shared: add nm_utils_strv_dup_packed() util

shared/nm-glib-aux/nm-shared-utils.c

@@ -3422,6 +3422,74 @@ _nm_utils_strv_dup (const char *const*strv,
 	return v;
 }
 
+const char **
+_nm_utils_strv_dup_packed (const char *const*strv,
+                           gssize len)
+
+{
+	const char **result;
+	gsize mem_len;
+	gsize pre_len;
+	gsize len2;
+	char *sbuf;
+	gsize i;
+
+	nm_assert (len >= -1);
+
+	mem_len = 0;
+	if (G_LIKELY (len < 0)) {
+		if (   !strv
+		    || !strv[0]) {
+			/* This function never returns an empty strv array. If you need that, handle it
+			 * yourself. */
+			return NULL;
+		}
+		for (i = 0; strv[i]; i++)
+			mem_len += strlen (strv[i]);
+		len2 = i;
+	} else {
+		if (len == 0)
+			return NULL;
+		len2 = len;
+		for (i = 0; i < len; i++) {
+			if (G_LIKELY (strv[i]))
+				mem_len += strlen (strv[i]);
+		}
+	}
+	mem_len += len2;
+
+	pre_len = sizeof (const char *) * (len2 + 1u);
+
+	result = g_malloc (pre_len + mem_len);
+	sbuf = &(((char *) result)[pre_len]);
+	for (i = 0; i < len2; i++) {
+		gsize l;
+
+		if (G_UNLIKELY (!strv[i])) {
+			/* Technically there is no problem with accepting NULL strings. But that
+			 * does not really result in a strv array, and likely this only happens due
+			 * to a bug. We want to catch such bugs by asserting.
+			 *
+			 * We clear the remainder of the buffer and fail with an assertion. */
+			len2++;
+			for (; i < len2; i++)
+				result[i] = NULL;
+			g_return_val_if_reached (result);;
+		}
+
+		result[i] = sbuf;
+
+		l = strlen (strv[i]) + 1u;
+		memcpy (sbuf, strv[i], l);
+		sbuf += l;
+	}
+	result[i] = NULL;
+	nm_assert (i == len2);
+	nm_assert (sbuf == (&((const char *) result)[pre_len]) + mem_len);
+
+	return result;
+}
+
 /*****************************************************************************/
 
 gssize

shared/nm-glib-aux/nm-shared-utils.h

@@ -1533,6 +1533,11 @@ char **_nm_utils_strv_dup (const char *const*strv,
 
 #define nm_utils_strv_dup(strv, len, deep_copied) _nm_utils_strv_dup (NM_CAST_STRV_CC (strv), (len), (deep_copied))
 
+const char **_nm_utils_strv_dup_packed (const char *const*strv,
+                                        gssize len);
+
+#define nm_utils_strv_dup_packed(strv, len) _nm_utils_strv_dup_packed (NM_CAST_STRV_CC (strv), (len))
+
 /*****************************************************************************/
 
 GSList *nm_utils_g_slist_find_str (const GSList *list,

shared/nm-glib-aux/tests/test-shared-general.c

@@ -941,6 +941,51 @@ test_is_specific_hostname (void)
 
 /*****************************************************************************/
 
+static void
+test_strv_dup_packed (void)
+{
+	gs_unref_ptrarray GPtrArray *src = NULL;
+	int i_run;
+
+
+	src = g_ptr_array_new_with_free_func (g_free);
+
+	for (i_run = 0; i_run < 500; i_run++) {
+		const int strv_len = nmtst_get_rand_word_length (NULL);
+		gs_free const char **strv_cpy = NULL;
+		const char *const*strv_src;
+		int i, j;
+
+		g_ptr_array_set_size (src, 0);
+		for (i = 0; i < strv_len; i++) {
+			const int word_len = nmtst_get_rand_word_length (NULL);
+			NMStrBuf sbuf = NM_STR_BUF_INIT (0, nmtst_get_rand_bool ());
+
+			for (j = 0; j < word_len; j++)
+				nm_str_buf_append_c (&sbuf, 'a' + (nmtst_get_rand_uint32 () % 20));
+
+			g_ptr_array_add (src, nm_str_buf_finalize (&sbuf, NULL) ?: g_new0 (char, 1));
+		}
+		g_ptr_array_add (src, NULL);
+
+		strv_src = (const char *const*) src->pdata;
+		g_assert (strv_src);
+		g_assert (NM_PTRARRAY_LEN (strv_src) == strv_len);
+
+		strv_cpy = nm_utils_strv_dup_packed (strv_src,
+		                                     nmtst_get_rand_bool () ? (gssize) strv_len : (gssize) -1);
+		if (strv_len == 0)
+			g_assert (!strv_cpy);
+		else
+			g_assert (strv_cpy);
+		g_assert (NM_PTRARRAY_LEN (strv_cpy) == strv_len);
+		if (strv_cpy)
+			g_assert (_nm_utils_strv_equal ((char **) strv_cpy, (char **) strv_src));
+	}
+}
+
+/*****************************************************************************/
+
 NMTST_DEFINE ();
 
 int main (int argc, char **argv)
@@ -965,6 +1010,7 @@ int main (int argc, char **argv)
 	g_test_add_func ("/general/test_nm_utils_parse_next_line", test_nm_utils_parse_next_line);
 	g_test_add_func ("/general/test_in_strset_ascii_case", test_in_strset_ascii_case);
 	g_test_add_func ("/general/test_is_specific_hostname", test_is_specific_hostname);
+	g_test_add_func ("/general/test_strv_dup_packed", test_strv_dup_packed);
 
 	return g_test_run ();
 }