	if (c.value)
-		pager_program = c.value;
-	return c.want;
+	strbuf_release(&key);
+	return want;
 }