Module layout 

Layout contracts as runtime truth.

LayoutContract is the central trait for Hopper’s state-first architecture. It ties together discriminator, version, and layout fingerprint into a single compile-time contract that the runtime can validate before granting typed access.

This is what makes Hopper different from every other Solana framework: layouts are not just metadata or serialization hints. They are runtime contracts that gate account access, enforce compatibility, and enable schema evolution.

No competitor (Pinocchio, Steel, Quasar) has anything equivalent.

Structs

HopperHeader

The canonical 16-byte header at the start of every Hopper account.

LayoutInfo

Runtime metadata snapshot of an account’s layout identity.

Constants

DEFAULT_SCHEMA_EPOCH

Default schema-evolution epoch written by init_header.

Traits

LayoutContract

A compile-time layout contract binding type identity to wire format.

Functions

init_header

Initialize an account’s header from a layout contract type.

read_disc

Read the discriminator from account data (byte 0).

read_flags

Read the flags from account data (bytes 2..4) as u16 LE.

read_layout_id

Read the 8-byte layout_id from account data (bytes 4..12).

read_schema_epoch

Read the schema_epoch field from an already-written header.

read_version

Read the version from account data (byte 1).

write_header

Write a complete Hopper header to the beginning of data.

write_header_with_epoch

Write a Hopper header with a caller-specified schema epoch.