dd3c6d1303After some discussion with PVH I realise that the repo structure in the last reorg was very rust-centric. In an attempt to put each language on a level footing move the rust code and project files into ./rust
78 lines
1.8 KiB
Rust
78 lines
1.8 KiB
Rust
//! This module is essentially a type level Option. It is used in sitations where we know at
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//! compile time whether an `OpObserver` is available to track changes in a transaction.
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use crate::{ChangeHash, OpObserver};
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mod private {
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pub trait Sealed {}
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impl<O: super::OpObserver> Sealed for super::Observed<O> {}
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impl Sealed for super::UnObserved {}
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}
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pub trait Observation: private::Sealed {
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type Obs: OpObserver;
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type CommitResult;
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fn observer(&mut self) -> Option<&mut Self::Obs>;
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fn make_result(self, hash: ChangeHash) -> Self::CommitResult;
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fn branch(&self) -> Self;
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fn merge(&mut self, other: &Self);
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}
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#[derive(Clone, Debug)]
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pub struct Observed<Obs: OpObserver>(Obs);
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impl<O: OpObserver> Observed<O> {
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pub(crate) fn new(o: O) -> Self {
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Self(o)
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}
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pub(crate) fn observer(&mut self) -> &mut O {
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&mut self.0
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}
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}
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impl<Obs: OpObserver> Observation for Observed<Obs> {
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type Obs = Obs;
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type CommitResult = (Obs, ChangeHash);
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fn observer(&mut self) -> Option<&mut Self::Obs> {
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Some(&mut self.0)
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}
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fn make_result(self, hash: ChangeHash) -> Self::CommitResult {
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(self.0, hash)
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}
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fn branch(&self) -> Self {
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Self(self.0.branch())
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}
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fn merge(&mut self, other: &Self) {
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self.0.merge(&other.0)
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}
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}
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#[derive(Clone, Default, Debug)]
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pub struct UnObserved;
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impl UnObserved {
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pub fn new() -> Self {
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Self
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}
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}
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impl Observation for UnObserved {
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type Obs = ();
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type CommitResult = ChangeHash;
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fn observer(&mut self) -> Option<&mut Self::Obs> {
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None
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}
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fn make_result(self, hash: ChangeHash) -> Self::CommitResult {
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hash
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}
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fn branch(&self) -> Self {
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Self
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}
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fn merge(&mut self, _other: &Self) {}
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}
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