[titlebar] Add titlebar_client_get()

Signed-off-by: Julien Danjou <julien@danjou.info>

client.c

@@ -1131,12 +1131,11 @@ luaA_client_name_set(lua_State *L)
 static int
 luaA_client_titlebar_set(lua_State *L)
 {
-    client_t *cl, **c = luaL_checkudata(L, 1, "client");
+    client_t **c = luaL_checkudata(L, 1, "client");
     titlebar_t **t = luaL_checkudata(L, 2, "titlebar");
 
-    for(cl = globalconf.clients; cl; cl = cl->next)
-        if(cl->titlebar == *t)
-            luaL_error(L, "titlebar is already used by another client");
+    if(client_getbytitlebar(*t))
+        luaL_error(L, "titlebar is already used by another client");
 
     /* If client had a titlebar, unref it */
     if((*c)->titlebar)

titlebar.c

@@ -32,8 +32,24 @@
 
 extern awesome_t globalconf;
 
+/** Get a client by its titlebar.
+ * \param titlebar The titlebar.
+ * \return A client.
+ */
+client_t *
+client_getbytitlebar(titlebar_t *titlebar)
+{
+    client_t *c;
+
+    for(c = globalconf.clients; c; c = c->next)
+        if(c->titlebar == titlebar)
+            return c;
+
+    return NULL;
+}
+
 /** Get a client by its titlebar window.
- * \param The window.
+ * \param win The window.
  * \return A client.
  */
 client_t *
@@ -478,6 +494,22 @@ luaA_titlebar_widget_get(lua_State *L)
     return 1;
 }
 
+/** Get the client which the titlebar is attached to. That is a the same as
+ * checking if every clients's titlebar is equal to titlebar.
+ * \return A client if the titlebar is attached, nil otherwise.
+ */
+static int
+luaA_titlebar_client_get(lua_State *L)
+{
+    titlebar_t **titlebar = luaL_checkudata(L, 1, "titlebar");
+    client_t *c;
+
+    if((c = client_getbytitlebar(*titlebar)))
+        return luaA_client_userdata_new(c);
+
+    return 0;
+}
+
 /** Create a new titlebar userdata.
  * \param t The titlebar.
  */
@@ -524,6 +556,7 @@ const struct luaL_reg awesome_titlebar_meta[] =
 {
     { "widget_add", luaA_titlebar_widget_add },
     { "widget_get", luaA_titlebar_widget_get },
+    { "client_get", luaA_titlebar_client_get },
     { "__eq", luaA_titlebar_eq },
     { "__gc", luaA_titlebar_gc },
     { "__tostring", luaA_titlebar_tostring },

titlebar.h

@@ -24,6 +24,7 @@
 
 #include "structs.h"
 
+client_t * client_getbytitlebar(titlebar_t *);
 client_t * client_getbytitlebarwin(xcb_window_t);
 void titlebar_draw(client_t *);
 void titlebar_update_geometry_floating(client_t *);