diff options
Diffstat (limited to 'ffi/src/lib.rs')
| -rw-r--r-- | ffi/src/lib.rs | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/ffi/src/lib.rs b/ffi/src/lib.rs index 67312a56..8c73e1b0 100644 --- a/ffi/src/lib.rs +++ b/ffi/src/lib.rs @@ -53,19 +53,20 @@ //! # References //! //! When references are transferred across the FFI boundary, we use -//! `Option<&T>`, or `Option<&mut T>`. This takes advantage of the -//! NULL-pointer optimization that maps `NULL` to `None`, and `*p` to -//! `Some(&p)`. In Rust, references always point to some object, but -//! in C they can be `NULL`. +//! `*const T`, or `*mut T`. If the parameter is optional, a +//! `Option<&T>` or `Option<&mut T>` is used. //! //! Application code must adhere to Rust's reference rules: //! //! - Either one mutable reference or any number of immutable ones. +//! - All references are non-`NULL`. //! - All references are valid. //! //! In this crate we enforce the second rule by asserting that all -//! pointers handed in are non-`NULL` unless explicitly stated -//! (e.g. destructors may be called with a `NULL` reference). +//! pointers handed in are non-`NULL`. There are two exceptions: +//! +//! - It is explicitly stated by using `Option<&T>` or `Option<&mut T>`. +//! - Destructors (`sq_*_free`) may be called with `NULL`. //! //! # Lifetimes //! @@ -166,10 +167,12 @@ macro_rules! ffi_param_move { /// Panics if called with NULL. macro_rules! ffi_param_ref { ($name:ident) => {{ - if $name.is_none() { + if $name.is_null() { panic!("Parameter {} is NULL", stringify!($name)); } - $name.unwrap() + unsafe { + &*$name + } }}; } @@ -180,10 +183,12 @@ macro_rules! ffi_param_ref { /// Panics if called with NULL. macro_rules! ffi_param_ref_mut { ($name:ident) => {{ - if $name.is_none() { + if $name.is_null() { panic!("Parameter {} is NULL", stringify!($name)); } - $name.unwrap() + unsafe { + &mut *$name + } }}; } |