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//! Internal helper macros for the typed collection wrappers.
//!
//! None of these are part of the public API — they are `pub(crate)`
//! re-exports usable only inside the `vsdb` crate.
macro_rules! define_map_wrapper {
(
$(#[$struct_doc:meta])*
$vis:vis struct $wrapper_name:ident <$($wrapper_generics:tt),*> {
$inner_vis:vis inner: $inner_type:ty,
$phantom_field:ident: $phantom_type:ty,
}
where $($trait_bounds:tt)+
) => {
$(#[$struct_doc])*
#[derive(PartialEq, Eq, Debug)]
$vis struct $wrapper_name<$($wrapper_generics),*> {
$inner_vis inner: $inner_type,
$phantom_field: $phantom_type,
}
impl<$($wrapper_generics),*> serde::Serialize for $wrapper_name<$($wrapper_generics),*> {
fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
$crate::common::serialize_typed_handle_meta::<Self, S>(&self.inner, serializer)
}
}
impl<'de, $($wrapper_generics),*> serde::Deserialize<'de> for $wrapper_name<$($wrapper_generics),*> {
fn deserialize<D>(deserializer: D) -> std::result::Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
$crate::common::deserialize_typed_handle_meta::<Self, $inner_type, D>(deserializer)
.map(|inner| Self { inner, $phantom_field: std::marker::PhantomData })
}
}
impl<$($wrapper_generics),*> $wrapper_name<$($wrapper_generics),*>
where
$($trait_bounds)+
{
/// # Safety
///
/// Creates a second handle to the same underlying storage, bypassing
/// Rust's aliasing guarantees. The caller **must** ensure no
/// concurrent writes to the same key through any handle. Multiple
/// writers on disjoint keys are safe. Concurrent reads alongside
/// writes are safe (the engine provides snapshot isolation).
#[inline(always)]
pub unsafe fn shadow(&self) -> Self {
Self {
// SAFETY: forwards this fn's `unsafe` contract — the
// caller guarantees no concurrent writes to the same
// key through any handle.
inner: unsafe { self.inner.shadow() },
$phantom_field: std::marker::PhantomData,
}
}
/// # Safety
///
/// Reconstructs a handle from a raw byte slice that was previously
/// produced by [`as_bytes`](Self::as_bytes) on a valid instance of
/// the **same type**. The caller must ensure `s` encodes a prefix
/// they have unique ownership of. Passing arbitrary bytes
/// (corrupted, truncated, or from a different type) is undefined
/// behavior and may cause panics or silent data corruption on
/// subsequent operations.
#[inline(always)]
pub unsafe fn from_bytes(s: impl AsRef<[u8]>) -> Self {
Self {
// SAFETY: forwards this fn's `unsafe` contract — the
// caller guarantees `s` encodes a uniquely-owned prefix.
inner: unsafe { <$inner_type>::from_bytes(s) },
$phantom_field: std::marker::PhantomData,
}
}
#[inline(always)]
pub fn as_bytes(&self) -> &[u8] {
self.inner.as_bytes()
}
/// Creates a new instance in the current ambient namespace
/// ([`Namespace::current`](vsdb_core::Namespace::current)).
#[inline(always)]
pub fn new() -> Self {
Self {
inner: <$inner_type>::new(),
$phantom_field: std::marker::PhantomData,
}
}
/// Creates a new instance placed in `ns` — the explicit form
/// of the ambient-scope placement performed by
/// [`new`](Self::new).
#[inline(always)]
pub fn new_in(ns: &$crate::common::Namespace) -> Self {
Self {
inner: <$inner_type>::new_in(ns),
$phantom_field: std::marker::PhantomData,
}
}
/// The namespace this structure lives in — the co-location
/// primitive: `new_in(&existing.namespace())` places new
/// data together with `existing`.
#[inline(always)]
pub fn namespace(&self) -> $crate::common::Namespace {
self.inner.namespace()
}
#[inline(always)]
pub fn clear(&mut self) {
self.inner.clear();
}
#[inline(always)]
pub fn is_the_same_instance(&self, other_hdr: &Self) -> bool {
self.inner.is_the_same_instance(&other_hdr.inner)
}
/// Returns the complete public identity of this instance:
/// `{ map_id, ns }` (`ns: None` ⇔ default namespace). A
/// pre-v16 bare `u64` id equals `InstanceId::from(u64)`.
#[inline(always)]
pub fn instance_id(&self) -> $crate::common::InstanceId {
let mut bytes = [0u8; 8];
bytes.copy_from_slice(self.as_bytes());
let ns_id = self.namespace().id();
$crate::common::InstanceId {
map_id: u64::from_le_bytes(bytes),
ns: (ns_id != $crate::common::DEFAULT_NS_ID).then_some(ns_id),
}
}
/// Persists this instance's metadata to disk (in its owning
/// namespace's meta directory) so that it can be recovered
/// later via [`from_meta`](Self::from_meta).
///
/// Returns the [`InstanceId`](vsdb_core::InstanceId) that
/// should be passed to `from_meta`.
pub fn save_meta(&self) -> $crate::common::error::Result<$crate::common::InstanceId> {
let id = self.instance_id();
$crate::common::save_instance_meta(id, self)?;
Ok(id)
}
/// Recovers an instance from previously saved metadata.
///
/// The caller must ensure that the underlying VSDB database still
/// contains the data referenced by this instance ID.
///
/// # Aliasing warning
///
/// The returned handle is a **full alias** of the original
/// instance, not an independent copy — it addresses the exact
/// same underlying key range (this is how
/// [`instance_id`](Self::instance_id) is recovered: it *is*
/// the raw prefix). If the original handle that produced
/// this `instance_id` (or another `from_meta`/`shadow`
/// restore of it) is still alive in-process, the same
/// no-concurrent-writes-to-the-same-key discipline
/// documented on [`shadow`](Self::shadow) applies across
/// **every** live alias: no concurrent writes to the same
/// key through any handle.
/// `from_meta` is intended to restore a handle after the
/// original has gone out of scope (e.g. across a process
/// restart); calling it while the original is still live
/// requires the same care as `shadow()`, even though this
/// function is safe Rust.
pub fn from_meta(
instance_id: impl Into<$crate::common::InstanceId>,
) -> $crate::common::error::Result<Self> {
$crate::common::load_instance_meta(instance_id.into())
}
}
impl<$($wrapper_generics),*> Clone for $wrapper_name<$($wrapper_generics),*>
{
fn clone(&self) -> Self {
Self {
inner: self.inner.clone(),
$phantom_field: std::marker::PhantomData,
}
}
}
impl<$($wrapper_generics),*> Default for $wrapper_name<$($wrapper_generics),*>
where
$($trait_bounds)+
{
fn default() -> Self {
Self::new()
}
}
};
}
pub(crate) use define_map_wrapper;
macro_rules! entry_or_insert_via_mock {
($slf:expr, $hdr_ty:ty, $get_mut_call:ident($($get_mut_args:expr),*), $mock_call:ident($($mock_args:expr),*)) => {{
let hdr = $slf.hdr as *mut $hdr_ty;
// SAFETY: `hdr` is cast straight from `$slf.hdr: &'a mut $hdr_ty`,
// so it is non-null, aligned, and carries that exclusive
// borrow's provenance for the full lifetime `'a`; nothing else
// touches `$slf.hdr` between the cast and the last use below.
// The two dereferences are in mutually exclusive match arms and
// never coexist; each reborrows exclusively within `'a`, so no
// aliasing occurs.
match unsafe { &mut *hdr }.$get_mut_call($($get_mut_args),*) {
Some(v) => v,
_ => unsafe { &mut *hdr }.$mock_call($($mock_args),*),
}
}};
}
pub(crate) use entry_or_insert_via_mock;
macro_rules! cow_bytes_bounds {
($bounds:expr) => {{
use std::{borrow::Cow, ops::Bound};
// Bind once: evaluating `$bounds` twice could yield inconsistent
// start/end bounds for non-idempotent expressions.
let b = &($bounds);
let l = match b.start_bound() {
Bound::Included(lo) => Bound::Included(Cow::Owned(
$crate::common::ende::KeyEnDeOrdered::to_bytes(lo),
)),
Bound::Excluded(lo) => Bound::Excluded(Cow::Owned(
$crate::common::ende::KeyEnDeOrdered::to_bytes(lo),
)),
Bound::Unbounded => Bound::Unbounded,
};
let h = match b.end_bound() {
Bound::Included(hi) => Bound::Included(Cow::Owned(
$crate::common::ende::KeyEnDeOrdered::to_bytes(hi),
)),
Bound::Excluded(hi) => Bound::Excluded(Cow::Owned(
$crate::common::ende::KeyEnDeOrdered::to_bytes(hi),
)),
Bound::Unbounded => Bound::Unbounded,
};
(l, h)
}};
}
pub(crate) use cow_bytes_bounds;