util: generalize code that checks whether PIDs are alive or unwaited for

[elogind.git] / src / shared / list.h

diff --git a/src/shared/list.h b/src/shared/list.h
index 9a491b990efe0f024d703c23f7eb9887ceee20c9..e55b91cea4ad9c0184ee07390ba78a11c9c81a0a 100644 (file)
--- a/src/shared/list.h
+++ b/src/shared/list.h
@@ -1,7 +1,6 @@
 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
 
-#ifndef foolisthfoo
-#define foolisthfoo
+#pragma once
 
 /***
   This file is part of systemd.
@@ -32,23 +31,23 @@
         t *name##_next, *name##_prev
 
 /* Initialize the list's head */
-#define LIST_HEAD_INIT(t,head)                                          \
+#define LIST_HEAD_INIT(head)                                            \
         do {                                                            \
                 (head) = NULL; }                                        \
         while(false)
 
 /* Initialize a list item */
-#define LIST_INIT(t,name,item)                                          \
+#define LIST_INIT(name,item)                                            \
         do {                                                            \
-                t *_item = (item);                                      \
+                typeof(*(item)) *_item = (item);                        \
                 assert(_item);                                          \
                 _item->name##_prev = _item->name##_next = NULL;         \
         } while(false)
 
 /* Prepend an item to the list */
-#define LIST_PREPEND(t,name,head,item)                                  \
+#define LIST_PREPEND(name,head,item)                                    \
         do {                                                            \
-                t **_head = &(head), *_item = (item);                   \
+                typeof(*(head)) **_head = &(head), *_item = (item);     \
                 assert(_item);                                          \
                 if ((_item->name##_next = *_head))                      \
                         _item->name##_next->name##_prev = _item;        \
@@ -57,9 +56,9 @@
         } while(false)
 
 /* Remove an item from the list */
-#define LIST_REMOVE(t,name,head,item)                                   \
+#define LIST_REMOVE(name,head,item)                                     \
         do {                                                            \
-                t **_head = &(head), *_item = (item);                   \
+                typeof(*(head)) **_head = &(head), *_item = (item);     \
                 assert(_item);                                          \
                 if (_item->name##_next)                                 \
                         _item->name##_next->name##_prev = _item->name##_prev; \
@@ -73,19 +72,19 @@
         } while(false)
 
 /* Find the head of the list */
-#define LIST_FIND_HEAD(t,name,item,head)                                \
+#define LIST_FIND_HEAD(name,item,head)                                  \
         do {                                                            \
-                t *_item = (item);                                      \
+                typeof(*(item)) *_item = (item);                        \
                 assert(_item);                                          \
                 while (_item->name##_prev)                              \
                        _item = _item->name##_prev;                      \
                 (head) = _item;                                         \
         } while (false)
 
-/* Find the head of the list */
-#define LIST_FIND_TAIL(t,name,item,tail)                                \
+/* Find the tail of the list */
+#define LIST_FIND_TAIL(name,item,tail)                                  \
         do {                                                            \
-                t *_item = (item);                                      \
+                typeof(*(item)) *_item = (item);                        \
                 assert(_item);                                          \
                 while (_item->name##_next)                              \
                         _item = _item->name##_next;                     \
@@ -93,9 +92,9 @@
         } while (false)
 
 /* Insert an item after another one (a = where, b = what) */
-#define LIST_INSERT_AFTER(t,name,head,a,b)                              \
+#define LIST_INSERT_AFTER(name,head,a,b)                                \
         do {                                                            \
-                t **_head = &(head), *_a = (a), *_b = (b);              \
+                typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
                 assert(_b);                                             \
                 if (!_a) {                                              \
                         if ((_b->name##_next = *_head))                 \
@@ -125,4 +124,9 @@
 #define LIST_FOREACH_AFTER(name,i,p)                                    \
         for ((i) = (p)->name##_next; (i); (i) = (i)->name##_next)
 
-#endif
+/* Loop starting from p->next until p->prev.
+   p can be adjusted meanwhile. */
+#define LIST_LOOP_BUT_ONE(name,i,head,p)                                \
+        for ((i) = (p)->name##_next ? (p)->name##_next : (head);        \
+             (i) != (p);                                                \
+             (i) = (i)->name##_next ? (i)->name##_next : (head))