X-Git-Url: http://git.vrable.net/?a=blobdiff_plain;f=bluesky%2Futil.c;h=bd5ddd36e483d55f8ead4237606a36a6bf5c9652;hb=e26a903ddf80011e3b72a780d7392a8333c996af;hp=2e6f0aa1d64227ce4bc56fc425285bce032161be;hpb=d97af3e024253910cd60350e0504ea64711fbb00;p=bluesky.git

diff --git a/bluesky/util.c b/bluesky/util.c
index 2e6f0aa..bd5ddd3 100644
--- a/bluesky/util.c
+++ b/bluesky/util.c
@@ -113,3 +113,64 @@ void bluesky_string_resize(BlueSkyRCStr *string, gsize len)
     string->data = g_realloc(string->data, len);
     string->len = len;
 }
+
+/* Cache LRU list management functions.  These manage the doubly-linked list of
+ * inodes sorted by accessed/modified time.  The FS lock should be held while
+ * calling these.
+ *
+ * _remove will unlink an inode from the linked list.
+ *
+ * _prepend and _append insert an inode at the head or tail of the linked list,
+ * and return a pointer to the linked list element (which should be stored in
+ * the inode); the inode should not already be in the list.
+ *
+ * _head and _tail simply return the first or last item inode in the list. */
+void bluesky_list_unlink(GList *head, GList *item)
+{
+    if (item == NULL)
+        return;
+
+    if (head->prev == item)
+        head->prev = item->prev;
+    head->next = g_list_delete_link(head->next, item);
+}
+
+GList *bluesky_list_prepend(GList *head, BlueSkyInode *inode)
+{
+    head->next = g_list_prepend(head->next, inode);
+    if (head->prev == NULL)
+        head->prev = g_list_last(head->next);
+    return head->next;
+}
+
+GList *bluesky_list_append(GList *head, BlueSkyInode *inode)
+{
+    if (head->next == NULL)
+        return bluesky_list_prepend(head, inode);
+
+    g_assert(head->prev != NULL && head->prev->next == NULL);
+
+    GList *link = g_list_alloc();
+    link->data = inode;
+    link->next = NULL;
+    link->prev = head->prev;
+    head->prev->next = link;
+    head->prev = link;
+    return link;
+}
+
+BlueSkyInode *bluesky_list_head(GList *head)
+{
+    if (head->next == NULL)
+        return NULL;
+    else
+        return (BlueSkyInode *)head->next->data;
+}
+
+BlueSkyInode *bluesky_list_tail(GList *head)
+{
+    if (head->prev == NULL)
+        return NULL;
+    else
+        return (BlueSkyInode *)head->prev->data;
+}