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use crate::{metadata::*, FieldsCursor, FieldsStorage};
use crate::{Db, ShapedLocation, TraitObject};
use alloc::{borrow::Cow, string::String};
use core::{any::TypeId, intrinsics::transmute};
use serde::ser::Error as serError;
use serde::ser::{
SerializeSeq, SerializeStruct, SerializeStructVariant, SerializeTuple, SerializeTupleStruct,
SerializeTupleVariant,
};
impl<'db> Db<'db> {
fn serialize_leaf<S: serde::Serializer>(
&self,
s: S,
tid: TypeId,
src: &ShapedLocation<'_, '_, '_>,
) -> Result<S::Ok, S::Error> {
let vtable = *self.serialize_vtables.get(&tid).unwrap();
let obj = unsafe {
// SAFETY: the vtable is correct because we populated it correctly in register_leaf.
transmute::<TraitObject, &dyn erased_serde::Serialize>(TraitObject {
vtable,
data: src.ptr as *mut _,
})
};
erased_serde::serialize(obj, s)
}
fn serialize_fields<'visitor, 'data, I: IntoIterator<Item = &'db Field<'db>>, Err>(
&'db self,
mut f: impl FnMut(Option<&'static str>, ShapedLocation<'db, 'data, 'visitor>) -> Result<(), Err>,
fields_of: &'visitor ShapedLocation<'db, 'data, 'visitor>,
fields: I,
ty_err: &impl Fn(String) -> Err,
) -> Result<(), Err> {
for &Field {
offset,
shape: _shape,
id,
name,
..
} in fields.into_iter()
{
// TODO: use the shape for free performance!
let (ty, storage) = self.lookup_id(id).map_err(ty_err)?;
unsafe {
f(
name,
ShapedLocation::new(
&ty,
FieldsStorage::from_inner(Cow::Borrowed(&storage.area)),
fields_of.ptr.add(offset),
),
)?;
}
}
Ok(())
}
}
/// Wrapper for serializing a value from memory via reflection. You're better off using `Db::serialize`.
pub(crate) struct Serialize<'db, 'data, 'visitor> {
db: &'db Db<'db>,
cursor: &'visitor FieldsCursor<'db>,
src: &'visitor ShapedLocation<'db, 'data, 'visitor>,
name: &'static str,
}
impl<'db, 'data, 'visitor> Serialize<'db, 'data, 'visitor> {
pub(crate) fn new(
db: &'db Db<'db>,
name: &'static str,
cursor: &'visitor FieldsCursor<'db>,
src: &'visitor ShapedLocation<'db, 'data, 'visitor>,
) -> Self {
Self {
db,
cursor,
src,
name,
}
}
pub(crate) fn subfield<'v2: 'visitor>(
&self,
field_location: &'v2 ShapedLocation<'db, 'data, 'visitor>,
) -> Serialize<'db, 'data, 'v2> {
Self {
src: field_location,
..*self
}
}
}
impl<'db, 'data, 'visitor> serde::Serialize for Serialize<'db, 'data, 'visitor> {
fn serialize<S>(&self, dst: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
let src = &self.src;
let db = self.db;
let cursor = self.cursor;
let name = self.name;
match &src.shape {
DataShape::Leaf(tid) => db.serialize_leaf(dst, *tid, src),
DataShape::Tuple(fields) => {
let mut tup = dst.serialize_tuple(fields.len as usize)?;
db.serialize_fields(
|_, src| tup.serialize_element(&self.subfield(&src)),
src,
unsafe { cursor.array(fields) },
&serError::custom,
)?;
tup.end()
}
DataShape::Struct(decl_kind, _labels_for_serde, fields) => match decl_kind {
DeclKind::Unit => dst.serialize_unit_struct(name),
DeclKind::Tuple => {
let mut tup = dst.serialize_tuple_struct(name, fields.len as usize)?;
db.serialize_fields(
|_, src| tup.serialize_field(&self.subfield(&src)),
src,
unsafe { cursor.array(fields) },
&serError::custom,
)?;
tup.end()
}
DeclKind::Struct => {
let mut struc = dst.serialize_struct(name, fields.len as usize)?;
db.serialize_fields(
|field_name, field_loc| {
struc.serialize_field(
field_name.expect("who unnamed the struct fields?"),
&self.subfield(&field_loc),
)
},
src,
unsafe { cursor.array(fields) },
&serError::custom,
)?;
struc.end()
}
DeclKind::Newtype => {
dst.serialize_newtype_struct(
name,
&self.subfield(
// SAFETY: newtype is its one field,
unsafe { &src.reshape(&cursor.peek_first_field(fields).shape) },
),
)
}
},
DataShape::Enum(_labels, arms) => {
// SAFETY: we know we're looking at an enum.
let (tag, variants) = unsafe { (src.read_discriminant(), cursor.array(arms)) };
let arm_idx = variants.binary_search_by_key(&tag, |arm| arm.discriminant);
let arm = match arm_idx {
// SAFETY: we just got ix
Ok(ix) => variants.get(ix).unwrap(),
Err(_) => {
return Err(serError::custom(
"runtime discriminant not described in reflection db",
))
}
};
match &arm.decl_kind {
DeclKind::Unit => {
dst.serialize_unit_variant(name, arm.variant_index as u32, arm.label)
}
DeclKind::Struct => {
let mut struc = dst.serialize_struct_variant(
name,
arm.variant_index as u32,
arm.label,
arm.fields.len as usize,
)?;
db.serialize_fields(
|name, src| {
struc.serialize_field(
name.expect("who unnamed the struct fields?"),
&self.subfield(&src),
)
},
src,
unsafe { cursor.array(&arm.fields) },
&serError::custom,
)?;
struc.end()
}
DeclKind::Tuple => {
let mut tup = dst.serialize_tuple_variant(
name,
arm.variant_index as u32,
arm.label,
arm.fields.len as usize,
)?;
db.serialize_fields(
|_, src| tup.serialize_field(&self.subfield(&src)),
src,
unsafe { cursor.array(&arm.fields) },
&serError::custom,
)?;
tup.end()
}
DeclKind::Newtype => {
dst.serialize_newtype_variant(
name,
arm.variant_index as u32,
arm.label,
// SAFETY: a newtype is its one field
unsafe {
&self.subfield(
&src.reshape(&cursor.peek_first_field(&arm.fields).shape),
)
},
)
}
}
}
&&DataShape::FixedArray { len, stride, shape } => {
//let (typ, storage) = db.lookup_id(type_id).map_err(serError::custom)?;
let mut seq = dst.serialize_seq(Some(len))?;
let shape = unsafe { cursor.shape(&shape) };
for ix in 0..len {
// SAFETY: ix is inbounds, if stride is correct we're good!
let slot_loc = unsafe {
ShapedLocation::from_shape(
shape,
self.src.fields.borrow(),
src.ptr.add(ix * stride).cast(),
)
};
seq.serialize_element(&Serialize::new(db, self.name, cursor, &slot_loc))?;
}
seq.end()
}
DataShape::Slice(_) => todo!(),
DataShape::Ref(_, _) => todo!(),
DataShape::Builtin(builtin) => {
macro_rules! serial {
($what:ident, $($lo:ident,$ser:ident,$up:ident);+) => {
match $what {
$(RustBuiltin::$up => { dst.$ser(src.ptr.cast::<$lo>().read()) },)+
}
}
}
unsafe {
serial!(
builtin,
u8, serialize_u8, U8;
i8, serialize_i8, I8;
u16, serialize_u16, U16;
i16, serialize_i16, I16;
u32, serialize_u32, U32;
i32, serialize_i32, I32;
u64, serialize_u64, U64;
i64, serialize_i64, I64;
u128, serialize_u128, U128;
i128, serialize_i128, I128;
f32, serialize_f32, F32;
f64, serialize_f64, F64;
bool, serialize_bool, BOOLIN;
char, serialize_char, CHAR
)
}
}
}
}
}