util/list: Remove hlist_* + generalize list_insert() to support append

I wanted the linked list abstraction to be convenient in use, yet result
in exactly the same kind of (generated) code as if each list was
hand-written. That's the reason for the hlist_*, but I'm starting to
doubt whether that optimization is really worth the effort of
maintaining two separate APIs.  I'm keeping the idea for an slist_
abstraction open, however; Saving memory on pointers in list nodes
likely *is* worth the effort.

I also figured that, with a tiny change, list_insert_before() could be
used as a list_insert_after(), too, so I fixed that and renamed it to a
single powerful list_insert().

3 files changed, 14 insertions, 29 deletions

diff --git a/src/hub/chat.c b/src/hub/chat.c
index e0a753d..d3e28b5 100644
--- a/src/hub/chat.c
+++ b/src/hub/chat.c
@@ -166,7 +166,7 @@ void hub_chat_message(hub_t *h, int64_t group, int64_t from, const char *message
 	strcpy(m->msg, message);
 
 	user_ref(h, from);
-	list_insert_before(*g, m, g->head);
+	list_insert(*g, m, g->head);
 	g->n++;
 	if((uint32_t)g->n > h->ch.props.ChatLogSize)
 		glog_pop(h, g);
diff --git a/src/util/list.h b/src/util/list.h
index d3a96be..a479b49 100644
--- a/src/util/list.h
+++ b/src/util/list.h
@@ -31,10 +31,6 @@
  * All macros starting with 's' (e.g. slist_ instead of list_) operate on
  * singly-linked lists. The nodes only need to have a 'next' pointer.
  *
- * All macros containing the 'h' (hlist_, shlist_) flag take only a single
- * pointer variable as list argument rather than a struct. This pointer is
- * treated as the `head' of a list.
- *
  * All macros containing the 'p' flag (plist_, splist_) accept an additional
  * prefix argument. This argument is prefixed to the names of the 'next' and
  * 'prev' pointers.
@@ -53,12 +49,15 @@
  */
 
 
-/* Insert an element in the list before _next.
- * To push an element to the head of the list: list_insert_before(l, n, l.head)
+/* Insert an element in the list before _next, or at the tail if _next is NULL.
+ * To insert an element at the head of the list: list_insert(l, n, l.head)
+ * To insert an element at the tail of the list: list_insert(l, n, NULL)
+ * To insert an element before element x: list_insert(l, n, x)
+ * To insert an element after element x:  list_insert(l, n, x->next)
  */
-#define list_insert_before(_l, _n, _next) do {\
+#define list_insert(_l, _n, _next) do {\
 		(_n)->next = (_next);\
-		(_n)->prev = (_next) ? (_next)->prev : NULL;\
+		(_n)->prev = (_n)->next ? (_n)->next->prev : (_l).tail;\
 		if((_n)->next) (_n)->next->prev = (_n);\
 		else           (_l).tail = (_n);\
 		if((_n)->prev) (_n)->prev->next = (_n);\
@@ -78,21 +77,5 @@
 	} while(0)
 
 
-#define hlist_insert_before(_l, _n, _next) do {\
-		(_n)->next = (_next);\
-		(_n)->prev = (_next) ? (_next)->prev : NULL;\
-		if((_n)->next) (_n)->next->prev = (_n);\
-		if((_n)->prev) (_n)->prev->next = (_n);\
-		else           (_l) = (_n);\
-	} while(0)
-
-
-#define hlist_remove(_l, _n) do {\
-		if((_n)->next) (_n)->next->prev = (_n)->prev;\
-		if((_n)->prev) (_n)->prev->next = (_n)->next;\
-		if((_n) == (_l)) (_l) = (_n)->next;\
-	} while(0)
-
-
 #endif
 /* vim: set noet sw=4 ts=4: */
diff --git a/src/util/logfile.c b/src/util/logfile.c
index fed611d..cc1bd75 100644
--- a/src/util/logfile.c
+++ b/src/util/logfile.c
@@ -30,7 +30,9 @@ struct logfile_t {
 	struct stat st;
 };
 
-static logfile_t *logfile_list;
+static struct {
+	logfile_t *head, *tail;
+} logfile_list;
 
 
 /* (Re)opens the log file and checks for inode and file size changes. */
@@ -74,14 +76,14 @@ logfile_t *logfile_open(const char *fn) {
 	l->fn = strdup(fn);
 	l->fd = -1;
 
-	hlist_insert_before(logfile_list, l, logfile_list);
+	list_insert(logfile_list, l, NULL);
 	logfile_checkfile(l);
 	return l;
 }
 
 
 void logfile_close(logfile_t *l) {
-	hlist_remove(logfile_list, l);
+	list_remove(logfile_list, l);
 
 	if(l->fd >= 0)
 		close(l->fd);
@@ -126,7 +128,7 @@ static void logfile_reopen(logfile_t *l) {
 
 void logfile_global_reopen() {
 	logfile_t *l;
-	for(l=logfile_list; l; l=l->next)
+	for(l=logfile_list.head; l; l=l->next)
 		logfile_reopen(l);
 }