Skip to content

Commit

Permalink
rustdoc: simplify JS search routine by not messing with lev distance
Browse files Browse the repository at this point in the history 
Since the sorting function accounts for an `index` field, there's not much
reason to also be applying changes to the levenshtein distance. Instead,
we can just not treat `lev` as a filter if there's already a non-sentinel
value for `index`.

This change gives slightly more weight to the index and path part, as
search criteria, than it used to. This changes some of the test cases,
but not in any obviously-"worse" way, and, in particular, substring matches
are a bigger deal than levenshtein distances (we're assuming that a typo
is less likely than someone just not typing the entire name).

Based on
rust-lang#103710 (comment)
  • Loading branch information
@notriddle
notriddle committed Jan 14, 2023
1 parent 4b51adf commit 59ba74c
Showing 1 changed file with 64 additions and 50 deletions.
114 changes: 64 additions & 50 deletions src/librustdoc/html/static/js/search.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -781,7 +781,29 @@ function initSearch(rawSearchIndex) {
return a - b;
}

// Sort by non levenshtein results and then levenshtein results by the distance
// sort by index of keyword in item name (no literal occurrence goes later)
a = (aaa.index < 0);
b = (bbb.index < 0);
if (a !== b) {
return a - b;
}

// Sort by distance in the path part, if specified
// (less changes required to match means higher rankings)
a = aaa.path_lev;
b = bbb.path_lev;
if (a !== b) {
return a - b;
}

// (later literal occurrence, if any, goes later)
a = aaa.index;
b = bbb.index;
if (a !== b) {
return a - b;
}

// Sort by distance in the name part, the last part of the path
// (less changes required to match means higher rankings)
a = (aaa.lev);
b = (bbb.lev);
Expand Down Expand Up @@ -810,19 +832,6 @@ function initSearch(rawSearchIndex) {
return (a > b ? +1 : -1);
}

// sort by index of keyword in item name (no literal occurrence goes later)
a = (aaa.index < 0);
b = (bbb.index < 0);
if (a !== b) {
return a - b;
}
// (later literal occurrence, if any, goes later)
a = aaa.index;
b = bbb.index;
if (a !== b) {
return a - b;
}

// special precedence for primitive and keyword pages
if ((aaa.item.ty === TY_PRIMITIVE && bbb.item.ty !== TY_KEYWORD) ||
(aaa.item.ty === TY_KEYWORD && bbb.item.ty !== TY_PRIMITIVE)) {
Expand Down Expand Up @@ -1230,15 +1239,19 @@ function initSearch(rawSearchIndex) {
* * `id` is the index in both `searchWords` and `searchIndex` arrays for this element.
* * `index` is an `integer`` used to sort by the position of the word in the item's name.
* * `lev` is the main metric used to sort the search results.
* * `path_lev` is zero if a single-component search query is used, otherwise it's the
* distance computed for everything other than the last path component.
*
* @param {Results} results
* @param {string} fullId
* @param {integer} id
* @param {integer} index
* @param {integer} lev
* @param {integer} path_lev
*/
function addIntoResults(results, fullId, id, index, lev) {
if (lev === 0 || (!parsedQuery.literalSearch && lev <= MAX_LEV_DISTANCE)) {
function addIntoResults(results, fullId, id, index, lev, path_lev) {
const inBounds = lev <= MAX_LEV_DISTANCE || index !== -1;
if (lev === 0 || (!parsedQuery.literalSearch && inBounds)) {
if (results[fullId] !== undefined) {
const result = results[fullId];
if (result.dontValidate || result.lev <= lev) {
Expand All @@ -1250,6 +1263,7 @@ function initSearch(rawSearchIndex) {
index: index,
dontValidate: parsedQuery.literalSearch,
lev: lev,
path_lev: path_lev,
};
}
}
Expand Down Expand Up @@ -1280,68 +1294,68 @@ function initSearch(rawSearchIndex) {
if (!row || (filterCrates !== null && row.crate !== filterCrates)) {
return;
}
let lev, lev_add = 0, index = -1;
let lev, index = -1, path_lev = 0;
const fullId = row.id;
const searchWord = searchWords[pos];

const in_args = findArg(row, elem, parsedQuery.typeFilter);
const returned = checkReturned(row, elem, parsedQuery.typeFilter);

addIntoResults(results_in_args, fullId, pos, index, in_args);
addIntoResults(results_returned, fullId, pos, index, returned);
// path_lev is 0 because no parent path information is currently stored
// in the search index
addIntoResults(results_in_args, fullId, pos, -1, in_args, 0);
addIntoResults(results_returned, fullId, pos, -1, returned, 0);

if (!typePassesFilter(parsedQuery.typeFilter, row.ty)) {
return;
}
const searchWord = searchWords[pos];

if (parsedQuery.literalSearch) {
if (searchWord === elem.name) {
addIntoResults(results_others, fullId, pos, -1, 0);
}
return;
const row_index = row.normalizedName.indexOf(elem.pathLast);
const word_index = searchWord.indexOf(elem.pathLast);

// lower indexes are "better" matches
// rank based on the "best" match
if (row_index === -1) {
index = word_index;
} else if (word_index === -1) {
index = row_index;
} else if (word_index < row_index) {
index = word_index;
} else {
index = row_index;
}

// No need to check anything else if it's a "pure" generics search.
if (elem.name.length === 0) {
if (row.type !== null) {
lev = checkGenerics(row.type, elem, MAX_LEV_DISTANCE + 1);
addIntoResults(results_others, fullId, pos, index, lev);
// path_lev is 0 because we know it's empty
addIntoResults(results_others, fullId, pos, index, lev, 0);
}
return;
}

if (elem.fullPath.length > 1) {
lev = checkPath(elem.pathWithoutLast, row);
if (lev > MAX_LEV_DISTANCE || (parsedQuery.literalSearch && lev !== 0)) {
path_lev = checkPath(elem.pathWithoutLast, row);
if (path_lev > MAX_LEV_DISTANCE) {
return;
} else if (lev > 0) {
lev_add = lev / 10;
}
}

if (searchWord.indexOf(elem.pathLast) > -1 ||
row.normalizedName.indexOf(elem.pathLast) > -1
) {
index = row.normalizedName.indexOf(elem.pathLast);
}
lev = levenshtein(searchWord, elem.pathLast);
if (lev > 0 && elem.pathLast.length > 2 && searchWord.indexOf(elem.pathLast) > -1) {
if (elem.pathLast.length < 6) {
lev = 1;
} else {
lev = 0;
if (parsedQuery.literalSearch) {
if (searchWord === elem.name) {
addIntoResults(results_others, fullId, pos, index, 0, path_lev);
}
}
lev += lev_add;
if (lev > MAX_LEV_DISTANCE) {
return;
} else if (index !== -1 && elem.fullPath.length < 2) {
lev -= 1;
}
if (lev < 0) {
lev = 0;

lev = levenshtein(searchWord, elem.pathLast);

if (index === -1 && lev + path_lev > MAX_LEV_DISTANCE) {
return;
}
addIntoResults(results_others, fullId, pos, index, lev);

addIntoResults(results_others, fullId, pos, index, lev, path_lev);
}

/**
Expand Down Expand Up @@ -1386,7 +1400,7 @@ function initSearch(rawSearchIndex) {
return;
}
const lev = Math.round(totalLev / nbLev);
addIntoResults(results, row.id, pos, 0, lev);
addIntoResults(results, row.id, pos, 0, lev, 0);
}

function innerRunQuery() {
Expand Down

0 comments on commit 59ba74c

Please sign in to comment.