Historical hash (#4683)

## Motivation

Add support for historical hashing

## Proposal

* Introduce a new combinator based on `ClonableView`

I ended up with a solution that is entirely separate from
`HashableView`.

## Test Plan

CI

## Release Plan

This won't be trivial to release in testnet but maybe still doable.

Author: ma2bd

linera-views/src/batch.rs

@@ -37,7 +37,7 @@ use crate::{
 /// * Deletion of a specific key.
 /// * Deletion of all keys matching a specific prefix.
 /// * Insertion or replacement of a key with a value.
-#[derive(Clone, Debug, Eq, PartialEq, WitType, WitLoad, WitStore)]
+#[derive(Clone, Debug, Eq, PartialEq, WitType, WitLoad, WitStore, Serialize)]
 pub enum WriteOperation {
     /// Delete the given key.
     Delete {
@@ -59,7 +59,7 @@ pub enum WriteOperation {
 }
 
 /// A batch of write operations.
-#[derive(Clone, Debug, Default, Eq, PartialEq)]
+#[derive(Clone, Debug, Default, Eq, PartialEq, Serialize)]
 pub struct Batch {
     /// The write operations.
     pub operations: Vec<WriteOperation>,

linera-views/src/lib.rs

@@ -124,6 +124,7 @@ pub use generic_array;
 #[doc(hidden)]
 pub use sha3;
 pub use views::{
-    bucket_queue_view, collection_view, hashable_wrapper, key_value_store_view, log_view, map_view,
-    queue_view, reentrant_collection_view, register_view, set_view,
+    bucket_queue_view, collection_view, hashable_wrapper, historical_hash_wrapper,
+    key_value_store_view, log_view, map_view, queue_view, reentrant_collection_view, register_view,
+    set_view,
 };

linera-views/src/views/bucket_queue_view.rs

@@ -12,6 +12,7 @@ use crate::{
     common::{from_bytes_option, from_bytes_option_or_default, HasherOutput},
     context::Context,
     hashable_wrapper::WrappedHashableContainerView,
+    historical_hash_wrapper::HistoricallyHashableView,
     store::ReadableKeyValueStore as _,
     views::{ClonableView, HashableView, Hasher, View, ViewError, MIN_VIEW_TAG},
 };
@@ -711,6 +712,10 @@ where
 pub type HashedBucketQueueView<C, T, const N: usize> =
     WrappedHashableContainerView<C, BucketQueueView<C, T, N>, HasherOutput>;
 
+/// Wrapper around `BucketQueueView` to compute hashes based on the history of changes.
+pub type HistoricallyHashedBucketQueueView<C, T, const N: usize> =
+    HistoricallyHashableView<C, BucketQueueView<C, T, N>>;
+
 #[cfg(with_graphql)]
 mod graphql {
     use std::borrow::Cow;

linera-views/src/views/collection_view.rs

@@ -19,6 +19,7 @@ use crate::{
     common::{CustomSerialize, HasherOutput, SliceExt as _, Update},
     context::{BaseKey, Context},
     hashable_wrapper::WrappedHashableContainerView,
+    historical_hash_wrapper::HistoricallyHashableView,
     store::ReadableKeyValueStore as _,
     views::{ClonableView, HashableView, Hasher, View, ViewError, MIN_VIEW_TAG},
 };
@@ -1784,14 +1785,26 @@ where
 pub type HashedByteCollectionView<C, W> =
     WrappedHashableContainerView<C, ByteCollectionView<C, W>, HasherOutput>;
 
+/// Wrapper around `ByteCollectionView` to compute hashes based on the history of changes.
+pub type HistoricallyHashedByteCollectionView<C, W> =
+    HistoricallyHashableView<C, ByteCollectionView<C, W>>;
+
 /// Type wrapping `CollectionView` while memoizing the hash.
 pub type HashedCollectionView<C, I, W> =
     WrappedHashableContainerView<C, CollectionView<C, I, W>, HasherOutput>;
 
+/// Wrapper around `CollectionView` to compute hashes based on the history of changes.
+pub type HistoricallyHashedCollectionView<C, I, W> =
+    HistoricallyHashableView<C, CollectionView<C, I, W>>;
+
 /// Type wrapping `CustomCollectionView` while memoizing the hash.
 pub type HashedCustomCollectionView<C, I, W> =
     WrappedHashableContainerView<C, CustomCollectionView<C, I, W>, HasherOutput>;
 
+/// Wrapper around `CustomCollectionView` to compute hashes based on the history of changes.
+pub type HistoricallyHashedCustomCollectionView<C, I, W> =
+    HistoricallyHashableView<C, CustomCollectionView<C, I, W>>;
+
 #[cfg(with_graphql)]
 mod graphql {
     use std::borrow::Cow;

linera-views/src/views/hashable_wrapper.rs

@@ -16,7 +16,7 @@ use crate::{
     views::{ClonableView, HashableView, Hasher, ReplaceContext, View, ViewError, MIN_VIEW_TAG},
 };
 
-/// A hash for `ContainerView` and storing of the hash for memoization purposes
+/// Wrapping a view to memoize its hash.
 #[derive(Debug)]
 pub struct WrappedHashableContainerView<C, W, O> {
     _phantom: PhantomData<C>,
@@ -25,7 +25,7 @@ pub struct WrappedHashableContainerView<C, W, O> {
     inner: W,
 }
 
-/// Key tags to create the sub-keys of a `MapView` on top of the base key.
+/// Key tags to create the sub-keys of a `WrappedHashableContainerView` on top of the base key.
 #[repr(u8)]
 enum KeyTag {
     /// Prefix for the indices of the view.