void co_resume(void)
{
cothread_ctx *tctx = co_get_thread_ctx();
co_call(tctx->co_curr->restarget);
tctx->co_curr->restarget = tctx->co_curr->caller;
}
static void co_runner(void)
{
cothread_ctx *tctx = co_get_thread_ctx();
coroutine *co = tctx->co_curr;
co->restarget = co->caller;
co->func(co->data);
co_exit();
}
void co_call(coroutine_t coro)
{
cothread_ctx *tctx = co_get_thread_ctx();
coroutine *co = (coroutine *) coro, *oldco = tctx->co_curr;
co->caller = tctx->co_curr;
tctx->co_curr = co;
co_switch_context(&oldco->ctx, &co->ctx);
}
static void co_switch_context(co_ctx_t *octx, co_ctx_t *nctx)
{
cothread_ctx *tctx = co_get_thread_ctx();
if (swapcontext(&octx->cc, &nctx->cc) < 0) {
fprintf(stderr, "[PCL] Context switch failed: curr=%p\n",
tctx->co_curr);
exit(1);
}
}
void co_delete(coroutine_t coro)
{
cothread_ctx *tctx = co_get_thread_ctx();
coroutine *co = (coroutine *) coro;
if (co == tctx->co_curr) {
fprintf(stderr, "[PCL] Cannot delete itself: curr=%p\n",
tctx->co_curr);
exit(1);
}
if (co->alloc)
free(co);
}
static void co_del_helper(void *data)
{
cothread_ctx *tctx;
coroutine *cdh;
for (;;) {
tctx = co_get_thread_ctx();
cdh = tctx->co_dhelper;
tctx->co_dhelper = NULL;
co_delete(tctx->co_curr->caller);
co_call((coroutine_t) cdh);
if (tctx->co_dhelper == NULL) {
fprintf(stderr,
"[PCL] Resume to delete helper coroutine: curr=%p caller=%p\n",
tctx->co_curr, tctx->co_curr->caller);
exit(1);
}
}
}
void co_exit_to(coroutine_t coro)
{
cothread_ctx *tctx = co_get_thread_ctx();
coroutine *co = (coroutine *) coro;
if (tctx->dchelper == NULL &&
(tctx->dchelper = co_create(co_del_helper, NULL,
tctx->stk, sizeof(tctx->stk))) == NULL) {
fprintf(stderr, "[PCL] Unable to create delete helper coroutine: curr=%p\n",
tctx->co_curr);
exit(1);
}
tctx->co_dhelper = co;
co_call((coroutine_t) tctx->dchelper);
fprintf(stderr, "[PCL] Stale coroutine called: curr=%p exitto=%p caller=%p\n",
tctx->co_curr, co, tctx->co_curr->caller);
exit(1);
}
/*
* This code comes from the GNU Pth implementation and uses the
* sigstack/sigaltstack() trick.
*
* The ingenious fact is that this variant runs really on _all_ POSIX
* compliant systems without special platform kludges. But be _VERY_
* carefully when you change something in the following code. The slightest
* change or reordering can lead to horribly broken code. Really every
* function call in the following case is intended to be how it is, doubt
* me...
*
* For more details we strongly recommend you to read the companion
* paper ``Portable Multithreading -- The Signal Stack Trick for
* User-Space Thread Creation'' from Ralf S. Engelschall.
*/
static void co_ctx_bootstrap(void)
{
cothread_ctx *tctx = co_get_thread_ctx();
co_ctx_t * volatile ctx_starting;
void (* volatile ctx_starting_func)(void);
/*
* Switch to the final signal mask (inherited from parent)
*/
sigprocmask(SIG_SETMASK, &ctx_creating_sigs, NULL);
/*
* Move startup details from static storage to local auto
* variables which is necessary because it has to survive in
* a local context until the thread is scheduled for real.
*/
ctx_starting = ctx_creating;
ctx_starting_func = (void (*)(void)) ctx_creating_func;
/*
* Save current machine state (on new stack) and
* go back to caller until we're scheduled for real...
*/
if (!setjmp(ctx_starting->cc))
longjmp(ctx_caller.cc, 1);
/*
* The new thread is now running: GREAT!
* Now we just invoke its init function....
*/
ctx_starting_func();
fprintf(stderr, "[PCL] Hmm, you really shouldn't reach this point: curr=%p\n",
tctx->co_curr);
exit(1);
}
coroutine_t co_current(void)
{
cothread_ctx *tctx = co_get_thread_ctx();
return (coroutine_t) tctx->co_curr;
}
void co_exit(void)
{
cothread_ctx *tctx = co_get_thread_ctx();
co_exit_to((coroutine_t) tctx->co_curr->restarget);
}
