rust error callback #4
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mikea
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| writeln!(out, " return error;"); | ||
| writeln!(out, " error.msg = msg;"); | ||
| writeln!(out, " error.len = len;"); | ||
| writeln!(out, " throw error;"); |
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This seems to throw a value of type Error... but don't we want to convert to a kj::Exception and throw it with kj::throwFatalException() (which adds stack traces, etc.)?
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we will set our own throw_rust_error callback that will do kj::throw. This function is used only if callback is not overriden
| writeln!(out, " error.msg = static_cast<char const *>(repr.ptr);"); | ||
| writeln!(out, " error.len = repr.len;"); | ||
| writeln!(out, " return error;"); | ||
| writeln!(out, " error.msg = msg;"); |
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what's the lifetime/ownership of msg? Is it pointing to Rust-owned memory?
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I have added a comment to cxx.h (not sure what's the best place for it): it points to c++ memory and will belong to c++.
https://github.com/cloudflare/workerd-cxx/blob/master/src/result.rs#L60
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Well I don't really know what's going on here but it seems plausible. :) Sorry for slow review, been swamped. |
Rather then throw things directly, introduce a global callback. We will override the callback in workerd to integrate with kj::Exception
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Introduce
::rust::throw_rust_errorcallback ofvoid (const char*, size_t)type. The callback is used every time rust functions returnsResult::Err(or triggers panic with #2).We will use the callback in workerd/edgeworker to integrate with kj::Exception