[wit-bindgen] provide more control over type ownership #6648
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This replaces the `duplicate_if_necessary` parameter to `wasmtime::component::bindgen` with a new `ownership` parameter which provides finer-grained control over whether and how generated types own their fields. The default is `Ownership::Owning`, which means types own their fields regardless of how they are used in functions. These types passed by reference when used as parameters to guest-exported functions. Note that this also affects how unnamed types (e.g. `list<list<string>>`) are passed: using a reference only at the top level (e.g. `&[Vec<String>]` instead of `&[&[&str]]`, which is more difficult to construct when using non-`'static` data). The other option is `Ownership::Borrowing`, which includes a `duplicate_if_necessary` field, providing the same code generation strategy as was used prior to this change. If we're happy with this approach, I'll open another PR in the `wit-bindgen` repo to match. This also fixes a bug that caused named types to be considered owned and/or borrowed when they shouldn't have been due to having fields with unnamed types which were owned and/or borrowed in unrelated interfaces. Signed-off-by: Joel Dice <[email protected]>
Signed-off-by: Joel Dice <[email protected]>
alexcrichton
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Looks good to me, thanks!
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This is the guest version of bytecodealliance/wasmtime#6648. This replaces the duplicate_if_necessary parameter to the Rust binding generator with a new ownership parameter which provides finer-grained control over whether and how generated types own their fields. The default is `Ownership::Owning`, which means types own their fields regardless of how they are used in functions. These types are passed by reference when used as parameters to guest-exported functions. Note that this also affects how unnamed types (e.g. `list<list<string>>`) are passed: using a reference only at the top level (e.g. `&[Vec<String>]` instead of `&[&[&str]]`, which is more difficult to construct when using non-'static data). The other option is `Ownership::Borrowing`, which includes a `duplicate_if_necessary` field, providing the same code generation strategy as was used prior to this change. Signed-off-by: Joel Dice <[email protected]>
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* provide more control over type ownership This is the guest version of bytecodealliance/wasmtime#6648. This replaces the duplicate_if_necessary parameter to the Rust binding generator with a new ownership parameter which provides finer-grained control over whether and how generated types own their fields. The default is `Ownership::Owning`, which means types own their fields regardless of how they are used in functions. These types are passed by reference when used as parameters to guest-exported functions. Note that this also affects how unnamed types (e.g. `list<list<string>>`) are passed: using a reference only at the top level (e.g. `&[Vec<String>]` instead of `&[&[&str]]`, which is more difficult to construct when using non-'static data). The other option is `Ownership::Borrowing`, which includes a `duplicate_if_necessary` field, providing the same code generation strategy as was used prior to this change. Signed-off-by: Joel Dice <[email protected]> * fix tests Signed-off-by: Joel Dice <[email protected]> * fix tests, part 2 Signed-off-by: Joel Dice <[email protected]> --------- Signed-off-by: Joel Dice <[email protected]>
rvolosatovs
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May 23, 2024
* provide more control over type ownership This is the guest version of bytecodealliance/wasmtime#6648. This replaces the duplicate_if_necessary parameter to the Rust binding generator with a new ownership parameter which provides finer-grained control over whether and how generated types own their fields. The default is `Ownership::Owning`, which means types own their fields regardless of how they are used in functions. These types are passed by reference when used as parameters to guest-exported functions. Note that this also affects how unnamed types (e.g. `list<list<string>>`) are passed: using a reference only at the top level (e.g. `&[Vec<String>]` instead of `&[&[&str]]`, which is more difficult to construct when using non-'static data). The other option is `Ownership::Borrowing`, which includes a `duplicate_if_necessary` field, providing the same code generation strategy as was used prior to this change. Signed-off-by: Joel Dice <[email protected]> * fix tests Signed-off-by: Joel Dice <[email protected]> * fix tests, part 2 Signed-off-by: Joel Dice <[email protected]> --------- Signed-off-by: Joel Dice <[email protected]>
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This replaces the
duplicate_if_necessaryparameter towasmtime::component::bindgenwith a newownershipparameter which provides finer-grained control over whether and how generated types own their fields.The default is
Ownership::Owning, which means types own their fields regardless of how they are used in functions. These types are passed by reference when used as parameters to guest-exported functions. Note that this also affects how unnamed types (e.g.list<list<string>>) are passed: using a reference only at the top level (e.g.&[Vec<String>]instead of&[&[&str]], which is more difficult to construct when using non-'staticdata).The other option is
Ownership::Borrowing, which includes aduplicate_if_necessaryfield, providing the same code generation strategy as was used prior to this change.If we're happy with this approach, I'll open another PR in the
wit-bindgenrepo to match.This also fixes a bug that caused named types to be considered owned and/or borrowed when they shouldn't have been due to having fields with unnamed types which were owned and/or borrowed in unrelated interfaces.