Use objc2-metal with metal naming scheme

To keep the diff smaller and easier to review, this uses a temporary
fork of `objc2-metal` and `objc2-quartz-core` whose methods use the
naming scheme of the `metal` crate.

One particular difficult part with this is that the `metal` crate has
several methods where the order of the arguments are swapped relative
to the corresponding Objective-C methods.

This includes most perilously (since these have both an offset and an
index argument, both of which are integers):
- `set_bytes`
- `set_vertex_bytes`
- `set_fragment_bytes`
- `set_buffer`
- `set_vertex_buffer`
- `set_fragment_buffer`
- `set_threadgroup_memory_length`

But also:
- `set_vertex_texture`
- `set_fragment_texture`
- `set_sampler_state`
- `set_vertex_sampler_state`
- `set_fragment_sampler_state`

Another noteworthy thing to mention is that `objc2-metal` does not (yet)
provide a fallback for MTLCopyAllDevices, so we have to do that
ourselves:
madsmtm/objc2@3543940

Author: madsmtm

CHANGELOG.md

@@ -195,6 +195,9 @@ By @brodycj in [#6924](https://github.com/gfx-rs/wgpu/pull/6924).
 - Fix building a BLAS with a transform buffer by adding a flag to indicate usage of the transform buffer. By @Vecvec in
 [#7062](https://github.com/gfx-rs/wgpu/pull/7062).
 
+#### Metal
+- Use autogenerated `objc2` bindings internally, which should resolve a lot of leaks and unsoundness. By @madsmtm in [#5641](https://github.com/gfx-rs/wgpu/pull/5641).
+
 #### Vulkan
 
 - Stop naga causing undefined behavior when a ray query misses. By @Vecvec in [#6752](https://github.com/gfx-rs/wgpu/pull/6752).

Cargo.lock

@@ -157,10 +157,59 @@ walkdir = "2"
 winit = { version = "0.29", features = ["android-native-activity"] }
 
 # Metal dependencies
-metal = "0.31.0"
-block = "0.1"
-core-graphics-types = "0.1"
-objc = "0.2.5"
+block2 = { version = "0.6", git = "https://github.com/madsmtm/objc2", branch = "metal-wgpu" }
+objc2 = { version = "0.6", git = "https://github.com/madsmtm/objc2", branch = "metal-wgpu" }
+objc2-core-foundation = { version = "0.3", default-features = false, features = [
+    "std",
+    "CFCGTypes",
+], git = "https://github.com/madsmtm/objc2", branch = "metal-wgpu" }
+objc2-foundation = { version = "0.3", default-features = false, features = [
+    "std",
+    "NSError",
+    "NSProcessInfo",
+    "NSRange",
+    "NSString",
+], git = "https://github.com/madsmtm/objc2", branch = "metal-wgpu" }
+objc2-metal = { version = "0.3", default-features = false, features = [
+    "std",
+    "block2",
+    "MTLAllocation",
+    "MTLBlitCommandEncoder",
+    "MTLBlitPass",
+    "MTLBuffer",
+    "MTLCaptureManager",
+    "MTLCaptureScope",
+    "MTLCommandBuffer",
+    "MTLCommandEncoder",
+    "MTLCommandQueue",
+    "MTLComputeCommandEncoder",
+    "MTLComputePass",
+    "MTLComputePipeline",
+    "MTLCounters",
+    "MTLDepthStencil",
+    "MTLDevice",
+    "MTLDrawable",
+    "MTLEvent",
+    "MTLLibrary",
+    "MTLPipeline",
+    "MTLPixelFormat",
+    "MTLRenderCommandEncoder",
+    "MTLRenderPass",
+    "MTLRenderPipeline",
+    "MTLResource",
+    "MTLSampler",
+    "MTLStageInputOutputDescriptor",
+    "MTLTexture",
+    "MTLTypes",
+    "MTLVertexDescriptor",
+], git = "https://github.com/madsmtm/objc2", branch = "metal-wgpu" }
+objc2-quartz-core = { version = "0.3", default-features = false, features = [
+    "std",
+    "objc2-core-foundation",
+    "CALayer",
+    "CAMetalLayer",
+    "objc2-metal",
+], git = "https://github.com/madsmtm/objc2", branch = "metal-wgpu" }
 raw-window-metal = "1.0"
 
 # Vulkan dependencies

Cargo.toml

@@ -18,10 +18,9 @@ rust-version = "1.76"
 [package.metadata.docs.rs]
 # Ideally we would enable all the features.
 #
-# However, the metal features fail to be documented because the docs.rs runner cross-compiling under
-# x86_64-unknown-linux-gnu and metal-rs cannot compile in that environment at the moment. The same applies
-# for the dx12 feature.
-features = ["vulkan", "gles", "renderdoc"]
+# However, the dx12 features fail to be documented because the docs.rs runner cross-compiling under
+# x86_64-unknown-linux-gnu cannot compile in that environment at the moment.
+features = ["metal", "vulkan", "gles", "renderdoc"]
 rustdoc-args = ["--cfg", "docsrs"]
 targets = [
     "x86_64-unknown-linux-gnu",
@@ -74,13 +73,15 @@ metal = [
     # Metal is only available on Apple platforms, therefore request MSL output also only if we target an Apple platform.
     "naga/msl-out",
     "dep:arrayvec",
-    "dep:block",
-    "dep:core-graphics-types",
+    "dep:block2",
     "dep:hashbrown",
     "dep:libc",
     "dep:log",
-    "dep:metal",
-    "dep:objc",
+    "dep:objc2",
+    "dep:objc2-core-foundation",
+    "dep:objc2-foundation",
+    "dep:objc2-metal",
+    "dep:objc2-quartz-core",
     "dep:profiling",
     "dep:raw-window-metal",
 ]
@@ -114,7 +115,7 @@ gles = [
     "dep:libloading",
     "dep:log",
     "dep:ndk-sys",
-    "dep:objc",
+    "dep:objc2",
     "dep:profiling",
     "dep:wasm-bindgen",
     "dep:web-sys",
@@ -272,10 +273,12 @@ mach-dxcompiler-rs = { workspace = true, optional = true }
 
 [target.'cfg(target_vendor = "apple")'.dependencies]
 # Backend: Metal
-block = { workspace = true, optional = true }
-core-graphics-types = { workspace = true, optional = true }
-metal = { workspace = true, optional = true }
-objc = { workspace = true, optional = true }
+block2 = { workspace = true, optional = true }
+objc2 = { workspace = true, optional = true }
+objc2-core-foundation = { workspace = true, optional = true }
+objc2-foundation = { workspace = true, optional = true }
+objc2-metal = { workspace = true, optional = true }
+objc2-quartz-core = { workspace = true, optional = true }
 
 # backend: Metal + Vulkan
 raw-window-metal = { workspace = true, optional = true }

wgpu-hal/Cargo.toml

@@ -1334,10 +1334,11 @@ impl crate::Surface for Surface {
                         let window_ptr = handle.ns_view.as_ptr();
                         #[cfg(target_os = "macos")]
                         let window_ptr = {
-                            use objc::{msg_send, runtime::Object, sel, sel_impl};
+                            use objc2::msg_send;
+                            use objc2::runtime::AnyObject;
                             // ns_view always have a layer and don't need to verify that it exists.
-                            let layer: *mut Object =
-                                msg_send![handle.ns_view.as_ptr().cast::<Object>(), layer];
+                            let layer: *mut AnyObject =
+                                msg_send![handle.ns_view.as_ptr().cast::<AnyObject>(), layer];
                             layer.cast::<ffi::c_void>()
                         };
                         window_ptr