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Introduce BTreeSchema

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This commit is contained in:
Paul Hauner 2019-04-26 11:55:26 +10:00
parent 794b48078c
commit 8976e652d2
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GPG Key ID: D362883A9218FCC6
4 changed files with 70 additions and 49 deletions
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2
eth2/utils/cached_tree_hash/src/errors.rs
View File

@ -13,6 +13,6 @@ pub enum Error {
BytesAreNotEvenChunks(usize),
NoModifiedFieldForChunk(usize),
NoBytesForChunk(usize),
NoOverlayForIndex(usize),
NoSchemaForIndex(usize),
NotLeafNode(usize),
}

22
eth2/utils/cached_tree_hash/src/impls/vec.rs
View File

@ -96,12 +96,12 @@ pub fn update_tree_hash_cache<T: CachedTreeHash<T>>(
vec: &Vec<T>,
cache: &mut TreeHashCache,
) -> Result<BTreeOverlay, Error> {
let old_overlay = cache.get_overlay(cache.overlay_index, cache.chunk_index)?;
let old_overlay = cache.get_overlay(cache.schema_index, cache.chunk_index)?;
let new_overlay = BTreeOverlay::new(vec, cache.chunk_index, old_overlay.depth);
cache.replace_overlay(cache.overlay_index, cache.chunk_index, new_overlay.clone())?;
cache.replace_overlay(cache.schema_index, cache.chunk_index, new_overlay.clone())?;
cache.overlay_index += 1;
cache.schema_index += 1;
match T::tree_hash_type() {
TreeHashType::Basic => {
@ -152,21 +152,21 @@ pub fn update_tree_hash_cache<T: CachedTreeHash<T>>(
//
// Viz., the list has been lengthened.
(None, Some(new)) => {
let (bytes, mut bools, overlays) =
let (bytes, mut bools, schemas) =
TreeHashCache::new(&vec[i], new_overlay.depth + 1)?.into_components();
// Record the number of overlays, this will be used later in the fn.
let num_overlays = overlays.len();
// Record the number of schemas, this will be used later in the fn.
let num_schemas = schemas.len();
// Flag the root node of the new tree as dirty.
bools[0] = true;
cache.splice(new.start..new.start + 1, bytes, bools);
cache
.overlays
.splice(cache.overlay_index..cache.overlay_index, overlays);
.schemas
.splice(cache.schema_index..cache.schema_index, schemas);
cache.overlay_index += num_overlays;
cache.schema_index += num_schemas;
}
// The item existed in the previous list but does not exist in this list.
//
@ -189,9 +189,9 @@ pub fn update_tree_hash_cache<T: CachedTreeHash<T>>(
}
}
// Clean out any excess overlays that may or may not be remaining if the list was
// Clean out any excess schemas that may or may not be remaining if the list was
// shortened.
cache.remove_proceeding_child_overlays(cache.overlay_index, new_overlay.depth);
cache.remove_proceeding_child_schemas(cache.schema_index, new_overlay.depth);
}
}

2
eth2/utils/cached_tree_hash/src/lib.rs
View File

@ -44,7 +44,7 @@ impl CachedTreeHasher {
{
// Reset the per-hash counters.
self.cache.chunk_index = 0;
self.cache.overlay_index = 0;
self.cache.schema_index = 0;
// Reset the "modified" flags for the cache.
self.cache.reset_modifications();

93
eth2/utils/cached_tree_hash/src/tree_hash_cache.rs
View File

@ -2,14 +2,39 @@ use super::*;
use crate::merkleize::{merkleize, pad_for_leaf_count};
use int_to_bytes::int_to_bytes32;
#[derive(Debug, PartialEq, Clone)]
pub struct BTreeSchema {
pub depth: usize,
pub lengths: Vec<usize>,
}
impl BTreeSchema {
pub fn into_overlay(self, offset: usize) -> BTreeOverlay {
BTreeOverlay {
offset,
depth: self.depth,
lengths: self.lengths,
}
}
}
impl Into<BTreeSchema> for BTreeOverlay {
fn into(self) -> BTreeSchema {
BTreeSchema {
depth: self.depth,
lengths: self.lengths,
}
}
}
#[derive(Debug, PartialEq, Clone)]
pub struct TreeHashCache {
pub cache: Vec<u8>,
pub chunk_modified: Vec<bool>,
pub overlays: Vec<BTreeOverlay>,
pub schemas: Vec<BTreeSchema>,
pub chunk_index: usize,
pub overlay_index: usize,
pub schema_index: usize,
}
impl Into<Vec<u8>> for TreeHashCache {
@ -51,10 +76,10 @@ impl TreeHashCache {
// Allocate enough bytes to store all the leaves.
let mut leaves = Vec::with_capacity(overlay.num_leaf_nodes() * HASHSIZE);
let mut overlays = Vec::with_capacity(leaves_and_subtrees.len());
let mut schemas = Vec::with_capacity(leaves_and_subtrees.len());
if T::tree_hash_type() == TreeHashType::List {
overlays.push(overlay);
schemas.push(overlay.into());
}
// Iterate through all of the leaves/subtrees, adding their root as a leaf node and then
@ -62,9 +87,9 @@ impl TreeHashCache {
for t in leaves_and_subtrees {
leaves.append(&mut t.root()?.to_vec());
let (mut bytes, _bools, mut t_overlays) = t.into_components();
let (mut bytes, _bools, mut t_schemas) = t.into_components();
cache.append(&mut bytes);
overlays.append(&mut t_overlays);
schemas.append(&mut t_schemas);
}
// Pad the leaves to an even power-of-two, using zeros.
@ -79,9 +104,9 @@ impl TreeHashCache {
Ok(Self {
chunk_modified: vec![false; cache.len() / BYTES_PER_CHUNK],
cache,
overlays,
schemas,
chunk_index: 0,
overlay_index: 0,
schema_index: 0,
})
}
@ -94,34 +119,31 @@ impl TreeHashCache {
return Err(Error::BytesAreNotEvenChunks(bytes.len()));
}
let overlays = match overlay {
Some(overlay) => vec![overlay],
let schemas = match overlay {
Some(overlay) => vec![overlay.into()],
None => vec![],
};
Ok(Self {
chunk_modified: vec![initial_modified_state; bytes.len() / BYTES_PER_CHUNK],
cache: bytes,
overlays,
schemas,
chunk_index: 0,
overlay_index: 0,
schema_index: 0,
})
}
pub fn get_overlay(
&self,
overlay_index: usize,
schema_index: usize,
chunk_index: usize,
) -> Result<BTreeOverlay, Error> {
let mut overlay = self
.overlays
.get(overlay_index)
.ok_or_else(|| Error::NoOverlayForIndex(overlay_index))?
.clone();
overlay.offset = chunk_index;
Ok(overlay)
Ok(self
.schemas
.get(schema_index)
.ok_or_else(|| Error::NoSchemaForIndex(schema_index))?
.clone()
.into_overlay(chunk_index))
}
pub fn reset_modifications(&mut self) {
@ -132,11 +154,11 @@ impl TreeHashCache {
pub fn replace_overlay(
&mut self,
overlay_index: usize,
schema_index: usize,
chunk_index: usize,
new_overlay: BTreeOverlay,
) -> Result<BTreeOverlay, Error> {
let old_overlay = self.get_overlay(overlay_index, chunk_index)?;
let old_overlay = self.get_overlay(schema_index, chunk_index)?;
// If the merkle tree required to represent the new list is of a different size to the one
// required for the previous list, then update our cache.
@ -173,22 +195,21 @@ impl TreeHashCache {
self.splice(old_overlay.chunk_range(), new_bytes, new_bools);
}
Ok(std::mem::replace(
&mut self.overlays[overlay_index],
new_overlay,
))
let old_schema = std::mem::replace(&mut self.schemas[schema_index], new_overlay.into());
Ok(old_schema.into_overlay(chunk_index))
}
pub fn remove_proceeding_child_overlays(&mut self, overlay_index: usize, depth: usize) {
pub fn remove_proceeding_child_schemas(&mut self, schema_index: usize, depth: usize) {
let end = self
.overlays
.schemas
.iter()
.skip(overlay_index)
.skip(schema_index)
.position(|o| o.depth <= depth)
.and_then(|i| Some(i + overlay_index))
.unwrap_or_else(|| self.overlays.len());
.and_then(|i| Some(i + schema_index))
.unwrap_or_else(|| self.schemas.len());
self.overlays.splice(overlay_index..end, vec![]);
self.schemas.splice(schema_index..end, vec![]);
}
pub fn update_internal_nodes(&mut self, overlay: &BTreeOverlay) -> Result<(), Error> {
@ -326,8 +347,8 @@ impl TreeHashCache {
Ok(())
}
pub fn into_components(self) -> (Vec<u8>, Vec<bool>, Vec<BTreeOverlay>) {
(self.cache, self.chunk_modified, self.overlays)
pub fn into_components(self) -> (Vec<u8>, Vec<bool>, Vec<BTreeSchema>) {
(self.cache, self.chunk_modified, self.schemas)
}
}