#55: Improve result sorting performance (#9602)

src/vs/base/common/arrays.ts

@@ -79,6 +79,29 @@ export function findFirst<T>(array: T[], p: (x: T) => boolean): number {
 	return low;
 }
 
+/**
+ * Returns the top N elements from the array.
+ *
+ * Faster than sorting the entire array when the array is a lot larger than N.
+ *
+ * @param array The unsorted array.
+ * @param compare A sort function for the elements.
+ * @param n The number of elements to return.
+ * @return The first n elemnts from array when sorted with compare.
+ */
+export function top<T>(array: T[], compare: (a: T, b: T) => number, n: number) {
+	const result = array.slice(0, n).sort(compare);
+	for (let i = n, m = array.length; i < m; i++) {
+		const element = array[i];
+		if (compare(element, result[n - 1]) < 0) {
+			result.pop();
+			const j = findFirst(result, e => compare(element, e) < 0);
+			result.splice(j, 0, element);
+		}
+	}
+	return result;
+}
+
 export function merge<T>(arrays: T[][], hashFn?: (element: T) => string): T[] {
 	const result = new Array<T>();
 	if (!hashFn) {

src/vs/base/common/comparers.ts

@@ -57,8 +57,8 @@ export function compareByPrefix(one: string, other: string, lookFor: string): nu
 	let elementBName = other.toLowerCase();
 
 	// Sort prefix matches over non prefix matches
-	let elementAPrefixMatch = elementAName.indexOf(lookFor) === 0;
-	let elementBPrefixMatch = elementBName.indexOf(lookFor) === 0;
+	let elementAPrefixMatch = strings.startsWith(elementAName, lookFor);
+	let elementBPrefixMatch = strings.startsWith(elementBName, lookFor);
 	if (elementAPrefixMatch !== elementBPrefixMatch) {
 		return elementAPrefixMatch ? -1 : 1;
 	}

src/vs/base/test/common/arrays.test.ts

@@ -60,5 +60,17 @@ suite('Arrays', () => {
 		assert.deepEqual(arrays.distinct(['32', 'constructor', 'proto', 'proto', 'constructor'], compare), ['32', 'constructor', 'proto']);
 		assert.deepEqual(arrays.distinct(['32', '4', '5', '32', '4', '5', '32', '4', '5', '5'], compare), ['32', '4', '5']);
 	});
+
+	test('top', function () {
+		const cmp = (a, b) => a - b;
+
+		assert.deepEqual(arrays.top([], cmp, 1), []);
+		assert.deepEqual(arrays.top([1], cmp, 0), []);
+		assert.deepEqual(arrays.top([1, 2], cmp, 1), [1]);
+		assert.deepEqual(arrays.top([2, 1], cmp, 1), [1]);
+		assert.deepEqual(arrays.top([1, 3, 2], cmp, 2), [1, 2]);
+		assert.deepEqual(arrays.top([3, 2, 1], cmp, 3), [1, 2, 3]);
+		assert.deepEqual(arrays.top([4, 6, 2, 7, 8, 3, 5, 1], cmp, 3), [1, 2, 3]);
+	});
 });
 

src/vs/workbench/parts/search/browser/openAnythingHandler.ts

@@ -5,6 +5,7 @@
 
 'use strict';
 
+import * as arrays from 'vs/base/common/arrays';
 import {TPromise} from 'vs/base/common/winjs.base';
 import nls = require('vs/nls');
 import {ThrottledDelayer} from 'vs/base/common/async';
@@ -182,27 +183,19 @@ export class OpenAnythingHandler extends QuickOpenHandler {
 				// Combine symbol results and file results
 				let result = [...results[0].entries, ...results[1].entries];
 
-				// Sort
-				const normalizedSearchValue = strings.stripWildcards(searchValue).toLowerCase();
-				result.sort((elementA, elementB) => QuickOpenEntry.compareByScore(elementA, elementB, searchValue, normalizedSearchValue, this.scorerCache));
-				const sortedResultTime = Date.now();
-
-				// Apply Range
-				result.forEach((element) => {
-					if (element instanceof FileEntry) {
-						(<FileEntry>element).setRange(searchWithRange ? searchWithRange.range : null);
-					}
-				});
-
 				// Cache for fast lookup
 				this.resultsToSearchCache[searchValue] = result;
 
-				// Cap the number of results to make the view snappy
-				const viewResults = result.length > OpenAnythingHandler.MAX_DISPLAYED_RESULTS ? result.slice(0, OpenAnythingHandler.MAX_DISPLAYED_RESULTS) : result;
+				// Sort
+				const normalizedSearchValue = strings.stripWildcards(searchValue).toLowerCase();
+				const compare = (elementA, elementB) => QuickOpenEntry.compareByScore(elementA, elementB, searchValue, normalizedSearchValue, this.scorerCache);
+				const viewResults = arrays.top(result, compare, OpenAnythingHandler.MAX_DISPLAYED_RESULTS);
+				const sortedResultTime = Date.now();
 
-				// Apply highlights to file entries
+				// Apply range and highlights to file entries
 				viewResults.forEach(entry => {
 					if (entry instanceof FileEntry) {
+						entry.setRange(searchWithRange ? searchWithRange.range : null);
 						const {labelHighlights, descriptionHighlights} = QuickOpenEntry.highlight(entry, searchValue, true /* fuzzy highlight */);
 						entry.setHighlights(labelHighlights, descriptionHighlights);
 					}
@@ -324,21 +317,15 @@ export class OpenAnythingHandler extends QuickOpenHandler {
 		const unsortedResultTime = Date.now();
 
 		// Sort
-		results.sort((elementA, elementB) => QuickOpenEntry.compareByScore(elementA, elementB, searchValue, normalizedSearchValueLowercase, this.scorerCache));
+		const compare = (elementA, elementB) => QuickOpenEntry.compareByScore(elementA, elementB, searchValue, normalizedSearchValueLowercase, this.scorerCache);
+		const viewResults = arrays.top(results, compare, OpenAnythingHandler.MAX_DISPLAYED_RESULTS);
 		const sortedResultTime = Date.now();
 
-		// Apply Range
-		results.forEach((element) => {
-			if (element instanceof FileEntry) {
-				(<FileEntry>element).setRange(range);
-			}
-		});
-
-		// Cap the number of results to make the view snappy
-		const viewResults = results.length > OpenAnythingHandler.MAX_DISPLAYED_RESULTS ? results.slice(0, OpenAnythingHandler.MAX_DISPLAYED_RESULTS) : results;
-
-		// Apply highlights
+		// Apply range and highlights
 		viewResults.forEach(entry => {
+			if (entry instanceof FileEntry) {
+				entry.setRange(range);
+			}
 			const {labelHighlights, descriptionHighlights} = QuickOpenEntry.highlight(entry, searchValue, true /* fuzzy highlight */);
 			entry.setHighlights(labelHighlights, descriptionHighlights);
 		});