forked from extern/nushell
0c4d5330ee
# Description This breaks `nu-plugin` up into four crates: - `nu-plugin-protocol`: just the type definitions for the protocol, no I/O. If someone wanted to wire up something more bare metal, maybe for async I/O, they could use this. - `nu-plugin-core`: the shared stuff between engine/plugin. Less stable interface. - `nu-plugin-engine`: everything required for the engine to talk to plugins. Less stable interface. - `nu-plugin`: everything required for the plugin to talk to the engine, what plugin developers use. Should be the most stable interface. No changes are made to the interface exposed by `nu-plugin` - it should all still be there. Re-exports from `nu-plugin-protocol` or `nu-plugin-core` are used as required. Plugins shouldn't ever have to use those crates directly. This should be somewhat faster to compile as `nu-plugin-engine` and `nu-plugin` can compile in parallel, and the engine doesn't need `nu-plugin` and plugins don't need `nu-plugin-engine` (except for test support), so that should reduce what needs to be compiled too. The only significant change here other than splitting stuff up was to break the `source` out of `PluginCustomValue` and create a new `PluginCustomValueWithSource` type that contains that instead. One bonus of that is we get rid of the option and it's now more type-safe, but it also means that the logic for that stuff (actually running the plugin for custom value ops) can live entirely within the `nu-plugin-engine` crate. # User-Facing Changes - New crates. - Added `local-socket` feature for `nu` to try to make it possible to compile without that support if needed. # Tests + Formatting - 🟢 `toolkit fmt` - 🟢 `toolkit clippy` - 🟢 `toolkit test` - 🟢 `toolkit test stdlib`
65 lines
2.2 KiB
Rust
65 lines
2.2 KiB
Rust
use nu_protocol::ShellError;
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use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
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/// Implements an atomically incrementing sequential series of numbers
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#[derive(Debug, Default)]
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pub struct Sequence(AtomicUsize);
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impl Sequence {
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/// Return the next available id from a sequence, returning an error on overflow
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#[track_caller]
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pub fn next(&self) -> Result<usize, ShellError> {
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// It's totally safe to use Relaxed ordering here, as there aren't other memory operations
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// that depend on this value having been set for safety
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//
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// We're only not using `fetch_add` so that we can check for overflow, as wrapping with the
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// identifier would lead to a serious bug - however unlikely that is.
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self.0
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.fetch_update(Relaxed, Relaxed, |current| current.checked_add(1))
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.map_err(|_| ShellError::NushellFailedHelp {
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msg: "an accumulator for identifiers overflowed".into(),
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help: format!("see {}", std::panic::Location::caller()),
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})
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}
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}
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#[test]
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fn output_is_sequential() {
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let sequence = Sequence::default();
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for (expected, generated) in (0..1000).zip(std::iter::repeat_with(|| sequence.next())) {
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assert_eq!(expected, generated.expect("error in sequence"));
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}
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}
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#[test]
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fn output_is_unique_even_under_contention() {
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let sequence = Sequence::default();
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std::thread::scope(|scope| {
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// Spawn four threads, all advancing the sequence simultaneously
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let threads = (0..4)
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.map(|_| {
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scope.spawn(|| {
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(0..100000)
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.map(|_| sequence.next())
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.collect::<Result<Vec<_>, _>>()
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})
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})
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.collect::<Vec<_>>();
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// Collect all of the results into a single flat vec
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let mut results = threads
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.into_iter()
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.flat_map(|thread| thread.join().expect("panicked").expect("error"))
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.collect::<Vec<usize>>();
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// Check uniqueness
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results.sort();
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let initial_length = results.len();
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results.dedup();
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let deduplicated_length = results.len();
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assert_eq!(initial_length, deduplicated_length);
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})
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}
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