From d75a59a2728c1713422524f643eb2e537dbba809 Mon Sep 17 00:00:00 2001
From: Dana Jansens <danakj@orodu.net>
Date: Fri, 29 Jul 2011 16:18:53 -0400
Subject: [PATCH] make empty sets still a ObClientSet* structure and not a
 NULL.

so we can differentient between a missing set and an empty set.
---
 openbox/client_set.c | 45 ++++++++++++++++++++++----------------------
 openbox/client_set.h |  3 ++-
 2 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/openbox/client_set.c b/openbox/client_set.c
index 9f70e7cb..fd9880a3 100644
--- a/openbox/client_set.c
+++ b/openbox/client_set.c
@@ -22,13 +22,16 @@
 
 #include <glib.h>
 
-void client_destroyed(ObClient *client, ObClientSet *set);
-
 struct _ObClientSet {
     GHashTable *h;
 };
 
-static ObClientSet* empty_set(void)
+static void client_destroyed(ObClient *client, ObClientSet *set)
+{
+    g_hash_table_remove(set->h, &client->window);
+}
+
+ObClientSet* client_set_empty(void)
 {
     ObClientSet *set;
 
@@ -45,7 +48,7 @@ ObClientSet* client_set_single(void)
 
     c = event_current_target();
     if (!c) return NULL;
-    set = empty_set();
+    set = client_set_empty();
     g_hash_table_insert(set->h, &c->window, c);
     return set;
 }
@@ -57,21 +60,14 @@ ObClientSet* client_set_all(void)
     GList *it;
 
     if (!client_list) return NULL;
-    set = g_slice_new(ObClientSet);
-    set->h = g_hash_table_new(g_int_hash, g_int_equal);
+    set = client_set_empty();
     for (it = client_list; it; it = g_list_next(it)) {
         ObClient *c = it->data;
         g_hash_table_insert(set->h, &c->window, c);
     }
-    client_add_destroy_notify((ObClientCallback)client_destroyed, set);
     return set;
 }
 
-void client_destroyed(ObClient *client, ObClientSet *set)
-{
-    g_hash_table_remove(set->h, &client->window);
-}
-
 void client_set_destroy(ObClientSet *set)
 {
     client_remove_destroy_notify_data((ObClientCallback)client_destroyed, set);
@@ -90,6 +86,9 @@ static void foreach_union(gpointer k, gpointer v, gpointer u)
 */
 ObClientSet* client_set_union(ObClientSet *a, ObClientSet *b)
 {
+    g_return_val_if_fail(a != NULL, NULL);
+    g_return_val_if_fail(b != NULL, NULL);
+
     g_hash_table_foreach(b->h, foreach_union, a->h);
     client_set_destroy(b);
     return a;
@@ -106,6 +105,9 @@ static gboolean foreach_intersection(gpointer k, gpointer v, gpointer u)
 */
 ObClientSet* client_set_intersection(ObClientSet *a, ObClientSet *b)
 {
+    g_return_val_if_fail(a != NULL, NULL);
+    g_return_val_if_fail(b != NULL, NULL);
+
     g_hash_table_foreach_remove(a->h, foreach_intersection, b->h);
     client_set_destroy(b);
     return a;
@@ -120,25 +122,24 @@ static gboolean foreach_reduce(gpointer k, gpointer v, gpointer u)
 
 ObClientSet* client_set_reduce(ObClientSet *set, ObClientSetReduceFunc f)
 {
+    g_return_val_if_fail(set != NULL, NULL);
+    g_return_val_if_fail(f != NULL, NULL);
+
     g_hash_table_foreach_remove(set->h, foreach_reduce, f);
-    if (g_hash_table_size(set->h) > 0)
-        return set;
-    client_set_destroy(set);
-    return NULL;
+    return set;
 }
 
 ObClientSet* client_set_expand(ObClientSet *set, ObClientSetExpandFunc f)
 {
     GList *it;
 
+    g_return_val_if_fail(set != NULL, NULL);
+    g_return_val_if_fail(f != NULL, NULL);
+
     for (it = client_list; it; it = g_list_next(it)) {
         ObClient *c = it->data;
-        if (!set || !g_hash_table_lookup(set->h, &c->window)) {
-            if (f(c)) {
-                if (!set) set = empty_set();
-                g_hash_table_insert(set->h, &c->window, c);
-            }
-        }
+        if (!g_hash_table_lookup(set->h, &c->window) && f(c))
+            g_hash_table_insert(set->h, &c->window, c);
     }
     return set;
 }
diff --git a/openbox/client_set.h b/openbox/client_set.h
index efdf2002..96b41e74 100644
--- a/openbox/client_set.h
+++ b/openbox/client_set.h
@@ -20,12 +20,13 @@
 
 struct _ObClient;
 
-/*! A set of ObClients. An empty set is always a NULL pointer. */
 typedef struct _ObClientSet ObClientSet;
 
 typedef gboolean (*ObClientSetReduceFunc)(struct _ObClient *c);
 typedef gboolean (*ObClientSetExpandFunc)(struct _ObClient *c);
 
+/*! Returns a new set of clients without anything in it. */
+ObClientSet* client_set_empty(void);
 /*! Returns a new set of clients with a single client in it.
   The client is the currently targeted window. */
 ObClientSet* client_set_single(void);
-- 
2.34.1