wplua: move under modules/module-lua-scripting

It's unlikely that wplua will ever be useful outside the context
of module-lua-scripting, so let's move it to keep all the code in one place

modules/module-lua-scripting/wplua/userdata.c

@@ -0,0 +1,78 @@
+/* WirePlumber
+ *
+ * Copyright © 2020 Collabora Ltd.
+ *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "wplua.h"
+#include "private.h"
+#include <wp/wp.h>
+
+GValue *
+_wplua_pushgvalue_userdata (lua_State * L, GType type)
+{
+  GValue *v = lua_newuserdata (L, sizeof (GValue));
+  memset (v, 0, sizeof (GValue));
+  g_value_init (v, type);
+  return v;
+}
+
+gboolean
+_wplua_isgvalue_userdata (lua_State *L, int idx, GType type)
+{
+  GValue *v;
+
+  if (!lua_isuserdata (L, idx))
+    return FALSE;
+  if (lua_rawlen (L, idx) != sizeof (GValue))
+    return FALSE;
+  if (!(v = lua_touserdata (L, idx)))
+    return FALSE;
+  if (type != G_TYPE_NONE && !g_type_is_a (G_VALUE_TYPE (v), type))
+    return FALSE;
+
+  return TRUE;
+}
+
+GType
+wplua_gvalue_userdata_type (lua_State *L, int idx)
+{
+  GValue *v;
+
+  if (!lua_isuserdata (L, idx))
+    return G_TYPE_INVALID;
+  if (lua_rawlen (L, idx) != sizeof (GValue))
+    return G_TYPE_INVALID;
+  if (!(v = lua_touserdata (L, idx)))
+    return G_TYPE_INVALID;
+
+  return G_VALUE_TYPE (v);
+}
+
+int
+_wplua_gvalue_userdata___gc (lua_State *L)
+{
+  GValue *v = lua_touserdata (L, 1);
+  wp_trace_boxed (G_VALUE_TYPE (v), g_value_peek_pointer (v),
+      "collected, v=%p", v);
+  g_value_unset (v);
+  return 0;
+}
+
+int
+_wplua_gvalue_userdata___eq (lua_State *L)
+{
+  if (_wplua_isgvalue_userdata (L, 1, G_TYPE_NONE) &&
+      _wplua_isgvalue_userdata (L, 2, G_TYPE_NONE)) {
+    GValue *v1 = lua_touserdata (L, 1);
+    GValue *v2 = lua_touserdata (L, 2);
+    gpointer p1 = g_value_peek_pointer (v1);
+    gpointer p2 = g_value_peek_pointer (v2);
+    lua_pushboolean (L, (p1 == p2));
+  } else {
+    lua_pushboolean (L, FALSE);
+  }
+  return 1;
+}