glib-aux: add nm_strv_dup_full() helper to preserve empty strv

2 files changed, 22 insertions, 8 deletions

diff --git a/src/libnm-glib-aux/nm-shared-utils.c b/src/libnm-glib-aux/nm-shared-utils.c
index 40bb59200d..7db45e1b90 100644
--- a/src/libnm-glib-aux/nm-shared-utils.c
+++ b/src/libnm-glib-aux/nm-shared-utils.c
@@ -3580,6 +3580,9 @@ nm_strv_make_deep_copied_n(const char **strv, gsize len)
  *   the returned array must be freed with g_strfreev(). Otherwise, the
  *   strings themself are not copied. You must take care of who owns the
  *   strings yourself.
+ * @preserved_empty: affects how to handle if the strv array is empty (length 0).
+ *   If TRUE, results in a non-NULL, empty, allocated strv array. If FALSE,
+ *   returns NULL instead of an empty strv array.
  *
  * Like g_strdupv(), with two differences:
  *
@@ -3598,7 +3601,10 @@ nm_strv_make_deep_copied_n(const char **strv, gsize len)
  *   cloned or not.
  */
 char **
-_nm_strv_dup(const char *const *strv, gssize len, gboolean deep_copied)
+_nm_strv_dup_full(const char *const *strv,
+                  gssize             len,
+                  gboolean           deep_copied,
+                  gboolean           preserve_empty)
 {
     gsize  i, l;
     char **v;
@@ -3607,13 +3613,16 @@ _nm_strv_dup(const char *const *strv, gssize len, gboolean deep_copied)
         l = NM_PTRARRAY_LEN(strv);
     else
         l = len;
-    if (l == 0) {
-        /* this function never returns an empty strv array. If you
-         * need that, handle it yourself. */
+
+    if (l == 0 && !preserve_empty) {
+        /* An empty strv array is not returned (as requested by
+         * !preserved_empty). Instead, return NULL. */
         return NULL;
     }
 
-    v = g_new(char *, l + 1);
+    nm_assert(l < G_MAXSIZE);
+
+    v = g_new(char *, l + 1u);
     for (i = 0; i < l; i++) {
         if (G_UNLIKELY(!strv[i])) {
             /* NULL strings are not allowed. Clear the remainder of the array
diff --git a/src/libnm-glib-aux/nm-shared-utils.h b/src/libnm-glib-aux/nm-shared-utils.h
index 11c87bec8f..74d7b1b921 100644
--- a/src/libnm-glib-aux/nm-shared-utils.h
+++ b/src/libnm-glib-aux/nm-shared-utils.h
@@ -1863,10 +1863,15 @@ nm_strv_make_deep_copied_nonnull(const char **strv)
     return nm_strv_make_deep_copied(strv) ?: nm_strv_empty_new();
 }
 
-char **_nm_strv_dup(const char *const *strv, gssize len, gboolean deep_copied);
+char **_nm_strv_dup_full(const char *const *strv,
+                         gssize             len,
+                         gboolean           deep_copied,
+                         gboolean           preserve_empty);
 
-#define nm_strv_dup(strv, len, deep_copied) \
-    _nm_strv_dup(NM_CAST_STRV_CC(strv), (len), (deep_copied))
+#define nm_strv_dup_full(strv, len, deep_copied, preserve_empty) \
+    _nm_strv_dup_full(NM_CAST_STRV_CC(strv), (len), (deep_copied), (preserve_empty))
+
+#define nm_strv_dup(strv, len, deep_copied) nm_strv_dup_full((strv), (len), (deep_copied), FALSE)
 
 const char **_nm_strv_dup_packed(const char *const *strv, gssize len);