garage/src/util/data.rs
Alex Auvolat dc0b78cdb8
[block-ref-repair] Block refcount recalculation and repair
- We always recalculate the reference count of a block before deleting
  it locally, to make sure that it is indeed zero.

- If we had to fetch a remote block but we were not able to get it,
  check that refcount is indeed > 0.

- Repair procedure that checks everything
2024-03-19 16:20:22 +01:00

177 lines
4.2 KiB
Rust

//! Contains common types and functions related to serialization and integrity
use rand::Rng;
use serde::de::{self, Visitor};
use serde::{Deserialize, Deserializer, Serialize, Serializer};
use std::fmt;
/// An array of 32 bytes
#[derive(Default, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Copy)]
pub struct FixedBytes32([u8; 32]);
impl From<[u8; 32]> for FixedBytes32 {
fn from(x: [u8; 32]) -> FixedBytes32 {
FixedBytes32(x)
}
}
impl std::convert::AsRef<[u8]> for FixedBytes32 {
fn as_ref(&self) -> &[u8] {
&self.0[..]
}
}
impl fmt::Debug for FixedBytes32 {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", hex::encode(&self.0[..8]))
}
}
struct FixedBytes32Visitor;
impl<'de> Visitor<'de> for FixedBytes32Visitor {
type Value = FixedBytes32;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a byte slice of size 32")
}
fn visit_bytes<E: de::Error>(self, value: &[u8]) -> Result<Self::Value, E> {
if value.len() == 32 {
let mut res = [0u8; 32];
res.copy_from_slice(value);
Ok(res.into())
} else {
Err(E::custom(format!(
"Invalid byte string length {}, expected 32",
value.len()
)))
}
}
}
impl<'de> Deserialize<'de> for FixedBytes32 {
fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<FixedBytes32, D::Error> {
deserializer.deserialize_bytes(FixedBytes32Visitor)
}
}
impl Serialize for FixedBytes32 {
fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
serializer.serialize_bytes(&self.0[..])
}
}
impl FixedBytes32 {
/// Access the content as a slice
pub fn as_slice(&self) -> &[u8] {
&self.0[..]
}
/// Access the content as a mutable slice
pub fn as_slice_mut(&mut self) -> &mut [u8] {
&mut self.0[..]
}
/// Copy to a slice
pub fn to_vec(self) -> Vec<u8> {
self.0.to_vec()
}
/// Try building a FixedBytes32 from a slice
/// Return None if the slice is not 32 bytes long
pub fn try_from(by: &[u8]) -> Option<Self> {
if by.len() != 32 {
return None;
}
let mut ret = [0u8; 32];
ret.copy_from_slice(by);
Some(Self(ret))
}
/// Return the next hash
pub fn increment(&self) -> Option<Self> {
let mut ret = *self;
for byte in ret.0.iter_mut().rev() {
if *byte == u8::MAX {
*byte = 0;
} else {
*byte = *byte + 1;
return Some(ret);
}
}
return None;
}
}
impl From<garage_net::NodeID> for FixedBytes32 {
fn from(node_id: garage_net::NodeID) -> FixedBytes32 {
FixedBytes32::try_from(node_id.as_ref()).unwrap()
}
}
impl From<FixedBytes32> for garage_net::NodeID {
fn from(bytes: FixedBytes32) -> garage_net::NodeID {
garage_net::NodeID::from_slice(bytes.as_slice()).unwrap()
}
}
/// A 32 bytes UUID
pub type Uuid = FixedBytes32;
/// A 256 bit cryptographic hash, can be sha256 or blake2 depending on provenance
pub type Hash = FixedBytes32;
/// Compute the sha256 of a slice
pub fn sha256sum(data: &[u8]) -> Hash {
use sha2::{Digest, Sha256};
let mut hasher = Sha256::new();
hasher.update(data);
let mut hash = [0u8; 32];
hash.copy_from_slice(&hasher.finalize()[..]);
hash.into()
}
/// Compute the blake2 of a slice
pub fn blake2sum(data: &[u8]) -> Hash {
use blake2::{Blake2b512, Digest};
let mut hasher = Blake2b512::new();
hasher.update(data);
let mut hash = [0u8; 32];
hash.copy_from_slice(&hasher.finalize()[..32]);
hash.into()
}
/// A 64 bit non cryptographic hash
pub type FastHash = u64;
/// Compute a (non cryptographic) of a slice
pub fn fasthash(data: &[u8]) -> FastHash {
use xxhash_rust::xxh3::Xxh3;
let mut h = Xxh3::new();
h.update(data);
h.digest()
}
/// Generate a random 32 bytes UUID
pub fn gen_uuid() -> Uuid {
rand::thread_rng().gen::<[u8; 32]>().into()
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_increment() {
let zero: FixedBytes32 = [0u8; 32].into();
let mut one: FixedBytes32 = [0u8; 32].into();
one.0[31] = 1;
let max: FixedBytes32 = [0xFFu8; 32].into();
assert_eq!(zero.increment(), Some(one));
assert_eq!(max.increment(), None);
let mut test: FixedBytes32 = [0u8; 32].into();
let i = 0x198DF97209F8FFFFu64;
test.0[24..32].copy_from_slice(&u64::to_be_bytes(i));
let mut test2: FixedBytes32 = [0u8; 32].into();
test2.0[24..32].copy_from_slice(&u64::to_be_bytes(i + 1));
assert_eq!(test.increment(), Some(test2));
}
}