Rename CachedTreeHash trait, add readme

This commit is contained in:
Paul Hauner 2019-04-24 18:23:58 +10:00
parent 7563755b15
commit cab5e59a6f
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10 changed files with 105 additions and 37 deletions

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@ -0,0 +1,76 @@
# Tree hashing
Provides both cached and non-cached tree hashing methods.
## Standard Tree Hash
```rust
use tree_hash_derive::TreeHash;
#[derive(TreeHash)]
struct Foo {
a: u64,
b: Vec<u64>,
}
fn main() {
let foo = Foo {
a: 42,
b: vec![1, 2, 3]
}
println!("root: {}", foo.tree_hash_root());
}
```
## Cached Tree Hash
```rust
use tree_hash_derive::{TreeHash, CachedTreeHash};
#[derive(TreeHash, CachedTreeHash)]
struct Foo {
a: u64,
b: Vec<u64>,
}
#[derive(TreeHash, CachedTreeHash)]
struct Bar {
a: Vec<Foo>,
b: u64,
}
fn main() {
let bar = Bar {
a: vec![
Foo {
a: 42,
b: vec![1, 2, 3]
}
],
b: 42
};
let modified_bar = Bar {
a: vec![
Foo {
a: 100,
b: vec![1, 2, 3, 4, 5, 6]
}
Foo {
a: 42,
b: vec![]
}
],
b: 99
};
let mut hasher = CachedTreeHasher::new(&bar).unwrap();
hasher.update(&modified_bar);
// Assert that the cached tree hash matches a standard tree hash.
assert_eq!(hasher.tree_hash_root(), modified_bar.tree_hash_root());
}
```

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@ -19,7 +19,7 @@ pub struct CachedTreeHasher {
impl CachedTreeHasher {
pub fn new<T>(item: &T) -> Result<Self, Error>
where
T: CachedTreeHashSubTree<T>,
T: CachedTreeHash<T>,
{
Ok(Self {
cache: TreeHashCache::new(item, 0)?,
@ -28,7 +28,7 @@ impl CachedTreeHasher {
pub fn update<T>(&mut self, item: &T) -> Result<(), Error>
where
T: CachedTreeHashSubTree<T>,
T: CachedTreeHash<T>,
{
// Reset the per-hash counters.
self.cache.chunk_index = 0;
@ -66,15 +66,7 @@ pub enum Error {
NotLeafNode(usize),
}
pub trait CachedTreeHash<T>: CachedTreeHashSubTree<T> + Sized {
fn update_internal_tree_hash_cache(self, old: T) -> Result<(Self, Self), Error>;
fn cached_tree_hash_root(&self) -> Option<Vec<u8>>;
fn clone_without_tree_hash_cache(&self) -> Self;
}
pub trait CachedTreeHashSubTree<Item>: TreeHash {
pub trait CachedTreeHash<Item>: TreeHash {
fn tree_hash_cache_overlay(
&self,
chunk_offset: usize,

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@ -11,7 +11,7 @@ pub struct BTreeOverlay {
impl BTreeOverlay {
pub fn new<T>(item: &T, initial_offset: usize, depth: usize) -> Result<Self, Error>
where
T: CachedTreeHashSubTree<T>,
T: CachedTreeHash<T>,
{
item.tree_hash_cache_overlay(initial_offset, depth)
}

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@ -2,7 +2,7 @@ use super::*;
mod vec;
impl CachedTreeHashSubTree<u64> for u64 {
impl CachedTreeHash<u64> for u64 {
fn new_tree_hash_cache(&self, _depth: usize) -> Result<TreeHashCache, Error> {
Ok(TreeHashCache::from_bytes(
merkleize(self.to_le_bytes().to_vec()),
@ -35,7 +35,7 @@ impl CachedTreeHashSubTree<u64> for u64 {
}
}
impl CachedTreeHashSubTree<usize> for usize {
impl CachedTreeHash<usize> for usize {
fn new_tree_hash_cache(&self, _depth: usize) -> Result<TreeHashCache, Error> {
Ok(TreeHashCache::from_bytes(
merkleize(self.to_le_bytes().to_vec()),

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@ -1,8 +1,8 @@
use super::*;
impl<T> CachedTreeHashSubTree<Vec<T>> for Vec<T>
impl<T> CachedTreeHash<Vec<T>> for Vec<T>
where
T: CachedTreeHashSubTree<T> + TreeHash,
T: CachedTreeHash<T> + TreeHash,
{
fn new_tree_hash_cache(&self, depth: usize) -> Result<TreeHashCache, Error> {
let mut overlay = self.tree_hash_cache_overlay(0, depth)?;
@ -186,7 +186,7 @@ where
fn get_packed_leaves<T>(vec: &Vec<T>) -> Result<Vec<u8>, Error>
where
T: CachedTreeHashSubTree<T>,
T: CachedTreeHash<T>,
{
let num_packed_bytes = (BYTES_PER_CHUNK / T::tree_hash_packing_factor()) * vec.len();
let num_leaves = num_sanitized_leaves(num_packed_bytes);

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@ -19,7 +19,7 @@ impl Into<Vec<u8>> for TreeHashCache {
impl TreeHashCache {
pub fn new<T>(item: &T, depth: usize) -> Result<Self, Error>
where
T: CachedTreeHashSubTree<T>,
T: CachedTreeHash<T>,
{
item.new_tree_hash_cache(depth)
}
@ -30,7 +30,7 @@ impl TreeHashCache {
depth: usize,
) -> Result<Self, Error>
where
T: CachedTreeHashSubTree<T>,
T: CachedTreeHash<T>,
{
let overlay = BTreeOverlay::new(item, 0, depth)?;

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@ -6,7 +6,7 @@ pub const BYTES_PER_CHUNK: usize = 32;
pub const HASHSIZE: usize = 32;
pub const MERKLE_HASH_CHUNCK: usize = 2 * BYTES_PER_CHUNK;
pub use cached_tree_hash::{BTreeOverlay, CachedTreeHashSubTree, Error, TreeHashCache};
pub use cached_tree_hash::{BTreeOverlay, CachedTreeHash, Error, TreeHashCache};
pub use signed_root::SignedRoot;
pub use standard_tree_hash::{merkle_root, TreeHash};

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@ -1,8 +1,8 @@
use int_to_bytes::int_to_bytes32;
use tree_hash::cached_tree_hash::*;
use tree_hash_derive::{CachedTreeHashSubTree, TreeHash};
use tree_hash_derive::{CachedTreeHash, TreeHash};
#[derive(Clone, Debug, TreeHash, CachedTreeHashSubTree)]
#[derive(Clone, Debug, TreeHash, CachedTreeHash)]
pub struct NestedStruct {
pub a: u64,
pub b: Inner,
@ -10,7 +10,7 @@ pub struct NestedStruct {
fn test_routine<T>(original: T, modified: Vec<T>)
where
T: CachedTreeHashSubTree<T>,
T: CachedTreeHash<T>,
{
let mut hasher = CachedTreeHasher::new(&original).unwrap();
@ -113,7 +113,7 @@ fn test_nested_list_of_u64() {
test_routine(original, modified);
}
#[derive(Clone, Debug, TreeHash, CachedTreeHashSubTree)]
#[derive(Clone, Debug, TreeHash, CachedTreeHash)]
pub struct StructWithVec {
pub a: u64,
pub b: Inner,
@ -224,7 +224,7 @@ fn test_vec_of_struct_with_vec() {
test_routine(original, modified);
}
#[derive(Clone, Debug, TreeHash, CachedTreeHashSubTree)]
#[derive(Clone, Debug, TreeHash, CachedTreeHash)]
pub struct StructWithVecOfStructs {
pub a: u64,
pub b: Inner,
@ -302,7 +302,7 @@ fn test_struct_with_vec_of_structs() {
test_routine(f, variants);
}
#[derive(Clone, Debug, TreeHash, CachedTreeHashSubTree)]
#[derive(Clone, Debug, TreeHash, CachedTreeHash)]
pub struct Inner {
pub a: u64,
pub b: u64,
@ -481,7 +481,7 @@ fn works_when_embedded() {
assert_eq!(&merkle[0..32], &root[..]);
}
impl CachedTreeHashSubTree<InternalCache> for InternalCache {
impl CachedTreeHash<InternalCache> for InternalCache {
fn new_tree_hash_cache(&self) -> Result<TreeHashCache, Error> {
let tree = TreeHashCache::from_leaves_and_subtrees(
self,
@ -562,7 +562,7 @@ impl TreeHash for Inner {
}
}
impl CachedTreeHashSubTree<Inner> for Inner {
impl CachedTreeHash<Inner> for Inner {
fn new_tree_hash_cache(&self) -> Result<TreeHashCache, Error> {
let tree = TreeHashCache::from_leaves_and_subtrees(
self,
@ -646,7 +646,7 @@ impl TreeHash for Outer {
}
}
impl CachedTreeHashSubTree<Outer> for Outer {
impl CachedTreeHash<Outer> for Outer {
fn new_tree_hash_cache(&self) -> Result<TreeHashCache, Error> {
let tree = TreeHashCache::from_leaves_and_subtrees(
self,

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@ -37,10 +37,10 @@ fn should_skip_hashing(field: &syn::Field) -> bool {
.any(|attr| attr.into_token_stream().to_string() == "# [ tree_hash ( skip_hashing ) ]")
}
/// Implements `tree_hash::CachedTreeHashSubTree` for some `struct`.
/// Implements `tree_hash::CachedTreeHash` for some `struct`.
///
/// Fields are hashed in the order they are defined.
#[proc_macro_derive(CachedTreeHashSubTree, attributes(tree_hash))]
#[proc_macro_derive(CachedTreeHash, attributes(tree_hash))]
pub fn subtree_derive(input: TokenStream) -> TokenStream {
let item = parse_macro_input!(input as DeriveInput);
@ -58,7 +58,7 @@ pub fn subtree_derive(input: TokenStream) -> TokenStream {
let num_items = idents_a.len();
let output = quote! {
impl tree_hash::CachedTreeHashSubTree<#name> for #name {
impl tree_hash::CachedTreeHash<#name> for #name {
fn new_tree_hash_cache(&self, depth: usize) -> Result<tree_hash::TreeHashCache, tree_hash::Error> {
let tree = tree_hash::TreeHashCache::from_leaves_and_subtrees(
self,

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@ -1,7 +1,7 @@
use tree_hash::{CachedTreeHashSubTree, SignedRoot, TreeHash};
use tree_hash_derive::{CachedTreeHashSubTree, SignedRoot, TreeHash};
use tree_hash::{CachedTreeHash, SignedRoot, TreeHash};
use tree_hash_derive::{CachedTreeHash, SignedRoot, TreeHash};
#[derive(Clone, Debug, TreeHash, CachedTreeHashSubTree)]
#[derive(Clone, Debug, TreeHash, CachedTreeHash)]
pub struct Inner {
pub a: u64,
pub b: u64,
@ -11,7 +11,7 @@ pub struct Inner {
fn test_standard_and_cached<T>(original: &T, modified: &T)
where
T: CachedTreeHashSubTree<T>,
T: CachedTreeHash<T>,
{
let mut cache = original.new_tree_hash_cache().unwrap();
@ -44,7 +44,7 @@ fn inner_standard_vs_cached() {
test_standard_and_cached(&original, &modified);
}
#[derive(Clone, Debug, TreeHash, CachedTreeHashSubTree)]
#[derive(Clone, Debug, TreeHash, CachedTreeHash)]
pub struct Uneven {
pub a: u64,
pub b: u64,