convert: refactor code to clarify ownership of check_roundtrip_encoding

The `check_roundtrip_encoding` variable is tracked in a `const char *`
even though it may contain allocated strings at times. The result is
that those strings may be leaking because we never free them.

Refactor the code to always store allocated strings in this variable.
The default value is handled in `check_roundtrip()` now, which is the
only user of the variable.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 13 insertions, 11 deletions

diff --git a/convert.c b/convert.c
index 35b25eb3cb..03c3c528f9 100644
--- a/convert.c
+++ b/convert.c
@@ -345,30 +345,32 @@ static int check_roundtrip(const char *enc_name)
 	 * space separated encodings (eg. "UTF-16, ASCII, CP1125").
 	 * Search for the given encoding in that string.
 	 */
-	const char *found = strcasestr(check_roundtrip_encoding, enc_name);
+	const char *encoding = check_roundtrip_encoding ?
+		check_roundtrip_encoding : "SHIFT-JIS";
+	const char *found = strcasestr(encoding, enc_name);
 	const char *next;
 	int len;
 	if (!found)
 		return 0;
 	next = found + strlen(enc_name);
-	len = strlen(check_roundtrip_encoding);
+	len = strlen(encoding);
 	return (found && (
 			/*
-			 * check that the found encoding is at the
-			 * beginning of check_roundtrip_encoding or
-			 * that it is prefixed with a space or comma
+			 * Check that the found encoding is at the beginning of
+			 * encoding or that it is prefixed with a space or
+			 * comma.
 			 */
-			found == check_roundtrip_encoding || (
+			found == encoding || (
 				(isspace(found[-1]) || found[-1] == ',')
 			)
 		) && (
 			/*
-			 * check that the found encoding is at the
-			 * end of check_roundtrip_encoding or
-			 * that it is suffixed with a space or comma
+			 * Check that the found encoding is at the end of
+			 * encoding or that it is suffixed with a space
+			 * or comma.
 			 */
-			next == check_roundtrip_encoding + len || (
-				next < check_roundtrip_encoding + len &&
+			next == encoding + len || (
+				next < encoding + len &&
 				(isspace(next[0]) || next[0] == ',')
 			)
 		));