redb-bincode 0.4.0

use std::fmt;
use std::marker::PhantomData;

use crate::{SortKey, SortOrder, BINCODE_CONFIG};

pub struct AccessGuard<'a, V, IV = &'static [u8]>
where
    IV: redb::Value + 'static,
{
    inner: redb::AccessGuard<'a, IV>,
    _v: PhantomData<V>,
}

impl<'a, V> From<redb::AccessGuard<'a, &'static [u8]>> for AccessGuard<'a, V> {
    fn from(inner: redb::AccessGuard<'a, &'static [u8]>) -> Self {
        Self {
            inner,
            _v: PhantomData,
        }
    }
}

impl<'a, S, V> From<redb::AccessGuard<'a, SortKey<S>>> for AccessGuard<'a, V, SortKey<S>>
where
    S: SortOrder + fmt::Debug,
{
    fn from(inner: redb::AccessGuard<'a, SortKey<S>>) -> Self {
        Self {
            inner,
            _v: PhantomData,
        }
    }
}

impl<V> AccessGuard<'_, V>
where
    V: bincode::Decode<()>,
{
    pub fn value(&self) -> V {
        self.value_try().expect("Invalid encoding")
    }

    pub fn value_try(&self) -> Result<V, bincode::error::DecodeError> {
        bincode::decode_from_slice(self.inner.value(), BINCODE_CONFIG).map(|v| v.0)
    }
}

impl<V, S> AccessGuard<'_, V, SortKey<S>>
where
    V: bincode::Decode<()>,
    S: SortOrder + fmt::Debug,
{
    pub fn value(&self) -> V {
        self.value_try().expect("Invalid encoding")
    }

    pub fn value_try(&self) -> Result<V, bincode::error::DecodeError> {
        bincode::decode_from_slice(self.inner.value(), BINCODE_CONFIG).map(|v| v.0)
    }
}