signal-desktop/app/base_config.ts
2021-10-25 14:41:44 -05:00

84 lines
2.2 KiB
TypeScript

// Copyright 2018-2020 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import { readFileSync, writeFileSync, unlinkSync } from 'fs';
import { get, set } from 'lodash';
const ENCODING = 'utf8';
type InternalConfigType = Record<string, unknown>;
export type ConfigType = {
set: (keyPath: string, value: unknown) => void;
get: (keyPath: string) => unknown;
remove: () => void;
// Test-only
_getCachedValue: () => InternalConfigType | undefined;
};
export function start(
name: string,
targetPath: string,
options?: { allowMalformedOnStartup?: boolean }
): ConfigType {
let cachedValue: InternalConfigType | undefined;
let incomingJson: string | undefined;
try {
incomingJson = readFileSync(targetPath, ENCODING);
cachedValue = incomingJson ? JSON.parse(incomingJson) : undefined;
console.log(`config/get: Successfully read ${name} config file`);
if (!cachedValue) {
console.log(
`config/get: ${name} config value was falsy, cache is now empty object`
);
cachedValue = Object.create(null);
}
} catch (error) {
if (!options?.allowMalformedOnStartup && error.code !== 'ENOENT') {
throw error;
}
if (incomingJson) {
console.log(
`config/get: ${name} config file was malformed, starting afresh`
);
} else {
console.log(
`config/get: Did not find ${name} config file (or it was empty), cache is now empty object`
);
}
cachedValue = Object.create(null);
}
function ourGet(keyPath: string): unknown {
return get(cachedValue, keyPath);
}
function ourSet(keyPath: string, value: unknown): void {
if (!cachedValue) {
throw new Error('ourSet: no cachedValue!');
}
set(cachedValue, keyPath, value);
console.log(`config/set: Saving ${name} config to disk`);
const outgoingJson = JSON.stringify(cachedValue, null, ' ');
writeFileSync(targetPath, outgoingJson, ENCODING);
}
function remove(): void {
console.log(`config/remove: Deleting ${name} config from disk`);
unlinkSync(targetPath);
cachedValue = Object.create(null);
}
return {
set: ourSet,
get: ourGet,
remove,
_getCachedValue: () => cachedValue,
};
}