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nushell/crates/nu-protocol/src
Ian Manske 6fd854ed9f
Replace ExternalStream with new ByteStream type ()
# 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 , fixes , and fixes .

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>
2024-05-16 07:11:18 -07:00
..
ast Remove usages of Call::positional_nth () 2024-05-15 19:59:42 +02:00
config Fix typo () 2024-05-03 16:14:13 -05:00
debugger Replace ExternalStream with new ByteStream type () 2024-05-16 07:11:18 -07:00
engine Remove stack debug assert () 2024-05-15 22:59:10 +00:00
errors Replace ExternalStream with new ByteStream type () 2024-05-16 07:11:18 -07:00
pipeline Replace ExternalStream with new ByteStream type () 2024-05-16 07:11:18 -07:00
plugin Rework for new clippy lints () 2024-05-02 19:29:03 +02:00
process Replace ExternalStream with new ByteStream type () 2024-05-16 07:11:18 -07:00
value Shrink Value by boxing Range/Closure () 2024-05-09 08:10:58 +08:00
alias.rs IO and redirection overhaul () 2024-03-14 15:51:55 -05:00
did_you_mean.rs Improve case insensitivity consistency () 2023-11-08 23:58:54 +01:00
eval_base.rs ListStream touchup () 2024-05-05 16:00:59 +00:00
eval_const.rs Replace ExternalStream with new ByteStream type () 2024-05-16 07:11:18 -07:00
example.rs Overhaul the plugin cache file with a new msgpack+brotli format () 2024-04-21 07:36:26 -05:00
id.rs Add virtual path abstraction layer () 2023-05-23 23:48:50 +03:00
lev_distance.rs Rework for new clippy lints () 2024-05-02 19:29:03 +02:00
lib.rs Replace ExternalStream with new ByteStream type () 2024-05-16 07:11:18 -07:00
module.rs Error on use path item1 item2, if item1 is not a module () 2023-12-05 11:38:45 +01:00
signature.rs Overhaul the plugin cache file with a new msgpack+brotli format () 2024-04-21 07:36:26 -05:00
span.rs Add ErrSpan extension trait for Result () 2024-04-23 10:39:55 +02:00
syntax_shape.rs open, rm, umv, cp, rm and du: Don't globs if inputs are variables or string interpolation () 2024-02-23 09:17:09 +08:00
ty.rs Shrink the size of Expr () 2024-04-24 15:46:35 +00:00