Add getSettingsFilePath() to LanguageExtension

sources/interfaces.ts

@@ -1,3 +1,5 @@
+import * as os from "os";
+import * as path from "path";
 import * as qub from "qub";
 
 /**
@@ -370,6 +372,15 @@ export abstract class LanguageExtension<ParsedDocumentType> implements Disposabl
         return this._extensionVersion;
     }
 
+    /**
+     * Get the file path to the settings file for this extension. This is the JSON file where
+     * details can be kept that need to be saved across VS Code sessions. This file may or may not
+     * exist.
+     */
+    public getSettingsFilePath(): string {
+        return path.join(os.homedir(), ".vscode", this.name + ".json");
+    }
+
     public getConfigurationValue<T>(propertyPath: string, defaultValue?: T): T {
         const configuration: Configuration = this.getConfiguration();
         return configuration ? configuration.get<T>(`${this._extensionName}.${propertyPath}`, defaultValue) : defaultValue;

tests/mocks.tests.ts

@@ -1,4 +1,6 @@
 import * as assert from "assert";
+import * as os from "os";
+import * as path from "path";
 import * as qub from "qub";
 
 import * as interfaces from "../sources/interfaces";
@@ -758,6 +760,8 @@ suite("Mocks", () => {
                 const extension = new mocks.PlaintextLanguageExtension(undefined);
                 assert.deepStrictEqual(extension.name, "Plaintext Tools");
                 assert.deepStrictEqual(extension.version, "1.0.0");
+
+                assert.deepStrictEqual(extension.getSettingsFilePath(), path.join(os.homedir(), ".vscode", "Plaintext Tools.json"));
             });
 
             test("with a platform", () => {
@@ -766,6 +770,8 @@ suite("Mocks", () => {
                 assert.deepStrictEqual(extension.name, "Plaintext Tools");
                 assert.deepStrictEqual(extension.version, "1.0.0");
 
+                assert.deepStrictEqual(extension.getSettingsFilePath(), path.join(os.homedir(), ".vscode", "Plaintext Tools.json"));
+
                 platform.setActiveTextEditor(new mocks.TextEditor(undefined));
                 platform.setActiveTextEditor(undefined);
                 platform.setConfiguration(new mocks.Configuration({}));