From: Jeff King <peff@peff.net>
Date: Wed, 30 Dec 2009 10:55:36 +0000 (-0500)
Subject: run-command: optimize out useless shell calls
X-Git-Tag: v1.7.0-rc0~94^2~4
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/f445644fd28d31a828731a618e9a9c79be89efd2?hp=--cc

run-command: optimize out useless shell calls

If there are no metacharacters in the program to be run, we
can just skip running the shell entirely and directly exec
the program.

The metacharacter test is pulled verbatim from
launch_editor, which already implements this optimization.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

f445644fd28d31a828731a618e9a9c79be89efd2
diff --git a/run-command.c b/run-command.c
index b2bdcfda3d..47ced570bd 100644
--- a/run-command.c
+++ b/run-command.c
@@ -28,15 +28,17 @@ static const char **prepare_shell_cmd(const char **argv)
 	if (argc < 1)
 		die("BUG: shell command is empty");
 
-	nargv[nargc++] = "sh";
-	nargv[nargc++] = "-c";
-
-	if (argc < 2)
-		nargv[nargc++] = argv[0];
-	else {
-		struct strbuf arg0 = STRBUF_INIT;
-		strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
-		nargv[nargc++] = strbuf_detach(&arg0, NULL);
+	if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
+		nargv[nargc++] = "sh";
+		nargv[nargc++] = "-c";
+
+		if (argc < 2)
+			nargv[nargc++] = argv[0];
+		else {
+			struct strbuf arg0 = STRBUF_INIT;
+			strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
+			nargv[nargc++] = strbuf_detach(&arg0, NULL);
+		}
 	}
 
 	for (argc = 0; argv[argc]; argc++)