Struct ForeignLens 

pub struct ForeignLens<'a, T: AccountLayout + LayoutContract> { /* private fields */ }

A verified read-only handle into a foreign account.

ForeignLens<'a, T> borrows the underlying account data for its lifetime. Field access (.get(), .field::<F, OFFSET>()) performs only pointer arithmetic. no further verification, because all cross-program invariants were pinned at construction.

Implementations

impl<'a, T: AccountLayout + LayoutContract> ForeignLens<'a, T>

pub fn open( account: &'a AccountView, manifest: &ForeignManifest, ) -> Result<Self, ProgramError>

Verify a foreign account against the supplied manifest and, on success, return a read-only lens into its body.

The four verification steps correspond one-to-one with the audit’s page-14 requirements:

1. owner match
2. discriminator match (both T::DISC and manifest.expected_disc)
3. wire-fingerprint match
4. schema_epoch in supported range

pub fn get(&self) -> &T

The full verified layout. Field access through this path is zero-cost; no further checks fire.

pub fn field<F: ZeroCopy, const OFFSET: usize>( &self, ) -> Result<&F, ProgramError>

Project a typed field by byte offset. Returns a pointer-cast reference with the lens’s lifetime.

OFFSET must be the field’s offset within the layout body (i.e. already past the 16-byte Hopper header). Callers should prefer the auto-emitted {FIELD}_OFFSET constants from #[hopper::state].