mpv/osdep/cocoa_events.m

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/*
* Cocoa Event Handling
*
* This file is part of mplayer2.
*
* mplayer2 is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mplayer2 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with mplayer2. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Implementation details:
* This file deals with custom event polling on MacOSX. When mplayer2 is paused
* it will asynchronously poll for events using select. This works correctly on
* Linux with X11 since the events are notified through the file descriptors
* where mplayer2 is listening on. On the other hand, the OSX window server
* notifies the processes for events using mach ports.
*
* The code below uses functionality from Cocoa that abstracts the async polling
* of events from the window server. When a Cocoa event comes in, the polling is
* interrupted and the event is dealt with in the next vo_check_events.
*
* To keep the select fd polling code working, that functionality is executed
* from another thread. Whoever finishes polling before the given time, be it
* Cocoa or the original select code, notifies the other for an immediate wake.
*/
#include "cocoa_events.h"
#include "video/out/cocoa_common.h"
#include "talloc.h"
#import <Cocoa/Cocoa.h>
#include <dispatch/dispatch.h>
// Bogus event subtype to wake the Cocoa code from polling state
#define MP_EVENT_SUBTYPE_WAKE_EVENTLOOP 100
// This is the threshold in milliseconds below which the Cocoa polling is not
// executed. There is some overhead caused by the synchronization between
// threads. Even if in practice it isn't noticeable, we try to avoid the useless
// waste of resources.
#define MP_ASYNC_THRESHOLD 50
struct priv {
dispatch_queue_t select_queue;
bool is_runloop_polling;
void (*read_all_fd_events)(struct input_ctx *ictx, int time);
};
static struct priv *p;
static void cocoa_wait_events(int mssleeptime)
{
NSTimeInterval sleeptime = mssleeptime / 1000.0;
NSEvent *event;
p->is_runloop_polling = YES;
event = [NSApp nextEventMatchingMask:NSAnyEventMask
untilDate:[NSDate dateWithTimeIntervalSinceNow:sleeptime]
inMode:NSEventTrackingRunLoopMode dequeue:NO];
// dequeue the next event if it is a fake to wake the cocoa polling
if (event && [event type] == NSApplicationDefined &&
[event subtype] == MP_EVENT_SUBTYPE_WAKE_EVENTLOOP) {
[NSApp nextEventMatchingMask:NSAnyEventMask untilDate:nil
inMode:NSEventTrackingRunLoopMode dequeue:YES];
}
p->is_runloop_polling = NO;
}
static void cocoa_wake_runloop()
{
if (p->is_runloop_polling) {
NSAutoreleasePool *pool = [NSAutoreleasePool new];
NSEvent *event;
/* Post an event so we'll wake the run loop that is async polling */
event = [NSEvent otherEventWithType: NSApplicationDefined
location: NSZeroPoint
modifierFlags: 0
timestamp: 0
windowNumber: 0
context: nil
subtype: MP_EVENT_SUBTYPE_WAKE_EVENTLOOP
data1: 0
data2: 0];
[NSApp postEvent:event atStart:NO];
[pool release];
}
}
void cocoa_events_init(struct input_ctx *ictx,
void (*read_all_fd_events)(struct input_ctx *ictx, int time))
{
NSApplicationLoad();
p = talloc_ptrtype(NULL, p);
*p = (struct priv){
.is_runloop_polling = NO,
.read_all_fd_events = read_all_fd_events,
.select_queue = dispatch_queue_create("org.mpv.select_queue",
NULL),
};
}
void cocoa_events_uninit(void)
{
talloc_free(p);
}
void cocoa_events_read_all_events(struct input_ctx *ictx, int time)
{
// don't bother delegating the select to the async queue if the blocking
// time is really low or if we are not running a GUI
if (time > MP_ASYNC_THRESHOLD && vo_cocoa_gui_running()) {
dispatch_async(p->select_queue, ^{
p->read_all_fd_events(ictx, time);
cocoa_wake_runloop();
});
cocoa_wait_events(time);
mp_input_wakeup(ictx);
// wait for the async queue to get empty.
dispatch_sync(p->select_queue, ^{});
} else {
p->read_all_fd_events(ictx, time);
}
}