portlight 0.0.2

Cross-platform window management for audio plugins
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123

use std::cell::{Cell, RefCell};
use std::collections::HashMap;
use std::ffi::c_void;
use std::panic::{self, AssertUnwindSafe};
use std::ptr::NonNull;
use std::rc::Rc;
use std::time::Duration;

use objc2_core_foundation::{
    kCFRunLoopCommonModes, CFAbsoluteTimeGetCurrent, CFRetained, CFRunLoop, CFRunLoopTimer,
    CFRunLoopTimerContext,
};

use crate::{EventLoop, Result};

extern "C-unwind" fn retain(info: *const c_void) -> *const c_void {
    unsafe { Rc::increment_strong_count(info as *const TimerState) };

    info
}

extern "C-unwind" fn release(info: *const c_void) {
    let result = panic::catch_unwind(AssertUnwindSafe(|| {
        unsafe { Rc::decrement_strong_count(info as *const TimerState) };
    }));

    // If a panic occurs while dropping the Rc<TimerState>, the only thing left to do is abort.
    if let Err(_panic) = result {
        std::process::abort();
    }
}

extern "C-unwind" fn callback(_timer: *mut CFRunLoopTimer, info: *mut c_void) {
    let state = unsafe { &*(info as *mut TimerState) };

    let result = panic::catch_unwind(AssertUnwindSafe(|| {
        state.handler.borrow_mut()();
    }));

    if let Err(panic) = result {
        state.event_loop.state.propagate_panic(panic);
    }
}

pub struct TimerState {
    timer: Cell<Option<CFRetained<CFRunLoopTimer>>>,
    event_loop: EventLoop,
    handler: RefCell<Box<dyn FnMut()>>,
}

impl TimerState {
    pub fn repeat<F>(
        event_loop: &EventLoop,
        duration: Duration,
        handler: F,
    ) -> Result<Rc<TimerState>>
    where
        F: FnMut() + 'static,
    {
        let event_loop_state = &event_loop.state;

        let state = Rc::new(TimerState {
            timer: Cell::new(None),
            event_loop: event_loop.clone(),
            handler: RefCell::new(Box::new(handler)),
        });

        let mut context = CFRunLoopTimerContext {
            version: 0,
            info: Rc::as_ptr(&state) as *mut c_void,
            retain: Some(retain),
            release: Some(release),
            copyDescription: None,
        };

        let now = CFAbsoluteTimeGetCurrent();
        let interval = duration.as_secs_f64();

        let timer = unsafe {
            CFRunLoopTimer::new(
                None,
                now + interval,
                interval,
                0,
                0,
                Some(callback),
                &mut context,
            )
        }
        .unwrap();

        let timer_ptr = CFRetained::as_ptr(&timer);
        event_loop_state.timers.timers.borrow_mut().insert(timer_ptr, Rc::clone(&state));

        let run_loop = CFRunLoop::main().unwrap();
        run_loop.add_timer(Some(&timer), unsafe { kCFRunLoopCommonModes });

        state.timer.set(Some(timer));

        Ok(state)
    }

    pub fn cancel(&self) {
        if let Some(timer) = self.timer.take() {
            let timer_ptr = CFRetained::as_ptr(&timer);
            self.event_loop.state.timers.timers.borrow_mut().remove(&timer_ptr);

            timer.invalidate();
        }
    }
}

pub struct Timers {
    timers: RefCell<HashMap<NonNull<CFRunLoopTimer>, Rc<TimerState>>>,
}

impl Timers {
    pub fn new() -> Timers {
        Timers {
            timers: RefCell::new(HashMap::new()),
        }
    }
}