forked from extern/nushell
b2c5af457e
This improves incremental build time when working on what was previously the root package. For example, previously all plugins would be rebuilt with a change to `src/commands/classified/external.rs`, but now only `nu-cli` will have to be rebuilt (and anything that depends on it).
62 lines
1.5 KiB
Rust
62 lines
1.5 KiB
Rust
use crate::commands::WholeStreamCommand;
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use crate::context::CommandRegistry;
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use crate::prelude::*;
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use nu_errors::ShellError;
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use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, Value};
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use nu_source::Tagged;
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pub struct Last;
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#[derive(Deserialize)]
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pub struct LastArgs {
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rows: Option<Tagged<u64>>,
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}
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impl WholeStreamCommand for Last {
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fn name(&self) -> &str {
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"last"
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}
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fn signature(&self) -> Signature {
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Signature::build("last").optional(
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"rows",
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SyntaxShape::Number,
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"starting from the back, the number of rows to return",
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)
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}
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fn usage(&self) -> &str {
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"Show only the last number of rows."
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}
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fn run(
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&self,
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args: CommandArgs,
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registry: &CommandRegistry,
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) -> Result<OutputStream, ShellError> {
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args.process(registry, last)?.run()
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}
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}
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fn last(LastArgs { rows }: LastArgs, context: RunnableContext) -> Result<OutputStream, ShellError> {
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let stream = async_stream! {
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let v: Vec<_> = context.input.into_vec().await;
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let rows_desired = if let Some(quantity) = rows {
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*quantity
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} else {
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1
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};
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let count = (rows_desired as usize);
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if count < v.len() {
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let k = v.len() - count;
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for x in v[k..].iter() {
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let y: Value = x.clone();
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yield ReturnSuccess::value(y)
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}
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}
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};
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Ok(stream.to_output_stream())
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}
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