impl<T> Read for UniquePtr<T> where ... Pin<&a mut T> : Read.
#1368
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This commit implements forwarding of `Read` trait implementation from `UniquePtr<T>` to the pointee type. This is quite similar to how `Box<T>` also forwards - see https://doc.rust-lang.org/std/boxed/struct.Box.html#impl-Read-for-Box%3CR%3E Just as with `Box<T>`, the `impl` cannot be provided in the crate introducing `T`, because this violates the orphan rule. This means that before this commit a wrapper newtype would be required to work around the orphan rule - e.g.: ``` struct UniquePtrOfReadTrait(cxx::UniquePtr<ffi::ReadTrait>); impl Read for UniquePtrOfReadTrait { … } ``` After this commit, one can provide an `impl` that works more directly with the C++ type `T` (the FFI will typically require passing `self: Pin<&mut ffi::ReadTrait>`): ``` impl<'a> Read for Pin<&'a mut ffi::ReadTrait> { … } ``` For a more specific motivating example, please see: https://docs.google.com/document/d/1EPn1Ss-hfOC6Ki_B5CC6GA_UFnY3TmoDLCP2HjP7bms
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After dtolnay/cxx#1368 we can simplify the FFI code a little bit, because now there is no need for a separate newtype wrapper for `cxx::UniquePtr<ffi::ReadTrait>`. Bug: chromium:359917956 Change-Id: Ib30413f45e0b41c54f87b35c78f6a65fda2015b3 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/889876 Reviewed-by: Brian Osman <[email protected]> Commit-Queue: Łukasz Anforowicz <[email protected]>
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This commit implements forwarding of `Write` trait implementation from `UniquePtr<T>` to the pointee type. This is quite similar to how `Box<T>` also forwards - see https://doc.rust-lang.org/std/boxed/struct.Box.html#impl-Write-for-Box%3CW%3E This commit has quite similar, orphan-rule-related motivation as the earlier dtolnay#1368 which covered the `Read` trait. For a more specific motivating example, please see http://review.skia.org/c/skia/+/923337/3/experimental/rust_png/ffi/FFI.rs#254
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This commit implements forwarding of `Write` trait implementation from `UniquePtr<T>` to the pointee type. This is quite similar to how `Box<T>` also forwards - see https://doc.rust-lang.org/std/boxed/struct.Box.html#impl-Write-for-Box%3CW%3E This commit has quite similar, orphan-rule-related motivation as the earlier dtolnay#1368 which covered the `Read` trait. For a more specific motivating example, please see http://review.skia.org/skia/+/923337/3/experimental/rust_png/ffi/FFI.rs#254
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This commit implements forwarding of
Readtrait implementation fromUniquePtr<T>to the pointee type. This is quite similar to howBox<T>also forwards - seehttps://doc.rust-lang.org/std/boxed/struct.Box.html#impl-Read-for-Box%3CR%3E
Just as with
Box<T>, theimplcannot be provided in the crate introducingT, because this violates the orphan rule. This means that before this commit a wrapper newtype would be required to work around the orphan rule - e.g.:After this commit, one can provide an
implthat works more directly with the C++ typeT(the FFI will typically require passingself: Pin<&mut ffi::ReadTrait>):For a more specific motivating example, please see: https://docs.google.com/document/d/1EPn1Ss-hfOC6Ki_B5CC6GA_UFnY3TmoDLCP2HjP7bms