jam.types.extrinsics.preimages module

Preimage-related extrinsic types for the JAM protocol.

class jam.types.extrinsics.preimages.Preimage(requester: U32, blob: Bytes)[source]

Bases: Codable, JsonSerde

Preimage structure.

requester: U32

blob: Bytes

__init__(requester: U32, blob: Bytes) → None

Initialize the Codable.

Parameters:

codec – Optional codec to use for encoding/decoding
enc_sequence – Optional function that returns sequence of fields to encode

static decode_from(buffer: bytes | bytearray | memoryview, offset: int = 0) → Tuple[T, int]

Decode from buffer. Must be implemented by subclasses or added via decorator.

Parameters:

buffer – Buffer to decode from
offset – Starting position in buffer

Returns:

The decoded value
Number of bytes read

Return type:

Tuple containing

encode_into(buffer: bytearray, offset: int = 0) → int: Encode into provided buffer.

encode_size() → int: Calculate number of bytes needed to encode.

class jam.types.extrinsics.preimages.PreimagesExtrinsic(initial: Sequence[T] = [], codec: Codec[T] | None = None)[source]

Bases: Vector[Preimage]

static decode_from(buffer: bytes | bytearray | memoryview, offset: int = 0) → Tuple[Vector[T], int]

Decode from buffer. Must be implemented by subclasses or added via decorator.

Parameters:

buffer – Buffer to decode from
offset – Starting position in buffer

Returns:

The decoded value
Number of bytes read

Return type:

Tuple containing