Cthulhu

Generate FFI-compatible extern fn from harmless fns using the power of proc macros. If you are wondering which ABI this is, remember: You can't spell Cthulhu without C!

Usage

It's a mystery.

Roadmap

v0.1 series

Let's get this show on the road.

• Introduce marshalers and their ToForeign and FromForeign traits
• Add procedural macros for invoking marshalers
• Generate safe runtime checking of unsafe boundaries
• Generate "exception handling" callbacks
• Handle all basic scalar primitives (including the bool special case)
• Introduce ReturnType trait for reflecting return values for complex types
• Encapsulate all information needed to generate functions into a single Function type
• Provide a micro-framework for demonstrating Cthulhu error handling

v0.2 series

Let's get more show out of this road.

• Implement a good resource cleanup story
• Implement a good Vec<T> story
• Implement a good ref/owned/ohno story
• Get strings in all their forms working safely and ergonomically
• Allow generating extern functions by invokeing on impl and mod levels
  • Auto-prefixing of functions with a "C namespace" of the user's choice
• Experiment with other syntaxes for declaring marshalers on longer type signatures
• Improve error handling and reporting (some spans are still garbage or wrong)
• Supply default marshalers for:
  • Path types per operating system
  • UTF-16 owned/borrowed strings
  • UTF-8 owned/borrowed strings
  • Arc<T>
• Make invoke syntax consistent with marshal
• Add debug logging to inform the user when a value has been consumed and should not be reused
• Clean up the tests and make them pass
• Support types whose representation in C would be multiple parameters or a struct

v1.0 series

Let's get this stable.

• Ability to generate APIs for Kotlin, Swift and C#
• Fuzzed so hard that the code is no longer fazed by aggressive abuse and invalid files

Background and philosophy

We enforce the usage of stdint.h types on the C side to simplify the implementation on the Rust side.

Interesting reads:

• Marshaling Data with Platform Invoke (.NET)

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.