nit: Do less allocations in `ui::menu::Item::label` implementations

This complicates the code a little but it often divides by two the number of allocations done by
the functions. LSP labels especially can easily be called dozens of time in a single menu popup,
when listing references for example.
pull/4406/head
Alexis (Poliorcetics) Bourget 2 years ago committed by Michael Davis
parent 3aea33a415
commit 34389e1d54

@ -54,7 +54,7 @@ use crate::{
use crate::job::{self, Jobs};
use futures_util::StreamExt;
use std::{collections::HashMap, fmt, future::Future};
use std::{collections::HashMap, fmt, fmt::Write, future::Future};
use std::{collections::HashSet, num::NonZeroUsize};
use std::{
@ -2416,19 +2416,18 @@ impl ui::menu::Item for MappableCommand {
type Data = ReverseKeymap;
fn label(&self, keymap: &Self::Data) -> Spans {
// formats key bindings, multiple bindings are comma separated,
// individual key presses are joined with `+`
let fmt_binding = |bindings: &Vec<Vec<KeyEvent>>| -> String {
bindings
.iter()
.map(|bind| {
bind.iter()
.map(|key| key.to_string())
.collect::<Vec<String>>()
.join("+")
bindings.iter().fold(String::new(), |mut acc, bind| {
if !acc.is_empty() {
acc.push_str(", ");
}
bind.iter().fold(false, |needs_plus, key| {
write!(&mut acc, "{}{}", if needs_plus { "+" } else { "" }, key)
.expect("Writing to a string can only fail on an Out-Of-Memory error");
true
});
acc
})
.collect::<Vec<String>>()
.join(", ")
};
match self {

@ -18,7 +18,9 @@ use crate::{
},
};
use std::{borrow::Cow, cmp::Ordering, collections::BTreeMap, path::PathBuf, sync::Arc};
use std::{
borrow::Cow, cmp::Ordering, collections::BTreeMap, fmt::Write, path::PathBuf, sync::Arc,
};
/// Gets the language server that is attached to a document, and
/// if it's not active displays a status message. Using this macro
@ -43,23 +45,32 @@ impl ui::menu::Item for lsp::Location {
type Data = PathBuf;
fn label(&self, cwdir: &Self::Data) -> Spans {
let file: Cow<'_, str> = (self.uri.scheme() == "file")
.then(|| {
self.uri
.to_file_path()
.map(|path| {
// strip root prefix
path.strip_prefix(&cwdir)
.map(|path| path.to_path_buf())
.unwrap_or(path)
})
.map(|path| Cow::from(path.to_string_lossy().into_owned()))
.ok()
})
.flatten()
.unwrap_or_else(|| self.uri.as_str().into());
let line = self.range.start.line;
format!("{}:{}", file, line).into()
// The preallocation here will overallocate a few characters since it will account for the
// URL's scheme, which is not used most of the time since that scheme will be "file://".
// Those extra chars will be used to avoid allocating when writing the line number (in the
// common case where it has 5 digits or less, which should be enough for a cast majority
// of usages).
let mut res = String::with_capacity(self.uri.as_str().len());
if self.uri.scheme() == "file" {
// With the preallocation above and UTF-8 paths already, this closure will do one (1)
// allocation, for `to_file_path`, else there will be two (2), with `to_string_lossy`.
let mut write_path_to_res = || -> Option<()> {
let path = self.uri.to_file_path().ok()?;
res.push_str(&path.strip_prefix(&cwdir).unwrap_or(&path).to_string_lossy());
Some(())
};
write_path_to_res();
} else {
// Never allocates since we declared the string with this capacity already.
res.push_str(self.uri.as_str());
}
// Most commonly, this will not allocate, especially on Unix systems where the root prefix
// is a simple `/` and not `C:\` (with whatever drive letter)
write!(&mut res, ":{}", self.range.start.line)
.expect("Will only failed if allocating fail");
res.into()
}
}
@ -73,10 +84,8 @@ impl ui::menu::Item for lsp::SymbolInformation {
} else {
match self.location.uri.to_file_path() {
Ok(path) => {
let relative_path = helix_core::path::get_relative_path(path.as_path())
.to_string_lossy()
.into_owned();
format!("{} ({})", &self.name, relative_path).into()
let get_relative_path = path::get_relative_path(path.as_path());
format!("{} ({})", &self.name, get_relative_path.to_string_lossy()).into()
}
Err(_) => format!("{} ({})", &self.name, &self.location.uri).into(),
}
@ -115,24 +124,21 @@ impl ui::menu::Item for PickerDiagnostic {
// remove background as it is distracting in the picker list
style.bg = None;
let code = self
let code: Cow<'_, str> = self
.diag
.code
.as_ref()
.map(|c| match c {
NumberOrString::Number(n) => n.to_string(),
NumberOrString::String(s) => s.to_string(),
NumberOrString::Number(n) => n.to_string().into(),
NumberOrString::String(s) => s.as_str().into(),
})
.map(|code| format!(" ({})", code))
.unwrap_or_default();
let path = match format {
DiagnosticsFormat::HideSourcePath => String::new(),
DiagnosticsFormat::ShowSourcePath => {
let path = path::get_truncated_path(self.url.path())
.to_string_lossy()
.into_owned();
format!("{}: ", path)
let path = path::get_truncated_path(self.url.path());
format!("{}: ", path.to_string_lossy())
}
};

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