rust-bitcoin-unsafe-fast/internals
Martin Habovstiak e8a42d5851 Unify/reduce usage of `unsafe`
Since the introduction of `Script` `unsafe` started slowly creeping in
as more types with similar semantics were added. The `unsafe` in these
cases is just for trivial conversions between various pointer-like
types. As such, it's possible to move these into a single macro that
takes care of the conversions at one place and avoid repeating the same
`unsafe` code in the codebase. This decreases the cost of audits which
now only need to happen in `internals`, focuses any changes to happen in
that single macro and decreases the chance that we will mess up
similarly to the recent `try_into().expect()` issue (but this time with
UB rather than panic).

The new macro accepts syntax very similar to the already-existing struct
declarations with these differences:

* The struct MUST NOT have `#[repr(transparent)]` - it's added by the
  macro
* If the struct uses `PhantomData` it must be the first field and the
  real data must be the second field (to allow unsized types).
* The struct must be immediately followed by an impl block containing at
  least on conversion function.
* If the struct has generics the impl block has to use the same names of
  generics.
* The conversion functions don't have bodies (similarly to required
  trait methods) and have a fixed set of allowed signatures.
* Underscore (`_`) must be used in place of the inner type in the
  conversion function parameters.

The existing code can simply call the macro with simple changes and get
the same behavior without any direct use of `unsafe`. This change
already calls the macro for all relevant existing types. There are still
some usages left unrelated to the macro, except one additional
conversion in reverse direction on `Script`. It could be moved as well
but since it's on a single place so far it's not really required.
2025-03-27 20:15:37 +01:00
..
contrib CI: Remove shebang from non-executable scripts 2024-05-31 10:10:00 +10:00
src Unify/reduce usage of `unsafe` 2025-03-27 20:15:37 +01:00
CHANGELOG.md Bump version of internals to 0.4.0 2024-09-18 12:22:59 +10:00
Cargo.toml Make `hex` in `internals` optional 2025-03-04 12:33:04 +01:00
README.md chore: format and standardize all markdowns files 2024-04-27 06:29:23 -03:00
build.rs 2024-08-25 automated rustfmt nightly 2024-08-25 01:14:09 +00:00

README.md

Rust Bitcoin Internals

This crate is only meant to be used internally by crates in the rust-bitcoin ecosystem.

This crate will never be stabilized, depend on it at your own risk.