lua: implement objecttable

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

lib/awful.lua.in

@@ -16,6 +16,7 @@ local io = io
 local math = math
 local setmetatable = setmetatable
 local table = table
+local otable = otable
 local capi =
 {
     screen = screen,
@@ -31,24 +32,6 @@ local capi =
 --- awful: AWesome Functions very UsefuL
 module("awful")
 
--- The ObjectTable class
-ObjectTable = {}
-ObjectTable.__index  = ObjectTable
---- Lookup in a table indexed by objects
-function ObjectTable.__index(self, key)
-    for k, v in pairs(self) do
-        if k == key then
-            return v
-        end
-    end
-end
-
-function ObjectTable.new()
-    local o =  {}
-    setmetatable(o, ObjectTable)
-    return o
-end
-
 -- Local variable handling theme
 local theme = {}
 
@@ -70,7 +53,7 @@ tag.history.data = {}
 tag.history.data.past = {}
 tag.history.data.current = {}
 titlebar = {}
-titlebar.data = ObjectTable.new()
+titlebar.data = otable()
 widget = {}
 widget.taglist = {}
 widget.taglist.label = {}

lua.c

@@ -436,6 +436,35 @@ luaA_fixups(lua_State *L)
     lua_pop(L, 1);
 }
 
+/** Object table.
+ * This table can use safely object as key.
+ * \param L The Lua VM state.
+ * \return The number of elements pushed on stack.
+ */
+int
+luaA_otable_index(lua_State *L)
+{
+    void **obj, **v;
+
+    if((obj = lua_touserdata(L, 2)))
+    {
+        /* begins at nil */
+        lua_pushnil(L);
+        while(lua_next(L, 1))
+        {
+            if((v = lua_touserdata(L, -2))
+               && *v == *obj)
+                return 1;
+            /* removes 'value'; keeps 'key' for next iteration */
+            lua_pop(L, 1);
+        }
+        return 0;
+    }
+    
+    lua_rawget(L, 1);
+    return 1;
+}
+
 /** Initialize the Lua VM
  */
 void
@@ -443,6 +472,16 @@ luaA_init(void)
 {
     lua_State *L;
 
+    static const struct luaL_reg otable_methods[] =
+    {
+        { "__call", luaA_otable_new },
+        { NULL, NULL }
+    };
+    static const struct luaL_reg otable_meta[] =
+    {
+        { "__index", luaA_otable_index },
+        { NULL, NULL }
+    };
     static const struct luaL_reg awesome_lib[] =
     {
         { "quit", luaA_quit },
@@ -493,6 +532,9 @@ luaA_init(void)
     /* Export keygrabber lib */
     luaL_register(L, "keygrabber", awesome_keygrabber_lib);
 
+    /* Export otable lib */
+    luaA_openlib(L, "otable", otable_methods, otable_meta);
+
     /* Export mouse */
     luaA_openlib(L, "mouse", awesome_mouse_methods, awesome_mouse_meta);
 

lua.h

@@ -220,6 +220,28 @@ luaA_dofunction(lua_State *L, luaA_function f, int nargs, int nret)
     return false;
 }
 
+int luaA_otable_index(lua_State *);
+
+/** Create a new object table with a metatable.
+ * This is useful to compare table with objects (udata) as keys.
+ * \param L The Lua stack.
+ * \return The number of elements pushed on stack.
+ */
+static inline int
+luaA_otable_new(lua_State *L)
+{
+    /* Our object */
+    lua_newtable(L);
+    /* The meta table */
+    lua_newtable(L);
+    lua_pushcfunction(L, luaA_otable_index);
+    /* Register index into the metatable */
+    lua_setfield(L, -2, "__index");
+    /* Set the meta table */
+    lua_setmetatable(L, -2);
+    return 1;
+}
+
 void luaA_init(void);
 void luaA_parserc(const char *);
 void luaA_pushpointer(lua_State *, void *, awesome_type_t);