use crate::{error::mdbx_result, Error, TransactionKind};
use derive_more::*;
use std::{borrow::Cow, slice};
use thiserror::Error;
pub trait TableObject<'tx> {
fn decode(data_val: &[u8]) -> Result<Self, Error>
where
Self: Sized;
#[doc(hidden)]
unsafe fn decode_val<K: TransactionKind>(
_: *const ffi::MDBX_txn,
data_val: &ffi::MDBX_val,
) -> Result<Self, Error>
where
Self: Sized,
{
let s = slice::from_raw_parts(data_val.iov_base as *const u8, data_val.iov_len);
TableObject::decode(s)
}
}
impl<'tx> TableObject<'tx> for Cow<'tx, [u8]> {
fn decode(_: &[u8]) -> Result<Self, Error> {
unreachable!()
}
#[doc(hidden)]
unsafe fn decode_val<K: TransactionKind>(
txn: *const ffi::MDBX_txn,
data_val: &ffi::MDBX_val,
) -> Result<Self, Error> {
let is_dirty = (!K::ONLY_CLEAN) && mdbx_result(ffi::mdbx_is_dirty(txn, data_val.iov_base))?;
let s = slice::from_raw_parts(data_val.iov_base as *const u8, data_val.iov_len);
Ok(if is_dirty {
Cow::Owned(s.to_vec())
} else {
Cow::Borrowed(s)
})
}
}
#[cfg(feature = "lifetimed-bytes")]
impl<'tx> TableObject<'tx> for lifetimed_bytes::Bytes<'tx> {
fn decode(_: &[u8]) -> Result<Self, Error> {
unreachable!()
}
#[doc(hidden)]
unsafe fn decode_val<K: TransactionKind>(
txn: *const ffi::MDBX_txn,
data_val: &ffi::MDBX_val,
) -> Result<Self, Error> {
Cow::<'tx, [u8]>::decode_val::<K>(txn, data_val).map(From::from)
}
}
impl<'tx> TableObject<'tx> for Vec<u8> {
fn decode(data_val: &[u8]) -> Result<Self, Error>
where
Self: Sized,
{
Ok(data_val.to_vec())
}
}
impl<'tx> TableObject<'tx> for () {
fn decode(_: &[u8]) -> Result<Self, Error> {
Ok(())
}
unsafe fn decode_val<K: TransactionKind>(
_: *const ffi::MDBX_txn,
_: &ffi::MDBX_val,
) -> Result<Self, Error> {
Ok(())
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, Deref, DerefMut)]
pub struct ObjectLength(pub usize);
impl<'tx> TableObject<'tx> for ObjectLength {
fn decode(data_val: &[u8]) -> Result<Self, Error>
where
Self: Sized,
{
Ok(Self(data_val.len()))
}
}
impl<'tx, const LEN: usize> TableObject<'tx> for [u8; LEN] {
fn decode(data_val: &[u8]) -> Result<Self, Error>
where
Self: Sized,
{
#[derive(Clone, Debug, Display, Error)]
struct InvalidSize<const LEN: usize> {
got: usize,
}
if data_val.len() != LEN {
return Err(Error::DecodeError(Box::new(InvalidSize::<LEN> {
got: data_val.len(),
})));
}
let mut a = [0; LEN];
a[..].copy_from_slice(data_val);
Ok(a)
}
}