Trait StorableType

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pub trait StorableType {
    type Handler;

    const LAYOUT: Layout;
    const SLOTS: usize = _;
    const BYTES: usize = _;
    const IS_PACKABLE: bool = _;
    const IS_DYNAMIC: bool = false;

    // Required method
    fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler;
}

Expand description

Helper trait to access storage layout information without requiring const generic parameter.

This trait provides compile-time layout information (slot count, byte size, packability) and a factory method for creating handlers. It enables the derive macro to compute struct layouts before the final slot count is known.

NOTE: Don’t need to implement the trait manually. Use #[derive(Storable)] instead.

Required Associated Constants§

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const LAYOUT: Layout

Describes how this type is laid out in storage.

Primitives use Layout::Bytes(N) where N is their size
Dynamic types (String, Bytes, Vec) use Layout::Slots(1)
Structs and arrays use Layout::Slots(N) where N is the slot count

Provided Associated Constants§

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const SLOTS: usize = _

Number of storage slots this type takes.

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const BYTES: usize = _

Number of bytes this type takes.

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const IS_PACKABLE: bool = _

Whether this type can be packed with adjacent fields.

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const IS_DYNAMIC: bool = false

Whether this type stores it’s data in its base slot or not.

Dynamic types (Bytes, String, Vec) store data at keccak256-addressed slots and need special cleanup. Non-dynamic types just zero their slots.

Required Associated Types§

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type Handler

The handler type that provides storage access for this type.

For primitives, this is Slot<Self>. For mappings, this is Self (mappings are their own handlers). For user-defined structs, this is a generated handler type (e.g., MyStructHandler).

Required Methods§

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fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

Creates a handler for this type at the given storage location.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Trait StorableType Copy item path

Required Associated Constants§

const LAYOUT: Layout

Provided Associated Constants§

const SLOTS: usize = _

const BYTES: usize = _

const IS_PACKABLE: bool = _

const IS_DYNAMIC: bool = false

Required Associated Types§

type Handler

Required Methods§

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

Dyn Compatibility§

Implementations on Foreign Types§

impl StorableType for bool

const LAYOUT: Layout

type Handler = Slot<bool>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for i8

const LAYOUT: Layout

type Handler = Slot<i8>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for i16

const LAYOUT: Layout

type Handler = Slot<i16>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for i32

const LAYOUT: Layout

type Handler = Slot<i32>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for i64

const LAYOUT: Layout

type Handler = Slot<i64>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for i128

const LAYOUT: Layout

type Handler = Slot<i128>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for u8

const LAYOUT: Layout

type Handler = Slot<u8>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for u16

const LAYOUT: Layout

type Handler = Slot<u16>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for u32

const LAYOUT: Layout

type Handler = Slot<u32>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for u64

const LAYOUT: Layout

type Handler = Slot<u64>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for u128

const LAYOUT: Layout

type Handler = Slot<u128>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for String

const LAYOUT: Layout

const IS_DYNAMIC: bool = true

type Handler = BytesLikeHandler<String>

fn handle(slot: U256, _ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for Address

const LAYOUT: Layout

type Handler = Slot<Address>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for Bytes

const LAYOUT: Layout

const IS_DYNAMIC: bool = true

type Handler = BytesLikeHandler<Bytes>

fn handle(slot: U256, _ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for FixedBytes<1usize>

const LAYOUT: Layout

type Handler = Slot<FixedBytes<1>>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

impl StorableType for FixedBytes<2usize>

const LAYOUT: Layout

type Handler = Slot<FixedBytes<2>>

fn handle(slot: U256, ctx: LayoutCtx, address: Address) -> Self::Handler

Trait StorableType