perf tools: Add same_cmd_with_prefix() helper

Wrap repeated code in helper function same_cmd_with_prefix for more
clearly.
Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220906032906.21395-2-shangxiaojing@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/perf.c

@@ -99,10 +99,16 @@ struct pager_config {
 	int val;
 };
 
+static bool same_cmd_with_prefix(const char *var, struct pager_config *c,
+				  const char *header)
+{
+	return (strstarts(var, header) && !strcmp(var + strlen(header), c->cmd));
+}
+
 static int pager_command_config(const char *var, const char *value, void *data)
 {
 	struct pager_config *c = data;
-	if (strstarts(var, "pager.") && !strcmp(var + 6, c->cmd))
+	if (same_cmd_with_prefix(var, c, "pager."))
 		c->val = perf_config_bool(var, value);
 	return 0;
 }
@@ -121,9 +127,9 @@ static int check_pager_config(const char *cmd)
 static int browser_command_config(const char *var, const char *value, void *data)
 {
 	struct pager_config *c = data;
-	if (strstarts(var, "tui.") && !strcmp(var + 4, c->cmd))
+	if (same_cmd_with_prefix(var, c, "tui."))
 		c->val = perf_config_bool(var, value);
-	if (strstarts(var, "gtk.") && !strcmp(var + 4, c->cmd))
+	if (same_cmd_with_prefix(var, c, "gtk."))
 		c->val = perf_config_bool(var, value) ? 2 : 0;
 	return 0;
 }