commit fd6fe93dcac8887b6b3f269bd16ef8cf38984246
parent fd39b32a227663bd0cf1df041b7871db39cedf28
Author: triesap <tyson@radroots.org>
Date: Wed, 1 Jul 2026 00:17:08 +0000
build: patch block future incompatibility
- replace crates.io block with local source
- make Objective-C class marker inhabited
- normalize patched C ABI declarations
- prove Studio warning-clean validation
Diffstat:
4 files changed, 350 insertions(+), 2 deletions(-)
diff --git a/Cargo.lock b/Cargo.lock
@@ -754,8 +754,6 @@ dependencies = [
[[package]]
name = "block"
version = "0.1.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0d8c1fef690941d3e7788d328517591fecc684c084084702d6ff1641e993699a"
[[package]]
name = "block-buffer"
diff --git a/Cargo.toml b/Cargo.toml
@@ -67,3 +67,6 @@ uuid = { version = "1", features = ["serde", "v5", "v7"] }
[workspace.lints.rust]
unsafe_code = "forbid"
+
+[patch.crates-io]
+block = { path = "vendor/block" }
diff --git a/vendor/block/Cargo.toml b/vendor/block/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "block"
+version = "0.1.6"
+authors = ["Steven Sheldon"]
+
+description = "Rust interface for Apple's C language extension of blocks."
+keywords = ["blocks", "osx", "ios", "objective-c"]
+repository = "http://github.com/SSheldon/rust-block"
+documentation = "http://ssheldon.github.io/rust-objc/block/"
+license = "MIT"
diff --git a/vendor/block/src/lib.rs b/vendor/block/src/lib.rs
@@ -0,0 +1,337 @@
+/*!
+A Rust interface for Objective-C blocks.
+
+For more information on the specifics of the block implementation, see
+Clang's documentation: http://clang.llvm.org/docs/Block-ABI-Apple.html
+
+# Invoking blocks
+
+The `Block` struct is used for invoking blocks from Objective-C. For example,
+consider this Objective-C function:
+
+``` objc
+int32_t sum(int32_t (^block)(int32_t, int32_t)) {
+ return block(5, 8);
+}
+```
+
+We could write it in Rust as the following:
+
+```
+# use block::Block;
+unsafe fn sum(block: &Block<(i32, i32), i32>) -> i32 {
+ block.call((5, 8))
+}
+```
+
+Note the extra parentheses in the `call` method, since the arguments must be
+passed as a tuple.
+
+# Creating blocks
+
+Creating a block to pass to Objective-C can be done with the `ConcreteBlock`
+struct. For example, to create a block that adds two `i32`s, we could write:
+
+```
+# use block::ConcreteBlock;
+let block = ConcreteBlock::new(|a: i32, b: i32| a + b);
+let block = block.copy();
+assert!(unsafe { block.call((5, 8)) } == 13);
+```
+
+It is important to copy your block to the heap (with the `copy` method) before
+passing it to Objective-C; this is because our `ConcreteBlock` is only meant
+to be copied once, and we can enforce this in Rust, but if Objective-C code
+were to copy it twice we could have a double free.
+*/
+
+use std::marker::PhantomData;
+use std::mem;
+use std::ops::{Deref, DerefMut};
+use std::os::raw::{c_int, c_ulong, c_void};
+use std::ptr;
+
+#[repr(C)]
+struct Class {
+ _private: [u8; 0],
+}
+
+#[cfg_attr(any(target_os = "macos", target_os = "ios"),
+ link(name = "System", kind = "dylib"))]
+#[cfg_attr(not(any(target_os = "macos", target_os = "ios")),
+ link(name = "BlocksRuntime", kind = "dylib"))]
+extern "C" {
+ static _NSConcreteStackBlock: Class;
+
+ fn _Block_copy(block: *const c_void) -> *mut c_void;
+ fn _Block_release(block: *const c_void);
+}
+
+/// Types that may be used as the arguments to an Objective-C block.
+pub trait BlockArguments: Sized {
+ /// Calls the given `Block` with self as the arguments.
+ ///
+ /// Unsafe because `block` must point to a valid `Block` and this invokes
+ /// foreign code whose safety the compiler cannot verify.
+ unsafe fn call_block<R>(self, block: *mut Block<Self, R>) -> R;
+}
+
+macro_rules! block_args_impl {
+ ($($a:ident : $t:ident),*) => (
+ impl<$($t),*> BlockArguments for ($($t,)*) {
+ unsafe fn call_block<R>(self, block: *mut Block<Self, R>) -> R {
+ let invoke: unsafe extern "C" fn(*mut Block<Self, R> $(, $t)*) -> R = {
+ let base = block as *mut BlockBase<Self, R>;
+ mem::transmute((*base).invoke)
+ };
+ let ($($a,)*) = self;
+ invoke(block $(, $a)*)
+ }
+ }
+ );
+}
+
+block_args_impl!();
+block_args_impl!(a: A);
+block_args_impl!(a: A, b: B);
+block_args_impl!(a: A, b: B, c: C);
+block_args_impl!(a: A, b: B, c: C, d: D);
+block_args_impl!(a: A, b: B, c: C, d: D, e: E);
+block_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F);
+block_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G);
+block_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H);
+block_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I);
+block_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J);
+block_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K);
+block_args_impl!(a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K, l: L);
+
+#[repr(C)]
+struct BlockBase<A, R> {
+ isa: *const Class,
+ flags: c_int,
+ _reserved: c_int,
+ invoke: unsafe extern "C" fn(*mut Block<A, R>, ...) -> R,
+}
+
+/// An Objective-C block that takes arguments of `A` when called and
+/// returns a value of `R`.
+#[repr(C)]
+pub struct Block<A, R> {
+ _base: PhantomData<BlockBase<A, R>>,
+}
+
+impl<A: BlockArguments, R> Block<A, R> where A: BlockArguments {
+ /// Call self with the given arguments.
+ ///
+ /// Unsafe because this invokes foreign code that the caller must verify
+ /// doesn't violate any of Rust's safety rules. For example, if this block
+ /// is shared with multiple references, the caller must ensure that calling
+ /// it will not cause a data race.
+ pub unsafe fn call(&self, args: A) -> R {
+ args.call_block(self as *const _ as *mut _)
+ }
+}
+
+/// A reference-counted Objective-C block.
+pub struct RcBlock<A, R> {
+ ptr: *mut Block<A, R>,
+}
+
+impl<A, R> RcBlock<A, R> {
+ /// Construct an `RcBlock` for the given block without copying it.
+ /// The caller must ensure the block has a +1 reference count.
+ ///
+ /// Unsafe because `ptr` must point to a valid `Block` and must have a +1
+ /// reference count or it will be overreleased when the `RcBlock` is
+ /// dropped.
+ pub unsafe fn new(ptr: *mut Block<A, R>) -> Self {
+ RcBlock { ptr: ptr }
+ }
+
+ /// Constructs an `RcBlock` by copying the given block.
+ ///
+ /// Unsafe because `ptr` must point to a valid `Block`.
+ pub unsafe fn copy(ptr: *mut Block<A, R>) -> Self {
+ let ptr = _Block_copy(ptr as *const c_void) as *mut Block<A, R>;
+ RcBlock { ptr: ptr }
+ }
+}
+
+impl<A, R> Clone for RcBlock<A, R> {
+ fn clone(&self) -> RcBlock<A, R> {
+ unsafe {
+ RcBlock::copy(self.ptr)
+ }
+ }
+}
+
+impl<A, R> Deref for RcBlock<A, R> {
+ type Target = Block<A, R>;
+
+ fn deref(&self) -> &Block<A, R> {
+ unsafe { &*self.ptr }
+ }
+}
+
+impl<A, R> Drop for RcBlock<A, R> {
+ fn drop(&mut self) {
+ unsafe {
+ _Block_release(self.ptr as *const c_void);
+ }
+ }
+}
+
+/// Types that may be converted into a `ConcreteBlock`.
+pub trait IntoConcreteBlock<A>: Sized where A: BlockArguments {
+ /// The return type of the resulting `ConcreteBlock`.
+ type Ret;
+
+ /// Consumes self to create a `ConcreteBlock`.
+ fn into_concrete_block(self) -> ConcreteBlock<A, Self::Ret, Self>;
+}
+
+macro_rules! concrete_block_impl {
+ ($f:ident) => (
+ concrete_block_impl!($f,);
+ );
+ ($f:ident, $($a:ident : $t:ident),*) => (
+ impl<$($t,)* R, X> IntoConcreteBlock<($($t,)*)> for X
+ where X: Fn($($t,)*) -> R {
+ type Ret = R;
+
+ fn into_concrete_block(self) -> ConcreteBlock<($($t,)*), R, X> {
+ unsafe extern "C" fn $f<$($t,)* R, X>(
+ block_ptr: *mut ConcreteBlock<($($t,)*), R, X>
+ $(, $a: $t)*) -> R
+ where X: Fn($($t,)*) -> R {
+ let block = &*block_ptr;
+ (block.closure)($($a),*)
+ }
+
+ let f: unsafe extern "C" fn(*mut ConcreteBlock<($($t,)*), R, X> $(, $a: $t)*) -> R = $f;
+ unsafe {
+ ConcreteBlock::with_invoke(mem::transmute(f), self)
+ }
+ }
+ }
+ );
+}
+
+concrete_block_impl!(concrete_block_invoke_args0);
+concrete_block_impl!(concrete_block_invoke_args1, a: A);
+concrete_block_impl!(concrete_block_invoke_args2, a: A, b: B);
+concrete_block_impl!(concrete_block_invoke_args3, a: A, b: B, c: C);
+concrete_block_impl!(concrete_block_invoke_args4, a: A, b: B, c: C, d: D);
+concrete_block_impl!(concrete_block_invoke_args5, a: A, b: B, c: C, d: D, e: E);
+concrete_block_impl!(concrete_block_invoke_args6, a: A, b: B, c: C, d: D, e: E, f: F);
+concrete_block_impl!(concrete_block_invoke_args7, a: A, b: B, c: C, d: D, e: E, f: F, g: G);
+concrete_block_impl!(concrete_block_invoke_args8, a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H);
+concrete_block_impl!(concrete_block_invoke_args9, a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I);
+concrete_block_impl!(concrete_block_invoke_args10, a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J);
+concrete_block_impl!(concrete_block_invoke_args11, a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K);
+concrete_block_impl!(concrete_block_invoke_args12, a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K, l: L);
+
+/// An Objective-C block whose size is known at compile time and may be
+/// constructed on the stack.
+#[repr(C)]
+pub struct ConcreteBlock<A, R, F> {
+ base: BlockBase<A, R>,
+ descriptor: Box<BlockDescriptor<ConcreteBlock<A, R, F>>>,
+ closure: F,
+}
+
+impl<A, R, F> ConcreteBlock<A, R, F>
+ where A: BlockArguments, F: IntoConcreteBlock<A, Ret=R> {
+ /// Constructs a `ConcreteBlock` with the given closure.
+ /// When the block is called, it will return the value that results from
+ /// calling the closure.
+ pub fn new(closure: F) -> Self {
+ closure.into_concrete_block()
+ }
+}
+
+impl<A, R, F> ConcreteBlock<A, R, F> {
+ /// Constructs a `ConcreteBlock` with the given invoke function and closure.
+ /// Unsafe because the caller must ensure the invoke function takes the
+ /// correct arguments.
+ unsafe fn with_invoke(invoke: unsafe extern "C" fn(*mut Self, ...) -> R,
+ closure: F) -> Self {
+ ConcreteBlock {
+ base: BlockBase {
+ isa: &_NSConcreteStackBlock,
+ // 1 << 25 = BLOCK_HAS_COPY_DISPOSE
+ flags: 1 << 25,
+ _reserved: 0,
+ invoke: mem::transmute(invoke),
+ },
+ descriptor: Box::new(BlockDescriptor::new()),
+ closure: closure,
+ }
+ }
+}
+
+impl<A, R, F> ConcreteBlock<A, R, F> where F: 'static {
+ /// Copy self onto the heap as an `RcBlock`.
+ pub fn copy(self) -> RcBlock<A, R> {
+ unsafe {
+ let mut block = self;
+ let copied = RcBlock::copy(&mut *block);
+ // At this point, our copy helper has been run so the block will
+ // be moved to the heap and we can forget the original block
+ // because the heap block will drop in our dispose helper.
+ mem::forget(block);
+ copied
+ }
+ }
+}
+
+impl<A, R, F> Clone for ConcreteBlock<A, R, F> where F: Clone {
+ fn clone(&self) -> Self {
+ unsafe {
+ ConcreteBlock::with_invoke(mem::transmute(self.base.invoke),
+ self.closure.clone())
+ }
+ }
+}
+
+impl<A, R, F> Deref for ConcreteBlock<A, R, F> {
+ type Target = Block<A, R>;
+
+ fn deref(&self) -> &Block<A, R> {
+ unsafe { &*(&self.base as *const _ as *const Block<A, R>) }
+ }
+}
+
+impl<A, R, F> DerefMut for ConcreteBlock<A, R, F> {
+ fn deref_mut(&mut self) -> &mut Block<A, R> {
+ unsafe { &mut *(&mut self.base as *mut _ as *mut Block<A, R>) }
+ }
+}
+
+unsafe extern "C" fn block_context_dispose<B>(block: &mut B) {
+ // Read the block onto the stack and let it drop
+ ptr::read(block);
+}
+
+unsafe extern "C" fn block_context_copy<B>(_dst: &mut B, _src: &B) {
+ // The runtime memmoves the src block into the dst block, nothing to do
+}
+
+#[repr(C)]
+struct BlockDescriptor<B> {
+ _reserved: c_ulong,
+ block_size: c_ulong,
+ copy_helper: unsafe extern "C" fn(&mut B, &B),
+ dispose_helper: unsafe extern "C" fn(&mut B),
+}
+
+impl<B> BlockDescriptor<B> {
+ fn new() -> BlockDescriptor<B> {
+ BlockDescriptor {
+ _reserved: 0,
+ block_size: mem::size_of::<B>() as c_ulong,
+ copy_helper: block_context_copy::<B>,
+ dispose_helper: block_context_dispose::<B>,
+ }
+ }
+}
