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

use crate::internals::function_wrapper::*;
use crate::prelude::*;
use std::sync::{Arc, RwLock};

#[derive(Clone)]
pub struct Observer<'a, T>
where
  T: Clone + Send + Sync,
{
  fn_next: FunctionWrapper<'a, T, ()>,
  fn_error: FunctionWrapper<'a, RxError, ()>,
  fn_complete: FunctionWrapper<'a, (), ()>,
  fn_on_unsubscribe: Arc<RwLock<Option<FunctionWrapper<'a, (), ()>>>>,
}

impl<'a, T> Observer<'a, T>
where
  T: Clone + Send + Sync,
{
  pub fn new<Next, Error, Complete>(
    next: Next,
    error: Error,
    complete: Complete,
  ) -> Observer<'a, T>
  where
    Next: Fn(T) + Send + Sync + 'a,
    Error: Fn(RxError) + Send + Sync + 'a,
    Complete: Fn() -> () + Send + Sync + 'a,
  {
    Observer::<T> {
      fn_next: FunctionWrapper::new(next),
      fn_error: FunctionWrapper::new(error),
      fn_complete: FunctionWrapper::new(move |_| complete()),
      fn_on_unsubscribe: Arc::new(RwLock::new(None)),
    }
  }
  pub fn next(&self, x: T) {
    self.fn_next.call_if_available(x);
  }
  pub fn error(&self, x: RxError) {
    self.fn_error.call_and_clear_if_available(x);
  }
  pub fn complete(&self) {
    self.fn_complete.call_and_clear_if_available(());
  }
  pub fn unsubscribe(&self) {
    self.fn_next.clear();
    self.fn_error.clear();
    self.fn_complete.clear();
    if let Some(f) = &*self.fn_on_unsubscribe.read().unwrap() {
      f.call(());
    }
    *self.fn_on_unsubscribe.write().unwrap() = None;
  }
  pub fn is_subscribed(&self) -> bool {
    self.fn_next.exists() && self.fn_error.exists() && self.fn_complete.exists()
  }
  pub(crate) fn set_on_unsubscribe<F>(&self, f: F)
  where
    F: Fn() -> () + Send + Sync + 'a,
  {
    *self.fn_on_unsubscribe.write().unwrap() =
      Some(FunctionWrapper::new(move |_| f()));
  }
}

#[cfg(test)]
mod test {
  use crate::prelude::*;
  use std::thread;

  #[test]
  fn basic() {
    let ob = Observer::new(
      print_next_fmt!("{}"),
      print_error_as!(&str),
      print_complete!(),
    );
    ob.next(1);
    ob.next(2);
    ob.error(RxError::from_error("ERR!"));
    ob.complete();
  }

  #[test]
  fn basic_with_capture() {
    let gain = 100;
    let ob = Observer::new(
      move |x| println!("next {}", x + gain),
      print_error_as!(&str),
      print_complete!(),
    );
    ob.next(1);
    ob.next(2);
    ob.error(RxError::from_error("ERR!"));
    ob.complete();
  }

  #[test]
  fn close() {
    let ob = Observer::new(
      print_next_fmt!("{}"),
      print_error!(),
      print_complete!(),
    );
    ob.next(1);
    ob.next(2);
    ob.unsubscribe();
  }

  #[test]
  fn clone_into_thread() {
    let ob = Observer::new(
      print_next_fmt!("{}"),
      print_error!(),
      print_complete!(),
    );
    let a = ob.clone();
    let b = ob.clone();
    let th_a = thread::spawn(move || {
      for n in 0..100 {
        a.next(n);
      }
      a.complete();
    });
    let th_b = thread::spawn(move || {
      for n in 0..10 {
        b.next(100 + n);
      }
      b.complete();
    });

    th_a.join().ok();
    th_b.join().ok();
  }
}