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

use crate::internals::stream_controller::*;
use crate::prelude::*;
use std::{
  marker::PhantomData,
  sync::{Arc, RwLock},
};

#[derive(Clone)]
pub struct Skip<Item>
where
  Item: Clone + Send + Sync,
{
  count: usize,
  _item: PhantomData<Item>,
}

impl<'a, Item> Skip<Item>
where
  Item: Clone + Send + Sync,
{
  pub fn new(count: usize) -> Skip<Item> {
    Skip { count, _item: PhantomData }
  }
  pub fn execute(&self, source: Observable<'a, Item>) -> Observable<'a, Item> {
    let count = self.count;

    Observable::<Item>::create(move |s| {
      let n = Arc::new(RwLock::new(0));

      let sctl = StreamController::new(s);
      let sctl_next = sctl.clone();
      let sctl_error = sctl.clone();
      let sctl_complete = sctl.clone();

      source.inner_subscribe(sctl.new_observer(
        move |_, x| {
          let emit = {
            let mut n = n.write().unwrap();
            let nn = *n;
            *n += 1;
            nn >= count
          };
          if emit {
            sctl_next.sink_next(x);
          }
        },
        move |_, e| {
          sctl_error.sink_error(e);
        },
        move |serial| sctl_complete.sink_complete(&serial),
      ));
    })
  }
}

impl<'a, Item> Observable<'a, Item>
where
  Item: Clone + Send + Sync,
{
  pub fn skip(&self, count: usize) -> Observable<'a, Item> {
    Skip::new(count).execute(self.clone())
  }
}

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

  #[test]
  fn basic() {
    let o = Observable::create(|s| {
      for n in 0..5 {
        s.next(n);
      }
      s.complete();
    });

    o.skip(2).subscribe(
      print_next_fmt!("{}"),
      print_error!(),
      print_complete!(),
    );
  }

  #[test]
  fn thread() {
    let o = Observable::create(|s| {
      for n in 0..5 {
        if !s.is_subscribed() {
          println!("break!");
          break;
        }
        println!("emit {}", n);
        s.next(n);
        thread::sleep(time::Duration::from_millis(100));
      }
      if s.is_subscribed() {
        s.complete();
      }
    });

    o.skip(2).subscribe(
      print_next_fmt!("{}"),
      print_error!(),
      print_complete!(),
    );
    thread::sleep(time::Duration::from_millis(1000));
  }
}