fabaccess-bffh/bffhd/resources/state/value.rs
Nadja Reitzenstein b02afe5575 Splitting config
2022-04-21 23:04:07 +02:00

649 lines
20 KiB
Rust

use std::{any::Any, fmt, hash::Hash, ptr, str::FromStr};
use ptr_meta::{DynMetadata, Pointee};
use rkyv::{
out_field, Archive, ArchivePointee, ArchiveUnsized, Archived, ArchivedMetadata, Deserialize,
DeserializeUnsized, Fallible, Serialize, SerializeUnsized,
};
use rkyv_dyn::{DynDeserializer, DynError, DynSerializer};
use crate::utils::oid::ObjectIdentifier;
// Not using linkme because dynamically loaded modules
use inventory;
use rkyv::ser::{ScratchSpace, Serializer};
use serde::de::Error as SerdeError;
use serde::ser::SerializeMap;
use std::alloc::Layout;
use std::collections::HashMap;
use std::fmt::Formatter;
use std::mem::MaybeUninit;
/// Adding a custom type to BFFH state management:
///
/// 1. Implement `serde`'s [`Serialize`](serde::Serialize) and [`Deserialize`](serde::Deserialize)
/// - `derive()`d instances work just fine, but keep stability over releases in mind.
/// 2. Implement rkyv's [`Serialize`](rkyv::Serialize).
/// 3. Implement TypeOid on your Archived type (i.e. `<T as Archive>::Archived`)
/// 4. Implement this
pub trait Value: Any + fmt::Debug + erased_serde::Serialize + Sync {
/// Initialize `&mut self` from `deserializer`
///
/// At the point this is called &mut self is of undefined value but guaranteed to be well
/// aligned and non-null. Any read access into &mut self before all of &self is brought into
/// a valid state is however undefined behaviour.
/// To this end you *must* initialize `self` **completely**. Serde will do the right thing if
/// you directly deserialize the type you're implementing `Value` for, but for manual
/// implementations this is important to keep in mind.
fn deserialize_init<'de>(
&mut self,
deserializer: &mut dyn erased_serde::Deserializer<'de>,
) -> Result<(), erased_serde::Error>;
/// Implement `PartialEq` dynamically.
///
/// This should return `true` iff the Value is of the same type and `self` == `other` for
/// non-dynamic types would return `true`.
/// It is safe to always return `false`.
fn dyn_eq(&self, other: &dyn Value) -> bool;
fn as_value(&self) -> &dyn Value;
fn as_any(&self) -> &dyn Any;
}
erased_serde::serialize_trait_object!(Value);
erased_serde::serialize_trait_object!(SerializeValue);
erased_serde::serialize_trait_object!(DeserializeValue);
impl<T> Value for T
where
T: Any
+ fmt::Debug
+ PartialEq
+ Sync
+ erased_serde::Serialize
+ for<'de> serde::Deserialize<'de>,
{
fn deserialize_init<'de>(
&mut self,
deserializer: &mut dyn erased_serde::Deserializer<'de>,
) -> Result<(), erased_serde::Error> {
*self = erased_serde::deserialize(deserializer)?;
Ok(())
}
fn dyn_eq(&self, other: &dyn Value) -> bool {
other
.as_any()
.downcast_ref()
.map_or(false, |other: &T| other == self)
}
fn as_value(&self) -> &dyn Value {
self
}
fn as_any(&self) -> &dyn Any {
self
}
}
impl PartialEq for dyn Value {
fn eq(&self, other: &Self) -> bool {
self.dyn_eq(other)
}
}
#[repr(transparent)]
pub(super) struct DynVal<'a>(pub &'a dyn SerializeValue);
impl<'a> serde::Serialize for DynVal<'a> {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
let mut ser = serializer.serialize_map(Some(1))?;
let oid = self.0.archived_type_oid();
ser.serialize_entry(oid, self.0)?;
ser.end()
}
}
#[repr(transparent)]
pub(super) struct DynOwnedVal(pub Box<dyn SerializeValue>);
impl<'de> serde::Deserialize<'de> for DynOwnedVal {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
deserializer.deserialize_map(DynValVisitor)
}
}
struct DynValVisitor;
impl<'de> serde::de::Visitor<'de> for DynValVisitor {
type Value = DynOwnedVal;
fn expecting(&self, formatter: &mut Formatter) -> fmt::Result {
write!(formatter, "an one entry map from OID to some value object")
}
fn visit_map<A: serde::de::MapAccess<'de>>(self, mut map: A) -> Result<Self::Value, A::Error> {
// Bad magic code. Problem we have to solve: We only know how to parse whatever comes
// after the OID after having looked at the OID. We have zero static type info available
// during deserialization. So:
// Get OID first. That's easy, we know it's the key, we know how to read it.
let oid: ObjectIdentifier = map.next_key()?.ok_or(A::Error::missing_field("oid"))?;
// Get the Value vtable for that OID. Or fail because we don't know that OID, either works.
let valimpl = IMPL_REGISTRY.get(ImplId::from_type_oid(&oid)).ok_or(
serde::de::Error::invalid_value(
serde::de::Unexpected::Other("unknown oid"),
&"oid an implementation was registered for",
),
)?;
// Casting random usize you find on the side of the road as vtable on unchecked pointers.
// What could possibly go wrong? >:D
let valbox: MaybeUninit<Box<dyn SerializeValue>> = unsafe {
// "recreate" vtable as fat ptr metadata (we literally just cast an `usize` but the
// only way to put this usize into that spot is by having a valid vtable cast so it's
// probably almost safe)
let meta = valimpl.pointer_metadata();
// Don't bother checking here. The only way this could be bad is if the vtable above
// is bad an in that case a segfault here would be *much better* than whatever is
// going to happen afterwards.
let layout = Layout::from_size_align_unchecked(meta.size_of(), meta.align_of());
// Hello yes I would like a Box the old fashioned way.
// Oh you're asking why we're allocating stuff here and never ever bother zeroing or
// validate in any other way if this is sane?
// Well...
let ptr: *mut () = std::alloc::alloc(layout).cast::<()>();
let b = Box::from_raw(ptr_meta::from_raw_parts_mut(ptr, meta));
// We make this a MaybeUninit so `Drop` is never called on the uninitialized value
MaybeUninit::new(b)
};
// ... The only way we can make Value a trait object by having it deserialize *into
// it's own uninitialized representation*. Yeah don't worry, this isn't the worst part of
// the game yet. >:D
let seed = InitIntoSelf(valbox);
let val = map.next_value_seed(seed)?;
Ok(DynOwnedVal(val))
}
}
struct InitIntoSelf(MaybeUninit<Box<dyn SerializeValue>>);
impl<'de> serde::de::DeserializeSeed<'de> for InitIntoSelf {
type Value = Box<dyn SerializeValue>;
fn deserialize<D>(mut self, deserializer: D) -> Result<Self::Value, D::Error>
where
D: serde::Deserializer<'de>,
{
let mut deser = <dyn erased_serde::Deserializer>::erase(deserializer);
// Unsafe as hell but if we never read from this reference before initializing it's not
// undefined behaviour.
let selfptr = unsafe { &mut *self.0.as_mut_ptr() };
// Hey, better initialize late than never.
selfptr
.deserialize_init(&mut deser)
.map_err(|e| D::Error::custom(e))?;
// Assuming `deserialize_init` didn't error and did its job this is now safe.
unsafe { Ok(self.0.assume_init()) }
}
}
pub trait TypeOid {
fn type_oid() -> &'static ObjectIdentifier;
fn type_name() -> &'static str;
fn type_desc() -> &'static str;
}
impl<S: ScratchSpace + Serializer + ?Sized> SerializeUnsized<S> for dyn SerializeValue {
fn serialize_unsized(&self, mut serializer: &mut S) -> Result<usize, S::Error> {
self.serialize_dynoid(&mut serializer)
.map_err(|e| *e.downcast::<S::Error>().unwrap())
}
fn serialize_metadata(&self, serializer: &mut S) -> Result<Self::MetadataResolver, S::Error> {
let oid = self.archived_type_oid();
oid.serialize(serializer)
}
}
/// Serialize dynamic types by storing an OID alongside
pub trait SerializeDynOid {
fn serialize_dynoid(&self, serializer: &mut dyn DynSerializer) -> Result<usize, DynError>;
fn archived_type_oid(&self) -> &'static ObjectIdentifier;
}
impl<T> SerializeDynOid for T
where
T: for<'a> Serialize<dyn DynSerializer + 'a>,
T::Archived: TypeOid,
{
fn serialize_dynoid(&self, serializer: &mut dyn DynSerializer) -> Result<usize, DynError> {
serializer.serialize_value(self)
}
fn archived_type_oid(&self) -> &'static ObjectIdentifier {
Archived::<T>::type_oid()
}
}
pub trait DeserializeDynOid {
unsafe fn deserialize_dynoid(
&self,
deserializer: &mut dyn DynDeserializer,
alloc: &mut dyn FnMut(Layout) -> *mut u8,
) -> Result<*mut (), DynError>;
fn deserialize_dynoid_metadata(
&self,
deserializer: &mut dyn DynDeserializer,
) -> Result<<dyn SerializeValue as Pointee>::Metadata, DynError>;
}
#[ptr_meta::pointee]
pub trait SerializeValue: Value + SerializeDynOid {
fn dyn_clone(&self) -> Box<dyn SerializeValue>;
}
impl<T: Archive + Value + SerializeDynOid + Clone> SerializeValue for T
where
T::Archived: RegisteredImpl,
{
fn dyn_clone(&self) -> Box<dyn SerializeValue> {
Box::new(self.clone())
}
}
impl PartialEq for dyn SerializeValue {
fn eq(&self, other: &Self) -> bool {
self.dyn_eq(other.as_value())
}
}
impl Clone for Box<dyn SerializeValue> {
fn clone(&self) -> Self {
self.dyn_clone()
}
}
#[ptr_meta::pointee]
pub trait DeserializeValue: DeserializeDynOid {}
impl<T: DeserializeDynOid> DeserializeValue for T {}
impl ArchivePointee for dyn DeserializeValue {
type ArchivedMetadata = ArchivedValueMetadata;
fn pointer_metadata(archived: &Self::ArchivedMetadata) -> <Self as Pointee>::Metadata {
archived.pointer_metadata()
}
}
impl<D: Fallible + ?Sized> DeserializeUnsized<dyn SerializeValue, D> for dyn DeserializeValue {
unsafe fn deserialize_unsized(
&self,
mut deserializer: &mut D,
mut alloc: impl FnMut(Layout) -> *mut u8,
) -> Result<*mut (), D::Error> {
self.deserialize_dynoid(&mut deserializer, &mut alloc)
.map_err(|e| *e.downcast().unwrap())
}
fn deserialize_metadata(
&self,
mut deserializer: &mut D,
) -> Result<<dyn SerializeValue as Pointee>::Metadata, D::Error> {
self.deserialize_dynoid_metadata(&mut deserializer)
.map_err(|e| *e.downcast().unwrap())
}
}
impl ArchiveUnsized for dyn SerializeValue {
type Archived = dyn DeserializeValue;
type MetadataResolver = <ObjectIdentifier as Archive>::Resolver;
unsafe fn resolve_metadata(
&self,
pos: usize,
resolver: Self::MetadataResolver,
out: *mut ArchivedMetadata<Self>,
) {
let (oid_pos, oid) = out_field!(out.type_oid);
let type_oid = self.archived_type_oid();
type_oid.resolve(pos + oid_pos, resolver, oid);
}
}
#[derive(Debug)]
pub struct ArchivedValueMetadata {
pub type_oid: Archived<ObjectIdentifier>,
}
impl ArchivedValueMetadata {
pub unsafe fn emplace(type_oid: Archived<ObjectIdentifier>, out: *mut Self) {
let p = ptr::addr_of_mut!((*out).type_oid);
ptr::write(p, type_oid);
}
pub fn vtable(&self) -> usize {
IMPL_REGISTRY
.get(ImplId::from_type_oid(&self.type_oid))
.expect(&format!(
"Unregistered \
type \
oid \
{:?}",
self.type_oid
))
.vtable
}
pub fn pointer_metadata(&self) -> DynMetadata<dyn DeserializeValue> {
unsafe { core::mem::transmute(self.vtable()) }
}
}
#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
pub struct ImplId<'a> {
type_oid: &'a [u8],
}
impl<'a> ImplId<'a> {
pub fn from_type_oid(type_oid: &'a [u8]) -> Self {
Self { type_oid }
}
}
impl ImplId<'static> {
fn new<T: TypeOid>() -> Self {
Self {
type_oid: &T::type_oid(),
}
}
}
#[derive(Copy, Clone, Debug)]
struct ImplData<'a> {
pub vtable: usize,
pub name: &'a str,
pub desc: &'a str,
pub info: ImplDebugInfo,
}
#[derive(Copy, Clone, Debug)]
#[doc(hidden)]
pub struct ImplDebugInfo {
pub file: &'static str,
pub line: u32,
pub column: u32,
}
impl ImplData<'_> {
pub unsafe fn pointer_metadata<T: ?Sized>(&self) -> DynMetadata<T> {
core::mem::transmute(self.vtable)
}
}
#[derive(Debug)]
pub struct ImplEntry<'a> {
id: ImplId<'a>,
data: ImplData<'a>,
}
inventory::collect!(ImplEntry<'static>);
impl ImplEntry<'_> {
#[doc(hidden)]
pub fn new<T: TypeOid + RegisteredImpl>() -> Self {
Self {
id: ImplId::new::<T>(),
data: ImplData {
vtable: <T as RegisteredImpl>::vtable(),
name: <T as TypeOid>::type_name(),
desc: <T as TypeOid>::type_desc(),
info: <T as RegisteredImpl>::debug_info(),
},
}
}
}
#[derive(Debug)]
struct ImplRegistry {
oid_to_data: HashMap<ImplId<'static>, ImplData<'static>>,
}
impl ImplRegistry {
fn new() -> Self {
Self {
oid_to_data: HashMap::new(),
}
}
fn add_entry(&mut self, entry: &'static ImplEntry) {
let old_val = self.oid_to_data.insert(entry.id, entry.data);
if let Some(old) = old_val {
eprintln!("Value impl oid conflict for {:?}", entry.id.type_oid);
eprintln!(
"Existing impl registered at {}:{}:{}",
old.info.file, old.info.line, old.info.column
);
eprintln!(
"New impl registered at {}:{}:{}",
entry.data.info.file, entry.data.info.line, entry.data.info.column
);
}
assert!(old_val.is_none());
}
fn get(&self, type_oid: ImplId) -> Option<ImplData> {
self.oid_to_data.get(&type_oid).map(|d| *d)
}
}
lazy_static::lazy_static! {
// FIXME: Dynamic modules *will* break this.
static ref IMPL_REGISTRY: ImplRegistry = {
let mut reg = ImplRegistry::new();
for entry in inventory::iter::<ImplEntry> {
reg.add_entry(entry);
}
reg
};
}
pub unsafe trait RegisteredImpl {
fn vtable() -> usize;
fn debug_info() -> ImplDebugInfo;
}
#[macro_use]
pub mod macros {
#[macro_export]
macro_rules! debug_info {
() => {
$crate::resources::state::value::ImplDebugInfo {
file: ::core::file!(),
line: ::core::line!(),
column: ::core::column!(),
}
};
}
#[macro_export]
macro_rules! oiddeser {
( $y:ty, $z:ty ) => {
impl $crate::resources::state::value::DeserializeDynOid for $y
where
$y: for<'a> ::rkyv::Deserialize<$z, (dyn ::rkyv_dyn::DynDeserializer + 'a)>,
{
unsafe fn deserialize_dynoid(
&self,
deserializer: &mut dyn ::rkyv_dyn::DynDeserializer,
alloc: &mut dyn FnMut(::core::alloc::Layout) -> *mut u8,
) -> Result<*mut (), ::rkyv_dyn::DynError> {
let ptr = alloc(::core::alloc::Layout::new::<$z>()).cast::<$z>();
ptr.write(self.deserialize(deserializer)?);
Ok(ptr as *mut ())
}
fn deserialize_dynoid_metadata(
&self,
_: &mut dyn ::rkyv_dyn::DynDeserializer,
) -> ::std::result::Result<<dyn $crate::resources::state::value::SerializeValue
as
::ptr_meta::Pointee>::Metadata, ::rkyv_dyn::DynError> {
unsafe {
Ok(core::mem::transmute(ptr_meta::metadata(
::core::ptr::null::<$z>() as *const dyn $crate::resources::state::value::SerializeValue,
)))
}
}
}
};
}
#[macro_export]
macro_rules! oidvalue {
( $x:ident, $y:ty ) => {
$crate::oidvalue! {$x, $y, $y}
};
( $x:ident, $y:ty, $z:ty ) => {
$crate::oiddeser! {$z, $y}
impl $crate::resources::state::value::TypeOid for $z {
fn type_oid() -> &'static $crate::utils::oid::ObjectIdentifier {
&$x
}
fn type_name() -> &'static str {
stringify!($y)
}
fn type_desc() -> &'static str {
"builtin"
}
}
unsafe impl $crate::resources::state::value::RegisteredImpl for $z {
fn vtable() -> usize {
unsafe {
::core::mem::transmute(ptr_meta::metadata(
::core::ptr::null::<$z>() as *const dyn $crate::resources::state::value::DeserializeValue
))
}
}
fn debug_info() -> $crate::resources::state::value::ImplDebugInfo {
$crate::debug_info!()
}
}
::inventory::submit! {$crate::resources::state::value::ImplEntry::new::<$z>()}
};
}
}
lazy_static::lazy_static! {
pub static ref OID_BOOL: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.1").unwrap()
};
pub static ref OID_U8: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.2").unwrap()
};
pub static ref OID_U16: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.3").unwrap()
};
pub static ref OID_U32: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.4").unwrap()
};
pub static ref OID_U64: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.5").unwrap()
};
pub static ref OID_U128: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.6").unwrap()
};
pub static ref OID_I8: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.7").unwrap()
};
pub static ref OID_I16: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.8").unwrap()
};
pub static ref OID_I32: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.9").unwrap()
};
pub static ref OID_I64: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.10").unwrap()
};
pub static ref OID_I128: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.11").unwrap()
};
pub static ref OID_VEC3U8: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.1.13").unwrap()
};
pub static ref OID_POWERED: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.2.1").unwrap()
};
pub static ref OID_INTENSITY: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.2.2").unwrap()
};
pub static ref OID_COLOUR: ObjectIdentifier = {
ObjectIdentifier::from_str("1.3.6.1.4.1.48398.612.2.3").unwrap()
};
}
oidvalue!(OID_BOOL, bool);
oidvalue!(OID_U8, u8);
oidvalue!(OID_U16, u16);
oidvalue!(OID_U32, u32);
oidvalue!(OID_U64, u64);
oidvalue!(OID_U128, u128);
oidvalue!(OID_I8, i8);
oidvalue!(OID_I16, i16);
oidvalue!(OID_I32, i32);
oidvalue!(OID_I64, i64);
oidvalue!(OID_I128, i128);
#[derive(
serde::Serialize,
serde::Deserialize,
Debug,
Copy,
Clone,
PartialEq,
Eq,
Hash,
rkyv::Archive,
rkyv::Serialize,
rkyv::Deserialize,
)]
#[archive_attr(derive(Debug, PartialEq, serde::Serialize, serde::Deserialize))]
pub struct Vec3u8 {
pub a: u8,
pub b: u8,
pub c: u8,
}
oidvalue!(OID_VEC3U8, Vec3u8, ArchivedVec3u8);
#[cfg(test)]
mod tests {
use super::*;
use rand::distributions::Standard;
use rand::prelude::Distribution;
use rand::Rng;
impl Distribution<Vec3u8> for Standard {
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Vec3u8 {
let a = self.sample(rng);
let b = self.sample(rng);
let c = self.sample(rng);
Vec3u8 { a, b, c }
}
}
}