forked from extern/nushell
6fd854ed9f
# Description
This PR introduces a `ByteStream` type which is a `Read`-able stream of
bytes. Internally, it has an enum over three different byte stream
sources:
```rust
pub enum ByteStreamSource {
Read(Box<dyn Read + Send + 'static>),
File(File),
Child(ChildProcess),
}
```
This is in comparison to the current `RawStream` type, which is an
`Iterator<Item = Vec<u8>>` and has to allocate for each read chunk.
Currently, `PipelineData::ExternalStream` serves a weird dual role where
it is either external command output or a wrapper around `RawStream`.
`ByteStream` makes this distinction more clear (via `ByteStreamSource`)
and replaces `PipelineData::ExternalStream` in this PR:
```rust
pub enum PipelineData {
Empty,
Value(Value, Option<PipelineMetadata>),
ListStream(ListStream, Option<PipelineMetadata>),
ByteStream(ByteStream, Option<PipelineMetadata>),
}
```
The PR is relatively large, but a decent amount of it is just repetitive
changes.
This PR fixes #7017, fixes #10763, and fixes #12369.
This PR also improves performance when piping external commands. Nushell
should, in most cases, have competitive pipeline throughput compared to,
e.g., bash.
| Command | Before (MB/s) | After (MB/s) | Bash (MB/s) |
| -------------------------------------------------- | -------------:|
------------:| -----------:|
| `throughput \| rg 'x'` | 3059 | 3744 | 3739 |
| `throughput \| nu --testbin relay o> /dev/null` | 3508 | 8087 | 8136 |
# User-Facing Changes
- This is a breaking change for the plugin communication protocol,
because the `ExternalStreamInfo` was replaced with `ByteStreamInfo`.
Plugins now only have to deal with a single input stream, as opposed to
the previous three streams: stdout, stderr, and exit code.
- The output of `describe` has been changed for external/byte streams.
- Temporary breaking change: `bytes starts-with` no longer works with
byte streams. This is to keep the PR smaller, and `bytes ends-with`
already does not work on byte streams.
- If a process core dumped, then instead of having a `Value::Error` in
the `exit_code` column of the output returned from `complete`, it now is
a `Value::Int` with the negation of the signal number.
# After Submitting
- Update docs and book as necessary
- Release notes (e.g., plugin protocol changes)
- Adapt/convert commands to work with byte streams (high priority is
`str length`, `bytes starts-with`, and maybe `bytes ends-with`).
- Refactor the `tee` code, Devyn has already done some work on this.
---------
Co-authored-by: Devyn Cairns <devyn.cairns@gmail.com>
63 lines
1.9 KiB
Rust
63 lines
1.9 KiB
Rust
use super::inspect_table;
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use nu_engine::command_prelude::*;
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use terminal_size::{terminal_size, Height, Width};
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#[derive(Clone)]
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pub struct Inspect;
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impl Command for Inspect {
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fn name(&self) -> &str {
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"inspect"
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}
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fn usage(&self) -> &str {
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"Inspect pipeline results while running a pipeline."
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}
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fn signature(&self) -> nu_protocol::Signature {
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Signature::build("inspect")
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.input_output_types(vec![(Type::Any, Type::Any)])
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.allow_variants_without_examples(true)
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.category(Category::Debug)
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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 input_metadata = input.metadata();
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let input_val = input.into_value(call.head)?;
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if input_val.is_nothing() {
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return Err(ShellError::PipelineEmpty {
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dst_span: call.head,
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});
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}
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let original_input = input_val.clone();
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let description = input_val.get_type().to_string();
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let (cols, _rows) = match terminal_size() {
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Some((w, h)) => (Width(w.0), Height(h.0)),
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None => (Width(0), Height(0)),
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};
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let table = inspect_table::build_table(input_val, description, cols.0 as usize);
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// Note that this is printed to stderr. The reason for this is so it doesn't disrupt the regular nushell
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// tabular output. If we printed to stdout, nushell would get confused with two outputs.
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eprintln!("{table}\n");
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Ok(original_input.into_pipeline_data_with_metadata(input_metadata))
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}
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fn examples(&self) -> Vec<Example> {
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vec![Example {
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description: "Inspect pipeline results",
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example: "ls | inspect | get name | inspect",
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result: None,
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}]
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}
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}
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