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Implement Versionize for VecDeque #13

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10 changes: 9 additions & 1 deletion CHANGELOG.md
Original file line number Diff line number Diff line change
@@ -1,3 +1,11 @@
# v0.1.0
# Changelog

## [Unreleased]

### Added

- Implemented `Versionize` for `VecDeque` as a primitive.

## v0.1.0

- "versionize" v0.1.0 first release.
2 changes: 1 addition & 1 deletion coverage_config_aarch64.json
Original file line number Diff line number Diff line change
@@ -1 +1 @@
{"coverage_score": 92.3, "exclude_path": "", "crate_features": ""}
{"coverage_score": 92.4, "exclude_path": "", "crate_features": ""}
69 changes: 69 additions & 0 deletions src/primitives.rs
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@
//! Serialization support for primitive data types.
#![allow(clippy::float_cmp)]

use std::collections::VecDeque;

use self::super::{VersionMap, Versionize, VersionizeError, VersionizeResult};
use vmm_sys_util::fam::{FamStruct, FamStructWrapper};

Expand Down Expand Up @@ -335,6 +337,53 @@ where
}
}

impl<T> Versionize for VecDeque<T>
where
T: Versionize,
{
#[inline]
fn serialize<W: std::io::Write>(
&self,
mut writer: &mut W,
version_map: &VersionMap,
app_version: u16,
) -> VersionizeResult<()> {
// Serialize in the same fashion as bincode:
// Write len.
bincode::serialize_into(&mut writer, &self.len())
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Can we rely on the Vec primitive here and just use Into/From instead of duplicating the Vec code:

Docs say: This avoids reallocating where possible, but the conditions for that are strict, and subject to change, and so shouldn't be relied upon unless the Vec came from From<VecDeque> and hasn't been reallocated.

.map_err(|ref err| VersionizeError::Serialize(format!("{:?}", err)))?;
// Walk the vecdeque and write each elemenet.
for element in self {
element
.serialize(writer, version_map, app_version)
.map_err(|ref err| VersionizeError::Serialize(format!("{:?}", err)))?;
}
Ok(())
}

#[inline]
fn deserialize<R: std::io::Read>(
mut reader: &mut R,
version_map: &VersionMap,
app_version: u16,
) -> VersionizeResult<Self> {
let mut v = VecDeque::new();
let len: u64 = bincode::deserialize_from(&mut reader)
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nit-ish:

Serialized len() is usize: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.len

Let's use the same thing here just in case u64 differs in size from usize:

Suggested change
let len: u64 = bincode::deserialize_from(&mut reader)
let len: usize = bincode::deserialize_from(&mut reader)

.map_err(|ref err| VersionizeError::Deserialize(format!("{:?}", err)))?;
for _ in 0..len {
let element: T = T::deserialize(reader, version_map, app_version)
.map_err(|ref err| VersionizeError::Deserialize(format!("{:?}", err)))?;
v.push_back(element);
}
Ok(v)
}

// Not used yet.
fn version() -> u16 {
1
}
}

// Implement versioning for FAM structures by using the FamStructWrapper interface.
impl<T: Default + FamStruct + Versionize> Versionize for FamStructWrapper<T>
where
Expand Down Expand Up @@ -622,6 +671,26 @@ mod tests {
assert_eq!(store, restore);
}

#[test]
fn test_ser_de_vecdeque() {
let vm = VersionMap::new();
let mut snapshot_mem = vec![0u8; 64];

let mut store = VecDeque::new();
store.push_back("test 1".to_owned());
store.push_back("test 2".to_owned());
store.push_back("test 3".to_owned());

store
.serialize(&mut snapshot_mem.as_mut_slice(), &vm, 1)
.unwrap();
let restore =
<VecDeque<String> as Versionize>::deserialize(&mut snapshot_mem.as_slice(), &vm, 1)
.unwrap();

assert_eq!(store, restore);
}

#[test]
fn test_ser_de_option() {
let vm = VersionMap::new();
Expand Down