Add msg_send_bool!

Author: madsmtm

objc2-foundation/src/object.rs

@@ -1,6 +1,6 @@
-use objc2::msg_send;
 use objc2::rc::{DefaultId, Id, Owned, Shared};
-use objc2::runtime::{Bool, Class, Object};
+use objc2::runtime::{Class, Object};
+use objc2::{msg_send, msg_send_bool};
 
 use super::NSString;
 
@@ -17,8 +17,7 @@ impl NSObject {
     }
 
     pub fn is_equal(&self, other: &NSObject) -> bool {
-        let result: Bool = unsafe { msg_send![self, isEqual: other] };
-        result.as_bool()
+        unsafe { msg_send_bool![self, isEqual: other] }
     }
 
     pub fn description(&self) -> Id<NSString, Shared> {
@@ -30,8 +29,7 @@ impl NSObject {
     }
 
     pub fn is_kind_of(&self, cls: &Class) -> bool {
-        let result: Bool = unsafe { msg_send![self, isKindOfClass: cls] };
-        result.as_bool()
+        unsafe { msg_send_bool![self, isKindOfClass: cls] }
     }
 }
 

objc2-foundation/src/string.rs

@@ -8,11 +8,11 @@ use std::os::raw::c_char;
 
 use alloc::borrow::ToOwned;
 use objc2::ffi;
-use objc2::msg_send;
 use objc2::rc::DefaultId;
 use objc2::rc::{autoreleasepool, AutoreleasePool};
 use objc2::rc::{Id, Shared};
-use objc2::runtime::{Bool, Class, Object};
+use objc2::runtime::{Class, Object};
+use objc2::{msg_send, msg_send_bool};
 
 use crate::{NSComparisonResult, NSCopying, NSMutableCopying, NSMutableString, NSObject};
 
@@ -182,8 +182,7 @@ impl NSString {
     #[doc(alias = "hasPrefix")]
     #[doc(alias = "hasPrefix:")]
     pub fn has_prefix(&self, prefix: &NSString) -> bool {
-        let res: Bool = unsafe { msg_send![self, hasPrefix: prefix] };
-        res.is_true()
+        unsafe { msg_send_bool![self, hasPrefix: prefix] }
     }
 
     /// Whether the given string matches the ending characters of this string.
@@ -192,8 +191,7 @@ impl NSString {
     #[doc(alias = "hasSuffix")]
     #[doc(alias = "hasSuffix:")]
     pub fn has_suffix(&self, suffix: &NSString) -> bool {
-        let res: Bool = unsafe { msg_send![self, hasSuffix: suffix] };
-        res.is_true()
+        unsafe { msg_send_bool![self, hasSuffix: suffix] }
     }
 
     // pub fn from_nsrange(range: NSRange) -> Id<Self, Shared>

objc2-foundation/src/thread.rs

@@ -1,6 +1,5 @@
-use objc2::msg_send;
 use objc2::rc::{Id, Shared};
-use objc2::runtime::Bool;
+use objc2::{msg_send, msg_send_bool};
 
 use crate::{NSObject, NSString};
 
@@ -34,8 +33,7 @@ impl NSThread {
 
     /// Returns `true` if the thread is the main thread.
     pub fn is_main(&self) -> bool {
-        let res: Bool = unsafe { msg_send![self, isMainThread] };
-        res.is_true()
+        unsafe { msg_send_bool![self, isMainThread] }
     }
 
     /// The name of the thread.
@@ -47,14 +45,12 @@ impl NSThread {
 
 /// Whether the application is multithreaded according to Cocoa.
 pub fn is_multi_threaded() -> bool {
-    let res: Bool = unsafe { msg_send![NSThread::class(), isMultiThreaded] };
-    res.is_true()
+    unsafe { msg_send_bool![NSThread::class(), isMultiThreaded] }
 }
 
 /// Whether the current thread is the main thread.
 pub fn is_main_thread() -> bool {
-    let res: Bool = unsafe { msg_send![NSThread::class(), isMainThread] };
-    res.is_true()
+    unsafe { msg_send_bool![NSThread::class(), isMainThread] }
 }
 
 #[cfg(test)]

objc2/CHANGELOG.md

@@ -16,6 +16,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 * Added `Id::retain_autoreleased` to allow following Cocoas memory management
   rules more efficiently.
 * Consistently allow trailing commas in `msg_send!`.
+* Added `msg_send_bool!`, a less error-prone version of `msg_send!` for
+  Objective-C methods that return `BOOL`.
 
 ### Changed
 * **BREAKING**: Changed signature of `Id::new` and `Id::retain` from

objc2/src/bool.rs

@@ -16,11 +16,10 @@ use core::fmt;
 /// # Example
 ///
 /// ```no_run
-/// use objc2::{class, msg_send};
+/// use objc2::{class, msg_send, msg_send_bool};
 /// use objc2::runtime::{Object, Bool};
 /// let ns_value: *mut Object = unsafe { msg_send![class!(NSValue), initWithBool: Bool::YES] };
-/// let rtn: Bool = unsafe { msg_send![ns_value, boolValue] };
-/// assert!(rtn.as_bool());
+/// assert!(unsafe { msg_send_bool![ns_value, boolValue] });
 /// ```
 #[repr(transparent)]
 // We don't implement comparison traits because they could be implemented with

objc2/src/lib.rs

@@ -29,7 +29,7 @@
 //!
 #![cfg_attr(apple, doc = "```")]
 #![cfg_attr(not(apple), doc = "```no_run")]
-//! use objc2::{class, msg_send};
+//! use objc2::{class, msg_send, msg_send_bool};
 //! use objc2::ffi::NSUInteger;
 //! use objc2::rc::{Id, Owned};
 //! use objc2::runtime::{Bool, Object};
@@ -43,8 +43,8 @@
 //!
 //! // Usage
 //! let hash: NSUInteger = unsafe { msg_send![obj, hash] };
-//! let is_kind: Bool = unsafe { msg_send![obj, isKindOfClass: cls] };
-//! assert!(is_kind.as_bool());
+//! let is_kind = unsafe { msg_send_bool![obj, isKindOfClass: cls] };
+//! assert!(is_kind);
 //! ```
 //!
 //! Note that this very simple example contains **a lot** of `unsafe` (which

objc2/src/macros.rs

@@ -166,3 +166,39 @@ macro_rules! msg_send {
         result
     });
 }
+
+/// A less error-prone version of [`msg_send!`] for methods returning `BOOL`.
+///
+/// Objective-C's `BOOL` is different from Rust's [`bool`] (see [`Bool`]), so
+/// a conversion step must be performed before using it - this macro does that
+/// for you!
+///
+/// [`Bool`]: crate::runtime::Bool
+///
+/// Equivalent to the following:
+///
+/// ```ignore
+/// # use objc2::msg_send;
+/// # use objc2::runtime::Bool;
+/// # let obj: *mut Object = 0 as *mut Object;
+/// {
+///     let result: Bool = msg_send![obj, selector];
+///     result.as_bool()
+/// };
+/// ```
+///
+/// # Examples
+///
+/// ```no_run
+/// # use objc2::msg_send_bool;
+/// # use objc2::runtime::Object;
+/// # let obj: *mut Object = 0 as *mut Object;
+/// assert!(unsafe { msg_send_bool![obj, isEqual: obj] });
+/// ```
+#[macro_export]
+macro_rules! msg_send_bool {
+    [$($msg_send_args:tt)+] => ({
+        let result: $crate::runtime::Bool = $crate::msg_send![$($msg_send_args)+];
+        result.as_bool()
+    });
+}

objc2/src/runtime.rs

@@ -170,8 +170,7 @@ impl Ivar {
 
     /// Returns the offset of self.
     pub fn offset(&self) -> isize {
-        let offset = unsafe { ffi::ivar_getOffset(self.as_ptr()) };
-        offset as isize
+        unsafe { ffi::ivar_getOffset(self.as_ptr()) }
     }
 
     /// Returns the `Encoding` of self.