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//! # Raw bindings to `Block.h`
use core::cell::UnsafeCell;
use core::ffi::c_void;
use core::marker::{PhantomData, PhantomPinned};
use std::os::raw::c_int;
/// Type for block class ISAs.
///
/// This will likely become an extern type in the future.
#[repr(C)]
#[allow(missing_debug_implementations)]
pub struct Class {
/// The size probably doesn't really matter here, as we only ever use the
/// classes behind pointers, but let's import it with the correct size to
/// be sure.
///
/// This applies with the compiler-rt runtime and with Apple's runtime.
#[cfg(not(any(feature = "gnustep-1-7", feature = "unstable-objfw")))]
_priv: [*mut c_void; 32],
/// The size of this is unknown, so let's use a ZST so the compiler
/// doesn't assume anything about the size.
#[cfg(any(feature = "gnustep-1-7", feature = "unstable-objfw"))]
_priv: [u8; 0],
/// Mark as `!Send + !Sync + !Unpin` and as mutable behind shared
/// references (`!Freeze`).
///
/// Same as `objc_sys::OpaqueData`.
_opaque: UnsafeCell<PhantomData<(*const UnsafeCell<()>, PhantomPinned)>>,
}
// TODO: Use `extern "C-unwind"` when in MSRV (because the runtime functions
// may call external routines).
extern "C" {
/// Class ISA used for global blocks.
pub static _NSConcreteGlobalBlock: Class;
/// Class ISA used for stack blocks.
pub static _NSConcreteStackBlock: Class;
/// Copy/retain a block.
///
/// When called on a:
/// - Global block: Does nothing.
/// - Stack block: `memmove`s the block to a new heap allocation, calls
/// the copy helper, and returns the new malloc block.
/// - Malloc block: Increments the retain count.
///
/// Returns `NULL` on allocation failure.
#[doc(alias = "Block_copy")]
pub fn _Block_copy(block: *const c_void) -> *mut c_void;
/// Release a block.
///
/// When called on a:
/// - Global block: Does nothing.
/// - Stack block: Does nothing.
/// - Malloc block: Decrements the retain count, and if it reaches zero,
/// calls the dispose helper and frees the underlying storage.
#[doc(alias = "Block_release")]
pub fn _Block_release(block: *const c_void);
/// Copy a block field or `__block` variable from one location to another.
///
/// Called by C compilers to clone fields inside copy helper routines, and
/// to handle memory management of `__block` marked variables.
pub fn _Block_object_assign(dest_addr: *mut c_void, object: *const c_void, flags: c_int);
/// Dispose an object previously copied using `_Block_object_assign`.
///
/// Called by C compilers to drop fields inside dispose helper routines,
/// and handle memory management of `__block` marked variables.
pub fn _Block_object_dispose(object: *const c_void, flags: c_int);
}
/// `Block_private.h`
#[allow(missing_docs)]
#[cfg(any(test, feature = "unstable-private"))]
pub mod private {
use super::*;
#[cfg(any(doc, target_vendor = "apple", feature = "gnustep-1-7"))]
use std::os::raw::c_char;
#[cfg(any(doc, target_vendor = "apple", feature = "compiler-rt"))]
use std::os::raw::c_ulong;
extern "C" {
pub static _NSConcreteMallocBlock: Class;
#[cfg(any(doc, target_vendor = "apple", feature = "compiler-rt"))]
pub static _NSConcreteAutoBlock: Class;
#[cfg(any(doc, target_vendor = "apple", feature = "compiler-rt"))]
pub static _NSConcreteFinalizingBlock: Class;
#[cfg(any(doc, target_vendor = "apple", feature = "compiler-rt"))]
pub static _NSConcreteWeakBlockVariable: Class;
#[cfg(any(doc, target_vendor = "apple", feature = "compiler-rt"))]
pub fn Block_size(block: *mut c_void) -> c_ulong; // usize
// Whether the return value of the block is on the stack.
// macOS 10.7
#[cfg(any(doc, target_vendor = "apple"))]
pub fn _Block_use_stret(block: *mut c_void) -> bool;
// Returns a string describing the block's GC layout.
// This uses the GC skip/scan encoding.
// May return NULL.
// macOS 10.7
#[cfg(any(doc, target_vendor = "apple"))]
pub fn _Block_layout(block: *mut c_void) -> *const c_char;
// Returns a string describing the block's layout.
// This uses the "extended layout" form described above.
// May return NULL.
// macOS 10.8
#[cfg(any(doc, target_vendor = "apple"))]
pub fn _Block_extended_layout(block: *mut c_void) -> *const c_char;
// Callable only from the ARR weak subsystem while in exclusion zone
// macOS 10.7
#[cfg(any(doc, target_vendor = "apple"))]
pub fn _Block_tryRetain(block: *const c_void) -> bool;
// Callable only from the ARR weak subsystem while in exclusion zone
// macOS 10.7
#[cfg(any(doc, target_vendor = "apple"))]
pub fn _Block_isDeallocating(block: *const c_void) -> bool;
// indicates whether block was compiled with compiler that sets the ABI
// related metadata bits
// macOS 10.7
#[cfg(any(doc, target_vendor = "apple", feature = "gnustep-1-7"))]
pub fn _Block_has_signature(block: *mut c_void) -> bool;
// Returns a string describing the block's parameter and return types.
// The encoding scheme is the same as Objective-C @encode.
// Returns NULL for blocks compiled with some compilers.
// macOS 10.7
#[cfg(any(doc, target_vendor = "apple", feature = "gnustep-1-7"))]
pub fn _Block_signature(block: *mut c_void) -> *const c_char;
}
}
#[cfg(test)]
mod tests {
use super::*;
use core::ptr;
use std::println;
#[test]
fn smoke() {
assert_eq!(unsafe { _Block_copy(ptr::null_mut()) }, ptr::null_mut());
unsafe { _Block_release(ptr::null_mut()) };
}
#[test]
fn test_linkable() {
println!("{:?}", unsafe { ptr::addr_of!(_NSConcreteGlobalBlock) });
println!("{:?}", unsafe { ptr::addr_of!(_NSConcreteStackBlock) });
println!("{:?}", unsafe {
ptr::addr_of!(private::_NSConcreteMallocBlock)
});
println!("{:p}", _Block_copy as unsafe extern "C" fn(_) -> _);
println!(
"{:p}",
_Block_object_assign as unsafe extern "C" fn(_, _, _)
);
println!("{:p}", _Block_object_dispose as unsafe extern "C" fn(_, _));
println!("{:p}", _Block_release as unsafe extern "C" fn(_));
}
}