First impl of fallible allocations#3494
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coolreader18 wants to merge 6 commits into
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youknowone
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Dec 9, 2021
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| struct SetLenOnDrop<'a, T> { | ||
| vec: &'a mut Vec<T>, | ||
| local_len: usize, | ||
| } | ||
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| impl<'a, T> SetLenOnDrop<'a, T> { | ||
| #[inline] | ||
| fn new(vec: &'a mut Vec<T>) -> Self { | ||
| SetLenOnDrop { | ||
| local_len: vec.len(), | ||
| vec, | ||
| } | ||
| } | ||
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| #[inline] | ||
| fn increment_len(&mut self, increment: usize) { | ||
| self.local_len += increment; | ||
| } | ||
| } |
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This idea looks good. I think it can have similar interface like MaybeUninit because they have similar concept.
struct VecBuilder {
vec: Vec<T>,
len: usize,
}
impl VecUninit {
fn try_with_len(len: usize) -> TryReserveResult {
Self::try_with_capacity(len, len)
}
/// SAFETY: len <= capacity
unsafe fn try_with_capacity(capacity: usize, len: usize) -> TryReserveResult {
debug_assert!(len <= capacity);
Self {
vec: Vec::try_with_capacity(...)
len,
}
}
unsafe fn assume_init(self) -> Vec {
self.vec.set_len(self.len);
self.vec
}
}
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Oh.. this is just copied from the standard library. I should add a comment.
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| pub trait PyErrResultExt { | ||
| type Ok; | ||
| fn map_pyerr(self, vm: &VirtualMachine) -> PyResult<Self::Ok>; | ||
| } | ||
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| impl<T, E: IntoPyException> PyErrResultExt for Result<T, E> { | ||
| type Ok = T; | ||
| #[inline] | ||
| fn map_pyerr(self, vm: &VirtualMachine) -> PyResult<T> { | ||
| self.map_err(|e| e.into_pyexception(vm)) | ||
| } | ||
| } |
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Glad you like it! I've been thinking about something like this for a while, to get rid of ".map_err(|e| e.into_pyexception(vm))` everywhere
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I think this is different approach but solving a part of problems I tried to handle in #3326
Member
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bumping here, any chance we could rebase this and get it in? |
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This PR doesn't change a ton of things to use fallible allocations, but it does set up a framework for switching over to fallible allocations inside RustPython.
Related to #3493