os161/kern/include/threadlist.h
2015-12-23 00:50:04 +00:00

106 lines
4.1 KiB
C

/*
* Copyright (c) 2009
* The President and Fellows of Harvard College.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _THREADLIST_H_
#define _THREADLIST_H_
struct thread; /* from <thread.h> */
/*
* AmigaOS-style linked list of threads.
*
* The two threadlistnodes in the threadlist structure are always on
* the list, as bookends; this removes all the special cases in the
* list handling code. However, this means that iterating starts with
* the "second" element in the list (tl_head.tln_next, or
* tl_tail.tln_prev) and it ends at the last element that's actually a
* thread.
*
* Note that this means that assigning or memcpying threadlist
* structures will break them. Don't do that...
*
* ->tln_self always points to the thread that contains the
* threadlistnode. We could avoid this if we wanted to instead use
*
* (struct thread *)((char *)node - offsetof(struct thread, t_listnode))
*
* to get the thread pointer. But that's gross.
*/
struct threadlistnode {
struct threadlistnode *tln_prev;
struct threadlistnode *tln_next;
struct thread *tln_self;
};
struct threadlist {
struct threadlistnode tl_head;
struct threadlistnode tl_tail;
unsigned tl_count;
};
/* Initialize and clean up a thread list node. */
void threadlistnode_init(struct threadlistnode *tln, struct thread *self);
void threadlistnode_cleanup(struct threadlistnode *tln);
/* Initialize and clean up a thread list. Must be empty at cleanup. */
void threadlist_init(struct threadlist *tl);
void threadlist_cleanup(struct threadlist *tl);
/* Check if it's empty */
bool threadlist_isempty(struct threadlist *tl);
/* Add and remove: at ends */
void threadlist_addhead(struct threadlist *tl, struct thread *t);
void threadlist_addtail(struct threadlist *tl, struct thread *t);
struct thread *threadlist_remhead(struct threadlist *tl);
struct thread *threadlist_remtail(struct threadlist *tl);
/* Add and remove: in middle. (TL is needed to maintain ->tl_count.) */
void threadlist_insertafter(struct threadlist *tl,
struct thread *onlist, struct thread *addee);
void threadlist_insertbefore(struct threadlist *tl,
struct thread *addee, struct thread *onlist);
void threadlist_remove(struct threadlist *tl, struct thread *t);
/* Iteration; itervar should previously be declared as (struct thread *) */
#define THREADLIST_FORALL(itervar, tl) \
for ((itervar) = (tl).tl_head.tln_next->tln_self; \
(itervar) != NULL; \
(itervar) = (itervar)->t_listnode.tln_next->tln_self)
#define THREADLIST_FORALL_REV(itervar, tl) \
for ((itervar) = (tl).tl_tail.tln_prev->tln_self; \
(itervar) != NULL; \
(itervar) = (itervar)->t_listnode.tln_prev->tln_self)
#endif /* _THREADLIST_H_ */