Module storage

Solidity compatible storage types and persistent storage access.

The Stylus node software is composed of two, fully-composable virtual machines.

• The Stylus VM, which compiles WASM contracts built with SDKs like this one.
• The Ethereum Virtual Machine, which interprets EVM bytecode from languages like Solidity and Vyper.

Though these two VMs differ in execution, they are backed by the same EVM State Trie. This means that Stylus contracts have access to the same, key-value based persistent storage familiar to Solidity devs.

Because this resource is foreign to Rust, this module provides standard types and traits for accessing state when writing programs. To protect the user, the Stylus SDK safeguards storage access by leveraging Rust’s borrow checker. It should never be possible to alias Storage without unsafe Rust, eliminating entire classes of errors at compile time.

For a walkthrough of this module’s features, please see The Feature Overview.

Structs

StorageAddress

Accessor for a storage-backed Address.

StorageArray

Accessor for a storage-backed array.

StorageBlockHash

Accessor for a storage-backed BlockHash.

StorageBlockNumber

Accessor for a storage-backed BlockNumber.

StorageBool

Accessor for a storage-backed bool.

StorageBytes

Accessor for storage-backed bytes.

StorageCache

Global accessor to persistent storage that relies on VM-level caching.

StorageFixedBytes

Accessor for a storage-backed FixedBytes.

StorageGuard

Binds a storage accessor to a lifetime to prevent aliasing. Because this type doesn’t implement DerefMut, mutable methods on the accessor aren’t available. For a mutable accessor, see StorageGuardMut.

StorageGuardMut

Binds a storage accessor to a lifetime to prevent aliasing.

StorageMap

Accessor for a storage-backed map.

StorageSigned

Accessor for a storage-backed Signed.

StorageString

Accessor for storage-backed bytes

StorageUint

Accessor for a storage-backed alloy_primitives::Uint.

StorageVec

Accessor for a storage-backed vector.

Traits

Erase

Trait for accessors that can be used to completely erase their underlying value. Note that some collections, like StorageMap, don’t implement this trait.

GlobalStorage

Trait for managing access to persistent storage. Implemented by the StorageCache type.

SimpleStorageType

Trait for simple accessors that store no more than their wrapped value. The type’s representation must be entirely inline, or storage leaks become possible. Note: it is a logic error if erasure does anything more than writing the zero-value.

StorageKey

Trait that allows types to be the key of a StorageMap.

StorageType

Accessor trait that lets a type be used in persistent storage. Users can implement this trait to add novel data structures to their contract definitions. The Stylus SDK by default provides only solidity types, which are represented the same way.

Type Aliases

StorageB8

Accessor for a storage-backed alloy_primitives::aliases::B8.

StorageB16

Accessor for a storage-backed alloy_primitives::aliases::B16.

StorageB32

Accessor for a storage-backed alloy_primitives::aliases::B32.

StorageB64

Accessor for a storage-backed alloy_primitives::aliases::B64.

StorageB96

Accessor for a storage-backed alloy_primitives::aliases::B96.

StorageB128

Accessor for a storage-backed alloy_primitives::aliases::B128.

StorageB160

Accessor for a storage-backed [alloy_primitives::aliases::B160].

StorageB192

Accessor for a storage-backed alloy_primitives::aliases::B192.

StorageB224

Accessor for a storage-backed alloy_primitives::aliases::B224.

StorageB256

Accessor for a storage-backed alloy_primitives::aliases::B256.

StorageI8

Accessor for a storage-backed alloy_primitives::aliases::I8.

StorageI16

Accessor for a storage-backed alloy_primitives::aliases::I16.

StorageI32

Accessor for a storage-backed alloy_primitives::aliases::I32.

StorageI64

Accessor for a storage-backed alloy_primitives::aliases::I64.

StorageI128

Accessor for a storage-backed alloy_primitives::aliases::I128.

StorageI160

Accessor for a storage-backed alloy_primitives::aliases::I160.

StorageI192

Accessor for a storage-backed alloy_primitives::aliases::I192.

StorageI256

Accessor for a storage-backed alloy_primitives::aliases::I256.

StorageU8

Accessor for a storage-backed alloy_primitives::aliases::U8.

StorageU16

Accessor for a storage-backed alloy_primitives::aliases::U16.

StorageU32

Accessor for a storage-backed alloy_primitives::aliases::U32.

StorageU64

Accessor for a storage-backed alloy_primitives::aliases::U64.

StorageU128

Accessor for a storage-backed alloy_primitives::aliases::U128.

StorageU160

Accessor for a storage-backed alloy_primitives::aliases::U160.

StorageU192

Accessor for a storage-backed alloy_primitives::aliases::U192.

StorageU256

Accessor for a storage-backed alloy_primitives::aliases::U256.