Trait objc2_encode::Encode

source ·

pub unsafe trait Encode {
    const ENCODING: Encoding;
}

Expand description

Types that have an Objective-C type-encoding.

Usually you will want to implement RefEncode as well.

If your type is an opaque type you should not need to implement this; there you will only need RefEncode.

Safety

The type must be FFI-safe, meaning a C-compatible repr (repr(C), repr(u8), repr(transparent) where the inner types are C-compatible, and so on). See the nomicon on other reprs.

Objective-C will make assumptions about the type (like its size, alignment and ABI) from its encoding, so the implementer must verify that the encoding is accurate.

Concretely, Self::ENCODING must match the result of running @encode in Objective-C with the type in question.

You should also beware of having Drop types implement this, since when passed to Objective-C via. objc2::msg_send! their destructor will not be called!

Examples

Implementing for a struct:

#[repr(C)]
struct MyType {
    a: i32,
    b: f64,
    c: *const c_void,
}

unsafe impl Encode for MyType {
    const ENCODING: Encoding = Encoding::Struct(
        // The name of the type that Objective-C sees.
        "MyType",
        &[
            // Delegate to field's implementations.
            // The order is the same as in the definition.
            i32::ENCODING,
            f64::ENCODING,
            <*const c_void>::ENCODING,
        ],
    );
}

// Note: You would also implement `RefEncode` for this type.

Required Associated Constants§

source

const ENCODING: Encoding

The Objective-C type-encoding for this type.

Trait objc2_encode::Encode

Safety

Examples

Required Associated Constants§

const ENCODING: Encoding

Implementations on Foreign Types§

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode, J: Encode, K: Encode> Encode for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode> Encode for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E) -> Ret

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode> Encode for Option<unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret>

const ENCODING: Encoding = _

impl Encode for NonZeroU32

const ENCODING: Encoding = u32::ENCODING

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode> Encode for unsafe extern "C" fn(_: A, _: B, _: C, _: D, ...) -> Ret

const ENCODING: Encoding = _

impl Encode for u32

const ENCODING: Encoding = Encoding::UInt

impl<'a, T: RefEncode + ?Sized> Encode for &'a T

const ENCODING: Encoding = T::ENCODING_REF

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode> Encode for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, ...) -> Ret

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode, J: Encode, K: Encode> Encode for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode> Encode for Option<unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, ...) -> Ret>

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode, J: Encode, K: Encode> Encode for Option<unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret>

const ENCODING: Encoding = _

impl Encode for *mut c_void

const ENCODING: Encoding = _

impl<T: Encode> Encode for MaybeUninit<T>

const ENCODING: Encoding = T::ENCODING

impl<T: RefEncode + ?Sized> Encode for *mut T

const ENCODING: Encoding = T::ENCODING_REF

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode> Encode for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, ...) -> Ret

const ENCODING: Encoding = _

impl Encode for NonZeroI32

const ENCODING: Encoding = i32::ENCODING

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode, J: Encode, K: Encode> Encode for Option<extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret>

const ENCODING: Encoding = _

impl<Ret: Encode> Encode for Option<unsafe extern "C" fn() -> Ret>

const ENCODING: Encoding = _

impl Encode for u16

const ENCODING: Encoding = Encoding::UShort

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode> Encode for Option<extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret>

const ENCODING: Encoding = _

impl Encode for AtomicIsize

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode> Encode for unsafe extern "C" fn(_: A, _: B, ...) -> Ret

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode> Encode for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode> Encode for Option<unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, ...) -> Ret>

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode, J: Encode, K: Encode, L: Encode> Encode for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L, ...) -> Ret

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode> Encode for Option<extern "C" fn(_: A, ...) -> Ret>

const ENCODING: Encoding = _

impl Encode for Option<NonZeroU32>

const ENCODING: Encoding = u32::ENCODING

impl Encode for NonZeroI64

const ENCODING: Encoding = i64::ENCODING

impl<'a, T: RefEncode + ?Sized> Encode for &'a mut T

const ENCODING: Encoding = T::ENCODING_REF

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode> Encode for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, ...) -> Ret

const ENCODING: Encoding = _

impl Encode for AtomicU32

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode> Encode for Option<extern "C" fn(_: A, _: B, _: C, _: D, ...) -> Ret>

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode> Encode for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, ...) -> Ret

const ENCODING: Encoding = _

impl Encode for AtomicU16

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode> Encode for unsafe extern "C" fn(_: A, _: B, _: C, ...) -> Ret

const ENCODING: Encoding = _

impl<Ret: Encode, A: Encode, B: Encode, C: Encode, D: Encode, E: Encode, F: Encode, G: Encode, H: Encode, I: Encode, J: Encode> Encode for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, ...) -> Ret

const ENCODING: Encoding = _

impl Encode for Option<NonZeroU8>

const ENCODING: Encoding = u8::ENCODING