logo
  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
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
//! Archived versions of shared pointers.

#[cfg(feature = "validation")]
pub mod validation;

use crate::{
    ser::{Serializer, SharedSerializeRegistry},
    ArchivePointee, ArchiveUnsized, MetadataResolver, RelPtr, SerializeUnsized,
};
use core::{borrow::Borrow, cmp, fmt, hash, marker::PhantomData, ops::Deref, pin::Pin, ptr};

/// An archived `Rc`.
///
/// This is a thin wrapper around a [`RelPtr`] to the archived type paired with a "flavor" type.
/// Because there may be many varieties of shared pointers and they may not be used together, the
/// flavor helps check that memory is not being shared incorrectly during validation.
#[repr(transparent)]
pub struct ArchivedRc<T: ArchivePointee + ?Sized, F>(RelPtr<T>, PhantomData<F>);

impl<T: ArchivePointee + ?Sized, F> ArchivedRc<T, F> {
    /// Gets the value of the `ArchivedRc`.
    #[inline]
    pub fn get(&self) -> &T {
        unsafe { &*self.0.as_ptr() }
    }

    /// Gets the pinned mutable value of this `ArchivedRc`.
    ///
    /// # Safety
    ///
    /// Any other `ArchivedRc` pointers to the same value must not be dereferenced for the duration
    /// of the returned borrow.
    #[inline]
    pub unsafe fn get_pin_mut_unchecked(self: Pin<&mut Self>) -> Pin<&mut T> {
        self.map_unchecked_mut(|s| &mut *s.0.as_mut_ptr())
    }

    /// Resolves an archived `Rc` from a given reference.
    ///
    /// # Safety
    ///
    /// - `pos` must be the position of `out` within the archive
    /// - `resolver` must be the result of serializing `value`
    #[inline]
    pub unsafe fn resolve_from_ref<U: ArchiveUnsized<Archived = T> + ?Sized>(
        value: &U,
        pos: usize,
        resolver: RcResolver<MetadataResolver<U>>,
        out: *mut Self,
    ) {
        let (fp, fo) = out_field!(out.0);
        value.resolve_unsized(pos + fp, resolver.pos, resolver.metadata_resolver, fo);
    }

    /// Serializes an archived `Rc` from a given reference.
    #[inline]
    pub fn serialize_from_ref<
        U: SerializeUnsized<S> + ?Sized,
        S: Serializer + SharedSerializeRegistry + ?Sized,
    >(
        value: &U,
        serializer: &mut S,
    ) -> Result<RcResolver<MetadataResolver<U>>, S::Error> {
        Ok(RcResolver {
            pos: serializer.serialize_shared(value)?,
            metadata_resolver: value.serialize_metadata(serializer)?,
        })
    }
}

impl<T: ArchivePointee + ?Sized, F> AsRef<T> for ArchivedRc<T, F> {
    #[inline]
    fn as_ref(&self) -> &T {
        self.get()
    }
}

impl<T: ArchivePointee + ?Sized, F> Borrow<T> for ArchivedRc<T, F> {
    #[inline]
    fn borrow(&self) -> &T {
        self.get()
    }
}

impl<T: ArchivePointee + fmt::Debug + ?Sized, F> fmt::Debug for ArchivedRc<T, F> {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.get().fmt(f)
    }
}

impl<T: ArchivePointee + ?Sized, F> Deref for ArchivedRc<T, F> {
    type Target = T;

    #[inline]
    fn deref(&self) -> &Self::Target {
        self.get()
    }
}

impl<T: ArchivePointee + fmt::Display + ?Sized, F> fmt::Display for ArchivedRc<T, F> {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.get().fmt(f)
    }
}

impl<T: ArchivePointee + Eq + ?Sized, F> Eq for ArchivedRc<T, F> {}

impl<T: ArchivePointee + hash::Hash + ?Sized, F> hash::Hash for ArchivedRc<T, F> {
    fn hash<H: hash::Hasher>(&self, state: &mut H) {
        self.get().hash(state)
    }
}

impl<T: ArchivePointee + Ord + ?Sized, F> Ord for ArchivedRc<T, F> {
    fn cmp(&self, other: &Self) -> cmp::Ordering {
        self.get().cmp(other.get())
    }
}

impl<T, TF, U, UF> PartialEq<ArchivedRc<U, UF>> for ArchivedRc<T, TF>
where
    T: ArchivePointee + PartialEq<U> + ?Sized,
    U: ArchivePointee + ?Sized,
{
    fn eq(&self, other: &ArchivedRc<U, UF>) -> bool {
        self.get().eq(other.get())
    }
}

impl<T, TF, U, UF> PartialOrd<ArchivedRc<U, UF>> for ArchivedRc<T, TF>
where
    T: ArchivePointee + PartialOrd<U> + ?Sized,
    U: ArchivePointee + ?Sized,
{
    fn partial_cmp(&self, other: &ArchivedRc<U, UF>) -> Option<cmp::Ordering> {
        self.get().partial_cmp(other.get())
    }
}

impl<T, F> fmt::Pointer for ArchivedRc<T, F> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt::Pointer::fmt(&self.0.base(), f)
    }
}

/// The resolver for `Rc`.
pub struct RcResolver<T> {
    pos: usize,
    metadata_resolver: T,
}

/// An archived `rc::Weak`.
///
/// This is essentially just an optional [`ArchivedRc`].
#[repr(u8)]
pub enum ArchivedRcWeak<T: ArchivePointee + ?Sized, F> {
    /// A null weak pointer
    None,
    /// A weak pointer to some shared pointer
    Some(ArchivedRc<T, F>),
}

impl<T: ArchivePointee + ?Sized, F> ArchivedRcWeak<T, F> {
    /// Attempts to upgrade the weak pointer to an `ArchivedArc`.
    ///
    /// Returns `None` if a null weak pointer was serialized.
    #[inline]
    pub fn upgrade(&self) -> Option<&ArchivedRc<T, F>> {
        match self {
            ArchivedRcWeak::None => None,
            ArchivedRcWeak::Some(r) => Some(r),
        }
    }

    /// Attempts to upgrade a pinned mutable weak pointer.
    #[inline]
    pub fn upgrade_pin_mut(self: Pin<&mut Self>) -> Option<Pin<&mut ArchivedRc<T, F>>> {
        unsafe {
            match self.get_unchecked_mut() {
                ArchivedRcWeak::None => None,
                ArchivedRcWeak::Some(r) => Some(Pin::new_unchecked(r)),
            }
        }
    }

    /// Resolves an archived `Weak` from a given optional reference.
    ///
    /// # Safety
    ///
    /// - `pos` must be the position of `out` within the archive
    /// - `resolver` must be the result of serializing `value`
    #[inline]
    pub unsafe fn resolve_from_ref<U: ArchiveUnsized<Archived = T> + ?Sized>(
        value: Option<&U>,
        pos: usize,
        resolver: RcWeakResolver<MetadataResolver<U>>,
        out: *mut Self,
    ) {
        match resolver {
            RcWeakResolver::None => {
                let out = out.cast::<ArchivedRcWeakVariantNone>();
                ptr::addr_of_mut!((*out).0).write(ArchivedRcWeakTag::None);
            }
            RcWeakResolver::Some(resolver) => {
                let out = out.cast::<ArchivedRcWeakVariantSome<T, F>>();
                ptr::addr_of_mut!((*out).0).write(ArchivedRcWeakTag::Some);

                let (fp, fo) = out_field!(out.1);
                ArchivedRc::resolve_from_ref(value.unwrap(), pos + fp, resolver, fo);
            }
        }
    }

    /// Serializes an archived `Weak` from a given optional reference.
    #[inline]
    pub fn serialize_from_ref<U, S>(
        value: Option<&U>,
        serializer: &mut S,
    ) -> Result<RcWeakResolver<MetadataResolver<U>>, S::Error>
    where
        U: SerializeUnsized<S, Archived = T> + ?Sized,
        S: Serializer + SharedSerializeRegistry + ?Sized,
    {
        Ok(match value {
            None => RcWeakResolver::None,
            Some(r) => RcWeakResolver::Some(ArchivedRc::<T, F>::serialize_from_ref(r, serializer)?),
        })
    }
}

impl<T: ArchivePointee + fmt::Debug + ?Sized, F> fmt::Debug for ArchivedRcWeak<T, F> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "(Weak)")
    }
}

/// The resolver for `rc::Weak`.
pub enum RcWeakResolver<T> {
    /// The weak pointer was null
    None,
    /// The weak pointer was to some shared pointer
    Some(RcResolver<T>),
}

#[allow(dead_code)]
#[repr(u8)]
enum ArchivedRcWeakTag {
    None,
    Some,
}

#[repr(C)]
struct ArchivedRcWeakVariantNone(ArchivedRcWeakTag);

#[repr(C)]
struct ArchivedRcWeakVariantSome<T: ArchivePointee + ?Sized, F>(
    ArchivedRcWeakTag,
    ArchivedRc<T, F>,
);