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SlotStore

pamoja_update

Trait SlotStore 

Source 
pub trait SlotStore {
    // Required methods
    fn slot_count(&self) -> u8;
    fn capacity(&self, slot: u8) -> Result<u32>;
    fn record(&self, slot: u8) -> Result<SlotRecord>;
    fn set_record(&mut self, slot: u8, record: SlotRecord) -> Result<()>;
    fn erase(&mut self, slot: u8) -> Result<()>;
    fn write(&mut self, slot: u8, offset: u32, bytes: &[u8]) -> Result<()>;
    fn read(&self, slot: u8, offset: u32, buf: &mut [u8]) -> Result<usize>;
}
Expand description

Somewhere to keep images, and the device’s belief about each one.

An implementation must keep the record durable across a reboot. If it does not, a device that loses power mid-update cannot tell what it was doing, which is exactly the situation slots exist to survive.

Required Methods§

Source

fn slot_count(&self) -> u8

Returns how many slots this device has.

Source

fn capacity(&self, slot: u8) -> Result<u32>

Returns how many bytes a slot can hold.

§Arguments
  • slot - the slot to size.
§Returns

The slot’s capacity in bytes.

§Errors

Returns Refusal::NoSuchSlot if the slot does not exist.

Source

fn record(&self, slot: u8) -> Result<SlotRecord>

Reads what the device believes about a slot.

§Arguments
  • slot - the slot to read.
§Returns

The slot’s record.

§Errors

Returns Refusal::NoSuchSlot if the slot does not exist.

Source

fn set_record(&mut self, slot: u8, record: SlotRecord) -> Result<()>

Writes what the device believes about a slot, durably.

§Arguments
  • slot - the slot to describe.
  • record - the new record.
§Returns

Ok(()) once the record will survive a reboot.

§Errors

Returns Refusal::NoSuchSlot if the slot does not exist.

Source

fn erase(&mut self, slot: u8) -> Result<()>

Clears a slot’s contents and marks it empty.

§Arguments
  • slot - the slot to clear.
§Returns

Ok(()) once the slot holds nothing.

§Errors

Returns Refusal::NoSuchSlot if the slot does not exist.

Source

fn write(&mut self, slot: u8, offset: u32, bytes: &[u8]) -> Result<()>

Writes image bytes at an offset within a slot.

§Arguments
  • slot - the slot to write into.
  • offset - where in the slot the bytes belong.
  • bytes - the bytes to write.
§Returns

Ok(()) once the bytes are stored.

§Errors

Returns Refusal::NoSuchSlot if the slot does not exist, or Refusal::SlotTooSmall if the write would run past the slot’s end.

Source

fn read(&self, slot: u8, offset: u32, buf: &mut [u8]) -> Result<usize>

Reads image bytes from an offset within a slot.

§Arguments
  • slot - the slot to read from.
  • offset - where in the slot to start.
  • buf - the destination.
§Returns

How many bytes were read, which is short only at the slot’s end.

§Errors

Returns Refusal::NoSuchSlot if the slot does not exist.

Dyn Compatibility§

This trait is dyn compatible.

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

Implementors§