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|
/*!
Utilities for reference counting Objective-C objects.
The utilities of the `rc` module provide ARC-like semantics for working with
Objective-C's reference counted objects in Rust.
A `StrongPtr` retains an object and releases the object when dropped.
A `WeakPtr` will not retain the object, but can be upgraded to a `StrongPtr`
and safely fails if the object has been deallocated.
These utilities are not intended to provide a fully safe interface, but can be
useful when writing higher-level Rust wrappers for Objective-C code.
For more information on Objective-C's reference counting, see Apple's documentation:
<https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/MemoryMgmt.html>
# Example
``` no_run
# #[macro_use] extern crate objc;
# use objc::rc::{autoreleasepool, StrongPtr};
# fn main() {
// StrongPtr will release the object when dropped
let obj = unsafe {
StrongPtr::new(msg_send![class!(NSObject), new])
};
// Cloning retains the object an additional time
let cloned = obj.clone();
autoreleasepool(|| {
// Autorelease consumes the StrongPtr, but won't
// actually release until the end of an autoreleasepool
cloned.autorelease();
});
// Weak references won't retain the object
let weak = obj.weak();
drop(obj);
assert!(weak.load().is_null());
# }
```
*/
mod strong;
mod weak;
mod autorelease;
pub use self::strong::StrongPtr;
pub use self::weak::WeakPtr;
pub use self::autorelease::autoreleasepool;
// These tests use NSObject, which isn't present for GNUstep
#[cfg(all(test, any(target_os = "macos", target_os = "ios")))]
mod tests {
use runtime::Object;
use super::StrongPtr;
use super::autoreleasepool;
#[test]
fn test_strong_clone() {
fn retain_count(obj: *mut Object) -> usize {
unsafe { msg_send![obj, retainCount] }
}
let obj = unsafe {
StrongPtr::new(msg_send![class!(NSObject), new])
};
assert!(retain_count(*obj) == 1);
let cloned = obj.clone();
assert!(retain_count(*cloned) == 2);
assert!(retain_count(*obj) == 2);
drop(obj);
assert!(retain_count(*cloned) == 1);
}
#[test]
fn test_weak() {
let obj = unsafe {
StrongPtr::new(msg_send![class!(NSObject), new])
};
let weak = obj.weak();
let strong = weak.load();
assert!(*strong == *obj);
drop(strong);
drop(obj);
assert!(weak.load().is_null());
}
#[test]
fn test_weak_copy() {
let obj = unsafe {
StrongPtr::new(msg_send![class!(NSObject), new])
};
let weak = obj.weak();
let weak2 = weak.clone();
let strong = weak2.load();
assert!(*strong == *obj);
}
#[test]
fn test_autorelease() {
let obj = unsafe {
StrongPtr::new(msg_send![class!(NSObject), new])
};
fn retain_count(obj: *mut Object) -> usize {
unsafe { msg_send![obj, retainCount] }
}
let cloned = obj.clone();
autoreleasepool(|| {
obj.autorelease();
assert!(retain_count(*cloned) == 2);
});
// make sure that the autoreleased value has been released
assert!(retain_count(*cloned) == 1);
}
}
|
