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//! This crate provides high-level bindings to the [Ruby] virtual machine. //! //! # Installation //! //! This crate is available [on crates.io][crate] and can be used by adding the //! following to your project's [`Cargo.toml`]: //! //! ```toml //! [dependencies] //! rosy = "0.0.2" //! ``` //! //! Rosy has functionality that is only available for certain Ruby versions. The //! following features can currently be enabled: //! //! - `ruby_2_6` //! //! For example: //! //! ```toml //! [dependencies.rosy] //! version = "0.0.2" //! features = ["ruby_2_6"] //! ``` //! //! Finally add this to your crate root (`main.rs` or `lib.rs`): //! //! ``` //! extern crate rosy; //! ``` //! //! # Initialization //! //! The Ruby virtual machine is initialized via [`vm::init`]: //! //! ``` //! rosy::vm::init().expect("Failed to initialize Ruby"); //! ``` //! //! This should be called //! once by the thread expected to be associated with Ruby. All mutations to //! Ruby objects from there on are only safe from that same thread since the VM //! is not known to be thread-safe. //! //! # Cleaning Up //! //! When done with the Ruby VM, one should call [`vm::destroy`], which will //! return a status code appropriate for exiting the program. //! //! ``` //! # rosy::vm::init().unwrap(); //! if let Err(code) = unsafe { rosy::vm::destroy() } { //! std::process::exit(code); //! } //! ``` //! //! # Catching Ruby Exceptions //! //! With Rosy, your Rust code can be [`protected`](fn.protected.html) from Ruby //! exceptions when calling unchecked functions that may throw. //! //! Not catching an exception from Rust will result in a segmentation fault at //! best. As a result, every function that throws an exception is annotated as //! [`unsafe`] in Rust-land. If a function is found to not uphold this //! invariant, please report it at [issue #4][issue4] or file a pull request to //! fix this. //! //! ``` //! # rosy::vm::init().unwrap(); //! use rosy::{Object, String}; //! //! let string = String::from("hello\r\n"); //! //! let value: usize = rosy::protected(|| unsafe { //! string.call_unchecked("chomp!"); //! string.len() //! }).unwrap(); //! //! assert_eq!(value, 5); //! ``` //! //! [`Cargo.toml`]: https://doc.rust-lang.org/cargo/reference/manifest.html //! [crate]: https://crates.io/crates/rosy //! [Ruby]: https://www.ruby-lang.org //! [`vm::init`]: vm/fn.init.html //! [`vm::destroy`]: vm/fn.destroy.html //! [`unsafe`]: https://doc.rust-lang.org/book/ch19-01-unsafe-rust.html //! [issue4]: https://github.com/oceanpkg/rosy/issues/4 #![cfg_attr(nightly, feature(doc_cfg))] #![deny(missing_docs)] #![cfg_attr(all(test, nightly), feature(test))] #[cfg(all(test, nightly))] extern crate test; include!(env!("ROSY_RUBY_VERSION_CONST")); use std::{mem, ptr}; #[path = "ruby_bindings/mod.rs"] mod ruby; mod rosy; mod util; pub mod array; pub mod exception; pub mod gc; pub mod hash; pub mod mixin; pub mod object; pub mod prelude; pub mod string; pub mod symbol; pub mod vm; #[doc(inline)] pub use self::{ array::Array, exception::{AnyException, Exception}, hash::Hash, mixin::{Mixin, Class, Module}, object::{AnyObject, Object, RosyObject}, rosy::Rosy, string::String, symbol::{Symbol, SymbolId}, }; /// A simplified form of /// [`Result`](https://doc.rust-lang.org/std/result/enum.Result.html) for /// when exceptions are caught. pub type Result<T = (), E = AnyException> = std::result::Result<T, E>; /// Calls `f` and returns its output or an exception if one is raised in `f`. /// /// # Examples /// /// This is great for calling methods that may not exist: /// /// ``` /// # rosy::vm::init(); /// use rosy::{Object, String, protected}; /// /// let string = String::from("¡Hola!"); /// let result = protected(|| unsafe { string.call_unchecked("likes_pie?") }); /// /// assert!(result.is_err()); /// ``` /// /// Calls can even be nested like so: /// /// ``` /// # rosy::vm::init(); /// use rosy::{Object, String, protected}; /// /// let string = String::from("Hiii!!!"); /// /// let outer = protected(|| { /// protected(|| unsafe { /// string.call_unchecked("likes_pie?") /// }).unwrap_err(); /// string /// }); /// /// assert_eq!(outer.unwrap(), string); /// ``` #[inline] pub fn protected<F, O>(f: F) -> Result<O> where F: FnOnce() -> O { if util::matches_ruby_size_align::<O>() { return unsafe { protected_size_opt(f) }; } unsafe extern "C" fn wrapper<F, O>(ctx: ruby::VALUE) -> ruby::VALUE where F: FnOnce() -> O { let (f, out) = &mut *(ctx as *mut (Option<F>, &mut O)); // Get the `F` out of `Option<F>` to call by-value, which is required by // the `FnOnce` trait let f = f.take().unwrap_or_else(|| std::hint::unreachable_unchecked()); ptr::write(*out, f()); AnyObject::nil().raw() } unsafe { // Required to prevent stack unwinding (if there's a `panic!` in `f()`) // from dropping `out`, which is uninitialized memory until `f()` use mem::ManuallyDrop; // These shenanigans allow us to pass in a pointer to `f`, with a // pointer to its uninitialized output, into `rb_protect` to make them // accessible from `wrapper` let mut out = ManuallyDrop::new(mem::uninitialized::<O>()); let mut ctx = (Some(f), &mut *out); let ctx = &mut ctx as *mut (Option<F>, &mut O) as ruby::VALUE; let mut err = 0; ruby::rb_protect(Some(wrapper::<F, O>), ctx, &mut err); match err { 0 => Ok(ManuallyDrop::into_inner(out)), _ => Err(AnyException::_take_current()), } } } // A version of `protected` that makes use of the size and layout of `O` // matching that of `ruby::VALUE`. This slightly reduces the number of emitted // instructions and removes the need for stack-allocating `ctx`. #[inline] unsafe fn protected_size_opt<F, O>(f: F) -> Result<O> where F: FnOnce() -> O { use mem::ManuallyDrop; unsafe extern "C" fn wrapper<F, O>(ctx: ruby::VALUE) -> ruby::VALUE where F: FnOnce() -> O { let f: &mut Option<F> = &mut *(ctx as *mut Option<F>); // Get the `F` out of `Option<F>` to call by-value, which is required by // the `FnOnce` trait let f = f.take().unwrap_or_else(|| std::hint::unreachable_unchecked()); let value = ManuallyDrop::new(f()); ptr::read(&value as *const ManuallyDrop<O> as *const ruby::VALUE) } let mut ctx = Some(f); let ctx = &mut ctx as *mut Option<F> as ruby::VALUE; let mut err = 0; let val = ruby::rb_protect(Some(wrapper::<F, O>), ctx, &mut err); match err { 0 => Ok(ptr::read(&val as *const ruby::VALUE as *const O)), _ => Err(AnyException::_take_current()), } }