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>
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|---|---|---|
| .. | ||
| src | ||
| build.rs | ||
| Cargo.toml | ||
| LICENSE | ||
| README.md | ||
nu-cmd-lang
the base language and command crate of nu
The commands in this crate are the core commands of the nu language. It is also the base crate upon which all other command crates sit on top of including:
- nu-command
- nu-cli
- nu-cmd-dataframe
- nu-cmd-extra
As time goes on and the nu language develops further in parallel with nushell we will be adding other command crates to the system.
What does it mean to be a base crate ?
A base crate is one with minimal dependencies in our system so that other developers can come along and use this crate without having a lot of baggage in terms of other crates which will bloat their underlying application.
Background on nu-cmd-lang
This crate was designed to be a small, concise set of tools or commands that serve as the foundation layer of both nu and nushell. These are the core commands needed to have a nice working version of the nu language without all of the support that the other commands provide inside nushell. Prior to the launch of this crate all of our commands were housed in the crate nu-command. Moving forward we would like to slowly break out the commands in nu-command into different crates; the naming and how this will work and where all the commands will be located is a "work in progress" especially now that the standard library is starting to become more popular as a location for commands. As time goes on some of our commands written in rust will be migrated to nu and when this happens they will be moved into the standard library.