Trait MemoryProvider 

pub trait MemoryProvider {
    const PAGE_SIZE: u64;

    // Required methods
    fn size(&self) -> u64;
    fn pages(&self) -> u64;
    fn grow(&mut self, new_pages: u64) -> MemoryResult<u64>;
    fn read(&mut self, offset: u64, buf: &mut [u8]) -> MemoryResult<()>;
    fn write(&mut self, offset: u64, buf: &[u8]) -> MemoryResult<()>;
}

Memory Provider trait defines the interface for interacting with the underlying memory.

Abstracting memory access allows different implementations for production (e.g. stable memory) and testing (heap-based).

Required Associated Constants

const PAGE_SIZE: u64

The size of a memory page in bytes.

Required Methods

fn size(&self) -> u64

Gets the current size of the memory in bytes.

fn pages(&self) -> u64

Gets the amount of pages currently allocated.

fn grow(&mut self, new_pages: u64) -> MemoryResult<u64>

Attempts to grow the memory by new_pages (added pages).

Returns an error if it wasn’t possible. Otherwise, returns the previous size in bytes that was reserved.

Actual reserved size after the growth will be previous_size + (new_pages * PAGE_SIZE).

fn read(&mut self, offset: u64, buf: &mut [u8]) -> MemoryResult<()>

Reads data from memory starting at offset into the provided buffer buf.

Returns an error if offset + buf.len() exceeds the current memory size.

fn write(&mut self, offset: u64, buf: &[u8]) -> MemoryResult<()>

Writes data from the provided buffer buf into memory starting at offset.

Returns an error if offset + buf.len() exceeds the current memory size.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl MemoryProvider for HeapMemoryProvider

const PAGE_SIZE: u64 = WASM_PAGE_SIZE