Module cap 

The zero-sized capability token Cap<P> and its thread-safe variant SendCap<P>.

Cap<P> is the core proof type in capsec. Holding a Cap<FsRead> proves you have permission to read files. It is:

• Zero-sized — no runtime cost, erased at compilation
• Unconstructible externally — Cap::new() is pub(crate), so only CapRoot::grant can create them
• !Send + !Sync — scoped to the creating thread by default

Use make_send to explicitly opt into cross-thread transfer when needed (e.g., for tokio::spawn).

Structs

Cap

A zero-sized capability token proving the holder has permission P.

SendCap

A thread-safe capability token that can be sent across threads.