ufotofu 0.10.1

Abstractions for lazily consuming and producing sequences
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
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199

use crate::prelude::*;

/// A (bulk) producer wrapper which changes the error (type) of the wrapped producer, by passing errors through a function.
///
/// Use the `AsRef<P>` and `AsMut<P>` impls to access the wrapped producer.
///
/// Created via [`ProducerExt::to_map_error`].
///
/// <br/>Counterpart: the [consumer::MapError] type.
#[derive(Debug)]

pub struct MapError<P, Fun> {
    inner: P,
    fun: Option<Fun>,
}

impl<P, Fun> MapError<P, Fun> {
    pub(crate) fn new(inner: P, fun: Fun) -> Self {
        Self {
            inner,
            fun: Some(fun),
        }
    }

    /// Consumes `self` and returns the wrapped producer.
    pub fn into_inner(self) -> P {
        self.inner
    }
}

impl<P, Fun> AsRef<P> for MapError<P, Fun> {
    fn as_ref(&self) -> &P {
        &self.inner
    }
}

impl<P, Fun> AsMut<P> for MapError<P, Fun> {
    fn as_mut(&mut self) -> &mut P {
        &mut self.inner
    }
}

impl<P, Fun, NewErr> Producer for MapError<P, Fun>
where
    P: Producer,
    Fun: FnOnce(P::Error) -> NewErr,
{
    type Item = P::Item;
    type Final = P::Final;
    type Error = NewErr;

    async fn produce(&mut self) -> Result<Either<Self::Item, Self::Final>, Self::Error> {
        self.inner.produce().await.map_err(|err| {
            (self
                .fun
                .take()
                .expect("Must not use a producer after it emitted an error"))(err)
        })
    }

    async fn slurp(&mut self) -> Result<(), Self::Error> {
        self.inner.slurp().await.map_err(|err| {
            (self
                .fun
                .take()
                .expect("Must not use a producer after it emitted an error"))(err)
        })
    }
}

impl<P, Fun, NewErr> BulkProducer for MapError<P, Fun>
where
    P: BulkProducer,
    Fun: FnOnce(P::Error) -> NewErr,
{
    async fn expose_items_gracefully<F, R>(
        &mut self,
        f: F,
    ) -> Result<Either<R, (F, Self::Final)>, (F, Self::Error)>
    where
        F: AsyncFnOnce(&[Self::Item]) -> (usize, R),
    {
        self.inner.expose_items_gracefully(f).await.map_err(|err| {
            (
                err.0,
                (self
                    .fun
                    .take()
                    .expect("Must not use a producer after it emitted an error"))(
                    err.1
                ),
            )
        })
    }
}

/// A (bulk) producer wrapper which changes the error (type) of the wrapped producer, by passing errors through an async function.
///
/// Use the `AsRef<P>` and `AsMut<P>` impls to access the wrapped producer.
///
/// Created via [`ProducerExt::to_map_async_error`].
///
/// <br/>Counterpart: the [consumer::MapAsyncError] type.
#[derive(Debug)]

pub struct MapAsyncError<P, Fun> {
    inner: P,
    fun: Option<Fun>,
}

impl<P, Fun> MapAsyncError<P, Fun> {
    pub(crate) fn new(inner: P, fun: Fun) -> Self {
        Self {
            inner,
            fun: Some(fun),
        }
    }

    /// Consumes `self` and returns the wrapped producer.
    pub fn into_inner(self) -> P {
        self.inner
    }
}

impl<P, Fun> AsRef<P> for MapAsyncError<P, Fun> {
    fn as_ref(&self) -> &P {
        &self.inner
    }
}

impl<P, Fun> AsMut<P> for MapAsyncError<P, Fun> {
    fn as_mut(&mut self) -> &mut P {
        &mut self.inner
    }
}

impl<P, Fun, NewErr> Producer for MapAsyncError<P, Fun>
where
    P: Producer,
    Fun: AsyncFnOnce(P::Error) -> NewErr,
{
    type Item = P::Item;
    type Final = P::Final;
    type Error = NewErr;

    async fn produce(&mut self) -> Result<Either<Self::Item, Self::Final>, Self::Error> {
        match self.inner.produce().await {
            Ok(yay) => Ok(yay),
            Err(err) => Err((self
                .fun
                .take()
                .expect("Must not use a producer after it emitted an error"))(
                err
            )
            .await),
        }
    }

    async fn slurp(&mut self) -> Result<(), Self::Error> {
        match self.inner.slurp().await {
            Ok(yay) => Ok(yay),
            Err(err) => Err((self
                .fun
                .take()
                .expect("Must not use a producer after it emitted an error"))(
                err
            )
            .await),
        }
    }
}

impl<P, Fun, NewErr> BulkProducer for MapAsyncError<P, Fun>
where
    P: BulkProducer,
    Fun: AsyncFnOnce(P::Error) -> NewErr,
{
    async fn expose_items_gracefully<F, R>(
        &mut self,
        f: F,
    ) -> Result<Either<R, (F, Self::Final)>, (F, Self::Error)>
    where
        F: AsyncFnOnce(&[Self::Item]) -> (usize, R),
    {
        match self.inner.expose_items_gracefully(f).await {
            Ok(yay) => Ok(yay),
            Err(err) => Err((
                err.0,
                (self
                    .fun
                    .take()
                    .expect("Must not use a producer after it emitted an error"))(
                    err.1
                )
                .await,
            )),
        }
    }
}