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// +build linux, darwin, freebsd, openbsd, netbsd, haiku
// +private
package thread
import "core:sync"
import "core:sys/unix"
import "core:time"
_IS_SUPPORTED :: true
CAS :: sync.atomic_compare_exchange_strong
// NOTE(tetra): Aligned here because of core/unix/pthread_linux.odin/pthread_t.
// Also see core/sys/darwin/mach_darwin.odin/semaphore_t.
Thread_Os_Specific :: struct #align(16) {
unix_thread: unix.pthread_t, // NOTE: very large on Darwin, small on Linux.
cond: sync.Cond,
mutex: sync.Mutex,
}
//
// Creates a thread which will run the given procedure.
// It then waits for `start` to be called.
//
_create :: proc(procedure: Thread_Proc, priority: Thread_Priority) -> ^Thread {
__unix_thread_entry_proc :: proc "c" (t: rawptr) -> rawptr {
t := (^Thread)(t)
// We need to give the thread a moment to start up before we enable cancellation.
can_set_thread_cancel_state := unix.pthread_setcancelstate(unix.PTHREAD_CANCEL_ENABLE, nil) == 0
sync.lock(&t.mutex)
t.id = sync.current_thread_id()
for (.Started not_in sync.atomic_load(&t.flags)) {
// HACK: use a timeout so in the event that the condition is signalled at THIS comment's exact point
// (after checking flags, before starting the wait) it gets itself out of that deadlock after a ms.
sync.wait_with_timeout(&t.cond, &t.mutex, time.Millisecond)
}
if .Joined in sync.atomic_load(&t.flags) {
return nil
}
// Enable thread's cancelability.
if can_set_thread_cancel_state {
unix.pthread_setcanceltype (unix.PTHREAD_CANCEL_ASYNCHRONOUS, nil)
unix.pthread_setcancelstate(unix.PTHREAD_CANCEL_ENABLE, nil)
}
{
init_context := t.init_context
// NOTE(tetra, 2023-05-31): Must do this AFTER thread.start() is called, so that the user can set the init_context, etc!
// Here on Unix, we start the OS thread in a running state, and so we manually have it wait on a condition
// variable above. We must perform that waiting BEFORE we select the context!
context = _select_context_for_thread(init_context)
defer _maybe_destroy_default_temp_allocator(init_context)
t.procedure(t)
}
sync.atomic_or(&t.flags, { .Done })
sync.unlock(&t.mutex)
if .Self_Cleanup in sync.atomic_load(&t.flags) {
t.unix_thread = {}
// NOTE(ftphikari): It doesn't matter which context 'free' received, right?
context = {}
free(t, t.creation_allocator)
}
return nil
}
attrs: unix.pthread_attr_t
if unix.pthread_attr_init(&attrs) != 0 {
return nil // NOTE(tetra, 2019-11-01): POSIX OOM.
}
defer unix.pthread_attr_destroy(&attrs)
// NOTE(tetra, 2019-11-01): These only fail if their argument is invalid.
assert(unix.pthread_attr_setdetachstate(&attrs, unix.PTHREAD_CREATE_JOINABLE) == 0)
when ODIN_OS != .Haiku && ODIN_OS != .NetBSD {
assert(unix.pthread_attr_setinheritsched(&attrs, unix.PTHREAD_EXPLICIT_SCHED) == 0)
}
thread := new(Thread)
if thread == nil {
return nil
}
thread.creation_allocator = context.allocator
// Set thread priority.
policy: i32
res: i32
when ODIN_OS != .Haiku && ODIN_OS != .NetBSD {
res = unix.pthread_attr_getschedpolicy(&attrs, &policy)
assert(res == 0)
}
params: unix.sched_param
res = unix.pthread_attr_getschedparam(&attrs, ¶ms)
assert(res == 0)
low := unix.sched_get_priority_min(policy)
high := unix.sched_get_priority_max(policy)
switch priority {
case .Normal: // Okay
case .Low: params.sched_priority = low + 1
case .High: params.sched_priority = high
}
res = unix.pthread_attr_setschedparam(&attrs, ¶ms)
assert(res == 0)
thread.procedure = procedure
if unix.pthread_create(&thread.unix_thread, &attrs, __unix_thread_entry_proc, thread) != 0 {
free(thread, thread.creation_allocator)
return nil
}
return thread
}
_start :: proc(t: ^Thread) {
sync.atomic_or(&t.flags, { .Started })
sync.signal(&t.cond)
}
_is_done :: proc(t: ^Thread) -> bool {
return .Done in sync.atomic_load(&t.flags)
}
_join :: proc(t: ^Thread) {
// sync.guard(&t.mutex)
if unix.pthread_equal(unix.pthread_self(), t.unix_thread) {
return
}
// Preserve other flags besides `.Joined`, like `.Started`.
unjoined := sync.atomic_load(&t.flags) - {.Joined}
joined := unjoined + {.Joined}
// Try to set `t.flags` from unjoined to joined. If it returns joined,
// it means the previous value had that flag set and we can return.
if res, ok := CAS(&t.flags, unjoined, joined); res == joined && !ok {
return
}
// Prevent non-started threads from blocking main thread with initial wait
// condition.
if .Started not_in unjoined {
_start(t)
}
unix.pthread_join(t.unix_thread, nil)
}
_join_multiple :: proc(threads: ..^Thread) {
for t in threads {
_join(t)
}
}
_destroy :: proc(t: ^Thread) {
_join(t)
t.unix_thread = {}
free(t, t.creation_allocator)
}
_terminate :: proc(t: ^Thread, exit_code: int) {
// NOTE(Feoramund): For thread cancellation to succeed on BSDs and
// possibly Darwin systems, the thread must call one of the pthread
// cancelation points at some point after this.
//
// The most obvious one of these is `pthread_cancel`, but there is an
// entire list of functions that act as cancelation points available in the
// pthreads manual page.
//
// This is in contrast to behavior I have seen on Linux where the thread is
// just terminated.
unix.pthread_cancel(t.unix_thread)
}
_yield :: proc() {
unix.sched_yield()
}
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