feat: Initial clean release of CHM

packages/lib/models/settings/FileHandler.ts

@@ -0,0 +1,86 @@
+import Logger from '@joplin/utils/Logger';
+import shim from '../../shim';
+import Setting from '../Setting';
+
+const logger = Logger.create('Settings');
+
+export type SettingValues = Record<string, unknown>;
+
+export interface FileHandlerOptions {
+	overwrite?: boolean;
+}
+
+export default class FileHandler {
+
+	private filePath_: string;
+	private valueJsonCache_: string = null;
+	private parsedJsonCache_: SettingValues = null;
+
+	public constructor(filePath: string) {
+		this.filePath_ = filePath;
+	}
+
+	public async load(): Promise<SettingValues> {
+		if (!this.valueJsonCache_) {
+			if (!(await shim.fsDriver().exists(this.filePath_))) {
+				this.valueJsonCache_ = '{}';
+			} else {
+				this.valueJsonCache_ = await shim.fsDriver().readFile(this.filePath_, 'utf8');
+			}
+			this.parsedJsonCache_ = null;
+		}
+
+		if (this.parsedJsonCache_) return this.parsedJsonCache_;
+
+		let result: SettingValues;
+		try {
+			const values = JSON.parse(this.valueJsonCache_);
+			delete values['$id'];
+			delete values['$schema'];
+			result = values;
+		} catch (error) {
+			// Most likely the user entered invalid JSON - in this case we move
+			// the broken file to a new name (otherwise it would be overwritten
+			// by valid JSON and user will lose all their settings).
+			logger.error(`Could not parse JSON file: ${this.filePath_}`, error);
+			await shim.fsDriver().move(this.filePath_, `${this.filePath_}-${Date.now()}-invalid.bak`);
+			result = {};
+		}
+
+		this.parsedJsonCache_ = result;
+
+		return result;
+	}
+
+	public async save(values: SettingValues, options: FileHandlerOptions = {}) {
+		values = { ...values };
+		const overwrite = !!options.overwrite;
+
+		if (!overwrite) {
+			// Merge with existing settings. This prevents settings stored by disabled or not-yet-loaded
+			// plugins from being deleted.
+			for (const key in this.parsedJsonCache_) {
+				const includesSetting = Object.prototype.hasOwnProperty.call(values, key);
+				if (!includesSetting) {
+					values[key] = this.parsedJsonCache_[key];
+				}
+			}
+		}
+
+		const json = `${JSON.stringify({
+			'$schema': Setting.schemaUrl,
+			...values,
+		}, null, '\t')}\n`;
+
+		if (json === this.valueJsonCache_) return;
+
+		await shim.fsDriver().writeFile(this.filePath_, json, 'utf8');
+		this.valueJsonCache_ = json;
+
+		if (overwrite) {
+			// Prevent pre-existing settings from being re-instated by subsequent saving of settings
+			this.parsedJsonCache_ = values;
+		}
+	}
+
+}