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
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147

use crate::context::AudioNodeId;
use crate::AudioRenderCapacityEvent;

use std::any::Any;
use std::collections::HashMap;
use std::hash::Hash;
use std::sync::{Arc, Mutex};

use crossbeam_channel::Receiver;

/// The Event interface
#[derive(Debug, Clone)]
#[non_exhaustive]
pub struct Event {
    pub type_: &'static str,
}

#[derive(Hash, Eq, PartialEq, Debug)]
pub(crate) enum EventType {
    Ended(AudioNodeId),
    SinkChange,
    StateChange,
    RenderCapacity,
    ProcessorError(AudioNodeId),
    Diagnostics,
}

/// The Error Event interface
#[non_exhaustive]
#[derive(Debug)]
pub struct ErrorEvent {
    /// The error message
    pub message: String,
    /// The object with which panic was originally invoked.
    pub error: Box<dyn Any + Send>,
    /// Inherits from this base Event
    pub event: Event,
}

#[derive(Debug)]
pub(crate) enum EventPayload {
    None,
    RenderCapacity(AudioRenderCapacityEvent),
    ProcessorError(ErrorEvent),
    Diagnostics(Vec<u8>),
}

#[derive(Debug)]
pub(crate) struct EventDispatch {
    type_: EventType,
    payload: EventPayload,
}

impl EventDispatch {
    pub fn ended(id: AudioNodeId) -> Self {
        EventDispatch {
            type_: EventType::Ended(id),
            payload: EventPayload::None,
        }
    }

    pub fn sink_change() -> Self {
        EventDispatch {
            type_: EventType::SinkChange,
            payload: EventPayload::None,
        }
    }

    pub fn state_change() -> Self {
        EventDispatch {
            type_: EventType::StateChange,
            payload: EventPayload::None,
        }
    }

    pub fn render_capacity(value: AudioRenderCapacityEvent) -> Self {
        EventDispatch {
            type_: EventType::RenderCapacity,
            payload: EventPayload::RenderCapacity(value),
        }
    }

    pub fn processor_error(id: AudioNodeId, value: ErrorEvent) -> Self {
        EventDispatch {
            type_: EventType::ProcessorError(id),
            payload: EventPayload::ProcessorError(value),
        }
    }

    pub fn diagnostics(value: Vec<u8>) -> Self {
        EventDispatch {
            type_: EventType::Diagnostics,
            payload: EventPayload::Diagnostics(value),
        }
    }
}

pub(crate) enum EventHandler {
    Once(Box<dyn FnOnce(EventPayload) + Send + 'static>),
    Multiple(Box<dyn FnMut(EventPayload) + Send + 'static>),
}

#[derive(Clone, Default)]
pub(crate) struct EventLoop {
    event_handlers: Arc<Mutex<HashMap<EventType, EventHandler>>>,
}

impl EventLoop {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn run(&self, event_channel: Receiver<EventDispatch>) {
        let self_clone = self.clone();

        std::thread::spawn(move || loop {
            // this thread is dedicated to event handling so we can block
            for event in event_channel.iter() {
                let mut event_handler_lock = self_clone.event_handlers.lock().unwrap();
                let callback_option = event_handler_lock.remove(&event.type_);
                drop(event_handler_lock); // release Mutex while running callback

                if let Some(callback) = callback_option {
                    match callback {
                        EventHandler::Once(f) => (f)(event.payload),
                        EventHandler::Multiple(mut f) => {
                            (f)(event.payload);
                            self_clone
                                .event_handlers
                                .lock()
                                .unwrap()
                                .insert(event.type_, EventHandler::Multiple(f));
                        }
                    };
                }
            }
        });
    }

    pub fn set_handler(&self, event: EventType, callback: EventHandler) {
        self.event_handlers.lock().unwrap().insert(event, callback);
    }

    pub fn clear_handler(&self, event: EventType) {
        self.event_handlers.lock().unwrap().remove(&event);
    }
}