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Handle the const struct * and struct * patterns #2304

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merged 2 commits into from
Nov 10, 2022

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@pvdrz pvdrz commented Oct 11, 2022

Given that C keeps a different namespace for structs and aliases. The following pattern

typedef const struct foo {
    void *bar;
} *foo;

is valid C code and produces both a struct and a pointer called foo. Given that Rust does not make this distinction, we add the _ptr prefix to the pointer type alias to avoid any name collisions.

Fixes: #2227

bindgen/ir/ty.rs Outdated Show resolved Hide resolved
bindgen/ir/ty.rs Outdated
if !ctx.options().c_naming {
if let Some(inner_name) = dbg!(inner_spelling
.strip_prefix("const struct ")
.and_then(|s| s.strip_suffix(" *")))
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This textual approach seems unreliable; what if there isn't a space before the *? Possibly other cases?

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This textual representation is generated by clang and it doesn't seem to be affected by adding/removing spaces from the source code. For example:

typedef const struct foo {
    char bar;
}*foo;

works just fine.

@pvdrz pvdrz changed the title Handle the const struct * pattern. Handle the const struct * and struct * patterns Oct 18, 2022
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pvdrz commented Oct 18, 2022

@goffrie thanks for your review! I updated the PR with some changes if you want to give it a second look

@pvdrz pvdrz requested a review from emilio October 24, 2022 15:14
bindgen/ir/ty.rs Outdated
// collisions.
if !ctx.options().c_naming {
if let Some(inner_name) = inner_spelling
.strip_prefix("const struct ")
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This feels a bit hackish, relying on libclang's serialization... Can we use pointee_type() and cursor equality instead? If not I guess this is ok...

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I did a commit using pointee_type but I don't get the cursor equality part, wdym?

@pvdrz pvdrz force-pushed the const-struct-ptr branch 2 times, most recently from f7716a5 to e4ba626 Compare November 8, 2022 20:33
Given that C keeps a different namespace for `struct`s and aliases. The
following patterns
```c
typedef const struct foo {
    void *inner;
} *foo;

typedef struct bar {
    void *inner;
} *bar;
```
are valid C code and produces both a `struct` and a pointer called `foo`
and `bar` in different namespaces. Given that Rust does not make this
distinction, we add the `_ptr` prefix to the pointer type aliases to
avoid any name collisions.
bindgen/ir/ty.rs Outdated Show resolved Hide resolved
bindgen/ir/ty.rs Outdated Show resolved Hide resolved
bindgen-tests/tests/headers/struct_ptr.h Outdated Show resolved Hide resolved
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Thanks!

@pvdrz pvdrz merged commit db4ea32 into rust-lang:master Nov 10, 2022
@pvdrz pvdrz deleted the const-struct-ptr branch November 10, 2022 15:43
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Multiple definitions when a pointer gets typedef’d to the same name as a struct
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