objc2 0.3.0-beta.3.patch-leaks

mod __rewrite_self_arg;
mod declare_class;
mod extern_class;
mod extern_methods;

/// Gets a reference to a [`Class`] from the given name.
///
/// [`Class`]: crate::runtime::Class
///
///
/// # Panics
///
/// Panics if no class with the given name can be found.
///
/// To check for a class that may not exist, use [`Class::get`].
///
/// [`Class::get`]: crate::runtime::Class::get
///
///
/// # Features
///
/// If the experimental `"unstable-static-class"` feature is enabled, this
/// will emit special statics that will be replaced by dyld when the program
/// starts up.
///
/// Errors that were previously runtime panics may now turn into linker errors
/// if you try to use a class which is not available. Additionally, you may
/// have to call `msg_send![cls, class]` on the result if you want to use it
/// in a dynamic context (e.g. dynamically declaring classes).
///
/// See the [corresponding section][sel#features] in the [`sel!`] macro for
/// more details on the limitations of this. The
/// `"unstable-static-class-inlined"` corresponds to the
/// `"unstable-static-sel-inlined"` feature here.
///
/// [sel#features]: crate::sel#features
/// [`sel!`]: crate::sel
///
/// # Examples
///
/// ```no_run
/// # use objc2::class;
/// let cls = class!(NSObject);
/// ```
#[macro_export]
macro_rules! class {
    ($name:ident) => {{
        $crate::__class_inner!($name, $crate::__hash_idents!($name))
    }};
}

#[doc(hidden)]
#[macro_export]
#[cfg(not(feature = "unstable-static-class"))]
macro_rules! __class_inner {
    ($name:ident, $_hash:expr) => {{
        use $crate::__macro_helpers::{concat, panic, stringify, CachedClass, None, Some};
        static CACHED_CLASS: CachedClass = CachedClass::new();
        let name = concat!(stringify!($name), '\0');
        #[allow(unused_unsafe)]
        let cls = unsafe { CACHED_CLASS.get(name) };
        match cls {
            Some(cls) => cls,
            None => panic!("Class with name {} could not be found", stringify!($name)),
        }
    }};
}

/// Register a selector with the Objective-C runtime.
///
/// Returns the [`Sel`] corresponding to the specified selector.
///
/// [`Sel`]: crate::runtime::Sel
///
///
/// # Panics
///
/// Panics if the runtime failed allocating space for the selector.
///
///
/// # Specification
///
/// This has similar syntax and functionality as the `@selector` directive in
/// Objective-C.
///
/// This calls [`Sel::register`] internally. The result is cached for
/// efficiency. The cache for certain common selectors (`alloc`, `init` and
/// `new`) is deduplicated to reduce code-size.
///
/// Non-ascii identifiers are ill-tested, if supported at all.
///
/// [`Sel::register`]: crate::runtime::Sel::register
///
///
/// # Features
///
/// If the experimental `"unstable-static-sel"` feature is enabled, this will
/// emit special statics that will be replaced by the dynamic linker (dyld)
/// when the program starts up - in exactly the same manner as normal
/// Objective-C code does.
/// This should be significantly faster (and allow better native debugging),
/// however due to the Rust compilation model, and since we don't have
/// low-level control over it, it is currently unlikely that this will work
/// correctly in all cases.
/// See the source code and [rust-lang/rust#53929] for more info.
///
/// Concretely, this may fail at:
/// - link-time (likely)
/// - dynamic link-time/just before the program is run (fairly likely)
/// - runtime, causing UB (unlikely)
///
/// The `"unstable-static-sel-inlined"` feature is the even more extreme
/// version - it yields the best performance and is closest to real
/// Objective-C code, but probably won't work unless your code and its
/// inlining is written in a very certain way.
///
/// Enabling LTO greatly increases the chance that these features work.
///
/// [rust-lang/rust#53929]: https://github.com/rust-lang/rust/issues/53929
///
///
/// # Examples
///
/// Get a few different selectors:
///
/// ```rust
/// use objc2::sel;
/// let sel = sel!(alloc);
/// let sel = sel!(description);
/// let sel = sel!(_privateMethod);
/// let sel = sel!(storyboardWithName:bundle:);
/// let sel = sel!(
///     otherEventWithType:
///     location:
///     modifierFlags:
///     timestamp:
///     windowNumber:
///     context:
///     subtype:
///     data1:
///     data2:
/// );
/// ```
///
/// Whitespace is ignored:
///
/// ```
/// # use objc2::sel;
/// let sel1 = sel!(setObject:forKey:);
/// let sel2 = sel!(  setObject  :
///
///     forKey  : );
/// assert_eq!(sel1, sel2);
/// ```
///
/// Invalid selector:
///
/// ```compile_fail
/// # use objc2::sel;
/// let sel = sel!(aSelector:withoutTrailingColon);
/// ```
///
/// Unsupported usage that you may run into when using macros - fails to
/// compile when the `"unstable-static-sel"` feature is enabled.
///
/// Instead, define a wrapper function that retrieves the selector.
///
#[cfg_attr(not(feature = "unstable-static-sel"), doc = "```no_run")]
#[cfg_attr(feature = "unstable-static-sel", doc = "```compile_fail")]
/// use objc2::sel;
/// macro_rules! x {
///     ($x:ident) => {
///         // One of these is fine
///         sel!($x);
///         // But using the identifier again in the same way is not!
///         sel!($x);
///     };
/// }
/// // Identifier `abc`
/// x!(abc);
/// ```
#[macro_export]
macro_rules! sel {
    (alloc) => ({
        $crate::__macro_helpers::alloc()
    });
    (init) => ({
        $crate::__macro_helpers::init()
    });
    (new) => ({
        $crate::__macro_helpers::new()
    });
    ($first:ident $(: $($rest:ident :)*)?) => ({
        use $crate::__macro_helpers::{concat, stringify, str};
        const SELECTOR_DATA: &str = concat!(stringify!($first), $(':', $(stringify!($rest), ':',)*)? '\0');
        $crate::__sel_inner!(SELECTOR_DATA, $crate::__hash_idents!($first $($($rest)*)?))
    });
}

#[doc(hidden)]
#[macro_export]
#[cfg(not(feature = "unstable-static-sel"))]
macro_rules! __sel_inner {
    ($data:expr, $_hash:expr) => {{
        use $crate::__macro_helpers::CachedSel;
        static CACHED_SEL: CachedSel = CachedSel::new();
        #[allow(unused_unsafe)]
        unsafe {
            CACHED_SEL.get($data)
        }
    }};
}

#[doc(hidden)]
#[macro_export]
macro_rules! __inner_statics_apple_generic {
    {
        @string_to_known_length_bytes;
        $x:ident;
    } => {{
        // Convert the `&[u8]` slice to an array with known length, so
        // that we can place that directly in a static.
        let mut res: [u8; $x.len()] = [0; $x.len()];
        let mut i = 0;
        while i < $x.len() {
            res[i] = $x[i];
            i += 1;
        }
        res
    }};
    {
        @image_info;
        $image_info_section:literal;
        $hash:expr;
    } => {
        /// We always emit the image info tag, since we need it to:
        /// - End up in the same codegen unit as the other statics below.
        /// - End up in the final binary so it can be read by dyld.
        ///
        /// Unfortunately however, this leads to duplicated tags - the linker
        /// reports `__DATA/__objc_imageinfo has unexpectedly large size XXX`,
        /// but things still seems to work.
        #[link_section = $image_info_section]
        #[export_name = $crate::__macro_helpers::concat!(
            "\x01L_OBJC_IMAGE_INFO_",
            $hash,
        )]
        #[used] // Make sure this reaches the linker
        static _IMAGE_INFO: $crate::ffi::__ImageInfo = $crate::ffi::__ImageInfo::system();
    };
    {
        @module_info;
        $hash:expr;
    } => {
        #[link_section = "__TEXT,__cstring,cstring_literals"]
        #[export_name = $crate::__macro_helpers::concat!(
            "\x01L_OBJC_CLASS_NAME_",
            $hash,
            "_MODULE_INFO"
        )]
        static MODULE_INFO_NAME: [$crate::__macro_helpers::u8; 1] = [0];

        /// Emit module info.
        ///
        /// This is similar to image info, and must be present in the final
        /// binary on macOS 32-bit.
        #[link_section = "__OBJC,__module_info,regular,no_dead_strip"]
        #[export_name = $crate::__macro_helpers::concat!(
            "\x01L_OBJC_MODULES_",
            $hash,
        )]
        #[used] // Make sure this reaches the linker
        static _MODULE_INFO: $crate::__macro_helpers::ModuleInfo = $crate::__macro_helpers::ModuleInfo::new(
            MODULE_INFO_NAME.as_ptr()
        );
    };
    {
        @sel;
        $var_name_section:literal;
        $selector_ref_section:literal;
        $data:expr;
        $hash:expr;
    } => {
        use $crate::__macro_helpers::{u8, UnsafeCell};
        use $crate::runtime::Sel;

        const X: &[u8] = $data.as_bytes();

        /// Clang marks this with LLVM's `unnamed_addr`.
        /// See rust-lang/rust#18297
        /// Should only be an optimization (?)
        #[link_section = $var_name_section]
        #[export_name = $crate::__macro_helpers::concat!(
            "\x01L_OBJC_METH_VAR_NAME_",
            $hash,
        )]
        static NAME_DATA: [u8; X.len()] = $crate::__inner_statics_apple_generic! {
            @string_to_known_length_bytes;
            X;
        };

        /// Place the constant value in the correct section.
        ///
        /// We use `UnsafeCell` because this somewhat resembles internal
        /// mutation - this pointer will be changed by dyld at startup, so we
        /// _must_ prevent Rust/LLVM from trying to "peek inside" it and just
        /// use a pointer to `NAME_DATA` directly.
        ///
        /// Clang does this by marking `REF` with LLVM's
        /// `externally_initialized`.
        ///
        /// `static mut` is used so that we don't need to wrap the
        /// `UnsafeCell` in something that implements `Sync`.
        ///
        ///
        /// # Safety
        ///
        /// I'm quite uncertain of how safe this is, since the Rust abstract
        /// machine has no concept of a static that is initialized outside of
        /// it - perhaps it would be better to use `read_volatile` instead of
        /// relying on `UnsafeCell`? Or perhaps `MaybeUninit` would help?
        ///
        /// See the [`ctor`](https://crates.io/crates/ctor) crate for more
        /// info on "life before main".
        #[link_section = $selector_ref_section]
        #[export_name = $crate::__macro_helpers::concat!(
            "\x01L_OBJC_SELECTOR_REFERENCES_",
            $hash,
        )]
        static mut REF: UnsafeCell<Sel> = unsafe {
            UnsafeCell::new(Sel::__internal_from_ptr(NAME_DATA.as_ptr().cast()))
        };
    };
    {
        @class;
        $name:ident;
        $hash:expr;
    } => {
        use $crate::__macro_helpers::UnsafeCell;
        use $crate::runtime::Class;

        extern "C" {
            /// Link to the Objective-C class static.
            ///
            /// This uses the special symbol that static and dynamic linkers
            /// knows about.
            ///
            /// Failure modes:
            /// - Unknown class: Static linker error.
            /// - OS version < Class introduced version: Dynamic linker error
            ///   on program startup.
            /// - Deployment target > Class introduced version: No error,
            ///   though _should_ be a static linker error.
            ///
            /// Ideally, we'd have some way of allowing this to be weakly
            /// linked, and return `Option<&Class>` in that case, but Rust
            /// doesn't have the capability to do so yet!
            /// <https://github.com/rust-lang/rust/issues/29603>
            /// <https://stackoverflow.com/a/16936512>
            /// <http://sealiesoftware.com/blog/archive/2010/4/8/Do-it-yourself_Objective-C_weak_import.html>
            #[link_name = $crate::__macro_helpers::concat!(
                "OBJC_CLASS_$_",
                $crate::__macro_helpers::stringify!($name),
            )]
            static CLASS: Class;
        }

        /// SAFETY: Same as `REF` above in `@sel`.
        #[link_section = "__DATA,__objc_classrefs,regular,no_dead_strip"]
        #[export_name = $crate::__macro_helpers::concat!(
            "\x01L_OBJC_CLASSLIST_REFERENCES_$_",
            $crate::__hash_idents!($name),
        )]
        static mut REF: UnsafeCell<&Class> = unsafe {
            UnsafeCell::new(&CLASS)
        };
    };
    {
        @class_old;
        $name:ident;
        $hash:expr;
    } => {
        use $crate::__macro_helpers::{u8, UnsafeCell};
        use $crate::runtime::Class;

        const X: &[u8] = $crate::__macro_helpers::stringify!($name).as_bytes();

        /// Similar to NAME_DATA above in `@sel`.
        #[link_section = "__TEXT,__cstring,cstring_literals"]
        #[export_name = $crate::__macro_helpers::concat!(
            "\x01L_OBJC_CLASS_NAME_",
            $crate::__hash_idents!($name),
        )]
        static NAME_DATA: [u8; X.len()] = $crate::__inner_statics_apple_generic! {
            @string_to_known_length_bytes;
            X;
        };

        /// SAFETY: Same as `REF` above in `@sel`.
        #[link_section = "__OBJC,__cls_refs,literal_pointers,no_dead_strip"]
        #[export_name = $crate::__macro_helpers::concat!(
            "\x01L_OBJC_CLASS_REFERENCES_",
            $crate::__hash_idents!($name),
        )]
        static mut REF: UnsafeCell<&Class> = unsafe {
            let ptr: *const Class = NAME_DATA.as_ptr().cast();
            UnsafeCell::new(&*ptr)
        };
    }
}

// These sections are found by reading clang/LLVM sources
#[doc(hidden)]
#[macro_export]
#[cfg(all(feature = "apple", not(all(target_os = "macos", target_arch = "x86"))))]
macro_rules! __inner_statics {
    (@image_info $hash:expr) => {
        $crate::__inner_statics_apple_generic! {
            @image_info;
            "__DATA,__objc_imageinfo,regular,no_dead_strip";
            $hash;
        }
    };
    (@sel $data:expr, $hash:expr) => {
        $crate::__inner_statics_apple_generic! {
            @sel;
            "__TEXT,__objc_methname,cstring_literals";
            // Clang uses `no_dead_strip` in the link section for some reason,
            // which other tools (notably some LLVM tools) now assume is
            // present, so we have to add it as well.
            "__DATA,__objc_selrefs,literal_pointers,no_dead_strip";
            $data;
            $hash;
        }
    };
    (@class $name:ident, $hash:expr) => {
        $crate::__inner_statics_apple_generic! {
            @class;
            $name;
            $hash;
        }
    };
}

#[doc(hidden)]
#[macro_export]
#[cfg(all(feature = "apple", target_os = "macos", target_arch = "x86"))]
macro_rules! __inner_statics {
    (@image_info $hash:expr) => {
        $crate::__inner_statics_apple_generic! {
            @image_info;
            "__OBJC,__image_info,regular";
            $hash;
        }
    };
    (@sel $data:expr, $hash:expr) => {
        $crate::__inner_statics_apple_generic! {
            @sel;
            "__TEXT,__cstring,cstring_literals";
            "__OBJC,__message_refs,literal_pointers,no_dead_strip";
            $data;
            $hash;
        }
    };
    (@class $name:ident, $hash:expr) => {
        $crate::__inner_statics_apple_generic! {
            @class_old;
            $name;
            $hash;
        }
        $crate::__inner_statics_apple_generic! {
            @module_info;
            $hash;
        }
    };
}

#[doc(hidden)]
#[macro_export]
#[cfg(not(feature = "apple"))]
macro_rules! __inner_statics {
    (@image_info $($args:tt)*) => {
        // TODO
    };
    (@sel $($args:tt)*) => {
        // TODO
        $crate::__macro_helpers::compile_error!(
            "The `\"unstable-static-sel\"` feature is not yet supported on GNUStep!"
        )
    };
    (@class $($args:tt)*) => {
        // TODO
        $crate::__macro_helpers::compile_error!(
            "The `\"unstable-static-class\"` feature is not yet supported on GNUStep!"
        )
    };
}

#[doc(hidden)]
#[macro_export]
#[cfg(all(
    feature = "unstable-static-sel",
    not(feature = "unstable-static-sel-inlined")
))]
macro_rules! __sel_inner {
    ($data:expr, $hash:expr) => {{
        $crate::__inner_statics!(@image_info $hash);
        $crate::__inner_statics!(@sel $data, $hash);

        /// HACK: Wrap the access in a non-generic, `#[inline(never)]`
        /// function to make the compiler group it into the same codegen unit
        /// as the statics.
        ///
        /// See the following link for details on how the compiler decides
        /// to partition code into codegen units:
        /// <https://doc.rust-lang.org/1.61.0/nightly-rustc/rustc_monomorphize/partitioning/index.html>
        #[inline(never)]
        fn objc_static_workaround() -> $crate::runtime::Sel {
            // SAFETY: The actual selector is replaced by dyld when the
            // program is loaded.
            //
            // This is similar to a volatile read, except it can be stripped
            // if unused.
            unsafe { *REF.get() }
        }

        objc_static_workaround()
    }};
}

#[doc(hidden)]
#[macro_export]
#[cfg(all(feature = "unstable-static-sel-inlined"))]
macro_rules! __sel_inner {
    ($data:expr, $hash:expr) => {{
        $crate::__inner_statics!(@image_info $hash);
        $crate::__inner_statics!(@sel $data, $hash);

        #[allow(unused_unsafe)]
        // SAFETY: See above
        unsafe { *REF.get() }
    }};
}

#[doc(hidden)]
#[macro_export]
#[cfg(all(
    feature = "unstable-static-class",
    not(feature = "unstable-static-class-inlined")
))]
macro_rules! __class_inner {
    ($name:ident, $hash:expr) => {{
        $crate::__inner_statics!(@image_info $hash);
        $crate::__inner_statics!(@class $name, $hash);

        #[inline(never)]
        fn objc_static_workaround() -> &'static Class {
            // SAFETY: Same as __sel_inner
            unsafe { *REF.get() }
        }

        objc_static_workaround()
    }};
}

#[doc(hidden)]
#[macro_export]
#[cfg(all(feature = "unstable-static-class-inlined"))]
macro_rules! __class_inner {
    ($name:ident, $hash:expr) => {{
        $crate::__inner_statics!(@image_info $hash);
        $crate::__inner_statics!(@class $name, $hash);

        #[allow(unused_unsafe)]
        // SAFETY: See above
        unsafe { *REF.get() }
    }};
}

/// Send a message to an object or class.
///
/// This is wildly `unsafe`, even more so than sending messages in
/// Objective-C, because this macro can't inspect header files to see the
/// expected types, and because Rust has more safety invariants to uphold.
/// Make sure to review the safety section below!
///
/// The recommended way of using this macro is by defining a wrapper function:
///
/// ```
/// # use std::os::raw::{c_int, c_char};
/// # use objc2::msg_send;
/// # use objc2::runtime::Object;
/// unsafe fn do_something(obj: &Object, arg: c_int) -> *const c_char {
///     msg_send![obj, doSomething: arg]
/// }
/// ```
///
/// This way we are clearly communicating to Rust that: The method
/// `doSomething:` works with a shared reference to the object. It takes a
/// C-style signed integer, and returns a pointer to what is probably a
/// C-compatible string. Now it's much, _much_ easier to make a safe
/// abstraction around this!
///
/// There exists a variant of this macro, [`msg_send_id!`], which can help
/// with upholding certain requirements of methods that return Objective-C's
/// `id`, or other object pointers. Use that whenever you want to call such a
/// method!
///
/// [`msg_send_id!`]: crate::msg_send_id
///
///
/// # Specification
///
/// The syntax is similar to the message syntax in Objective-C, except with
/// an (optional, though consider that deprecated) comma between arguments,
/// since that works much better with rustfmt.
///
/// The first expression, know as the "receiver", can be any type that
/// implements [`MessageReceiver`], like a reference or a pointer to an
/// object, or even a reference to an [`rc::Id`] containing an object.
///
/// The expression can be wrapped in `super`, with an optional superclass
/// as the second argument. If no specific superclass is specified, the
/// direct superclass is retrieved from [`ClassType`].
///
/// All arguments, and the return type, must implement [`Encode`].
///
/// This macro translates into a call to [`sel!`], and afterwards a fully
/// qualified call to [`MessageReceiver::send_message`]. Note that this means
/// that auto-dereferencing of the receiver is not supported, and that the
/// receiver is consumed. You may encounter a little trouble with `&mut`
/// references, try refactoring into a separate method or reborrowing the
/// reference.
///
/// Variadic arguments are currently not supported.
///
/// [`MessageReceiver`]: crate::MessageReceiver
/// [`rc::Id`]: crate::rc::Id
/// [`ClassType`]: crate::ClassType
/// [`Encode`]: crate::Encode
/// [`sel!`]: crate::sel
/// [`MessageReceiver::send_message`]: crate::MessageReceiver::send_message
///
///
/// # `bool` handling
///
/// Objective-C's `BOOL` is different from Rust's [`bool`], and hence a
/// conversion step must be performed before using it. This is _very_ easy to
/// forget (because it'll happen to work in _most_ cases), so for ease of use,
/// this macro does the conversion step automatically whenever the argument or
/// return type is `bool`!
///
/// That means that any Objective-C method that take or return `BOOL` can
/// simply be translated to use `bool` on the Rust side.
///
/// If you want to handle the conversion explicitly, or the Objective-C method
/// expects a pointer to a `BOOL`, use [`runtime::Bool`] instead.
///
/// [`runtime::Bool`]: crate::runtime::Bool
///
///
/// # Panics
///
/// Panics if the `"catch-all"` feature is enabled and the Objective-C method
/// throws an exception. Exceptions may still cause UB until
/// `extern "C-unwind"` is stable, see [RFC-2945].
///
/// Panics if the `"verify_message"` feature is enabled and the Objective-C
/// method's argument's encoding does not match the encoding of the given
/// arguments. This is highly recommended to enable while testing!
///
/// [RFC-2945]: https://rust-lang.github.io/rfcs/2945-c-unwind-abi.html
///
///
/// # Safety
///
/// Similar to defining and calling an `extern` function in a foreign function
/// interface. In particular, you must uphold the following requirements:
///
/// 1. The selector corresponds to a valid method that is available on the
///    receiver.
///
/// 2. The argument types match what the receiver excepts for this selector.
///
/// 3. The return type match what the receiver returns for this selector.
///
/// 4. The call must not violate Rust's mutability rules, for example if
///    passing an `&T`, the Objective-C method must not mutate the variable
///    (of course except if the variable is inside [`std::cell::UnsafeCell`]).
///
/// 5. If the receiver is a raw pointer it must be valid (aligned,
///    dereferenceable, initialized and so on). Messages to `null` pointers
///    are allowed (though heavily discouraged), but _only_ if the return type
///    itself is a pointer.
///
/// 6. The method must not (yet) throw an exception.
///
/// 7. You must uphold any additional safety requirements (explicit and
///    implicit) that the method has. For example:
///    - Methods that take pointers usually require that the pointer is valid,
///      and sometimes non-null.
///    - Sometimes, a method may only be called on the main thread.
///    - The lifetime of returned pointers usually follows certain rules, and
///      may not be valid outside of an [`autoreleasepool`] ([`msg_send_id!`]
///      can greatly help with that).
///
/// 8. TODO: Maybe more?
///
/// [`autoreleasepool`]: crate::rc::autoreleasepool
/// [`msg_send_id!`]: crate::msg_send_id
///
///
/// # Examples
///
/// Sending messages to an object.
///
/// ```no_run
/// use objc2::msg_send;
/// use objc2::runtime::Object;
///
/// let obj: *mut Object;
/// # obj = 0 as *mut Object;
/// let description: *const Object = unsafe { msg_send![obj, description] };
/// // Usually you'd use msg_send_id here ^
/// let _: () = unsafe { msg_send![obj, setArg1: 1i32, arg2: true] };
/// let arg1: i32 = unsafe { msg_send![obj, getArg1] };
/// let arg2: bool = unsafe { msg_send![obj, getArg2] };
/// ```
///
/// Sending messages to the direct superclass of an object.
///
/// ```no_run
/// use objc2::msg_send;
/// # use objc2::ns_string;
/// # use objc2::foundation::{NSString as MyObject};
///
/// let obj: &MyObject; // Some object that implements ClassType
/// # obj = ns_string!("");
/// let _: () = unsafe { msg_send![super(obj), someMethod] };
/// ```
///
/// Sending messages to a specific superclass of an object.
///
/// ```no_run
/// # use objc2::class;
/// use objc2::msg_send;
/// use objc2::runtime::{Class, Object};
///
/// // Since we specify the superclass ourselves, this doesn't need to
/// // implement ClassType
/// let obj: *mut Object;
/// # obj = 0 as *mut Object;
/// let superclass: &Class;
/// # superclass = class!(NSObject);
/// let arg3: u32 = unsafe { msg_send![super(obj, superclass), getArg3] };
/// ```
#[macro_export]
macro_rules! msg_send {
    [super($obj:expr), $selector:ident $(,)?] => ({
        let sel = $crate::sel!($selector);
        let result;
        // Note: `sel` and `result` can be accessed from the `obj` and
        // `superclass` expressions - we won't (yet) bother with preventing
        // that though.
        result = $crate::MessageReceiver::__send_super_message_static($obj, sel, ());
        result
    });
    [super($obj:expr), $($selector:ident : $argument:expr),+ $(,)?] => ({
        let sel = $crate::sel!($($selector :)+);
        let result;
        result = $crate::MessageReceiver::__send_super_message_static($obj, sel, ($($argument,)+));
        result
    });
    [super($obj:expr, $superclass:expr), $selector:ident $(,)?] => ({
        let sel = $crate::sel!($selector);
        let result;
        result = $crate::MessageReceiver::send_super_message($obj, $superclass, sel, ());
        result
    });
    [super($obj:expr, $superclass:expr), $($selector:ident : $argument:expr $(,)?)+] => ({
        let sel = $crate::sel!($($selector :)+);
        let result;
        result = $crate::MessageReceiver::send_super_message($obj, $superclass, sel, ($($argument,)+));
        result
    });
    [$obj:expr, $selector:ident $(,)?] => ({
        let sel = $crate::sel!($selector);
        let result;
        result = $crate::MessageReceiver::send_message($obj, sel, ());
        result
    });
    [$obj:expr, $($selector:ident : $argument:expr $(,)?)+] => ({
        let sel = $crate::sel!($($selector :)+);
        let result;
        result = $crate::MessageReceiver::send_message($obj, sel, ($($argument,)+));
        result
    });
}

/// Deprecated. Use [`msg_send!`] instead.
#[macro_export]
#[deprecated = "use a normal msg_send! instead, it will perform the conversion for you"]
macro_rules! msg_send_bool {
    [$($msg_send_args:tt)+] => ({
        // Use old impl for backwards compat
        let result: $crate::runtime::Bool = $crate::msg_send![$($msg_send_args)+];
        result.as_bool()
    });
}

/// [`msg_send!`] for methods returning `id`, `NSObject*`, or similar object
/// pointers.
///
/// Object pointers in Objective-C have certain rules for when they should be
/// retained and released across function calls. This macro helps doing that,
/// and returns an [`rc::Id`] with the object, optionally wrapped in an
/// [`Option`] if you want to handle failures yourself.
///
/// [`rc::Id`]: crate::rc::Id
///
///
/// # A little history
///
/// Objective-C's type system is... limited, so you can't easily tell who is
/// responsible for releasing an object. To remedy this problem, Apple/Cocoa
/// introduced approximately the following rule:
///
/// The caller is responsible for releasing objects return from methods that
/// begin with `new`, `alloc`, `copy`, `mutableCopy` or `init`, and method
/// that begins with `init` takes ownership of the receiver. See [Cocoa's
/// Memory Management Policy][mmRules] for a user-friendly introduction to
/// this concept.
///
/// In the past, users had to do `retain` and `release` calls themselves to
/// properly follow these rules. To avoid the memory management problems
/// associated with manual stuff like that, they [introduced "ARC"][arc-rel],
/// which codifies the rules as part of the language, and inserts the required
/// `retain` and `release` calls automatically.
///
/// [`msg_send!`] is similar to pre-ARC; you have to know when to retain and
/// when to release an object. [`msg_send_id!`] is similar to ARC; the rules
/// are simple enough that we can do them automatically!
///
/// [mmRules]: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmRules.html#//apple_ref/doc/uid/20000994-SW1
/// [arc-rel]: https://developer.apple.com/library/archive/releasenotes/ObjectiveC/RN-TransitioningToARC/Introduction/Introduction.html#//apple_ref/doc/uid/TP40011226
///
/// [`msg_send_id!`]: crate::msg_send_id
///
///
/// # Specification
///
/// The syntax is the same as in [`msg_send!`].
///
/// Attributes like `objc_method_family`, `ns_returns_retained`, `ns_consumed`
/// and so on must not present on the method - if they are, you should do
/// manual memory management using the [`msg_send!`] macro instead.
///
/// The accepted receiver and return types, and how we handle them, differ
/// depending on which, if any, of the [recognized selector
/// families][sel-families] the selector belongs to (here `T: Message` and
/// `O: Ownership`):
///
/// - The `new` family: The receiver must be `&Class`, and the return type
///   is a generic `Id<T, O>` or `Option<Id<T, O>>`.
///
/// - The `alloc` family: The receiver must be `&Class`, and the return type
///   is a generic `Id<Allocated<T>, O>` or `Option<Id<Allocated<T>, O>>`.
///
/// - The `init` family: The receiver must be `Option<Id<Allocated<T>, O>>`
///   as returned from `alloc`. The receiver is consumed, and a the
///   now-initialized `Id<T, O>` or `Option<Id<T, O>>` (with the same `T` and
///   `O`) is returned.
///
/// - The `copy` family: The receiver may be anything that implements
///   [`MessageReceiver`] and the return type is a generic `Id<T, O>` or
///   `Option<Id<T, O>>`.
///
/// - The `mutableCopy` family: Same as the `copy` family.
///
/// - No family: The receiver may be anything that implements
///   [`MessageReceiver`]. The result is retained using
///   [`Id::retain_autoreleased`], and a generic `Id<T, O>` or
///   `Option<Id<T, O>>` is returned. This retain is in most cases faster than
///   using autorelease pools!
///
/// See [the clang documentation][arc-retainable] for the precise
/// specification of Objective-C's ownership rules.
///
/// As you may have noticed, the return type is always either `Id<_, _>` or
/// `Option<Id<_, _>>`. Internally, the return type is always
/// `Option<Id<_, _>>` (for example: almost all `new` methods can fail if the
/// allocation failed), but for convenience, if the return type is `Id<_, _>`
/// this macro will automatically unwrap the object, or panic with an error
/// message if it couldn't be retrieved.
///
/// This macro doesn't support super methods yet, see [#173].
/// The `retain`, `release` and `autorelease` selectors are not supported, use
/// [`Id::retain`], [`Id::drop`] and [`Id::autorelease`] for that.
///
/// [sel-families]: https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-method-families
/// [`MessageReceiver`]: crate::MessageReceiver
/// [`Id::retain_autoreleased`]: crate::rc::Id::retain_autoreleased
/// [arc-retainable]: https://clang.llvm.org/docs/AutomaticReferenceCounting.html#retainable-object-pointers-as-operands-and-arguments
/// [#173]: https://github.com/madsmtm/objc2/pull/173
/// [`Id::retain`]: crate::rc::Id::retain
/// [`Id::drop`]: crate::rc::Id::drop
/// [`Id::autorelease`]: crate::rc::Id::autorelease
///
///
/// # Panics
///
/// Panics if the return type is specified as `Id<_, _>` and the method
/// returned NULL.
///
/// Additional panicking cases are documented in [`msg_send!`].
///
///
/// # Safety
///
/// Same as [`msg_send!`], with an expected return type of `id`,
/// `instancetype`, `NSObject*`, or other such object pointers. The method
/// must not have any attributes that changes the how it handles memory
/// management.
///
/// Note that if you're using this inside a context that expects unwinding to
/// have Objective-C semantics (like [`exception::catch`]), you should make
/// sure that the return type is `Option<Id<_, _>>` so that you don't get an
/// unexpected unwind through incompatible ABIs!
///
#[cfg_attr(
    feature = "exception",
    doc = "[`exception::catch`]: crate::exception::catch"
)]
#[cfg_attr(
    not(feature = "exception"),
    doc = "[`exception::catch`]: crate::exception#feature-not-enabled"
)]
///
///
/// # Examples
///
/// ```no_run
/// use objc2::{class, msg_send_id};
/// use objc2::ffi::NSUInteger;
/// use objc2::rc::{Id, Shared};
/// use objc2::runtime::Object;
// Allocate new object
/// let obj = unsafe { msg_send_id![class!(NSObject), alloc] };
/// // Consume the allocated object, return initialized object
/// let obj: Id<Object, Shared> = unsafe { msg_send_id![obj, init] };
/// // Copy the object
/// let copy: Id<Object, Shared> = unsafe { msg_send_id![&obj, copy] };
/// // Call ordinary selector that returns an object
/// // This time, we handle failures ourselves
/// let s: Option<Id<Object, Shared>> = unsafe { msg_send_id![&obj, description] };
/// let s = s.expect("description was NULL");
/// ```
#[macro_export]
macro_rules! msg_send_id {
    [$obj:expr, $selector:ident $(,)?] => ({
        $crate::__msg_send_id_helper!(@verify $selector);
        let sel = $crate::sel!($selector);
        const NAME: &[$crate::__macro_helpers::u8] = $crate::__macro_helpers::stringify!($selector).as_bytes();
        $crate::__msg_send_id_helper!(@get_assert_consts NAME);
        let result;
        result = <RS as $crate::__macro_helpers::MsgSendId<_, _, _>>::send_message_id($obj, sel, ());
        result
    });
    [$obj:expr, $($selector:ident : $argument:expr),+ $(,)?] => ({
        let sel = $crate::sel!($($selector:)+);
        const NAME: &[$crate::__macro_helpers::u8] =
            $crate::__macro_helpers::concat!($($crate::__macro_helpers::stringify!($selector), ':'),+).as_bytes();
        $crate::__msg_send_id_helper!(@get_assert_consts NAME);
        let result;
        result = <RS as $crate::__macro_helpers::MsgSendId<_, _, _>>::send_message_id($obj, sel, ($($argument,)+));
        result
    });
}

/// Helper macro to avoid exposing these in the docs for [`msg_send_id!`].
#[doc(hidden)]
#[macro_export]
macro_rules! __msg_send_id_helper {
    (@verify retain) => {{
        $crate::__macro_helpers::compile_error!(
            "msg_send_id![obj, retain] is not supported. Use `Id::retain` instead"
        )
    }};
    (@verify release) => {{
        $crate::__macro_helpers::compile_error!(
            "msg_send_id![obj, release] is not supported. Drop an `Id` instead"
        )
    }};
    (@verify autorelease) => {{
        $crate::__macro_helpers::compile_error!(
            "msg_send_id![obj, autorelease] is not supported. Use `Id::autorelease`"
        )
    }};
    (@verify $selector:ident) => {{}};
    (@get_assert_consts $selector:ident) => {
        use $crate::__macro_helpers::{bool, in_selector_family, RetainSemantics};
        const NEW: bool = in_selector_family($selector, b"new");
        const ALLOC: bool = in_selector_family($selector, b"alloc");
        const INIT: bool = in_selector_family($selector, b"init");
        const COPY_OR_MUT_COPY: bool = {
            in_selector_family($selector, b"copy") || in_selector_family($selector, b"mutableCopy")
        };
        type RS = RetainSemantics<NEW, ALLOC, INIT, COPY_OR_MUT_COPY>;
    };
}