1 files changed, 128 insertions, 0 deletions

diff --git a/packages/main/src/services/impl/ConfigPersistenceServiceImpl.ts b/packages/main/src/services/impl/ConfigPersistenceServiceImpl.ts
new file mode 100644
index 0000000..bffc38c
--- /dev/null
+++ b/packages/main/src/services/impl/ConfigPersistenceServiceImpl.ts
@@ -0,0 +1,128 @@
+
+/*
+ * Copyright (C)  2021-2022 Kristóf Marussy <kristof@marussy.com>
+ *
+ * This file is part of Sophie.
+ *
+ * Sophie is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { watch } from 'fs';
+import { readFile, stat, writeFile } from 'fs/promises';
+import JSON5 from 'json5';
+import throttle from 'lodash-es/throttle';
+import { join } from 'path';
+
+import type { ConfigPersistenceService, ReadConfigResult } from '../ConfigPersistenceService';
+import type { ConfigSnapshotOut } from  '../../stores/Config';
+import { Disposer, getLogger } from '../../utils';
+
+const log = getLogger('configPersistence');
+
+export class ConfigPersistenceServiceImpl implements ConfigPersistenceService {
+  private readonly configFilePath: string;
+
+  private writingConfig = false;
+
+  private timeLastWritten: Date | null = null;
+
+  constructor(
+    private readonly userDataDir: string,
+    private readonly configFileName: string = 'config.json5',
+  ) {
+    this.configFileName = configFileName;
+    this.configFilePath = join(this.userDataDir, this.configFileName);
+  }
+
+  async readConfig(): Promise<ReadConfigResult> {
+    let configStr;
+    try {
+      configStr = await readFile(this.configFilePath, 'utf8');
+    } catch (err) {
+      if ((err as NodeJS.ErrnoException).code === 'ENOENT') {
+        log.debug('Config file', this.configFilePath, 'was not found');
+        return { found: false };
+      }
+      throw err;
+    }
+    log.info('Read config file', this.configFilePath);
+    return {
+      found: true,
+      data: JSON5.parse(configStr),
+    };
+  }
+
+  async writeConfig(configSnapshot: ConfigSnapshotOut): Promise<void> {
+    const configJson = JSON5.stringify(configSnapshot, {
+      space: 2,
+    });
+    this.writingConfig = true;
+    try {
+      await writeFile(this.configFilePath, configJson, 'utf8');
+      const { mtime } = await stat(this.configFilePath);
+      log.trace('Config file', this.configFilePath, 'last written at', mtime);
+      this.timeLastWritten = mtime;
+    } finally {
+      this.writingConfig = false;
+    }
+    log.info('Wrote config file', this.configFilePath);
+  }
+
+  watchConfig(callback: () => Promise<void>, throttleMs: number): Disposer {
+    log.debug('Installing watcher for', this.userDataDir);
+
+    const configChanged = throttle(async () => {
+      let mtime: Date;
+      try {
+        const stats = await stat(this.configFilePath);
+        mtime = stats.mtime;
+        log.trace('Config file last modified at', mtime);
+      } catch (err) {
+        if ((err as NodeJS.ErrnoException).code === 'ENOENT') {
+          log.debug('Config file', this.configFilePath, 'was deleted after being changed');
+          return;
+        }
+        throw err;
+      }
+      if (!this.writingConfig
+        && (this.timeLastWritten === null || mtime > this.timeLastWritten)) {
+        log.debug(
+          'Found a config file modified at',
+          mtime,
+          'whish is newer than last written',
+          this.timeLastWritten,
+        );
+        return callback();
+      }
+    }, throttleMs);
+
+    const watcher = watch(this.userDataDir, {
+      persistent: false,
+    });
+
+    watcher.on('change', (eventType, filename) => {
+      if (eventType === 'change'
+        && (filename === this.configFileName || filename === null)) {
+        configChanged()?.catch((err) => {
+          console.log('Unhandled error while listening for config changes', err);
+        });
+      }
+    });
+
+    return () => {
+      log.trace('Removing watcher for', this.configFilePath);
+      watcher.close();
+    };
+  }
+}