Add smarter filename suggestions, #57528 (#58009)

* Add smarter suggestions

* Ignore user-configured associations & add tests

src/vs/base/common/mime.ts

@@ -225,19 +225,24 @@ export function isUnspecific(mime: string[] | string): boolean {
 	return mime.length === 1 && isUnspecific(mime[0]);
 }
 
+/**
+ * Returns a suggestion for the filename by the following logic:
+ * 1. If a relevant extension exists and is an actual filename extension (starting with a dot), suggest the prefix appended by the first one.
+ * 2. Otherwise, if there are other extensions, suggest the first one.
+ * 3. Otherwise, suggest the prefix.
+ */
 export function suggestFilename(langId: string, prefix: string): string {
-	for (let i = 0; i < registeredAssociations.length; i++) {
-		const association = registeredAssociations[i];
-		if (association.userConfigured) {
-			continue; // only support registered ones
-		}
+	const extensions = registeredAssociations
+		.filter(assoc => !assoc.userConfigured && assoc.extension && assoc.id === langId)
+		.map(assoc => assoc.extension);
+	const extensionsWithDotFirst = extensions
+		.filter(assoc => strings.startsWith(assoc, '.'));
 
-		if (association.id === langId && association.extension) {
-			return prefix + association.extension;
-		}
+	if (extensionsWithDotFirst.length > 0) {
+		return prefix + extensionsWithDotFirst[0];
 	}
 
-	return prefix; // without any known extension, just return the prefix
+	return extensions[0] || prefix;
 }
 
 interface MapExtToMediaMimes {
@@ -297,4 +302,4 @@ const mapExtToMediaMimes: MapExtToMediaMimes = {
 export function getMediaMime(path: string): string | undefined {
 	const ext = paths.extname(path);
 	return mapExtToMediaMimes[ext.toLowerCase()];
-}
+}

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

@@ -5,7 +5,7 @@
 'use strict';
 
 import * as assert from 'assert';
-import { guessMimeTypes, registerTextMime } from 'vs/base/common/mime';
+import { guessMimeTypes, registerTextMime, suggestFilename } from 'vs/base/common/mime';
 
 suite('Mime', () => {
 	test('Dynamically Register Text Mime', () => {
@@ -114,4 +114,53 @@ suite('Mime', () => {
 		let guess = guessMimeTypes('/some/path/dot.monaco.xml');
 		assert.deepEqual(guess, ['text/other', 'text/plain']);
 	});
+
+	test('Filename Suggestion - Suggest prefix only when there are no relevant extensions', () => {
+		const id = 'plumbus0';
+		const mime = `text/${id}`;
+		for (let extension of ['one', 'two']) {
+			registerTextMime({ id, mime, extension });
+		}
+
+		let suggested = suggestFilename('shleem', 'Untitled-1');
+		assert.equal(suggested, 'Untitled-1');
+	});
+
+	test('Filename Suggestion - Suggest prefix with first extension that begins with a dot', () => {
+		const id = 'plumbus1';
+		const mime = `text/${id}`;
+		for (let extension of ['plumbus', '.shleem', '.gazorpazorp']) {
+			registerTextMime({ id, mime, extension });
+		}
+
+		let suggested = suggestFilename('plumbus1', 'Untitled-1');
+		assert.equal(suggested, 'Untitled-1.shleem');
+	});
+
+	test('Filename Suggestion - Suggest first relevant extension when there are none that begin with a dot', () => {
+		const id = 'plumbus2';
+		const mime = `text/${id}`;
+		for (let extension of ['plumbus', 'shleem', 'gazorpazorp']) {
+			registerTextMime({ id, mime, extension });
+		}
+
+		let suggested = suggestFilename('plumbus2', 'Untitled-1');
+		assert.equal(suggested, 'plumbus');
+	});
+
+	test('Filename Suggestion - Should ignore user-configured associations', () => {
+		registerTextMime({ id: 'plumbus3', mime: 'text/plumbus3', extension: 'plumbus', userConfigured: true });
+		registerTextMime({ id: 'plumbus3', mime: 'text/plumbus3', extension: '.shleem', userConfigured: true });
+		registerTextMime({ id: 'plumbus3', mime: 'text/plumbus3', extension: '.gazorpazorp', userConfigured: false });
+
+		let suggested = suggestFilename('plumbus3', 'Untitled-1');
+		assert.equal(suggested, 'Untitled-1.gazorpazorp');
+
+		registerTextMime({ id: 'plumbus4', mime: 'text/plumbus4', extension: 'plumbus', userConfigured: true });
+		registerTextMime({ id: 'plumbus4', mime: 'text/plumbus4', extension: '.shleem', userConfigured: true });
+		registerTextMime({ id: 'plumbus4', mime: 'text/plumbus4', extension: '.gazorpazorp', userConfigured: true });
+
+		suggested = suggestFilename('plumbus4', 'Untitled-1');
+		assert.equal(suggested, 'Untitled-1');
+	});
 });