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Avoid allocations

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This commit is contained in:
Wang Ruochen 2022-05-05 10:14:11 -07:00
parent a70beea9e9
commit 81d7cbbbe2
1 changed files with 37 additions and 32 deletions
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69
crates/ide-assists/src/handlers/convert_let_else_to_match.rs
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@ -1,73 +1,77 @@
use syntax::ast::{edit::AstNodeEdit, AstNode, HasName, LetStmt, Pat};
use hir::Semantics;
use ide_db::RootDatabase;
use syntax::ast::{edit::AstNodeEdit, AstNode, HasName, LetStmt, Name, Pat};
use syntax::T;
use crate::{AssistContext, AssistId, AssistKind, Assists};
/// Gets a list of binders in a pattern, and whether they are mut.
fn binders_in_pat(pat: &Pat) -> Option<Vec<(String, bool)>> {
fn binders_in_pat(
acc: &mut Vec<(Name, bool)>,
pat: &Pat,
sem: &Semantics<RootDatabase>,
) -> Option<()> {
use Pat::*;
match pat {
IdentPat(p) => {
let ident = p.name()?.text().to_string();
let ident = p.name()?;
let ismut = p.ref_token().is_none() && p.mut_token().is_some();
let mut res = vec![(ident, ismut)];
acc.push((ident, ismut));
if let Some(inner) = p.pat() {
res.extend(binders_in_pat(&inner)?);
binders_in_pat(acc, &inner, sem)?;
}
Some(res)
Some(())
}
BoxPat(p) => p.pat().and_then(|p| binders_in_pat(&p)),
RestPat(_) | LiteralPat(_) | PathPat(_) | WildcardPat(_) | ConstBlockPat(_) => Some(vec![]),
BoxPat(p) => p.pat().and_then(|p| binders_in_pat(acc, &p, sem)),
RestPat(_) | LiteralPat(_) | PathPat(_) | WildcardPat(_) | ConstBlockPat(_) => Some(()),
OrPat(p) => {
let mut v = vec![];
for p in p.pats() {
v.extend(binders_in_pat(&p)?);
binders_in_pat(acc, &p, sem)?;
}
Some(v)
Some(())
}
ParenPat(p) => p.pat().and_then(|p| binders_in_pat(&p)),
ParenPat(p) => p.pat().and_then(|p| binders_in_pat(acc, &p, sem)),
RangePat(p) => {
let mut start = if let Some(st) = p.start() { binders_in_pat(&st)? } else { vec![] };
let end = if let Some(st) = p.end() { binders_in_pat(&st)? } else { vec![] };
start.extend(end);
Some(start)
if let Some(st) = p.start() {
binders_in_pat(acc, &st, sem)?
}
if let Some(ed) = p.end() {
binders_in_pat(acc, &ed, sem)?
}
Some(())
}
RecordPat(p) => {
let mut v = vec![];
for f in p.record_pat_field_list()?.fields() {
let pat = f.pat()?;
v.extend(binders_in_pat(&pat)?);
binders_in_pat(acc, &pat, sem)?;
}
Some(v)
Some(())
}
RefPat(p) => p.pat().and_then(|p| binders_in_pat(&p)),
RefPat(p) => p.pat().and_then(|p| binders_in_pat(acc, &p, sem)),
SlicePat(p) => {
let mut v = vec![];
for p in p.pats() {
v.extend(binders_in_pat(&p)?);
binders_in_pat(acc, &p, sem)?;
}
Some(v)
Some(())
}
TuplePat(p) => {
let mut v = vec![];
for p in p.fields() {
v.extend(binders_in_pat(&p)?);
binders_in_pat(acc, &p, sem)?;
}
Some(v)
Some(())
}
TupleStructPat(p) => {
let mut v = vec![];
for p in p.fields() {
v.extend(binders_in_pat(&p)?);
binders_in_pat(acc, &p, sem)?;
}
Some(v)
Some(())
}
// don't support macro pat yet
MacroPat(_) => None,
}
}
fn binders_to_str(binders: &[(String, bool)], addmut: bool) -> String {
fn binders_to_str(binders: &[(Name, bool)], addmut: bool) -> String {
let vars = binders
.iter()
.map(
@ -119,7 +123,8 @@ pub(crate) fn convert_let_else_to_match(acc: &mut Assists, ctx: &AssistContext)
return None;
}
let pat = let_stmt.pat()?;
let binders = binders_in_pat(&pat)?;
let mut binders = Vec::new();
binders_in_pat(&mut binders, &pat, &ctx.sema)?;
let target = let_stmt.syntax().text_range();
acc.add(
@ -139,7 +144,7 @@ pub(crate) fn convert_let_else_to_match(acc: &mut Assists, ctx: &AssistContext)
// remove the mut from the pattern
for (b, ismut) in binders.iter() {
if *ismut {
pat_no_mut = pat_no_mut.replace(&format!("mut {b}"), b);
pat_no_mut = pat_no_mut.replace(&format!("mut {b}"), &b.to_string());
}
}