summaryrefslogtreecommitdiffstats
path: root/third_party/rust/serde_bytes/src/de.rs
blob: e4a4732eea3a6558fa6ca1939b1704b6db6b4e46 (plain)
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
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
use crate::Bytes;
use core::fmt;
use core::marker::PhantomData;
use serde::de::{Error, Visitor};
use serde::Deserializer;

#[cfg(any(feature = "std", feature = "alloc"))]
use crate::ByteBuf;

#[cfg(any(feature = "std", feature = "alloc"))]
use core::cmp;

#[cfg(feature = "alloc")]
use alloc::borrow::Cow;
#[cfg(all(feature = "std", not(feature = "alloc")))]
use std::borrow::Cow;

#[cfg(feature = "alloc")]
use alloc::boxed::Box;
#[cfg(feature = "alloc")]
use alloc::string::String;
#[cfg(feature = "alloc")]
use alloc::vec::Vec;

#[cfg(any(feature = "std", feature = "alloc"))]
use serde::de::SeqAccess;

/// Types that can be deserialized via `#[serde(with = "serde_bytes")]`.
pub trait Deserialize<'de>: Sized {
    #[allow(missing_docs)]
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>;
}

impl<'de: 'a, 'a> Deserialize<'de> for &'a [u8] {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        // serde::Deserialize for &[u8] is already optimized, so simply forward to that.
        serde::Deserialize::deserialize(deserializer)
    }
}

#[cfg(any(feature = "std", feature = "alloc"))]
impl<'de> Deserialize<'de> for Vec<u8> {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        Deserialize::deserialize(deserializer).map(ByteBuf::into_vec)
    }
}

impl<'de: 'a, 'a> Deserialize<'de> for &'a Bytes {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        // serde::Deserialize for &[u8] is already optimized, so simply forward to that.
        serde::Deserialize::deserialize(deserializer).map(Bytes::new)
    }
}

#[cfg(any(feature = "std", feature = "alloc"))]
impl<'de> Deserialize<'de> for ByteBuf {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        // Via the serde::Deserialize impl for ByteBuf.
        serde::Deserialize::deserialize(deserializer)
    }
}

#[cfg(any(feature = "std", feature = "alloc"))]
impl<'de: 'a, 'a> Deserialize<'de> for Cow<'a, [u8]> {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        struct CowVisitor;

        impl<'de> Visitor<'de> for CowVisitor {
            type Value = Cow<'de, [u8]>;

            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                formatter.write_str("a byte array")
            }

            fn visit_borrowed_bytes<E>(self, v: &'de [u8]) -> Result<Self::Value, E>
            where
                E: Error,
            {
                Ok(Cow::Borrowed(v))
            }

            fn visit_borrowed_str<E>(self, v: &'de str) -> Result<Self::Value, E>
            where
                E: Error,
            {
                Ok(Cow::Borrowed(v.as_bytes()))
            }

            fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
            where
                E: Error,
            {
                Ok(Cow::Owned(v.to_vec()))
            }

            fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
            where
                E: Error,
            {
                Ok(Cow::Owned(v.as_bytes().to_vec()))
            }

            fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
            where
                E: Error,
            {
                Ok(Cow::Owned(v))
            }

            fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
            where
                E: Error,
            {
                Ok(Cow::Owned(v.into_bytes()))
            }

            fn visit_seq<V>(self, mut visitor: V) -> Result<Self::Value, V::Error>
            where
                V: SeqAccess<'de>,
            {
                let len = cmp::min(visitor.size_hint().unwrap_or(0), 4096);
                let mut bytes = Vec::with_capacity(len);

                while let Some(b) = visitor.next_element()? {
                    bytes.push(b);
                }

                Ok(Cow::Owned(bytes))
            }
        }

        deserializer.deserialize_bytes(CowVisitor)
    }
}

#[cfg(any(feature = "std", feature = "alloc"))]
impl<'de: 'a, 'a> Deserialize<'de> for Cow<'a, Bytes> {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        let cow: Cow<[u8]> = Deserialize::deserialize(deserializer)?;
        match cow {
            Cow::Borrowed(bytes) => Ok(Cow::Borrowed(Bytes::new(bytes))),
            Cow::Owned(bytes) => Ok(Cow::Owned(ByteBuf::from(bytes))),
        }
    }
}

#[cfg(any(feature = "std", feature = "alloc"))]
impl<'de> Deserialize<'de> for Box<[u8]> {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        Deserialize::deserialize(deserializer).map(Vec::into_boxed_slice)
    }
}

#[cfg(any(feature = "std", feature = "alloc"))]
impl<'de> Deserialize<'de> for Box<Bytes> {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        let bytes: Box<[u8]> = Deserialize::deserialize(deserializer)?;
        Ok(bytes.into())
    }
}

impl<'de, T> Deserialize<'de> for Option<T>
where
    T: Deserialize<'de>,
{
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        struct BytesVisitor<T> {
            out: PhantomData<T>,
        }

        impl<'de, T> Visitor<'de> for BytesVisitor<T>
        where
            T: Deserialize<'de>,
        {
            type Value = Option<T>;

            fn expecting(&self, f: &mut fmt::Formatter) -> fmt::Result {
                f.write_str("optional byte array")
            }

            fn visit_unit<E: Error>(self) -> Result<Self::Value, E> {
                Ok(None)
            }

            fn visit_none<E: Error>(self) -> Result<Self::Value, E> {
                Ok(None)
            }

            fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
            where
                D: Deserializer<'de>,
            {
                T::deserialize(deserializer).map(Some)
            }
        }

        let visitor = BytesVisitor { out: PhantomData };
        deserializer.deserialize_option(visitor)
    }
}