Struct CallbackMemory 

pub struct CallbackMemory<FReserve>
where
    FReserve: Fn(usize) -> BytesBuf + Send + Sync + 'static,
{ /* private fields */ }

Implements MemoryShared by delegating to a closure.

This can be used to construct wrapping memory providers that add logic or configuration on top of an existing memory provider.

Examples

Configure an inner memory provider with additional parameters:

use bytesbuf::mem::{CallbackMemory, GlobalPool, Memory};

// Create a callback memory that configures the inner provider.
let memory = CallbackMemory::new(move |min_len| {
    // Apply custom configuration when reserving memory.
    let page_aligned = true;
    io_context.reserve_with_config(min_len, page_aligned)
});

let buf = memory.reserve(64);
assert!(buf.capacity() >= 64);

For a complete implementation pattern, see examples/bb_has_memory_optimizing.rs.

Implementations

impl<FReserve> CallbackMemory<FReserve>

where FReserve: Fn(usize) -> BytesBuf + Send + Sync + 'static,

pub fn new(reserve_fn: FReserve) -> Self

Creates a new instance implemented via the provided callback.

pub fn reserve(&self, min_bytes: usize) -> BytesBuf

Reserves at least min_bytes bytes of memory capacity.

Returns an empty BytesBuf that can be used to fill the reserved memory with data.

The memory provider may provide more memory than requested.

The memory reservation request will always be fulfilled, obtaining more memory from the operating system if necessary.

Zero-sized reservations

Reserving zero bytes of memory is a valid operation and will return a BytesBuf with zero or more bytes of capacity.

Panics

May panic if the operating system runs out of memory.

Trait Implementations

impl<FReserve> Clone for CallbackMemory<FReserve>

where FReserve: Fn(usize) -> BytesBuf + Send + Sync + 'static,

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<FReserve> Debug for CallbackMemory<FReserve>

where FReserve: Fn(usize) -> BytesBuf + Send + Sync + 'static,

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

Formats the value using the given formatter.

impl<FReserve> Memory for CallbackMemory<FReserve>

where FReserve: Fn(usize) -> BytesBuf + Send + Sync + 'static,

fn reserve(&self, min_bytes: usize) -> BytesBuf

Reserves at least min_bytes bytes of memory capacity.