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use std::collections::VecDeque;
use nu_engine::CallExt;
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData, RawStream,
ShellError, Signature, Span, Type, Value,
};
#[derive(Clone)]
pub struct Lines;
impl Command for Lines {
fn name(&self) -> &str {
"lines"
}
fn usage(&self) -> &str {
"Converts input to lines."
}
fn signature(&self) -> nu_protocol::Signature {
Signature::build("lines")
.input_output_types(vec![(Type::Any, Type::List(Box::new(Type::String)))])
.switch("skip-empty", "skip empty lines", Some('s'))
.category(Category::Filters)
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let head = call.head;
let ctrlc = engine_state.ctrlc.clone();
let skip_empty = call.has_flag(engine_state, stack, "skip-empty")?;
let span = input.span().unwrap_or(call.head);
match input {
PipelineData::Value(Value::String { val, .. }, ..) => {
let lines = if skip_empty {
val.lines()
.filter_map(|s| {
if s.trim().is_empty() {
None
} else {
Some(Value::string(s, span))
}
})
.collect()
} else {
val.lines().map(|s| Value::string(s, span)).collect()
};
Ok(Value::list(lines, span).into_pipeline_data())
}
PipelineData::Empty => Ok(PipelineData::Empty),
PipelineData::ListStream(stream, ..) => {
let iter = stream
.into_iter()
.filter_map(move |value| {
let span = value.span();
if let Value::String { val, .. } = value {
Some(
val.lines()
.filter_map(|s| {
if skip_empty && s.trim().is_empty() {
None
} else {
Some(Value::string(s, span))
}
})
.collect::<Vec<_>>(),
)
} else {
None
}
})
.flatten();
Ok(iter.into_pipeline_data(engine_state.ctrlc.clone()))
}
PipelineData::Value(val, ..) => {
match val {
// Propagate existing errors
Value::Error { error, .. } => Err(*error),
_ => Err(ShellError::OnlySupportsThisInputType {
exp_input_type: "string or raw data".into(),
wrong_type: val.get_type().to_string(),
dst_span: head,
src_span: val.span(),
}),
}
}
PipelineData::ExternalStream { stdout: None, .. } => Ok(PipelineData::empty()),
PipelineData::ExternalStream {
stdout: Some(stream),
..
} => Ok(RawStreamLinesAdapter::new(stream, head, skip_empty)
.map(move |x| x.unwrap_or_else(|err| Value::error(err, head)))
.into_pipeline_data(ctrlc)),
}
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Split multi-line string into lines",
example: r#"$"two\nlines" | lines"#,
result: Some(Value::list(
vec![Value::test_string("two"), Value::test_string("lines")],
Span::test_data(),
)),
}]
}
}
#[derive(Debug)]
struct RawStreamLinesAdapter {
inner: RawStream,
inner_complete: bool,
skip_empty: bool,
span: Span,
incomplete_line: String,
queue: VecDeque<String>,
}
impl Iterator for RawStreamLinesAdapter {
type Item = Result<Value, ShellError>;
fn next(&mut self) -> Option<Self::Item> {
loop {
if let Some(s) = self.queue.pop_front() {
if self.skip_empty && s.trim().is_empty() {
continue;
}
return Some(Ok(Value::string(s, self.span)));
} else {
// inner is complete, feed out remaining state
if self.inner_complete {
return if self.incomplete_line.is_empty() {
None
} else {
Some(Ok(Value::string(
std::mem::take(&mut self.incomplete_line),
self.span,
)))
};
}
// pull more data from inner
if let Some(result) = self.inner.next() {
match result {
Ok(v) => {
let span = v.span();
match v {
// TODO: Value::Binary support required?
Value::String { val, .. } => {
self.span = span;
let mut lines = val.lines();
// handle incomplete line from previous
if !self.incomplete_line.is_empty() {
if let Some(first) = lines.next() {
self.incomplete_line.push_str(first);
self.queue.push_back(std::mem::take(
&mut self.incomplete_line,
));
}
}
// save completed lines
self.queue.extend(lines.map(String::from));
if !val.ends_with('\n') {
// incomplete line, save for next time
// if `val` and `incomplete_line` were empty,
// then pop will return none
if let Some(s) = self.queue.pop_back() {
self.incomplete_line = s;
}
}
}
// Propagate errors by explicitly matching them before the final case.
Value::Error { error, .. } => return Some(Err(*error)),
other => {
return Some(Err(ShellError::OnlySupportsThisInputType {
exp_input_type: "string".into(),
wrong_type: other.get_type().to_string(),
dst_span: self.span,
src_span: other.span(),
}));
}
}
}
Err(err) => return Some(Err(err)),
}
} else {
self.inner_complete = true;
}
}
}
}
}
impl RawStreamLinesAdapter {
pub fn new(inner: RawStream, span: Span, skip_empty: bool) -> Self {
Self {
inner,
span,
skip_empty,
incomplete_line: String::new(),
queue: VecDeque::new(),
inner_complete: false,
}
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_examples() {
use crate::test_examples;
test_examples(Lines {})
}
}