Objective-c header from CAMediaTimingFunction panics.

[simlay]

If you try to make bindgen work for all of the UIKit iOS Framework one of the issues that comes up is the reference to initWithControlPoints.

It seems that thesplit_name logic in

rust-bindgen/src/ir/objc.rs

Line 215 in 899f599

let split_name: Vec<_> = self

. self.name here is initWithControlPoints::::, and the .filter(|p| !p.is_empty()) removes the empty parameters.

Input C/C++ Header

@interface CAMediaTimingFunction
- (instancetype)initWithControlPoints:(float)c1x :(float)c1y :(float)c2x :(float)c2y;
@end

Bindgen Invocation

$ bindgen input.h -- -x objective-c

Actual Results

$ RUST_BACKTRACE=1 bindgen input.h -- -x objective-c
cargo:warning=couldn't execute `llvm-config --prefix` (error: No such file or directory (os error 2))
cargo:warning=set the LLVM_CONFIG_PATH environment variable to a valid `llvm-config` executable
thread 'main' panicked at 'Incorrect method name or arguments for objc method, [TokenStream [Ident { sym: c1x }, Punct { op: ':', spacing: Alone }, Ident { sym: f32 }], TokenStream [Ident { sym: c1y }, Punct { op: ':', spacing: Alone }, Ident { sym: f32 }], TokenStream [Ident { sym: c2x }, Punct { op: ':', spacing: Alone }, Ident { sym: f32 }], TokenStream [Ident { sym: c2y }, Punct { op: ':', spacing: Alone }, Ident { sym: f32 }]] vs [Ident(initWithControlPoints)]', /Users/simlay/.cargo/registry/src/jiasu.xzqcsaa.nyc.mn-1ecc6299db9ec823/bindgen-0.51.1/src/ir/objc.rs:232:13
stack backtrace:
   0: std::panicking::default_hook::{{closure}}
   1: std::panicking::default_hook
   2: std::panicking::rust_panic_with_hook
   3: std::panicking::continue_panic_fmt
   4: std::panicking::begin_panic_fmt
   5: bindgen::ir::objc::ObjCMethod::format_method_call
   6: bindgen::codegen::objc_method_codegen
   7: <bindgen::ir::objc::ObjCInterface as bindgen::codegen::CodeGenerator>::codegen
   8: <bindgen::ir::ty::Type as bindgen::codegen::CodeGenerator>::codegen
   9: <bindgen::ir::item::Item as bindgen::codegen::CodeGenerator>::codegen
  10: <bindgen::ir::module::Module as bindgen::codegen::CodeGenerator>::codegen::{{closure}}
  11: <bindgen::ir::module::Module as bindgen::codegen::CodeGenerator>::codegen
  12: <bindgen::ir::item::Item as bindgen::codegen::CodeGenerator>::codegen
  13: bindgen::ir::context::BindgenContext::gen
  14: bindgen::Builder::generate
  15: std::panicking::try::do_call
  16: __rust_maybe_catch_panic
  17: bindgen::main
  18: std::rt::lang_start::{{closure}}
  19: std::panicking::try::do_call
  20: __rust_maybe_catch_panic
  21: std::rt::lang_start_internal
  22: main

Expected Results

To not panic?

From what I can tell it should produce:

use objc;
#[allow(non_camel_case_types)]
pub type id = *mut objc::runtime::Object;
pub trait CAMediaTimingFunction {
    unsafe fn initWithControlPoints____(
        self,
        c1x: f32,
        c1y: f32,
        c2x: f32,
        c2y: f32,
    ) -> instancetype;
}
impl CAMediaTimingFunction for id {
    unsafe fn initWithControlPoints____(
        self,
        c1x: f32,
        c1y: f32,
        c2x: f32,
        c2y: f32,
    ) -> instancetype {
        msg_send!(self, initWithControlPoints: c1x:c1x c1y:c1y c2x:c2x c2y:c2y)
    }
}
pub type instancetype = id;

[simlay]

After more investigation, this is because the method keywords are not there. CIImage has a better example of this.

There's not a ton of documentation around this (and I'm not an expert at objective-c syntax) but from what I can tell when the method keywords aren't there, you just use the internal name.

Also, in case you're curios these method declarations go against apple's guidelines for method declarations.