tlist: remove type arg from tlist_top(), tlist_tail()

With the type canary, it's unnecessary.  Though the implementation is
a bit more awkward since they longer map directly through to list_top/tail.

ccan/failtest/failtest.c

@@ -570,7 +570,7 @@ static void free_everything(void)
 {
 	struct failtest_call *i;
 
-	while ((i = tlist_top(&history, struct failtest_call, list)) != NULL)
+	while ((i = tlist_top(&history, list)) != NULL)
 		free_call(i);
 
 	failtable_clear(&failtable);
@@ -755,7 +755,7 @@ static bool should_fail(struct failtest_call *call)
 			char *failpath;
 			struct failtest_call *c;
 
-			c = tlist_tail(&history, struct failtest_call, list);
+			c = tlist_tail(&history, list);
 			diff = time_sub(time_now(), start);
 			failpath = failpath_string();
 			p = strrchr(c->file, '/');
@@ -770,8 +770,7 @@ static bool should_fail(struct failtest_call *call)
 			free(failpath);
 		}
 		/* From here on, we have to clean up! */
-		our_history_start = tlist_tail(&history, struct failtest_call,
-					       list);
+		our_history_start = tlist_tail(&history, list);
 		close(control[0]);
 		close(output[0]);
 		/* Don't swallow stderr if we're tracing. */

ccan/failtest/failtest.h

@@ -214,7 +214,7 @@ enum failtest_result {
  *	static enum failtest_result dont_fail_alloc(struct tlist_calls *history)
  *	{
  *		struct failtest_call *call;
- *		call = tlist_tail(history, struct failtest_call, list);
+ *		call = tlist_tail(history, list);
  *		if (call->type == FAILTEST_MALLOC
  *			|| call->type == FAILTEST_CALLOC
  *			|| call->type == FAILTEST_REALLOC)

ccan/lbalance/lbalance.c

@@ -315,7 +315,7 @@ void lbalance_free(struct lbalance *lb)
 {
 	struct lbalance_task *task;
 
-	while ((task = tlist_top(&lb->tasks, struct lbalance_task, list))) {
+	while ((task = tlist_top(&lb->tasks, list))) {
 		assert(task->lb == lb);
 		tlist_del_from(&lb->tasks, task, list);
 		lb->num_tasks--;

ccan/tdb2/test/failtest_helper.c

@@ -72,7 +72,7 @@ block_repeat_failures(struct tlist_calls *history)
 {
 	const struct failtest_call *last;
 
-	last = tlist_tail(history, struct failtest_call, list);
+	last = tlist_tail(history, list);
 
 	if (failtest_suppress)
 		return FAIL_DONT_FAIL;

ccan/tlist/test/compile_fail-tlist_tail.c

@@ -16,21 +16,16 @@ int main(int argc, char *argv[])
 {
 	struct tlist_children children;
 	struct child child = { "child" };
-	void *c;
+#ifdef FAIL
+	struct cousin *c;
+#else
+	struct child *c;
+#endif
 
 	tlist_init(&children);
 	tlist_add(&children, &child, list);
 
-	c = tlist_tail(&children,
-#ifdef FAIL
-#if !HAVE_FLEXIBLE_ARRAY_MEMBER
-#error Need flexible array members to check type
-#endif
-		      struct cousin,
-#else
-		      struct child,
-#endif
-		      list);
+	c = tlist_tail(&children, list);
 	(void) c; /* Suppress unused-but-set-variable warning. */
 	return 0;
 }

ccan/tlist/test/compile_fail-tlist_top.c

@@ -16,21 +16,16 @@ int main(int argc, char *argv[])
 {
 	struct tlist_children children;
 	struct child child = { "child" };
-	void *c;
+#ifdef FAIL
+	struct cousin *c;
+#else
+	struct child *c;
+#endif
 
 	tlist_init(&children);
 	tlist_add(&children, &child, list);
 
-	c = tlist_top(&children,
-#ifdef FAIL
-#if !HAVE_FLEXIBLE_ARRAY_MEMBER
-#error Need flexible array members to check type
-#endif
-		      struct cousin,
-#else
-		      struct child,
-#endif
-		      list);
+	c = tlist_top(&children, list);
 	(void) c; /* Suppress unused-but-set-variable warning. */
 	return 0;
 }

ccan/tlist/test/run.c

@@ -73,10 +73,10 @@ int main(int argc, char *argv[])
 	ok1(tlist_check(&parent.children, NULL));
 
 	/* Test tlist_top */
-	ok1(tlist_top(&parent.children, struct child, list) == &c1);
+	ok1(tlist_top(&parent.children, list) == &c1);
 
 	/* Test list_tail */
-	ok1(tlist_tail(&parent.children, struct child, list) == &c3);
+	ok1(tlist_tail(&parent.children, list) == &c3);
 
 	/* Test tlist_for_each. */
 	i = 0;
@@ -141,7 +141,7 @@ int main(int argc, char *argv[])
 	ok1(tlist_empty(&parent.children));
 
 	/* Test list_top/list_tail on empty list. */
-	ok1(tlist_top(&parent.children, struct child, list) == NULL);
-	ok1(tlist_tail(&parent.children, struct child, list) == NULL);
+	ok1(tlist_top(&parent.children, list) == (struct child *)NULL);
+	ok1(tlist_tail(&parent.children, list) == (struct child *)NULL);
 	return exit_status();
 }

ccan/tlist/tlist.h

@@ -178,32 +178,36 @@
 /**
  * tlist_top - get the first entry in a list
  * @h: the tlist
- * @type: the type of the entry
  * @member: the list_node member of the type
  *
  * If the list is empty, returns NULL.
  *
  * Example:
  *	struct child *first;
- *	first = tlist_top(&parent->children, struct child, list);
+ *	first = tlist_top(&parent->children, list);
  */
-#define tlist_top(h, type, member) \
-	list_top(tlist_raw((h), (type *)NULL), type, member)
+#define tlist_top(h, member)						\
+	((tcon_type((h), canary))					\
+	 list_top_(&(h)->raw,						\
+		   (char *)(&(h)->_tcon[0].canary->member) -		\
+		   (char *)((h)->_tcon[0].canary)))
 
 /**
  * tlist_tail - get the last entry in a list
  * @h: the tlist
- * @type: the type of the entry
  * @member: the list_node member of the type
  *
  * If the list is empty, returns NULL.
  *
  * Example:
  *	struct child *last;
- *	last = tlist_tail(&parent->children, struct child, list);
+ *	last = tlist_tail(&parent->children, list);
  */
-#define tlist_tail(h, type, member) \
-	list_tail(tlist_raw((h), (type *)NULL), type, member)
+#define tlist_tail(h, member)						\
+	((tcon_type((h), canary))					\
+	 list_tail_(&(h)->raw,						\
+		    (char *)(&(h)->_tcon[0].canary->member) -		\
+		    (char *)((h)->_tcon[0].canary)))
 
 /**
  * tlist_for_each - iterate through a list.

tools/ccanlint/async.c

@@ -48,7 +48,7 @@ static void run_more(void)
 	while (num_running < lbalance_target(lb)) {
 		int p[2];
 
-		c = tlist_top(&pending, struct command, list);
+		c = tlist_top(&pending, list);
 		if (!c)
 			break;
 
@@ -189,7 +189,7 @@ void *collect_command(bool *ok, char **output)
 	struct command *c;
 	const void *ctx;
 
-	while ((c = tlist_top(&done, struct command, list)) == NULL) {
+	while ((c = tlist_top(&done, list)) == NULL) {
 		if (tlist_empty(&pending) && tlist_empty(&running))
 			return NULL;
 		reap_output();