1 files changed, 176 insertions, 0 deletions
diff --git a/src/libnm-glib-aux/nm-ref-string.h b/src/libnm-glib-aux/nm-ref-string.h
new file mode 100644
index 00000000..df37d583
--- /dev/null
+++ b/src/libnm-glib-aux/nm-ref-string.h
@@ -0,0 +1,176 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#ifndef __NM_REF_STRING_H__
+#define __NM_REF_STRING_H__
+
+/*****************************************************************************/
+
+typedef struct _NMRefString {
+    const gsize len;
+    union {
+        struct {
+            volatile int _ref_count;
+            const char   str[];
+        };
+        struct {
+            /* This union field is only used during lookup by external string.
+             * In that case, len will be set to G_MAXSIZE, and the actual len/str values
+             * are set in _priv_lookup. */
+            gsize       l_len;
+            const char *l_str;
+        } _priv_lookup;
+    };
+} NMRefString;
+
+/*****************************************************************************/
+
+void _nm_assert_nm_ref_string(NMRefString *rstr);
+
+static inline void
+nm_assert_nm_ref_string(NMRefString *rstr)
+{
+#if NM_MORE_ASSERTS
+    _nm_assert_nm_ref_string(rstr);
+#endif
+}
+
+/*****************************************************************************/
+
+NMRefString *nm_ref_string_new_len(const char *cstr, gsize len);
+
+static inline NMRefString *
+nm_ref_string_new(const char *cstr)
+{
+    return cstr ? nm_ref_string_new_len(cstr, strlen(cstr)) : NULL;
+}
+
+/*****************************************************************************/
+
+static inline NMRefString *
+nm_ref_string_ref(NMRefString *rstr)
+{
+    if (rstr) {
+        nm_assert_nm_ref_string(rstr);
+        g_atomic_int_inc(&rstr->_ref_count);
+    }
+    return rstr;
+}
+
+void _nm_ref_string_unref_slow_path(NMRefString *rstr);
+
+static inline void
+nm_ref_string_unref(NMRefString *rstr)
+{
+    int r;
+
+    if (!rstr)
+        return;
+
+    nm_assert_nm_ref_string(rstr);
+
+    /* fast-path: first try to decrement the ref-count without bringing it
+     * to zero. */
+    r = rstr->_ref_count;
+    if (G_LIKELY(r > 1 && g_atomic_int_compare_and_exchange(&rstr->_ref_count, r, r - 1)))
+        return;
+
+    _nm_ref_string_unref_slow_path(rstr);
+}
+
+NM_AUTO_DEFINE_FCN_VOID(NMRefString *, _nm_auto_ref_string, nm_ref_string_unref);
+#define nm_auto_ref_string nm_auto(_nm_auto_ref_string)
+
+/*****************************************************************************/
+
+static inline const char *
+nm_ref_string_get_str(NMRefString *rstr)
+{
+    return rstr ? rstr->str : NULL;
+}
+
+static inline gsize
+nm_ref_string_get_len(NMRefString *rstr)
+{
+    return rstr ? rstr->len : 0u;
+}
+
+static inline gboolean
+nm_ref_string_equal(NMRefString *a, NMRefString *b)
+{
+    return a == b;
+}
+
+static inline int
+nm_ref_string_cmp(NMRefString *a, NMRefString *b)
+{
+    NM_CMP_SELF(a, b);
+
+    /* It would be cheaper to first compare by length. But this
+     * way we get a nicer, ASCIIbethical sort order. */
+    NM_CMP_DIRECT_MEMCMP(a->str, b->str, NM_MIN(a->len, b->len));
+    NM_CMP_DIRECT(a->len, b->len);
+    return nm_assert_unreachable_val(0);
+}
+
+#define NM_CMP_DIRECT_REF_STRING(a, b) NM_CMP_RETURN_DIRECT(nm_ref_string_cmp((a), (b)))
+
+static inline gboolean
+nm_ref_string_equal_str(NMRefString *rstr, const char *str)
+{
+    if (!str)
+        return (!!rstr);
+
+    if (!rstr)
+        return FALSE;
+
+    return rstr->len == strlen(str) && (rstr->str == str || memcmp(rstr->str, str, rstr->len) == 0);
+}
+
+static inline gboolean
+NM_IS_REF_STRING(NMRefString *rstr)
+{
+    if (rstr)
+        nm_assert_nm_ref_string(rstr);
+
+    /* Technically, %NULL is also a valid NMRefString (according to nm_ref_string_new(),
+     * nm_ref_string_get_str() and nm_ref_string_unref()). However, NM_IS_REF_STRING()
+     * does not think so. If callers want to allow %NULL, they need to check
+     * separately. */
+    return !!rstr;
+}
+
+static inline NMRefString *
+NM_REF_STRING_UPCAST(const char *str)
+{
+    NMRefString *rstr;
+
+    if (!str)
+        return NULL;
+
+    rstr = (gpointer) (((char *) str) - G_STRUCT_OFFSET(NMRefString, str));
+    nm_assert_nm_ref_string(rstr);
+    return rstr;
+}
+
+static inline gboolean
+nm_ref_string_reset_str(NMRefString **ptr, const char *str)
+{
+    nm_auto_ref_string NMRefString *rstr = NULL;
+    gsize                           l;
+
+    nm_assert(ptr);
+
+    if (!str)
+        return nm_clear_pointer(ptr, nm_ref_string_unref);
+
+    l = strlen(str);
+
+    if ((*ptr) && (*ptr)->len == l && ((*ptr)->str == str || memcmp((*ptr)->str, str, l) == 0))
+        return FALSE;
+
+    rstr = *ptr;
+    *ptr = nm_ref_string_new_len(str, l);
+    return TRUE;
+}
+
+#endif /* __NM_REF_STRING_H__ */