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

use crate::HasHash;
use crate::HashableContent;
use crate::HoloHashOf;
use holochain_serialized_bytes::prelude::*;

/// Represents some piece of content along with its hash representation, so that
/// hashes need not be calculated multiple times.
/// Provides an easy constructor which consumes the content.
// TODO: consider making lazy with OnceCell
#[derive(Serialize, Deserialize)]
pub struct HoloHashed<C: HashableContent> {
    pub(crate) content: C,
    pub(crate) hash: HoloHashOf<C>,
}

impl<C: HashableContent> HasHash<C::HashType> for HoloHashed<C> {
    fn as_hash(&self) -> &HoloHashOf<C> {
        &self.hash
    }

    fn into_hash(self) -> HoloHashOf<C> {
        self.hash
    }
}

impl<C> HoloHashed<C>
where
    C: HashableContent,
{
    /// Combine content with its precalculated hash
    pub fn with_pre_hashed(content: C, hash: HoloHashOf<C>) -> Self {
        Self { content, hash }
    }

    // NB: as_hash and into_hash are provided by the HasHash impl

    /// Accessor for content
    pub fn as_content(&self) -> &C {
        &self.content
    }

    /// Convert to content
    pub fn into_content(self) -> C {
        self.content
    }

    /// Deconstruct as a tuple
    pub fn into_inner(self) -> (C, HoloHashOf<C>) {
        (self.content, self.hash)
    }
}

impl<C> Clone for HoloHashed<C>
where
    C: HashableContent + Clone,
{
    fn clone(&self) -> Self {
        Self {
            content: self.content.clone(),
            hash: self.hash.clone(),
        }
    }
}

impl<C> std::fmt::Debug for HoloHashed<C>
where
    C: HashableContent + std::fmt::Debug,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_fmt(format_args!("HoloHashed({:?})", self.content))?;
        Ok(())
    }
}

impl<C> std::convert::From<HoloHashed<C>> for (C, HoloHashOf<C>)
where
    C: HashableContent,
{
    fn from(g: HoloHashed<C>) -> (C, HoloHashOf<C>) {
        g.into_inner()
    }
}

impl<C> std::ops::Deref for HoloHashed<C>
where
    C: HashableContent,
{
    type Target = C;

    fn deref(&self) -> &Self::Target {
        self.as_content()
    }
}

impl<C> std::convert::AsRef<C> for HoloHashed<C>
where
    C: HashableContent,
{
    fn as_ref(&self) -> &C {
        self.as_content()
    }
}

impl<C> std::borrow::Borrow<C> for HoloHashed<C>
where
    C: HashableContent,
{
    fn borrow(&self) -> &C {
        self.as_content()
    }
}

impl<C> std::cmp::PartialEq for HoloHashed<C>
where
    C: HashableContent,
{
    fn eq(&self, other: &Self) -> bool {
        self.hash == other.hash
    }
}

impl<C> std::cmp::Eq for HoloHashed<C> where C: HashableContent {}

impl<C> std::hash::Hash for HoloHashed<C>
where
    C: HashableContent,
{
    fn hash<StdH: std::hash::Hasher>(&self, state: &mut StdH) {
        std::hash::Hash::hash(&self.hash, state)
    }
}