mirror of
https://github.com/nushell/nushell
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c747ec75c9
# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
ShellError, Signature, Span, Type, Value,
};
```
This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
ast::{Call, CellPath},
engine::{Command, EngineState, Stack},
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```
This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.
109 lines
3 KiB
Rust
109 lines
3 KiB
Rust
use nu_engine::command_prelude::*;
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use std::{
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thread,
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time::{Duration, Instant},
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};
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const CTRL_C_CHECK_INTERVAL: Duration = Duration::from_millis(100);
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#[derive(Clone)]
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pub struct Sleep;
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impl Command for Sleep {
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fn name(&self) -> &str {
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"sleep"
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}
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fn usage(&self) -> &str {
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"Delay for a specified amount of time."
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}
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fn signature(&self) -> Signature {
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Signature::build("sleep")
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.input_output_types(vec![(Type::Nothing, Type::Nothing)])
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.required("duration", SyntaxShape::Duration, "Time to sleep.")
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.rest("rest", SyntaxShape::Duration, "Additional time.")
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.category(Category::Platform)
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}
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fn search_terms(&self) -> Vec<&str> {
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vec!["delay", "wait", "timer"]
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}
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fn run(
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&self,
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engine_state: &EngineState,
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stack: &mut Stack,
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call: &Call,
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_input: PipelineData,
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) -> Result<PipelineData, ShellError> {
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fn duration_from_i64(val: i64) -> Duration {
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Duration::from_nanos(if val < 0 { 0 } else { val as u64 })
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}
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let duration: i64 = call.req(engine_state, stack, 0)?;
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let rest: Vec<i64> = call.rest(engine_state, stack, 1)?;
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let total_dur =
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duration_from_i64(duration) + rest.into_iter().map(duration_from_i64).sum::<Duration>();
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let deadline = Instant::now() + total_dur;
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loop {
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// sleep for 100ms, or until the deadline
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let time_until_deadline = deadline.saturating_duration_since(Instant::now());
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if time_until_deadline.is_zero() {
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break;
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}
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thread::sleep(CTRL_C_CHECK_INTERVAL.min(time_until_deadline));
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// exit early if Ctrl+C was pressed
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if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
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return Err(ShellError::InterruptedByUser {
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span: Some(call.head),
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});
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}
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}
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Ok(Value::nothing(call.head).into_pipeline_data())
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}
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fn examples(&self) -> Vec<Example> {
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vec![
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Example {
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description: "Sleep for 1sec",
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example: "sleep 1sec",
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result: Some(Value::nothing(Span::test_data())),
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},
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Example {
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description: "Sleep for 3sec",
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example: "sleep 1sec 1sec 1sec",
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result: None,
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},
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Example {
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description: "Send output after 1sec",
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example: "sleep 1sec; echo done",
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result: None,
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},
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]
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}
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}
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#[cfg(test)]
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mod tests {
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use super::Sleep;
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#[test]
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fn examples_work_as_expected() {
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use crate::test_examples;
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use std::time::Instant;
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let start = Instant::now();
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test_examples(Sleep {});
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let elapsed = start.elapsed();
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// only examples with actual output are run
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assert!(elapsed >= std::time::Duration::from_secs(1));
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assert!(elapsed < std::time::Duration::from_secs(2));
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}
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}
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