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

//! An archived version of `Box`.

use crate::{ArchivePointee, ArchiveUnsized, Fallible, RelPtr, SerializeUnsized};
use core::{borrow::Borrow, cmp, fmt, hash, ops::Deref, pin::Pin};

/// An archived [`Box`].
///
/// This is a thin wrapper around a [`RelPtr`] to the archived type.
#[repr(transparent)]
pub struct ArchivedBox<T: ArchivePointee + ?Sized>(RelPtr<T>);

impl<T: ArchivePointee + ?Sized> ArchivedBox<T> {
    /// Returns a reference to the value of this archived box.
    #[inline]
    pub fn get(&self) -> &T {
        unsafe { &*self.0.as_ptr() }
    }

    /// Returns a pinned mutable reference to the value of this archived box
    #[inline]
    pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> {
        unsafe { self.map_unchecked_mut(|s| &mut *s.0.as_mut_ptr()) }
    }

    /// Resolves an archived box from the given value and parameters.
    ///
    /// # 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: BoxResolver<U::MetadataResolver>,
        out: *mut Self,
    ) {
        let (fp, fo) = out_field!(out.0);
        value.resolve_unsized(pos + fp, resolver.pos, resolver.metadata_resolver, fo);
    }

    /// Serializes an archived box from the given value and serializer.
    #[inline]
    pub fn serialize_from_ref<U, S>(
        value: &U,
        serializer: &mut S,
    ) -> Result<BoxResolver<U::MetadataResolver>, S::Error>
    where
        U: SerializeUnsized<S, Archived = T> + ?Sized,
        S: Fallible + ?Sized,
    {
        Ok(BoxResolver {
            pos: value.serialize_unsized(serializer)?,
            metadata_resolver: value.serialize_metadata(serializer)?,
        })
    }
}

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

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

impl<T: ArchivePointee + ?Sized> fmt::Debug for ArchivedBox<T>
where
    T::ArchivedMetadata: fmt::Debug,
{
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_tuple("ArchivedBox").field(&self.0).finish()
    }
}

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

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

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

impl<T: ArchivePointee + Eq + ?Sized> Eq for ArchivedBox<T> {}

impl<T: ArchivePointee + hash::Hash + ?Sized> hash::Hash for ArchivedBox<T> {
    #[inline]
    fn hash<H: hash::Hasher>(&self, state: &mut H) {
        self.get().hash(state);
    }
}

impl<T: ArchivePointee + PartialEq<U> + ?Sized, U: ArchivePointee + ?Sized>
    PartialEq<ArchivedBox<U>> for ArchivedBox<T>
{
    #[inline]
    fn eq(&self, other: &ArchivedBox<U>) -> bool {
        self.get().eq(other.get())
    }
}

impl<T: ArchivePointee + PartialOrd + ?Sized> PartialOrd for ArchivedBox<T> {
    #[inline]
    fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
        self.get().partial_cmp(other.get())
    }
}

impl<T: ArchivePointee + ?Sized> fmt::Pointer for ArchivedBox<T> {
    #[inline]
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let ptr = self.get() as *const T;
        fmt::Pointer::fmt(&ptr, f)
    }
}

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

#[cfg(feature = "validation")]
const _: () = {
    use crate::validation::{
        owned::{CheckOwnedPointerError, OwnedPointerError},
        ArchiveContext, LayoutRaw,
    };
    use bytecheck::{CheckBytes, Error};
    use ptr_meta::Pointee;

    impl<T, C> CheckBytes<C> for ArchivedBox<T>
    where
        T: ArchivePointee + CheckBytes<C> + LayoutRaw + Pointee + ?Sized,
        C: ArchiveContext + ?Sized,
        T::ArchivedMetadata: CheckBytes<C>,
        C::Error: Error,
    {
        type Error = CheckOwnedPointerError<T, C>;

        #[inline]
        unsafe fn check_bytes<'a>(
            value: *const Self,
            context: &mut C,
        ) -> Result<&'a Self, Self::Error> {
            let rel_ptr = RelPtr::<T>::manual_check_bytes(value.cast(), context)
                .map_err(OwnedPointerError::PointerCheckBytesError)?;
            let ptr = context
                .check_subtree_rel_ptr(rel_ptr)
                .map_err(OwnedPointerError::ContextError)?;

            let range = context
                .push_prefix_subtree(ptr)
                .map_err(OwnedPointerError::ContextError)?;
            T::check_bytes(ptr, context).map_err(OwnedPointerError::ValueCheckBytesError)?;
            context
                .pop_prefix_range(range)
                .map_err(OwnedPointerError::ContextError)?;

            Ok(&*value)
        }
    }
};