Trait object serialization for rkyv.
API Documentation
Book
- The rkyv book covers the motivation and architecture of rkyv
Sister Crates:
- bytecheck, which rkyv uses for validation
- ptr_meta, which rkyv uses for pointer manipulation
rkyv_dyn in action
use rkyv::{
archived_value,
de::deserializers::AllocDeserializer,
ser::{
serializers::WriteSerializer,
Serializer,
},
Archive,
Archived,
Deserialize,
Serialize,
};
use rkyv_dyn::archive_dyn;
use rkyv_typename::TypeName;
#[archive_dyn(deserialize)]
trait ExampleTrait {
fn value(&self) -> String;
}
#[derive(Archive, Serialize, Deserialize)]
#[archive(derive(TypeName))]
struct StringStruct(String);
#[archive_dyn]
impl ExampleTrait for StringStruct {
fn value(&self) -> String {
self.0.clone()
}
}
impl ExampleTrait for Archived<StringStruct> {
fn value(&self) -> String {
self.0.as_str().to_string()
}
}
#[derive(Archive, Serialize, Deserialize)]
#[archive(derive(TypeName))]
struct IntStruct(i32);
#[archive_dyn(deserialize)]
impl ExampleTrait for IntStruct {
fn value(&self) -> String {
format!("{}", self.0)
}
}
impl ExampleTrait for Archived<IntStruct> {
fn value(&self) -> String {
format!("{}", self.0)
}
}
fn main() {
let boxed_int = Box::new(IntStruct(42)) as Box<dyn SerializeExampleTrait>;
let boxed_string = Box::new(StringStruct("hello world".to_string())) as Box<dyn SerializeExampleTrait>;
let mut serializer = WriteSerializer::new(Vec::new());
let int_pos = serializer.serialize_value(&boxed_int)
.expect("failed to archive boxed int");
let string_pos = serializer.serialize_value(&boxed_string)
.expect("failed to archive boxed string");
let buf = serializer.into_inner();
let archived_int = unsafe { archived_value::<Box<dyn SerializeExampleTrait>>(buf.as_ref(), int_pos) };
let archived_string = unsafe { archived_value::<Box<dyn SerializeExampleTrait>>(buf.as_ref(), string_pos) };
assert_eq!(archived_int.value(), "42");
assert_eq!(archived_string.value(), "hello world");
let deserialized_int: Box<dyn SerializeExampleTrait> = archived_int.deserialize(&mut AllocDeserializer).unwrap();
let deserialized_string: Box<dyn SerializeExampleTrait> = archived_string.deserialize(&mut AllocDeserializer).unwrap();
assert_eq!(deserialized_int.value(), "42");
assert_eq!(deserialized_string.value(), "hello world");
}