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/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
import Cocoa
struct Timing {
let time: UInt64
let closure: () -> Void
}
class PreciseTimer {
unowned var common: Common
let nanoPerSecond: Double = 1e+9
let machToNano: Double = {
var timebase: mach_timebase_info = mach_timebase_info()
mach_timebase_info(&timebase)
return Double(timebase.numer) / Double(timebase.denom)
}()
let condition = NSCondition()
var events: [Timing] = []
var isRunning: Bool = true
var isHighPrecision: Bool = false
var thread: pthread_t!
var threadPort: thread_port_t = thread_port_t()
let policyFlavor = thread_policy_flavor_t(THREAD_TIME_CONSTRAINT_POLICY)
let policyCount = MemoryLayout<thread_time_constraint_policy>.size /
MemoryLayout<integer_t>.size
var typeNumber: mach_msg_type_number_t {
return mach_msg_type_number_t(policyCount)
}
var threadAttr: pthread_attr_t = {
var attr = pthread_attr_t()
var param = sched_param()
pthread_attr_init(&attr)
param.sched_priority = sched_get_priority_max(SCHED_FIFO)
pthread_attr_setschedparam(&attr, ¶m)
pthread_attr_setschedpolicy(&attr, SCHED_FIFO)
return attr
}()
init?(common com: Common) {
common = com
pthread_create(&thread, &threadAttr, entryC, TypeHelper.bridge(obj: self))
if thread == nil {
common.log.warning("Couldn't create pthread for high precision timer")
return nil
}
threadPort = pthread_mach_thread_np(thread)
}
func updatePolicy(periodSeconds: Double = 1 / 60.0) {
let period = periodSeconds * nanoPerSecond / machToNano
var policy = thread_time_constraint_policy(
period: UInt32(period),
computation: UInt32(0.75 * period),
constraint: UInt32(0.85 * period),
preemptible: 1
)
let success = withUnsafeMutablePointer(to: &policy) {
$0.withMemoryRebound(to: integer_t.self, capacity: policyCount) {
thread_policy_set(threadPort, policyFlavor, $0, typeNumber)
}
}
isHighPrecision = success == KERN_SUCCESS
if !isHighPrecision {
common.log.warning("Couldn't create a high precision timer")
}
}
func terminate() {
condition.lock()
isRunning = false
condition.signal()
condition.unlock()
pthread_kill(thread, SIGALRM)
pthread_join(thread, nil)
}
func scheduleAt(time: UInt64, closure: @escaping () -> Void) {
condition.lock()
let firstEventTime = events.first?.time ?? 0
let lastEventTime = events.last?.time ?? 0
events.append(Timing(time: time, closure: closure))
if lastEventTime > time {
events.sort { $0.time < $1.time }
}
condition.signal()
condition.unlock()
if firstEventTime > time {
pthread_kill(thread, SIGALRM)
}
}
let threadSignal: @convention(c) (Int32) -> Void = { (_ sig: Int32) in }
let entryC: @convention(c) (UnsafeMutableRawPointer) -> UnsafeMutableRawPointer? = { (ptr: UnsafeMutableRawPointer) in
let ptimer: PreciseTimer = TypeHelper.bridge(ptr: ptr)
ptimer.entry()
return nil
}
func entry() {
signal(SIGALRM, threadSignal)
while isRunning {
condition.lock()
while events.count == 0 && isRunning {
condition.wait()
}
if !isRunning { break }
guard let event = events.first else {
continue
}
condition.unlock()
mach_wait_until(event.time)
condition.lock()
if events.first?.time == event.time && isRunning {
event.closure()
events.removeFirst()
}
condition.unlock()
}
}
}
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