Struct AccountStoragePatch 

pub struct AccountStoragePatch { /* private fields */ }

The AccountStoragePatch stores the changes between two states of account storage.

The patch consists of a map from StorageSlotName to StorageSlotPatch, where each slot patch records whether the slot was created, updated, or removed (see StorageValuePatch and StorageMapPatch).

Implementations

impl AccountStoragePatch

pub fn new() -> AccountStoragePatch

Creates a new, empty storage patch.

pub fn from_raw( patches: BTreeMap<StorageSlotName, StorageSlotPatch>, ) -> Result<AccountStoragePatch, AccountPatchError>

Creates a new storage patch from the provided map of slot patches.

Because the input is already a map keyed by slot name, slot name uniqueness holds by construction. Use AccountStoragePatch::from_entries to build a patch from a sequence that may contain duplicates.

Errors

Returns an error if the number of patches exceeds AccountStorage::MAX_NUM_STORAGE_SLOTS.

pub fn from_entries( entries: impl IntoIterator<Item = (StorageSlotName, StorageSlotPatch)>, ) -> Result<AccountStoragePatch, AccountPatchError>

Creates a new storage patch from the provided sequence of slot patches.

Errors

Returns an error if the same StorageSlotName appears more than once.

pub fn get(&self, slot_name: &StorageSlotName) -> Option<&StorageSlotPatch>

Returns the patch for the provided slot name, or None if no patch exists.

pub fn num_slots(&self) -> usize

Returns the number of slot patches.

pub fn values( &self, ) -> impl Iterator<Item = (&StorageSlotName, &StorageValuePatch)>

Returns an iterator over the value slot patches in this storage patch.

pub fn maps(&self) -> impl Iterator<Item = (&StorageSlotName, &StorageMapPatch)>

Returns an iterator over the map slot patches in this storage patch.

pub fn is_empty(&self) -> bool

Returns true if storage patch contains no patches.

pub fn merge( &mut self, other: AccountStoragePatch, ) -> Result<(), AccountPatchError>

Merges another patch into this one, with the entries of other taking precedence.

Each patch represents an atomic state change of account storage. This state change could be from a transaction, batch or block, as the latter two merge individual patches into a single one. Since the transaction is the lowest member in this hierarchy, the merge behavior is modelled so that whatever is valid (or invalid) to do in one transaction after another is also valid (or invalid) to merge.

In general the operations have the following meaning:

• Create takes the slot from absent to present.
• Update requires the slot is present and updates it.
• Remove takes the slot from present to absent.

The nine permutations of (current, incoming) resolve as follows:

• (Create, Create): Errors because the second create assumes the slot is absent, but the first already makes it present.
• (Create, Update): Merged to Create. The slot stays newly created, but carries the updated value.
• (Create, Remove): Cancels out, so the slot patch is dropped entirely. A slot created and then removed validly results in the slot being absent. This normalizes away such patches and makes the patch not commit to a no-op (removing a slot that doesn’t exist).
• (Update, Create): Errors because the create assumes the slot is absent, but the update already requires it is present.
• (Update, Update): Merged to Update, keeping the latest value.
• (Update, Remove): Merged to Remove.
• (Remove, Create): Merged to Create. A slot removed and then re-created nets to a (re-)creation carrying the new value. The resulting Create is applied to a base state that still has the slot, so this re-creates an existing slot with the carried value.
• (Remove, Update): Errors because the update requires a present slot, but the remove left it absent.
• (Remove, Remove): Errors because the second remove requires a present slot, but the first already makes it absent.

Value and map slots behave the same at the operation level, but map entries are merged entry-wise instead of being fully replaced.

The error cases never occur when merging patches coming out of transactions or patches that were aggregated from transactions, as these are exactly the cases that would not be allowed by the transaction kernel. For instance, updating a slot in tx 2 when tx 1 removed it would be rejected in tx 2, since it would not exist.

pub fn into_map(self) -> BTreeMap<StorageSlotName, StorageSlotPatch>

Consumes self and returns the underlying map of the storage patch.

Trait Implementations

impl Clone for AccountStoragePatch

fn clone(&self) -> AccountStoragePatch

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AccountStoragePatch

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for AccountStoragePatch

fn default() -> AccountStoragePatch

Returns the “default value” for a type.

impl Deserializable for AccountStoragePatch

fn read_from<R>( source: &mut R, ) -> Result<AccountStoragePatch, DeserializationError>

where R: ByteReader,

Reads a sequence of bytes from the provided source, attempts to deserialize these bytes into Self, and returns the result.

fn min_serialized_size() -> usize

Returns the minimum serialized size for one instance of this type.

fn read_from_bytes(bytes: &[u8]) -> Result<Self, DeserializationError>

Attempts to deserialize the provided bytes into Self and returns the result.

fn read_from_bytes_with_budget( bytes: &[u8], budget: usize, ) -> Result<Self, DeserializationError>

Deserializes Self from bytes with a byte budget limit.

impl Eq for AccountStoragePatch

impl PartialEq for AccountStoragePatch

fn eq(&self, other: &AccountStoragePatch) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serializable for AccountStoragePatch

fn write_into<W>(&self, target: &mut W)

where W: ByteWriter,

Serializes self into bytes and writes these bytes into the target.

fn get_size_hint(&self) -> usize

Returns an estimate of how many bytes are needed to represent self.

fn to_bytes(&self) -> Vec<u8>

Serializes self into a vector of bytes.

impl StructuralPartialEq for AccountStoragePatch