nushell/crates/nu-cli/src/completions/variable_completions.rs
Devyn Cairns 2ae9ad8676
Copy-on-write for record values (#12305)
# Description
This adds a `SharedCow` type as a transparent copy-on-write pointer that
clones to unique on mutate.

As an initial test, the `Record` within `Value::Record` is shared.

There are some pretty big wins for performance. I'll post benchmark
results in a comment. The biggest winner is nested access, as that would
have cloned the records for each cell path follow before and it doesn't
have to anymore.

The reusability of the `SharedCow` type is nice and I think it could be
used to clean up the previous work I did with `Arc` in `EngineState`.
It's meant to be a mostly transparent clone-on-write that just clones on
`.to_mut()` or `.into_owned()` if there are actually multiple
references, but avoids cloning if the reference is unique.

# User-Facing Changes
- `Value::Record` field is a different type (plugin authors)

# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting
- [ ] use for `EngineState`
- [ ] use for `Value::List`
2024-04-14 01:42:03 +00:00

362 lines
13 KiB
Rust

use crate::completions::{
Completer, CompletionOptions, MatchAlgorithm, SemanticSuggestion, SuggestionKind,
};
use nu_engine::{column::get_columns, eval_variable};
use nu_protocol::{
engine::{EngineState, Stack, StateWorkingSet},
Span, Value,
};
use reedline::Suggestion;
use std::{str, sync::Arc};
#[derive(Clone)]
pub struct VariableCompletion {
engine_state: Arc<EngineState>, // TODO: Is engine state necessary? It's already a part of working set in fetch()
stack: Stack,
var_context: (Vec<u8>, Vec<Vec<u8>>), // tuple with $var and the sublevels (.b.c.d)
}
impl VariableCompletion {
pub fn new(
engine_state: Arc<EngineState>,
stack: Stack,
var_context: (Vec<u8>, Vec<Vec<u8>>),
) -> Self {
Self {
engine_state,
stack,
var_context,
}
}
}
impl Completer for VariableCompletion {
fn fetch(
&mut self,
working_set: &StateWorkingSet,
prefix: Vec<u8>,
span: Span,
offset: usize,
_: usize,
options: &CompletionOptions,
) -> Vec<SemanticSuggestion> {
let mut output = vec![];
let builtins = ["$nu", "$in", "$env"];
let var_str = std::str::from_utf8(&self.var_context.0).unwrap_or("");
let var_id = working_set.find_variable(&self.var_context.0);
let current_span = reedline::Span {
start: span.start - offset,
end: span.end - offset,
};
let sublevels_count = self.var_context.1.len();
// Completions for the given variable
if !var_str.is_empty() {
// Completion for $env.<tab>
if var_str == "$env" {
let env_vars = self.stack.get_env_vars(&self.engine_state);
// Return nested values
if sublevels_count > 0 {
// Extract the target var ($env.<target-var>)
let target_var = self.var_context.1[0].clone();
let target_var_str =
str::from_utf8(&target_var).unwrap_or_default().to_string();
// Everything after the target var is the nested level ($env.<target-var>.<nested_levels>...)
let nested_levels: Vec<Vec<u8>> =
self.var_context.1.clone().into_iter().skip(1).collect();
if let Some(val) = env_vars.get(&target_var_str) {
for suggestion in nested_suggestions(val, &nested_levels, current_span) {
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
suggestion.suggestion.value.as_bytes(),
&prefix,
) {
output.push(suggestion);
}
}
return output;
}
} else {
// No nesting provided, return all env vars
for env_var in env_vars {
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
env_var.0.as_bytes(),
&prefix,
) {
output.push(SemanticSuggestion {
suggestion: Suggestion {
value: env_var.0,
description: None,
style: None,
extra: None,
span: current_span,
append_whitespace: false,
},
kind: Some(SuggestionKind::Type(env_var.1.get_type())),
});
}
}
return output;
}
}
// Completions for $nu.<tab>
if var_str == "$nu" {
// Eval nu var
if let Ok(nuval) = eval_variable(
&self.engine_state,
&self.stack,
nu_protocol::NU_VARIABLE_ID,
nu_protocol::Span::new(current_span.start, current_span.end),
) {
for suggestion in nested_suggestions(&nuval, &self.var_context.1, current_span)
{
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
suggestion.suggestion.value.as_bytes(),
&prefix,
) {
output.push(suggestion);
}
}
return output;
}
}
// Completion other variable types
if let Some(var_id) = var_id {
// Extract the variable value from the stack
let var = self.stack.get_var(var_id, Span::new(span.start, span.end));
// If the value exists and it's of type Record
if let Ok(value) = var {
for suggestion in nested_suggestions(&value, &self.var_context.1, current_span)
{
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
suggestion.suggestion.value.as_bytes(),
&prefix,
) {
output.push(suggestion);
}
}
return output;
}
}
}
// Variable completion (e.g: $en<tab> to complete $env)
for builtin in builtins {
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
builtin.as_bytes(),
&prefix,
) {
output.push(SemanticSuggestion {
suggestion: Suggestion {
value: builtin.to_string(),
description: None,
style: None,
extra: None,
span: current_span,
append_whitespace: false,
},
// TODO is there a way to get the VarId to get the type???
kind: None,
});
}
}
// TODO: The following can be refactored (see find_commands_by_predicate() used in
// command_completions).
let mut removed_overlays = vec![];
// Working set scope vars
for scope_frame in working_set.delta.scope.iter().rev() {
for overlay_frame in scope_frame.active_overlays(&mut removed_overlays).rev() {
for v in &overlay_frame.vars {
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
v.0,
&prefix,
) {
output.push(SemanticSuggestion {
suggestion: Suggestion {
value: String::from_utf8_lossy(v.0).to_string(),
description: None,
style: None,
extra: None,
span: current_span,
append_whitespace: false,
},
kind: Some(SuggestionKind::Type(
working_set.get_variable(*v.1).ty.clone(),
)),
});
}
}
}
}
// Permanent state vars
// for scope in &self.engine_state.scope {
for overlay_frame in self.engine_state.active_overlays(&removed_overlays).rev() {
for v in &overlay_frame.vars {
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
v.0,
&prefix,
) {
output.push(SemanticSuggestion {
suggestion: Suggestion {
value: String::from_utf8_lossy(v.0).to_string(),
description: None,
style: None,
extra: None,
span: current_span,
append_whitespace: false,
},
kind: Some(SuggestionKind::Type(
working_set.get_variable(*v.1).ty.clone(),
)),
});
}
}
}
output.dedup(); // TODO: Removes only consecutive duplicates, is it intended?
output
}
}
// Find recursively the values for sublevels
// if no sublevels are set it returns the current value
fn nested_suggestions(
val: &Value,
sublevels: &[Vec<u8>],
current_span: reedline::Span,
) -> Vec<SemanticSuggestion> {
let mut output: Vec<SemanticSuggestion> = vec![];
let value = recursive_value(val, sublevels).unwrap_or_else(Value::nothing);
let kind = SuggestionKind::Type(value.get_type());
match value {
Value::Record { val, .. } => {
// Add all the columns as completion
for col in val.columns() {
output.push(SemanticSuggestion {
suggestion: Suggestion {
value: col.clone(),
description: None,
style: None,
extra: None,
span: current_span,
append_whitespace: false,
},
kind: Some(kind.clone()),
});
}
output
}
Value::LazyRecord { val, .. } => {
// Add all the columns as completion
for column_name in val.column_names() {
output.push(SemanticSuggestion {
suggestion: Suggestion {
value: column_name.to_string(),
description: None,
style: None,
extra: None,
span: current_span,
append_whitespace: false,
},
kind: Some(kind.clone()),
});
}
output
}
Value::List { vals, .. } => {
for column_name in get_columns(vals.as_slice()) {
output.push(SemanticSuggestion {
suggestion: Suggestion {
value: column_name,
description: None,
style: None,
extra: None,
span: current_span,
append_whitespace: false,
},
kind: Some(kind.clone()),
});
}
output
}
_ => output,
}
}
// Extracts the recursive value (e.g: $var.a.b.c)
fn recursive_value(val: &Value, sublevels: &[Vec<u8>]) -> Result<Value, Span> {
// Go to next sublevel
if let Some((sublevel, next_sublevels)) = sublevels.split_first() {
let span = val.span();
match val {
Value::Record { val, .. } => {
if let Some((_, value)) = val.iter().find(|(key, _)| key.as_bytes() == sublevel) {
// If matches try to fetch recursively the next
recursive_value(value, next_sublevels)
} else {
// Current sublevel value not found
Err(span)
}
}
Value::LazyRecord { val, .. } => {
for col in val.column_names() {
if col.as_bytes() == *sublevel {
let val = val.get_column_value(col).map_err(|_| span)?;
return recursive_value(&val, next_sublevels);
}
}
// Current sublevel value not found
Err(span)
}
Value::List { vals, .. } => {
for col in get_columns(vals.as_slice()) {
if col.as_bytes() == *sublevel {
let val = val.get_data_by_key(&col).ok_or(span)?;
return recursive_value(&val, next_sublevels);
}
}
// Current sublevel value not found
Err(span)
}
_ => Ok(val.clone()),
}
} else {
Ok(val.clone())
}
}
impl MatchAlgorithm {
pub fn matches_u8_insensitive(&self, sensitive: bool, haystack: &[u8], needle: &[u8]) -> bool {
if sensitive {
self.matches_u8(haystack, needle)
} else {
self.matches_u8(&haystack.to_ascii_lowercase(), &needle.to_ascii_lowercase())
}
}
}