Crate musli_storage
source · [−]Expand description
Super simple storage encoding for Müsli
The storage encoding is partially upgrade safe:
- ✔ Can tolerate missing fields if they are annotated with
#[musli(default)]
. - ✗ Cannot skip over extra unrecognized fields.
This means that it’s suitable as a storage format, since the data model only evolves in one place. But unsuitable as a wire format since it cannot allow clients to upgrade independent of each other.
See musli-wire for a fully upgrade safe format.
use musli::{Encode, Decode};
#[derive(Debug, PartialEq, Encode, Decode)]
struct Version1 {
name: String,
}
#[derive(Debug, PartialEq, Encode, Decode)]
struct Version2 {
name: String,
#[musli(default)]
age: Option<u32>,
}
let version2 = musli_storage::to_vec(&Version2 {
name: String::from("Aristotle"),
age: Some(62),
})?;
assert!(musli_storage::decode::<_, Version1>(&version2[..]).is_err());
let version1 = musli_storage::to_vec(&Version1 {
name: String::from("Aristotle"),
})?;
let version2: Version2 = musli_storage::decode(&version1[..])?;
assert_eq!(version2, Version2 {
name: String::from("Aristotle"),
age: None,
});
Configuring
To tweak the behavior of the storage format you can use the StorageEncoding type:
use musli_storage::{Fixed, Variable, StorageEncoding};
use musli::mode::DefaultMode;
use musli::{Encode, Decode};
const CONFIG: StorageEncoding<DefaultMode, Fixed, Variable> = StorageEncoding::new()
.with_fixed_integers();
#[derive(Debug, PartialEq, Encode, Decode)]
struct Struct<'a> {
name: &'a str,
age: u32,
}
let mut out = Vec::new();
let expected = Struct {
name: "Aristotle",
age: 61,
};
CONFIG.encode(&mut out, &expected)?;
let actual = CONFIG.decode(&out[..])?;
assert_eq!(expected, actual);
Re-exports
pub use self::encoding::decode;
pub use self::encoding::encode;
pub use self::encoding::from_slice;
pub use self::encoding::to_fixed_bytes;
pub use self::encoding::StorageEncoding;
pub use self::encoding::to_vec;
pub use self::encoding::to_writer;
Modules
Module that defines StorageEncoding whith allows for customization of the encoding format, and the DEFAULT encoding configuration.
Structs
A fixed-length integer encoding which encodes something to a little-endian encoding.
A fixed-size bytes storage which keeps track of how much has been initialized.
A fixed-length encoding which encodes numbers to the width of L
and the
endianness of B
.
Enums
Type that indicates that the given numerical type should use variable-length encoding.