improves slist implementation (#29)

lib/webfuse/adapter/impl/session.c

@@ -65,7 +65,7 @@ struct wf_impl_session * wf_impl_session_create(
 static void wf_impl_session_dispose_filesystems(
     struct wf_slist * filesystems)
 {    
-    struct wf_slist_item * item = filesystems->first;
+    struct wf_slist_item * item = wf_slist_first(filesystems);
     while (NULL != item)
     {
         struct wf_slist_item * next = item->next;
@@ -156,11 +156,11 @@ static struct wf_impl_filesystem * wf_impl_session_get_filesystem(
 {
     struct wf_impl_filesystem * result = NULL;
 
-    struct wf_slist_item * item = session->filesystems.first;
+    struct wf_slist_item * item = wf_slist_first(&session->filesystems);
     while (NULL != item)
     {
         struct wf_slist_item * next = item->next;
-        struct wf_impl_filesystem * filesystem = wf_container_of(session->filesystems.first, struct wf_impl_filesystem, item);
+        struct wf_impl_filesystem * filesystem = wf_container_of(item, struct wf_impl_filesystem, item);
         if (wsi == filesystem->wsi)
         {
             result = filesystem;

lib/webfuse/adapter/impl/session_manager.c

@@ -12,7 +12,7 @@ void wf_impl_session_manager_init(
 void wf_impl_session_manager_cleanup(
     struct wf_impl_session_manager * manager)
 {
-    struct wf_slist_item * item = manager->sessions.first;
+    struct wf_slist_item * item = wf_slist_first(&manager->sessions);
     while (NULL != item)
     {
         struct wf_slist_item * next = item->next;
@@ -47,7 +47,7 @@ struct wf_impl_session * wf_impl_session_manager_get(
 {
     struct wf_impl_session * session = NULL;
 
-    struct wf_slist_item * item = manager->sessions.first;
+    struct wf_slist_item * item = wf_slist_first(&manager->sessions);
     while (NULL != item)
     {
         struct wf_slist_item * next = item->next;
@@ -68,11 +68,10 @@ void wf_impl_session_manager_remove(
     struct wf_impl_session_manager * manager,
     struct lws * wsi)
 {
-    struct wf_slist_item * item = manager->sessions.first;
-    struct wf_slist_item * prev = NULL;
-    while (NULL != item)
+    struct wf_slist_item * prev = &manager->sessions.head;
+    while (NULL != prev->next)
     {
-        struct wf_slist_item * next = item->next;
+        struct wf_slist_item * item = prev->next;
         struct wf_impl_session * session = wf_container_of(item, struct wf_impl_session, item);
         if (wsi == session->wsi)
         {
@@ -81,7 +80,6 @@ void wf_impl_session_manager_remove(
             break;
         }
 
-        prev = item;
-        item = next;
+        prev = prev->next;
     }
 }

lib/webfuse/core/message_queue.c

@@ -5,7 +5,7 @@
 void wf_message_queue_cleanup(
     struct wf_slist * queue)
 {
-    struct wf_slist_item * item = queue->first;
+    struct wf_slist_item * item = wf_slist_first(queue);
     while (NULL != item)
     {
         struct wf_slist_item * next = item->next;

lib/webfuse/core/slist.c

@@ -4,14 +4,20 @@
 void wf_slist_init(
     struct wf_slist * list)
 {
-    list->first = NULL;
-    list->last = NULL;
+    list->head.next = NULL;
+    list->last = &list->head;
 }
 
 bool wf_slist_empty(
     struct wf_slist * list)
 {
-    return (NULL == list->first);
+    return (list->last == &list->head);
+}
+
+struct wf_slist_item * wf_slist_first(
+    struct wf_slist * list)
+{
+    return list->head.next;
 }
 
 void wf_slist_append(
@@ -19,58 +25,36 @@ void wf_slist_append(
     struct wf_slist_item * item)
 {
     item->next = NULL;
+    list->last->next = item;
+    list->last = item;
 
-    if (NULL != list->last)
+    if (NULL == list->head.next)
     {
-        list->last->next = item;
-        list->last = item;
-    }
-    else
-    {
-        list->first = item;
-        list->last = item;
+        list->head.next = item;
     }
 }
 
 struct wf_slist_item * wf_slist_remove_first(
     struct wf_slist * list)
 {
-    struct wf_slist_item * const result = list->first;
-    if (NULL != result)
-    {
-        list->first = list->first->next;
-        if (NULL == list->first)
-        {
-            list->last = NULL;
-        }
-    } 
-
-    return result;
+    return wf_slist_remove_after(list, &list->head);
 }
 
 struct wf_slist_item * wf_slist_remove_after(
     struct wf_slist * list,
     struct wf_slist_item * prev)
 {
-    struct wf_slist_item * result = NULL;
 
-    if (NULL != prev)
+    struct wf_slist_item * result = prev->next;
+
+    if (NULL != result)
     {
-        result = prev->next;
-        if ((NULL != result) && (NULL != result->next))
-        {
-            prev->next = result->next;
-        }
-        else
+        prev->next = result->next;
+
+        if (list->last == result)
         {
             list->last = prev;
-            prev->next = NULL;
-        }
-        
-    }
-    else
-    {
-        result = wf_slist_remove_first(list);
+        }    
     }
 
     return result;

lib/webfuse/core/slist.h

@@ -17,7 +17,7 @@ struct wf_slist_item
 
 struct wf_slist
 {
-    struct wf_slist_item * first;
+    struct wf_slist_item head;
     struct wf_slist_item * last;
 };
 
@@ -27,6 +27,9 @@ extern void wf_slist_init(
 extern bool wf_slist_empty(
     struct wf_slist * list);
 
+extern struct wf_slist_item * wf_slist_first(
+    struct wf_slist * list);
+
 extern void wf_slist_append(
     struct wf_slist * list,
     struct wf_slist_item * item);

test/test_slist.cc

@@ -1,35 +1,139 @@
 #include <gtest/gtest.h>
 #include "webfuse/core/slist.h"
 
-TEST(wf_slist_remove_after, RemoveFirst)
+TEST(wf_slist, init)
 {
     struct wf_slist list;
-    struct wf_slist_item item[10];
+    wf_slist_init(&list);
+
+    ASSERT_EQ(nullptr, list.head.next);
+    ASSERT_EQ(nullptr, list.last->next);
+    ASSERT_EQ(&list.head, list.last);
+    ASSERT_TRUE(wf_slist_empty(&list));
+    ASSERT_EQ(nullptr, wf_slist_first(&list));    
+}
+
+TEST(wf_slist, append)
+{
+    struct wf_slist list;
+    struct wf_slist_item item[3];
 
     wf_slist_init(&list);
+    ASSERT_TRUE(wf_slist_empty(&list));
+
     wf_slist_append(&list, &item[0]);
+    ASSERT_NE(&list.head, list.last);
+    ASSERT_FALSE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[0], wf_slist_first(&list));    
+    ASSERT_EQ(&item[0], list.head.next);
+    ASSERT_EQ(&item[0], list.last);
+    ASSERT_EQ(nullptr, list.last->next);
+    ASSERT_EQ(nullptr, item[0].next);
 
-    wf_slist_item * removed = wf_slist_remove_after(&list, NULL);
-    ASSERT_TRUE(wf_slist_empty(&list));
-    ASSERT_EQ(nullptr, list.first);
-    ASSERT_EQ(nullptr, list.last);
+    wf_slist_append(&list, &item[1]);
+    ASSERT_NE(&list.head, list.last);
+    ASSERT_FALSE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[0], wf_slist_first(&list));    
+    ASSERT_EQ(&item[0], list.head.next);
+    ASSERT_EQ(&item[1], list.last);
+    ASSERT_EQ(nullptr, list.last->next);
+    ASSERT_EQ(&item[1], item[0].next);
+    ASSERT_EQ(nullptr, item[1].next);
+
+    wf_slist_append(&list, &item[2]);
+    ASSERT_NE(&list.head, list.last);
+    ASSERT_FALSE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[0], wf_slist_first(&list));    
+    ASSERT_EQ(&item[0], list.head.next);
+    ASSERT_EQ(&item[2], list.last);
+    ASSERT_EQ(nullptr, list.last->next);
+    ASSERT_EQ(&item[1], item[0].next);
+    ASSERT_EQ(&item[2], item[1].next);
+    ASSERT_EQ(nullptr, item[2].next);
+}
+
+TEST(wf_slist_remove_after, remove_first)
+{
+    struct wf_slist list;
+    struct wf_slist_item item[3];
+
+    wf_slist_init(&list);
+    wf_slist_append(&list, &item[0]);
+    wf_slist_append(&list, &item[1]);
+    wf_slist_append(&list, &item[2]);
+
+    wf_slist_item * removed;
+    
+    removed = wf_slist_remove_first(&list);
+    ASSERT_FALSE(wf_slist_empty(&list));
     ASSERT_EQ(&item[0], removed);
+
+    removed = wf_slist_remove_first(&list);
+    ASSERT_FALSE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[1], removed);
+
+    removed = wf_slist_remove_first(&list);
+    ASSERT_TRUE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[2], removed);
+
+    ASSERT_EQ(nullptr, list.head.next);
+    ASSERT_EQ(nullptr, list.last->next);
+    ASSERT_EQ(&list.head, list.last);
+    ASSERT_EQ(nullptr, wf_slist_first(&list));    
 }
 
-TEST(wf_slist_remove_after, RemoveLast)
+TEST(wf_slist_remove_after, remove_last)
 {
     struct wf_slist list;
-    struct wf_slist_item item[10];
+    struct wf_slist_item item[3];
 
     wf_slist_init(&list);
     wf_slist_append(&list, &item[0]);
     wf_slist_append(&list, &item[1]);
     wf_slist_append(&list, &item[2]);
 
-    wf_slist_item * removed = wf_slist_remove_after(&list, &item[1]);
+    wf_slist_item * removed;
+    
+    removed = wf_slist_remove_after(&list, &item[1]);
     ASSERT_FALSE(wf_slist_empty(&list));
-    ASSERT_EQ(&item[0], list.first);
-    ASSERT_EQ(&item[1], list.last);
-    ASSERT_EQ(nullptr, item[1].next);
     ASSERT_EQ(&item[2], removed);
+
+    removed = wf_slist_remove_after(&list, &item[0]);
+    ASSERT_FALSE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[1], removed);
+
+    removed = wf_slist_remove_after(&list, &list.head);
+    ASSERT_TRUE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[0], removed);
+
+    ASSERT_EQ(nullptr, list.head.next);
+    ASSERT_EQ(nullptr, list.last->next);
+    ASSERT_EQ(&list.head, list.last);
+    ASSERT_EQ(nullptr, wf_slist_first(&list));    
+}
+
+TEST(wf_slist_remove_after, remove_after)
+{
+    struct wf_slist list;
+    struct wf_slist_item item[3];
+
+    wf_slist_init(&list);
+    wf_slist_append(&list, &item[0]);
+    wf_slist_append(&list, &item[1]);
+    wf_slist_append(&list, &item[2]);
+
+    wf_slist_item * removed;
+    
+    removed = wf_slist_remove_after(&list, &item[0]);
+    ASSERT_FALSE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[1], removed);
+
+    ASSERT_NE(&list.head, list.last);
+    ASSERT_FALSE(wf_slist_empty(&list));
+    ASSERT_EQ(&item[0], wf_slist_first(&list));    
+    ASSERT_EQ(&item[0], list.head.next);
+    ASSERT_EQ(&item[2], list.last);
+    ASSERT_EQ(nullptr, list.last->next);
+    ASSERT_EQ(&item[2], item[0].next);
+    ASSERT_EQ(nullptr, item[2].next);
 }