selection_acquire: Also emit release when X11 selection is lost

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

event.c

@@ -25,6 +25,7 @@
 #include "objects/tag.h"
 #include "objects/selection_getter.h"
 #include "objects/drawin.h"
+#include "objects/selection_acquire.h"
 #include "objects/selection_watcher.h"
 #include "xwindow.h"
 #include "ewmh.h"
@@ -1013,7 +1014,8 @@ event_handle_selectionclear(xcb_selection_clear_event_t *ev)
     {
         warn("Lost WM_Sn selection, exiting...");
         g_main_loop_quit(globalconf.loop);
-    }
+    } else
+        selection_handle_selectionclear(ev);
 }
 
 /** \brief awesome xerror function.

objects/selection_acquire.c

@@ -28,17 +28,85 @@
 typedef struct selection_acquire_t
 {
     LUA_OBJECT_HEADER
+    /** The selection that is being owned. */
+    xcb_atom_t selection;
     /** Window used for owning the selection. */
     xcb_window_t window;
     /** Timestamp used for acquiring the selection. */
     xcb_timestamp_t timestamp;
-    /** Reference in the special table to this object. */
-    int ref;
 } selection_acquire_t;
 
 static lua_class_t selection_acquire_class;
 LUA_OBJECT_FUNCS(selection_acquire_class, selection_acquire_t, selection_acquire)
 
+static void
+luaA_pushatom(lua_State *L, xcb_atom_t atom)
+{
+    lua_pushnumber(L, atom);
+}
+
+static int
+selection_acquire_find_by_window(lua_State *L, xcb_window_t window)
+{
+    /* Iterate over all active selection acquire objects */
+    lua_pushliteral(L, REGISTRY_ACQUIRE_TABLE_INDEX);
+    lua_rawget(L, LUA_REGISTRYINDEX);
+    lua_pushnil(L);
+    while (lua_next(L, -2) != 0) {
+        if (lua_type(L, -1) == LUA_TUSERDATA) {
+            selection_acquire_t *selection = lua_touserdata(L, -1);
+            if (selection->window == window)
+            {
+                /* Remove table and key */
+                lua_remove(L, -2);
+                lua_remove(L, -2);
+                return 1;
+            }
+        }
+        /* Remove the value, leaving only the key */
+        lua_pop(L, 1);
+    }
+    /* Remove the table */
+    lua_pop(L, 1);
+
+    return 0;
+}
+
+static void
+selection_release(lua_State *L, int ud)
+{
+    selection_acquire_t *selection = luaA_checkudata(L, ud, &selection_acquire_class);
+
+    luaA_object_emit_signal(L, ud, "release", 0);
+
+    /* Destroy the window, this also releases the selection in X11 */
+    xcb_destroy_window(globalconf.connection, selection->window);
+    selection->window = XCB_NONE;
+
+    /* Unreference the object, it's now dead */
+    lua_pushliteral(L, REGISTRY_ACQUIRE_TABLE_INDEX);
+    lua_rawget(L, LUA_REGISTRYINDEX);
+    luaA_pushatom(L, selection->selection);
+    lua_pushnil(L);
+    lua_rawset(L, -3);
+
+    selection->selection = XCB_NONE;
+
+    lua_pop(L, 1);
+}
+
+void
+selection_handle_selectionclear(xcb_selection_clear_event_t *ev)
+{
+    lua_State *L = globalconf_get_lua_State();
+
+    if (selection_acquire_find_by_window(L, ev->owner) == 0)
+        return;
+
+    selection_release(L, -1);
+    lua_pop(L, 1);
+}
+
 static int
 luaA_selection_acquire_new(lua_State *L)
 {
@@ -51,13 +119,6 @@ luaA_selection_acquire_new(lua_State *L)
 
     name = luaL_checklstring(L, 2, &name_length);
 
-    /* Create a selection object */
-    selection = (void *) selection_acquire_class.allocator(L);
-    selection->window = xcb_generate_id(globalconf.connection);
-    xcb_create_window(globalconf.connection, globalconf.screen->root_depth,
-            selection->window, globalconf.screen->root, -1, -1, 1, 1, 0,
-            XCB_COPY_FROM_PARENT, globalconf.screen->root_visual, 0, NULL);
-
     /* Get the atom identifying the selection */
     reply = xcb_intern_atom_reply(globalconf.connection,
             xcb_intern_atom_unchecked(globalconf.connection, false, name_length, name),
@@ -65,8 +126,16 @@ luaA_selection_acquire_new(lua_State *L)
     name_atom = reply ? reply->atom : XCB_NONE;
     p_delete(&reply);
 
-    /* Try to acquire the selection */
+    /* Create a selection object */
+    selection = (void *) selection_acquire_class.allocator(L);
+    selection->selection = name_atom;
     selection->timestamp = globalconf.timestamp;
+    selection->window = xcb_generate_id(globalconf.connection);
+    xcb_create_window(globalconf.connection, globalconf.screen->root_depth,
+            selection->window, globalconf.screen->root, -1, -1, 1, 1, 0,
+            XCB_COPY_FROM_PARENT, globalconf.screen->root_visual, 0, NULL);
+
+    /* Try to acquire the selection */
     xcb_set_selection_owner(globalconf.connection, selection->window, name_atom, selection->timestamp);
     selection_reply = xcb_get_selection_owner_reply(globalconf.connection,
             xcb_get_selection_owner(globalconf.connection, name_atom),
@@ -80,12 +149,24 @@ luaA_selection_acquire_new(lua_State *L)
         return 0;
     }
 
-    /* Everything worked, register the object in table */
+    /* Everything worked, register the object in the table */
     lua_pushliteral(L, REGISTRY_ACQUIRE_TABLE_INDEX);
     lua_rawget(L, LUA_REGISTRYINDEX);
-    lua_pushvalue(L, -2);
-    selection->ref = luaL_ref(L, -2);
-    lua_pop(L, 1);
+
+    luaA_pushatom(L, name_atom);
+    lua_rawget(L, -2);
+    if (!lua_isnil(L, -1)) {
+        /* There is already another selection_acquire object for this selection,
+         * release it now. X11 does not send us SelectionClear events for our
+         * own changes to the selection.
+         */
+        selection_release(L, -1);
+    }
+
+    luaA_pushatom(L, name_atom);
+    lua_pushvalue(L, -4);
+    lua_rawset(L, -4);
+    lua_pop(L, 2);
 
     return 1;
 }
@@ -93,18 +174,8 @@ luaA_selection_acquire_new(lua_State *L)
 static int
 luaA_selection_acquire_release(lua_State *L)
 {
-    selection_acquire_t *selection = luaA_checkudata(L, 1, &selection_acquire_class);
-
-    xcb_destroy_window(globalconf.connection, selection->window);
-    selection->window = XCB_NONE;
-
-    /* Unreference the object, it's now dead */
-    lua_pushliteral(L, REGISTRY_ACQUIRE_TABLE_INDEX);
-    lua_rawget(L, LUA_REGISTRYINDEX);
-    luaL_unref(L, -1, selection->ref);
-    lua_pop(L, 1);
-
-    selection->ref = LUA_NOREF;
+    luaA_checkudata(L, 1, &selection_acquire_class);
+    selection_release(L, 1);
 
     return 0;
 }
@@ -112,7 +183,7 @@ luaA_selection_acquire_release(lua_State *L)
 static bool
 selection_acquire_checker(selection_acquire_t *selection)
 {
-    return selection->window != XCB_NONE;
+    return selection->selection != XCB_NONE;
 }
 
 void

objects/selection_acquire.h

@@ -23,8 +23,10 @@
 #define AWESOME_OBJECTS_SELECTION_ACQUIRE_H
 
 #include <lua.h>
+#include <xcb/xcb.h>
 
 void selection_acquire_class_setup(lua_State*);
+void selection_handle_selectionclear(xcb_selection_clear_event_t*);
 
 #endif