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9996e4a1f8
# Description Continuing from #12568, this PR further reduces the size of `Expr` from 64 to 40 bytes. It also reduces `Expression` from 128 to 96 bytes and `Type` from 32 to 24 bytes. This was accomplished by: - for `Expr` with multiple fields (e.g., `Expr::Thing(A, B, C)`), merging the fields into new AST struct types and then boxing this struct (e.g. `Expr::Thing(Box<ABC>)`). - replacing `Vec<T>` with `Box<[T]>` in multiple places. `Expr`s and `Expression`s should rarely be mutated, if at all, so this optimization makes sense. By reducing the size of these types, I didn't notice a large performance improvement (at least compared to #12568). But this PR does reduce the memory usage of nushell. My config is somewhat light so I only noticed a difference of 1.4MiB (38.9MiB vs 37.5MiB). --------- Co-authored-by: Stefan Holderbach <sholderbach@users.noreply.github.com>
100 lines
2.8 KiB
Rust
100 lines
2.8 KiB
Rust
use nu_cmd_base::input_handler::{operate, CellPathOnlyArgs};
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use nu_engine::command_prelude::*;
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#[derive(Clone)]
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pub struct BytesReverse;
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impl Command for BytesReverse {
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fn name(&self) -> &str {
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"bytes reverse"
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}
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fn signature(&self) -> Signature {
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Signature::build("bytes reverse")
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.input_output_types(vec![
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(Type::Binary, Type::Binary),
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(Type::table(), Type::table()),
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(Type::record(), Type::record()),
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])
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.allow_variants_without_examples(true)
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.rest(
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"rest",
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SyntaxShape::CellPath,
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"For a data structure input, reverse data at the given cell paths.",
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)
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.category(Category::Bytes)
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}
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fn usage(&self) -> &str {
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"Reverse the bytes in the pipeline."
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}
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fn search_terms(&self) -> Vec<&str> {
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vec!["convert", "inverse", "flip"]
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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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let cell_paths: Vec<CellPath> = call.rest(engine_state, stack, 0)?;
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let arg = CellPathOnlyArgs::from(cell_paths);
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operate(reverse, arg, input, call.head, engine_state.ctrlc.clone())
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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: "Reverse bytes `0x[1F FF AA AA]`",
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example: "0x[1F FF AA AA] | bytes reverse",
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result: Some(Value::binary(
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vec![0xAA, 0xAA, 0xFF, 0x1F],
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Span::test_data(),
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)),
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},
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Example {
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description: "Reverse bytes `0x[FF AA AA]`",
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example: "0x[FF AA AA] | bytes reverse",
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result: Some(Value::binary(vec![0xAA, 0xAA, 0xFF], Span::test_data())),
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},
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]
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}
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}
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fn reverse(val: &Value, _args: &CellPathOnlyArgs, span: Span) -> Value {
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let val_span = val.span();
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match val {
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Value::Binary { val, .. } => {
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let mut reversed_input = val.to_vec();
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reversed_input.reverse();
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Value::binary(reversed_input, val_span)
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}
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// Propagate errors by explicitly matching them before the final case.
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Value::Error { .. } => val.clone(),
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other => Value::error(
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ShellError::OnlySupportsThisInputType {
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exp_input_type: "binary".into(),
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wrong_type: other.get_type().to_string(),
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dst_span: span,
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src_span: other.span(),
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},
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span,
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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::*;
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#[test]
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fn test_examples() {
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use crate::test_examples;
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test_examples(BytesReverse {})
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}
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}
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