Bug 1890591 - Add some utilities to BackupResource for copying files and Sqlite databases. r=backup-reviewers,kpatenio

Differential Revision: https://phabricator.services.mozilla.com/D207155

browser/components/backup/resources/BackupResource.sys.mjs

@@ -2,6 +2,12 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Sqlite: "resource://gre/modules/Sqlite.sys.mjs",
+});
+
 // Convert from bytes to kilobytes (not kibibytes).
 export const BYTES_IN_KB = 1000;
 
@@ -129,6 +135,65 @@ export class BackupResource {
     return size;
   }
 
+  /**
+   * Copy a set of SQLite databases safely from a source directory to a
+   * destination directory. A new read-only connection is opened for each
+   * database, and then a backup is created.
+   *
+   * @param {string} sourcePath
+   *   Path to the source directory of the SQLite databases.
+   * @param {string} destPath
+   *   Path to the destination directory where the SQLite databases should be
+   *   copied to.
+   * @param {Array<string>} sqliteDatabases
+   *   An array of filenames of the SQLite databases to copy.
+   * @returns {Promise<undefined>}
+   */
+  static async copySqliteDatabases(sourcePath, destPath, sqliteDatabases) {
+    for (let fileName of sqliteDatabases) {
+      let sourceFilePath = PathUtils.join(sourcePath, fileName);
+      let destFilePath = PathUtils.join(destPath, fileName);
+      let connection;
+
+      try {
+        connection = await lazy.Sqlite.openConnection({
+          path: sourceFilePath,
+          readOnly: true,
+        });
+
+        await connection.backup(destFilePath);
+      } finally {
+        await connection.close();
+      }
+    }
+  }
+
+  /**
+   * A helper function to copy a set of files from a source directory to a
+   * destination directory. Callers should ensure that the source files can be
+   * copied safely before invoking this function. Files that do not exist will
+   * be ignored. Callers that wish to copy SQLite databases should use
+   * copySqliteDatabases() instead.
+   *
+   * @param {string} sourcePath
+   *   Path to the source directory of the files to be copied.
+   * @param {string} destPath
+   *   Path to the destination directory where the files should be
+   *   copied to.
+   * @param {string[]} fileNames
+   *   An array of filenames of the files to copy.
+   * @returns {Promise<undefined>}
+   */
+  static async copyFiles(sourcePath, destPath, fileNames) {
+    for (let fileName of fileNames) {
+      let sourceFilePath = PathUtils.join(sourcePath, fileName);
+      let destFilePath = PathUtils.join(destPath, fileName);
+      if (await IOUtils.exists(sourceFilePath)) {
+        await IOUtils.copy(sourceFilePath, destFilePath, { recursive: true });
+      }
+    }
+  }
+
   constructor() {}
 
   /**

browser/components/backup/resources/MiscDataBackupResource.sys.mjs

@@ -4,12 +4,6 @@
 
 import { BackupResource } from "resource:///modules/backup/BackupResource.sys.mjs";
 
-const lazy = {};
-
-ChromeUtils.defineESModuleGetters(lazy, {
-  Sqlite: "resource://gre/modules/Sqlite.sys.mjs",
-});
-
 /**
  * Class representing miscellaneous files for telemetry, site storage,
  * media device origin mapping, chrome privileged IndexedDB databases,
@@ -30,33 +24,14 @@ export class MiscDataBackupResource extends BackupResource {
       "enumerate_devices.txt",
       "SiteSecurityServiceState.bin",
     ];
-
-    for (let fileName of files) {
-      let sourcePath = PathUtils.join(profilePath, fileName);
-      let destPath = PathUtils.join(stagingPath, fileName);
-      if (await IOUtils.exists(sourcePath)) {
-        await IOUtils.copy(sourcePath, destPath, { recursive: true });
-      }
-    }
+    await BackupResource.copyFiles(profilePath, stagingPath, files);
 
     const sqliteDatabases = ["protections.sqlite"];
-
-    for (let fileName of sqliteDatabases) {
-      let sourcePath = PathUtils.join(profilePath, fileName);
-      let destPath = PathUtils.join(stagingPath, fileName);
-      let connection;
-
-      try {
-        connection = await lazy.Sqlite.openConnection({
-          path: sourcePath,
-          readOnly: true,
-        });
-
-        await connection.backup(destPath);
-      } finally {
-        await connection.close();
-      }
-    }
+    await BackupResource.copySqliteDatabases(
+      profilePath,
+      stagingPath,
+      sqliteDatabases
+    );
 
     // Bug 1890585 - we don't currently have the ability to copy the
     // chrome-privileged IndexedDB databases under storage/permanent/chrome, so

browser/components/backup/resources/PlacesBackupResource.sys.mjs

@@ -10,7 +10,6 @@ const lazy = {};
 ChromeUtils.defineESModuleGetters(lazy, {
   BookmarkJSONUtils: "resource://gre/modules/BookmarkJSONUtils.sys.mjs",
   PrivateBrowsingUtils: "resource://gre/modules/PrivateBrowsingUtils.sys.mjs",
-  Sqlite: "resource://gre/modules/Sqlite.sys.mjs",
 });
 
 XPCOMUtils.defineLazyPreferenceGetter(
@@ -60,22 +59,12 @@ export class PlacesBackupResource extends BackupResource {
       return { bookmarksOnly: true };
     }
 
-    for (let fileName of sqliteDatabases) {
-      let sourcePath = PathUtils.join(profilePath, fileName);
-      let destPath = PathUtils.join(stagingPath, fileName);
-      let connection;
+    await BackupResource.copySqliteDatabases(
+      profilePath,
+      stagingPath,
+      sqliteDatabases
+    );
 
-      try {
-        connection = await lazy.Sqlite.openConnection({
-          path: sourcePath,
-          readOnly: true,
-        });
-
-        await connection.backup(destPath);
-      } finally {
-        await connection.close();
-      }
-    }
     return null;
   }
 

browser/components/backup/resources/PreferencesBackupResource.sys.mjs

@@ -3,7 +3,6 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 import { BackupResource } from "resource:///modules/backup/BackupResource.sys.mjs";
-import { Sqlite } from "resource://gre/modules/Sqlite.sys.mjs";
 
 /**
  * Class representing files that modify preferences and permissions within a user profile.
@@ -28,32 +27,14 @@ export class PreferencesBackupResource extends BackupResource {
       "user.js",
       "chrome",
     ];
-
-    for (let fileName of simpleCopyFiles) {
-      let sourcePath = PathUtils.join(profilePath, fileName);
-      let destPath = PathUtils.join(stagingPath, fileName);
-      if (await IOUtils.exists(sourcePath)) {
-        await IOUtils.copy(sourcePath, destPath, { recursive: true });
-      }
-    }
+    await BackupResource.copyFiles(profilePath, stagingPath, simpleCopyFiles);
 
     const sqliteDatabases = ["permissions.sqlite", "content-prefs.sqlite"];
-
-    for (let fileName of sqliteDatabases) {
-      let sourcePath = PathUtils.join(profilePath, fileName);
-      let destPath = PathUtils.join(stagingPath, fileName);
-      let connection;
-
-      try {
-        connection = await Sqlite.openConnection({
-          path: sourcePath,
-        });
-
-        await connection.backup(destPath);
-      } finally {
-        await connection.close();
-      }
-    }
+    await BackupResource.copySqliteDatabases(
+      profilePath,
+      stagingPath,
+      sqliteDatabases
+    );
 
     // prefs.js is a special case - we have a helper function to flush the
     // current prefs state to disk off of the main thread.