4 releases
Uses old Rust 2015
0.1.6 | Aug 24, 2023 |
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0.1.5 | Mar 24, 2023 |
0.1.4 | Jan 13, 2021 |
0.1.3 | Sep 17, 2020 |
0.1.1 |
|
#1690 in Procedural macros
2,532 downloads per month
Used in 5 crates
37KB
574 lines
Versionize is a framework for version tolerant serializion/deserialization of Rust data structures, designed for usecases that need fast deserialization times and minimal size overhead. It does not aim to be a generic serialization framework and only the bincode backend is supported.
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Important note
This crate is currently used for cross-version serialization with the Firecracker snapshot-restore dev preview, but has not been tested for other use cases. It should be considered experimental software outside the Firecracker context. It’s likely that this crate will see both interface and implementation changes in the future.
Versionize in action
extern crate versionize;
extern crate versionize_derive;
use versionize::{VersionMap, Versionize, VersionizeResult};
use versionize_derive::Versionize;
// The test structure is at version 3.
#[derive(Debug, PartialEq, Versionize)]
pub struct Test {
a: u32,
#[version(start = 2, end = 3)]
b: u8,
#[version(start = 3, default_fn = "default_c")]
c: String,
}
impl Test {
// Default value for field `c`.
// The callback is invoked when deserialization from and older version
// where the field did not exist.
fn default_c(_source_version: u16) -> String {
"test_string".to_owned()
}
}
// Memory to hold the serialization output.
let mut mem = vec![0u8; 512];
// Create a new version map - it will start at version 1.
let mut version_map = VersionMap::new();
// Add new version and mark changes for Test struct: Set the current version
// to point to Test struct version 2.
version_map
.new_version()
.set_type_version(Test::type_id(), 2)
.new_version()
.set_type_version(Test::type_id(), 3);
let test_struct = Test {
a: 1337,
b: 0xFF,
c: "c_value".to_owned(),
};
// Serialize to version 2 - field c will not be serialized.
test_struct
.serialize(&mut mem.as_mut_slice(), &version_map, 2)
.unwrap();
// Deserialize from version 2 - c should contain the default_fn() return value.
let restored_test_struct = Test::deserialize(&mut mem.as_slice(), &version_map, 2).unwrap();
assert_eq!(
restored_test_struct,
Test {
a: 1337,
b: 255,
c: "test_string".to_owned()
}
);
Dependencies
~1.5MB
~36K SLoC