RFC-0004: Component ABI

Status: Draft | Version: 0.1.0

1. ABI principle

The stable ABI is C-compatible metadata plus PWE Schema. Rust private layout is never a public ABI.

2. Descriptor

#[repr(C)]
pub struct ComponentDescriptor {
    pub type_id: u128,
    pub version: u32,
    pub size: u32,
    pub alignment: u32,
    pub flags: u64,
    pub schema: *const SchemaDescriptor,
}

3. Flags

POD, TrivialCopy, Send, Sync, GPUReadable, GPUWritable, NetworkReplicated, Snapshotable, Deterministic, ZeroCopy.

4. Access

World owns storage. Domains receive ReadView/WriteView. Raw pointers must not escape a safe access scope.

5. Storage

Default layout is SoA; AoS/AoSoA are legal compiler transformations.

6. Capability

READ, WRITE, EXECUTE, GPU_READ, GPU_WRITE, NETWORK_READ, NETWORK_WRITE.

7. Lifecycle

Registered -> Allocated -> Active -> Migrating -> Inactive -> Destroyed.

8. Migration

Schema major changes require an explicit migration function. Entity identity must survive migration.

9. Hot reload

Only at a Migration Safe Point; no live code may observe partially migrated component storage.

10. Invariant

A plugin cannot directly mutate authoritative World memory without a valid capability and transaction.