Interface Message

src/message/mod.rs:50–104

Types that may be sent Objective-C messages. For example: objects, classes, and blocks.

/// Types that may be sent Objective-C messages.
/// For example: objects, classes, and blocks.
pub unsafe trait Message {
    /**
    Sends a message to self with the given selector and arguments.

    The correct version of `objc_msgSend` will be chosen based on the
    return type. For more information, see Apple's documentation:
    <https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ObjCRuntimeRef/index.html#//apple_ref/doc/uid/TP40001418-CH1g-88778>

    If the selector is known at compile-time, it is recommended to use the
    `msg_send!` macro rather than this method.
    */
    #[cfg(not(feature = "verify_message"))]
    unsafe fn send_message<A, R>(&self, sel: Sel, args: A)
            -> Result<R, MessageError>
            where Self: Sized, A: MessageArguments, R: Any {
        send_message(self, sel, args)
    }

    #[cfg(feature = "verify_message")]
    unsafe fn send_message<A, R>(&self, sel: Sel, args: A)
            -> Result<R, MessageError>
            where Self: Sized, A: MessageArguments + EncodeArguments,
            R: Any + Encode {
        send_message(self, sel, args)
    }

    /**
    Verifies that the argument and return types match the encoding of the
    method for the given selector.

    This will look up the encoding of the method for the given selector, `sel`,
    and return a `MessageError` if any encodings differ for the arguments `A`
    and return type `R`.

    # Example
    ``` no_run
    # #[macro_use] extern crate objc;
    # use objc::runtime::{BOOL, Class, Object};
    # use objc::Message;
    # fn main() {
    let obj: &Object;
    # obj = unsafe { msg_send![class!(NSObject), new] };
    let sel = sel!(isKindOfClass:);
    // Verify isKindOfClass: takes one Class and returns a BOOL
    let result = obj.verify_message::<(&Class,), BOOL>(sel);
    assert!(result.is_ok());
    # }
    ```
    */
    fn verify_message<A, R>(&self, sel: Sel) -> Result<(), MessageError>
            where Self: Sized, A: EncodeArguments, R: Encode {
        let obj = unsafe { &*(self as *const _ as *const Object) };
        verify_message_signature::<A, R>(obj.class(), sel)
    }
}

unsafe impl Message for Object { }