client: Add swapped, raised and lowered signals

This allow layout "arrange" to be called less often and react on
the cause of the change itself rather than it's consequences
(usually, the "focus" signal).

Previously, the layout were re-arranged everytime the focus changed.
Now, with "raised" and "lowered", it require less "arrange".

"swapped" allow smarted layouts. Currently, swapped cause a full
re-arrange. It re-read the "index" list from scratch and create
a "new" layout. With "swapped", incremental layout changes are
possible.

Fixes https://github.com/awesomeWM/awesome/issues/616

lib/awful/layout/init.lua

@@ -205,7 +205,8 @@ for s = 1, capi.screen.count() do
     end)
 end
 
-capi.client.connect_signal("focus", function(c) layout.arrange(c.screen) end)
+capi.client.connect_signal("raised", function(c) layout.arrange(c.screen) end)
+capi.client.connect_signal("lowered", function(c) layout.arrange(c.screen) end)
 capi.client.connect_signal("list", function()
                                    for screen = 1, capi.screen.count() do
                                        layout.arrange(screen)

objects/client.c

@@ -1602,6 +1602,17 @@ luaA_client_swap(lua_State *L)
         *ref_swap = c;
 
         luaA_class_emit_signal(L, &client_class, "list", 0);
+
+        luaA_object_push(L, swap);
+        lua_pushboolean(L, true);
+        luaA_object_emit_signal(L, -4, "swapped", 2);
+        lua_pop(L, 2);
+
+        luaA_object_push(L, swap);
+        luaA_object_push(L, c);
+        lua_pushboolean(L, false);
+        luaA_object_emit_signal(L, -3, "swapped", 2);
+        lua_pop(L, 3);
     }
 
     return 0;
@@ -1688,7 +1699,13 @@ static int
 luaA_client_raise(lua_State *L)
 {
     client_t *c = luaA_checkudata(L, 1, &client_class);
+
+    /* Avoid sending the signal if nothing was done */
+    if (c->transient_for == NULL && globalconf.stack.tab[globalconf.stack.len-1] == c)
+        return 0;
+
     client_raise(c);
+
     return 0;
 }
 
@@ -1701,12 +1718,21 @@ luaA_client_lower(lua_State *L)
 {
     client_t *c = luaA_checkudata(L, 1, &client_class);
 
+    /* Avoid sending the signal if nothing was done */
+    if (globalconf.stack.len && globalconf.stack.tab[0] == c)
+        return 0;
+
     stack_client_push(c);
 
     /* Traverse all transient layers. */
     for(client_t *tc = c->transient_for; tc; tc = tc->transient_for)
         stack_client_push(tc);
 
+    /* Notify the listeners */
+    luaA_object_push(L, c);
+    luaA_object_emit_signal(L, -1, "lowered", 0);
+    lua_pop(L, 1);
+
     return 0;
 }
 
@@ -2736,6 +2762,12 @@ client_class_setup(lua_State *L)
      * @signal .list
      */
     signal_add(&client_class.signals, "list");
+    /** When 2 clients are swapped
+     * @args client The other client
+     * @args is_source If self is the source or the destination of the swap
+     * @signal .swapped
+     */
+    signal_add(&client_class.signals, "swapped");
     /**
      * @signal .manage
      */
@@ -2979,6 +3011,14 @@ client_class_setup(lua_State *L)
      * @tag t The tag object.
      */
     signal_add(&client_class.signals, "untagged");
+    /**
+     * @signal .raised
+     */
+    signal_add(&client_class.signals, "raised");
+    /**
+     * @signal .lowered
+     */
+    signal_add(&client_class.signals, "lowered");
 }
 
 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

objects/client.h

@@ -208,6 +208,12 @@ client_raise(client_t *c)
 
     /* Push c on top of the stack. */
     stack_client_append(c);
+
+    /* Notify the listeners */
+    lua_State *L = globalconf_get_lua_State();
+    luaA_object_push(L, c);
+    luaA_object_emit_signal(L, -1, "raised", 0);
+    lua_pop(L, 1);
 }
 
 /** Check if a client has fixed size.