From d9bf81509305fef3b2f561770118d4b47f5f63c7 Mon Sep 17 00:00:00 2001
From: Mike Yuan <me@yhndnzj.com>
Date: Fri, 14 Feb 2025 20:27:55 +0100
Subject: [PATCH] string-util: introduce strprepend_with_separator()

---
 src/basic/string-util.c     | 14 --------------
 src/basic/string-util.h     | 13 ++++++++++++-
 src/core/mount.c            |  9 ++-------
 src/test/test-string-util.c | 11 ++++++++++-
 4 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/src/basic/string-util.c b/src/basic/string-util.c
index d2c538cfc4b..425f9742375 100644
--- a/src/basic/string-util.c
+++ b/src/basic/string-util.c
@@ -40,20 +40,6 @@ char* first_word(const char *s, const char *word) {
         return (char*) nw;
 }
 
-char* strprepend(char **x, const char *s) {
-        assert(x);
-
-        if (isempty(s) && *x)
-                return *x;
-
-        char *p = strjoin(strempty(s), *x);
-        if (!p)
-                return NULL;
-
-        free_and_replace(*x, p);
-        return *x;
-}
-
 char* strextendn(char **x, const char *s, size_t l) {
         assert(x);
         assert(s || l == 0);
diff --git a/src/basic/string-util.h b/src/basic/string-util.h
index b715e85299d..70722d9983c 100644
--- a/src/basic/string-util.h
+++ b/src/basic/string-util.h
@@ -86,7 +86,6 @@ static inline const char* empty_or_dash_to_null(const char *p) {
 
 char* first_word(const char *s, const char *word) _pure_;
 
-char* strprepend(char **x, const char *s);
 char* strextendn(char **x, const char *s, size_t l) _nonnull_if_nonzero_(2, 3);
 
 #define strjoin(a, ...) strextend_with_separator_internal(NULL, NULL, a, __VA_ARGS__, NULL)
@@ -177,6 +176,18 @@ char* strextend_with_separator_internal(char **x, const char *separator, ...) _s
 int strextendf_with_separator(char **x, const char *separator, const char *format, ...) _printf_(3,4);
 #define strextendf(x, ...) strextendf_with_separator(x, NULL, __VA_ARGS__)
 
+#define strprepend_with_separator(x, separator, ...)                            \
+        ({                                                                      \
+                char **_p_ = ASSERT_PTR(x), *_s_;                               \
+                _s_ = strextend_with_separator_internal(NULL, (separator), __VA_ARGS__, empty_to_null(*_p_), NULL); \
+                if (_s_) {                                                      \
+                        free(*_p_);                                             \
+                        *_p_ = _s_;                                             \
+                }                                                               \
+                _s_;                                                            \
+        })
+#define strprepend(x, ...) strprepend_with_separator(x, NULL, __VA_ARGS__)
+
 char* strrep(const char *s, unsigned n);
 
 #define strrepa(s, n)                                                   \
diff --git a/src/core/mount.c b/src/core/mount.c
index 94105d9db5e..aa6a41fc0f1 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -1169,14 +1169,9 @@ static int mount_set_mount_command(Mount *m, ExecCommand *c, const MountParamete
         if (r < 0)
                 return r;
 
-        if (remount) {
-                if (isempty(opts)) {
-                        opts = strdup("remount");
-                        if (!opts)
-                                return -ENOMEM;
-                } else if (!strprepend(&opts, "remount,"))
+        if (remount)
+                if (!strprepend_with_separator(&opts, ",", "remount"))
                         return -ENOMEM;
-        }
 
         if (!isempty(opts)) {
                 r = exec_command_append(c, "-o", opts, NULL);
diff --git a/src/test/test-string-util.c b/src/test/test-string-util.c
index fb3d28ed535..fa2de0f12be 100644
--- a/src/test/test-string-util.c
+++ b/src/test/test-string-util.c
@@ -1355,7 +1355,16 @@ TEST(strprepend) {
 
         ASSERT_STREQ(strprepend(&x, "xxx"), "xxx");
         ASSERT_STREQ(strprepend(&x, "bar"), "barxxx");
-        ASSERT_STREQ(strprepend(&x, "foo"), "foobarxxx");
+        ASSERT_STREQ(strprepend(&x, "foo", "4711"), "foo4711barxxx");
+        x = mfree(x);
+
+        ASSERT_STREQ(strprepend_with_separator(&x, "...", NULL), "");
+
+        ASSERT_STREQ(strprepend_with_separator(&x, "xyz", "a", "bb", "ccc"), "axyzbbxyzccc");
+        x = mfree(x);
+
+        ASSERT_STREQ(strprepend_with_separator(&x, ",", "start", "", "1", "234"), "start,,1,234");
+        ASSERT_STREQ(strprepend_with_separator(&x, ";", "more", "5", "678"), "more;5;678;start,,1,234");
 }
 
 TEST(strlevenshtein) {
-- 
2.47.3