Add awesome.register_xproperty (FS#1212)

This commits adds awesome.register_xproperty(). This allows lua code to register
arbitrary X11 properties with awesome which will then watch these properties.
Whenever such a property is changed on a client or drawin, we will emit the
xproperty::name signal.

This also adds window:get_xproperty(name) and window:set_xproperty(name, value)
which allows to mess with properties.

Signed-off-by: Uli Schlachter <psychon@znc.in>

globalconf.h

@@ -55,12 +55,14 @@ typedef struct button_t button_t;
 typedef struct widget_t widget_t;
 typedef struct client_t client_t;
 typedef struct tag tag_t;
+typedef struct xproperty xproperty_t;
 
 ARRAY_TYPE(button_t *, button)
 ARRAY_TYPE(tag_t *, tag)
 ARRAY_TYPE(screen_t, screen)
 ARRAY_TYPE(client_t *, client)
 ARRAY_TYPE(drawin_t *, drawin)
+ARRAY_TYPE(xproperty_t, xproperty)
 
 /** Main configuration structure */
 typedef struct
@@ -140,6 +142,8 @@ typedef struct
     bool need_lazy_banning;
     /** Tag list */
     tag_array_t tags;
+    /** List of registered xproperties */
+    xproperty_array_t xproperties;
 } awesome_t;
 
 extern awesome_t globalconf;

lib/wibox/init.lua.in

@@ -48,19 +48,10 @@ function wibox:set_fg(c)
     self._drawable:set_fg(c)
 end
 
---- Helper function to make wibox:buttons() work as expected
+for _, k in pairs{ "buttons", "struts", "geometry", "get_xproperty", "set_xproperty" } do
-function wibox:buttons(...)
+    wibox[k] = function(self, ...)
-    return self.drawin:buttons(...)
+        return self.drawin[k](self.drawin, ...)
     end
-
---- Helper function to make wibox:struts() work as expected
-function wibox:struts(...)
-    return self.drawin:struts(...)
-end
-
---- Helper function to make wibox:geometry() work as expected
-function wibox:geometry(...)
-    return self.drawin:geometry(...)
 end
 
 local function setup_signals(_wibox)

luaa.c

@@ -42,6 +42,7 @@
 #include "objects/drawable.h"
 #include "screen.h"
 #include "event.h"
+#include "property.h"
 #include "selection.h"
 #include "systray.h"
 #include "common/xcursor.h"
@@ -573,6 +574,7 @@ luaA_init(xdgHandle* xdg)
         { "emit_signal", luaA_awesome_emit_signal },
         { "systray", luaA_systray },
         { "load_image", luaA_load_image },
+        { "register_xproperty", luaA_register_xproperty },
         { "__index", luaA_awesome_index },
         { NULL, NULL }
     };

luadoc/awesome.lua

@@ -37,6 +37,12 @@ module("awesome")
 -- @name load_image
 -- @class function
 
+--- Register a new xproperty.
+-- @param name The name of the X11 property
+-- @param type One of "string", "number" or "boolean"
+-- @name register_xproperty
+-- @class function
+
 --- Add a global signal.
 -- @param name A string with the event name.
 -- @param func The function to call.

luadoc/client.lua

@@ -111,6 +111,17 @@ module("client")
 -- @name unmanage
 -- @class function
 
+--- Change a xproperty.
+-- @param name The name of the X11 property
+-- @param value The new value for the property
+-- @name set_xproperty
+-- @class function
+
+--- Get the value of a xproperty.
+-- @param name The name of the X11 property
+-- @name get_xproperty
+-- @class function
+
 --- Add a signal.
 -- @param name A signal name.
 -- @param func A function to call when the signal is emitted.

luadoc/drawin.lua

@@ -40,6 +40,17 @@ module("drawin")
 -- @name geometry
 -- @class function
 
+--- Change a xproperty.
+-- @param name The name of the X11 property
+-- @param value The new value for the property
+-- @name set_xproperty
+-- @class function
+
+--- Get the value of a xproperty.
+-- @param name The name of the X11 property
+-- @name get_xproperty
+-- @class function
+
 --- Add a signal.
 -- @param name A signal name.
 -- @param func A function to call when the signal is emitted.

objects/window.c

@@ -23,6 +23,7 @@
 #include "xwindow.h"
 #include "ewmh.h"
 #include "screen.h"
+#include "property.h"
 #include "objects/window.h"
 #include "common/atoms.h"
 #include "common/luaobject.h"
@@ -296,6 +297,101 @@ luaA_window_set_type(lua_State *L, window_t *w)
     return 0;
 }
 
+static xproperty_t *
+luaA_find_xproperty(lua_State *L, int idx)
+{
+    const char *name = luaL_checkstring(L, idx);
+    foreach(prop, globalconf.xproperties)
+        if (A_STREQ(prop->name, name))
+            return prop;
+    luaL_argerror(L, idx, "Unknown xproperty");
+    return NULL;
+}
+
+/** Set an xproperty.
+ * \param L The Lua VM state.
+ * \return The number of elements pushed on stack.
+ */
+static int
+luaA_window_set_xproperty(lua_State *L)
+{
+    window_t *w = luaA_checkudata(L, 1, &window_class);
+    xproperty_t *prop = luaA_find_xproperty(L, 2);
+    xcb_atom_t type;
+    uint8_t format;
+    size_t len;
+    uint32_t number;
+    const void *data;
+
+    if(lua_isnil(L, 3))
+    {
+        xcb_delete_property(globalconf.connection, w->window, prop->atom);
+    } else {
+        if(prop->type == PROP_STRING)
+        {
+            data = luaL_checklstring(L, 3, &len);
+            type = UTF8_STRING;
+            format = 8;
+        } else if(prop->type == PROP_NUMBER || prop->type == PROP_BOOLEAN)
+        {
+            if (prop->type == PROP_NUMBER)
+                number = luaL_checkinteger(L, 3);
+            else
+                number = luaA_checkboolean(L, 3);
+            data = &number;
+            len = 1;
+            type = XCB_ATOM_CARDINAL;
+            format = 32;
+        } else
+            fatal("Got an xproperty with invalid type");
+
+        xcb_change_property(globalconf.connection, XCB_PROP_MODE_REPLACE, w->window,
+                            prop->atom, type, format, len, data);
+    }
+    return 0;
+}
+
+/** Get an xproperty.
+ * \param L The Lua VM state.
+ * \return The number of elements pushed on stack.
+ */
+static int
+luaA_window_get_xproperty(lua_State *L)
+{
+    window_t *w = luaA_checkudata(L, 1, &window_class);
+    xproperty_t *prop = luaA_find_xproperty(L, 2);
+    xcb_atom_t type;
+    void *data;
+    xcb_get_property_reply_t *reply;
+
+    type = prop->type == PROP_STRING ? UTF8_STRING : XCB_ATOM_CARDINAL;
+    reply = xcb_get_property_reply(globalconf.connection,
+            xcb_get_property_unchecked(globalconf.connection, false, w->window,
+                prop->atom, type, 0, 4), NULL);
+    if(!reply)
+        return 0;
+
+    data = xcb_get_property_value(reply);
+
+    if(prop->type == PROP_STRING)
+        lua_pushlstring(L, data, reply->value_len);
+    else
+    {
+        if(reply->value_len <= 0)
+        {
+            p_delete(&reply);
+            return 0;
+        }
+        if(prop->type == PROP_NUMBER)
+            lua_pushinteger(L, *(uint32_t *) data);
+        else
+            lua_pushboolean(L, *(uint32_t *) data);
+    }
+
+    p_delete(&reply);
+    return 1;
+}
+
 /** Translate a window_type_t into the corresponding EWMH atom.
  * @param type The type to return.
  * @return The EWMH atom for this type.
@@ -360,6 +456,8 @@ window_class_setup(lua_State *L)
     {
         { "struts", luaA_window_struts },
         { "buttons", luaA_window_buttons },
+        { "set_xproperty", luaA_window_set_xproperty },
+        { "get_xproperty", luaA_window_get_xproperty },
         { NULL, NULL }
     };
 

property.c

@@ -378,12 +378,41 @@ property_handle_xrootpmap_id(uint8_t state,
     return 0;
 }
 
+/** The property notify event handler handling xproperties.
+ * \param ev The event.
+ */
+static void
+property_handle_propertynotify_xproperty(xcb_property_notify_event_t *ev)
+{
+    xproperty_t *prop;
+    xproperty_t lookup = { .atom = ev->atom };
+    buffer_t buf;
+    void *obj;
+
+    prop = xproperty_array_lookup(&globalconf.xproperties, &lookup);
+    if(!prop)
+        /* Property is not registered */
+        return;
+
+    obj = client_getbywin(ev->window);
+    if(!obj)
+        obj = drawin_getbywin(ev->window);
+    if(!obj)
+        return;
+
+    /* Get us the name of the property */
+    buffer_inita(&buf, a_strlen(prop->name) + a_strlen("xproperty::") + 1);
+    buffer_addf(&buf, "xproperty::%s", prop->name);
+
+    /* And emit the right signal */
+    luaA_object_push(globalconf.L, obj);
+    luaA_object_emit_signal(globalconf.L, -1, buf.s, 0);
+    lua_pop(globalconf.L, 1);
+    buffer_wipe(&buf);
+}
 
 /** The property notify event handler.
- * \param data Unused data.
- * \param connection The connection to the X server.
  * \param ev The event.
- * \return Status code, 0 if everything's fine.
  */
 void
 property_handle_propertynotify(xcb_property_notify_event_t *ev)
@@ -393,6 +422,8 @@ property_handle_propertynotify(xcb_property_notify_event_t *ev)
 
     globalconf.timestamp = ev->time;
 
+    property_handle_propertynotify_xproperty(ev);
+
     /* Find the correct event handler */
 #define HANDLE(atom_, cb) \
     if (ev->atom == atom_) \
@@ -436,4 +467,62 @@ property_handle_propertynotify(xcb_property_notify_event_t *ev)
     (*handler)(ev->state, ev->window);
 }
 
+/** Register a new xproperty.
+ * \param L The Lua VM state.
+ * \return The number of elements pushed on stack.
+ * \luastack
+ * \lparam The name of the X11 property
+ * \lparam One of "string", "number" or "boolean"
+ */
+int
+luaA_register_xproperty(lua_State *L)
+{
+    const char *name;
+    struct xproperty property;
+    struct xproperty *found;
+    const char *const args[] = { "string", "number", "boolean" };
+    xcb_intern_atom_reply_t *atom_r;
+    int type;
+
+    name = luaL_checkstring(L, 1);
+    type = luaL_checkoption(L, 2, NULL, args);
+    if (type == 0)
+        property.type = PROP_STRING;
+    else if (type == 1)
+        property.type = PROP_NUMBER;
+    else
+        property.type = PROP_BOOLEAN;
+
+    atom_r = xcb_intern_atom_reply(globalconf.connection,
+                                   xcb_intern_atom_unchecked(globalconf.connection, false,
+                                                             a_strlen(name), name),
+                                   NULL);
+    if(!atom_r)
+        return 0;
+
+    property.atom = atom_r->atom;
+    p_delete(&atom_r);
+
+    found = xproperty_array_lookup(&globalconf.xproperties, &property);
+    if(found)
+    {
+        /* Property already registered */
+        if(found->type != property.type)
+            return luaL_error(L, "xproperty '%s' already registered with different type", name);
+    }
+    else
+    {
+        buffer_t buf;
+        buffer_inita(&buf, a_strlen(name) + a_strlen("xproperty::") + 1);
+        buffer_addf(&buf, "xproperty::%s", name);
+
+        property.name = a_strdup(name);
+        xproperty_array_insert(&globalconf.xproperties, property);
+        signal_add(&window_class.signals, buf.s);
+        buffer_wipe(&buf);
+    }
+
+    return 0;
+}
+
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

property.h

@@ -46,6 +46,29 @@ PROPERTY(net_wm_icon);
 #undef PROPERTY
 
 void property_handle_propertynotify(xcb_property_notify_event_t *ev);
+int luaA_register_xproperty(lua_State *L);
+
+struct xproperty {
+    xcb_atom_t atom;
+    const char *name;
+    enum {
+        /* UTF8_STRING */
+        PROP_STRING,
+        /* CARDINAL */
+        PROP_NUMBER,
+        /* CARDINAL with values 0 and 1 (or "0 and != 0") */
+        PROP_BOOLEAN
+    } type;
+};
+
+static inline int
+xproperty_cmp(const void *a, const void *b)
+{
+    const xproperty_t *x = a, *y = b;
+    return x->atom - y->atom;
+}
+
+BARRAY_FUNCS(xproperty_t, xproperty, DO_NOTHING, xproperty_cmp)
 
 #endif
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80