Add Whitespace Query Support to Quick File Open

What it Does

Fixes [eclipse-theia#8747](eclipse-theia#8747)

- Allows whitespaces to be included in a `quick file open` search query.
- Performs both an exact and fuzzy search on the query with whitespaces.

How to Test

1. `ctrl + p` to `quick file open`
2. Search for a file with a query that includes whitespaces (eg. `readme core`)
3. Observe that whitespaces do not affect the search results

Signed-off-by: seantan22 <sean.a.tan@ericsson.com>

packages/file-search/src/node/file-search-service-impl.ts

@@ -80,24 +80,39 @@ export class FileSearchServiceImpl implements FileSearchService {
             searchPattern = searchPattern.replace(/\//g, '\\');
         }
 
+        const WHITESPACE_QUERY_SEPARATOR = ' ';
         const stringPattern = searchPattern.toLocaleLowerCase();
+        const stringPatterns = stringPattern.split(WHITESPACE_QUERY_SEPARATOR);
+
         await Promise.all(Object.keys(roots).map(async root => {
             try {
                 const rootUri = new URI(root);
                 const rootPath = FileUri.fsPath(rootUri);
                 const rootOptions = roots[root];
+
                 await this.doFind(rootUri, rootOptions, candidate => {
+
                     // Convert OS-native candidate path to a file URI string
                     const fileUri = FileUri.create(path.resolve(rootPath, candidate)).toString();
+
                     // Skip results that have already been matched.
                     if (exactMatches.has(fileUri) || fuzzyMatches.has(fileUri)) {
                         return;
                     }
-                    if (!searchPattern || searchPattern === '*' || candidate.toLocaleLowerCase().indexOf(stringPattern) !== -1) {
+
+                    // Determine if the candidate matches any of the patterns exactly or fuzzy
+                    const patternExists = stringPatterns.every(pattern => candidate.toLocaleLowerCase().indexOf(pattern) !== -1);
+                    if (patternExists) {
                         exactMatches.add(fileUri);
-                    } else if (opts.fuzzyMatch && fuzzy.test(searchPattern, candidate)) {
-                        fuzzyMatches.add(fileUri);
+                    } else {
+                        const fuzzyPatternExists = stringPatterns.every(pattern => fuzzy.test(pattern, candidate));
+                        if (!searchPattern || searchPattern === '*') {
+                            exactMatches.add(fileUri);
+                        } else if (opts.fuzzyMatch && fuzzyPatternExists) {
+                            fuzzyMatches.add(fileUri);
+                        }
                     }
+
                     // Preemptively terminate the search when the list of exact matches reaches the limit.
                     if (exactMatches.size === opts.limit) {
                         cancellationSource.cancel();