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`
This commit is contained in:
Devyn Cairns
2024-04-13 18:42:03 -07:00
committed by GitHub
parent b508d1028c
commit 2ae9ad8676
52 changed files with 328 additions and 222 deletions

View File

@ -68,9 +68,7 @@ impl Completer for VariableCompletion {
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.clone(), nested_levels, current_span)
{
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(),
@ -117,8 +115,7 @@ impl Completer for VariableCompletion {
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.clone(), current_span)
for suggestion in nested_suggestions(&nuval, &self.var_context.1, current_span)
{
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
@ -140,8 +137,7 @@ impl Completer for VariableCompletion {
// 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.clone(), current_span)
for suggestion in nested_suggestions(&value, &self.var_context.1, current_span)
{
if options.match_algorithm.matches_u8_insensitive(
options.case_sensitive,
@ -244,21 +240,21 @@ impl Completer for VariableCompletion {
// Find recursively the values for sublevels
// if no sublevels are set it returns the current value
fn nested_suggestions(
val: Value,
sublevels: Vec<Vec<u8>>,
val: &Value,
sublevels: &[Vec<u8>],
current_span: reedline::Span,
) -> Vec<SemanticSuggestion> {
let mut output: Vec<SemanticSuggestion> = vec![];
let value = recursive_value(val, sublevels);
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.into_iter() {
for col in val.columns() {
output.push(SemanticSuggestion {
suggestion: Suggestion {
value: col,
value: col.clone(),
description: None,
style: None,
extra: None,
@ -311,56 +307,47 @@ fn nested_suggestions(
}
// Extracts the recursive value (e.g: $var.a.b.c)
fn recursive_value(val: Value, sublevels: Vec<Vec<u8>>) -> Value {
fn recursive_value(val: &Value, sublevels: &[Vec<u8>]) -> Result<Value, Span> {
// Go to next sublevel
if let Some(next_sublevel) = sublevels.clone().into_iter().next() {
if let Some((sublevel, next_sublevels)) = sublevels.split_first() {
let span = val.span();
match val {
Value::Record { val, .. } => {
for item in *val {
// Check if index matches with sublevel
if item.0.as_bytes().to_vec() == next_sublevel {
// If matches try to fetch recursively the next
return recursive_value(item.1, sublevels.into_iter().skip(1).collect());
}
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)
}
// Current sublevel value not found
return Value::nothing(span);
}
Value::LazyRecord { val, .. } => {
for col in val.column_names() {
if col.as_bytes().to_vec() == next_sublevel {
return recursive_value(
val.get_column_value(col).unwrap_or_default(),
sublevels.into_iter().skip(1).collect(),
);
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
return Value::nothing(span);
Err(span)
}
Value::List { vals, .. } => {
for col in get_columns(vals.as_slice()) {
if col.as_bytes().to_vec() == next_sublevel {
return recursive_value(
Value::list(vals, span)
.get_data_by_key(&col)
.unwrap_or_default(),
sublevels.into_iter().skip(1).collect(),
);
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
return Value::nothing(span);
Err(span)
}
_ => return val,
_ => Ok(val.clone()),
}
} else {
Ok(val.clone())
}
val
}
impl MatchAlgorithm {