bjoernager/rust
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rustdoc-search: stop constructing pointless arrays in decode

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I'm not sure why I ever thought that would be okay. This is
clearly hot code, and should avoid Array.prototype.map when
it's not needed. In any case, it shows up in the profiler.

rustdoc-js-profiler:
https://notriddle.com/rustdoc-html-demo-11/decode-opt-1/index.html

Firefox profiler:
[Before](https://share.firefox.dev/3RRH2fR)
[After](https://share.firefox.dev/3Wblcq8)
This commit is contained in:
Michael Howell 2024-07-05 10:23:59 -07:00
parent 11dd90f761
commit fbb6300fc2
1 changed files with 7 additions and 11 deletions
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18
src/librustdoc/html/static/js/search.js
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@ -3293,10 +3293,9 @@ ${item.displayPath}<span class="${type}">${name}</span>\
} }
// call after consuming `{` // call after consuming `{`
decodeList() { decodeList() {
const cb = "}".charCodeAt(0);
let c = this.string.charCodeAt(this.offset); let c = this.string.charCodeAt(this.offset);
const ret = []; const ret = [];
while (c !== cb) { while (c !== 125) { // 125 = "}"
ret.push(this.decode()); ret.push(this.decode());
c = this.string.charCodeAt(this.offset); c = this.string.charCodeAt(this.offset);
} }
@ -3305,14 +3304,13 @@ ${item.displayPath}<span class="${type}">${name}</span>\
} }
// consumes and returns a list or integer // consumes and returns a list or integer
decode() { decode() {
const [ob, la] = ["{", "`"].map(c => c.charCodeAt(0));
let n = 0; let n = 0;
let c = this.string.charCodeAt(this.offset); let c = this.string.charCodeAt(this.offset);
if (c === ob) { if (c === 123) { // 123 = "{"
this.offset += 1; this.offset += 1;
return this.decodeList(); return this.decodeList();
} }
while (c < la) { while (c < 96) { // 96 = "`"
n = (n << 4) | (c & 0xF); n = (n << 4) | (c & 0xF);
this.offset += 1; this.offset += 1;
c = this.string.charCodeAt(this.offset); c = this.string.charCodeAt(this.offset);
@ -3325,15 +3323,14 @@ ${item.displayPath}<span class="${type}">${name}</span>\
} }
next() { next() {
const c = this.string.charCodeAt(this.offset); const c = this.string.charCodeAt(this.offset);
const [zero, ua, la] = ["0", "@", "`"].map(c => c.charCodeAt(0));
// sixteen characters after "0" are backref // sixteen characters after "0" are backref
if (c >= zero && c < ua) { if (c >= 48 && c < 64) { // 48 = "0", 64 = "@"
this.offset += 1; this.offset += 1;
return this.backrefQueue[c - zero]; return this.backrefQueue[c - 48];
} }
// special exception: 0 doesn't use backref encoding // special exception: 0 doesn't use backref encoding
// it's already one character, and it's always nullish // it's already one character, and it's always nullish
if (c === la) { if (c === 96) { // 96 = "`"
this.offset += 1; this.offset += 1;
return this.cons(0); return this.cons(0);
} }
@ -3472,7 +3469,6 @@ ${item.displayPath}<span class="${type}">${name}</span>\
searchIndex = []; searchIndex = [];
searchIndexDeprecated = new Map(); searchIndexDeprecated = new Map();
searchIndexEmptyDesc = new Map(); searchIndexEmptyDesc = new Map();
const charA = "A".charCodeAt(0);
let currentIndex = 0; let currentIndex = 0;
let id = 0; let id = 0;
@ -3639,7 +3635,7 @@ ${item.displayPath}<span class="${type}">${name}</span>\
// object defined above. // object defined above.
const row = { const row = {
crate, crate,
ty: itemTypes.charCodeAt(i) - charA, ty: itemTypes.charCodeAt(i) - 65, // 65 = "A"
name: itemNames[i], name: itemNames[i],
path, path,
descShard, descShard,