Bug 386394 - Add a BackupDB method to mozIStorageConnection. r=mano

storage/public/mozIStorageConnection.idl

@@ -51,7 +51,7 @@ interface nsIFile;
  * creating prepared statements, executing SQL, and examining database
  * errors.
  */
-[scriptable, uuid(0b3d9b17-6c07-4c39-9ee6-314f9fbc56a6)]
+[scriptable, uuid(43933f76-3376-4999-9096-6f1d545fe5f6)]
 interface mozIStorageConnection : nsISupports {
   /*
    * Initialization and status
@@ -201,6 +201,25 @@ interface mozIStorageConnection : nsISupports {
                       in long aNumArguments,
                       in mozIStorageFunction aFunction);
 
+  /*
+   * Utilities
+   */
+
+  /**
+   * Copies the current database file to the specified parent directory with the
+   * specified file name.  If the parent directory is not specified, it places
+   * the backup in the same directory as the current file.  This function
+   * ensures that the file being created is unique.
+   *
+   * @param aFileName
+   *        The name of the new file to create.
+   * @param [optional] aParentDirectory
+   *        The directory you'd like the file to be placed.
+   * @return The nsIFile representing the backup file.
+   */
+  nsIFile backupDB(in AString aFileName,
+                   [optional] in nsIFile aParentDirectory);
+
   /**
    * This is used to preload the database cache. It loads pages from the
    * start of the database file until the memory cache (specified by

storage/src/mozStorageConnection.cpp

@@ -497,6 +497,48 @@ mozStorageConnection::CreateFunction(const char *aFunctionName,
     return mFunctions->AppendElement(aFunction, PR_FALSE);
 }
 
+/**
+ ** Utilities
+ **/
+
+NS_IMETHODIMP
+mozStorageConnection::BackupDB(const nsAString &aFileName,
+                               nsIFile *aParentDirectory,
+                               nsIFile **backup)
+{
+    NS_ASSERTION(mDatabaseFile, "No database file to backup!");
+
+    nsresult rv;
+    nsCOMPtr<nsIFile> parentDir = aParentDirectory;
+    if (!parentDir) {
+        // This argument is optional, and defaults to the same parent directory
+        // as the current file.
+        rv = mDatabaseFile->GetParent(getter_AddRefs(parentDir));
+        NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    nsCOMPtr<nsIFile> backupDB;
+    rv = parentDir->Clone(getter_AddRefs(backupDB));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = backupDB->Append(aFileName);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = backupDB->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsAutoString fileName;
+    rv = backupDB->GetLeafName(fileName);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = backupDB->Remove(PR_FALSE);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    backupDB.swap(*backup);
+
+    return mDatabaseFile->CopyTo(parentDir, fileName);
+}
+
 /**
  * Mozilla-specific sqlite function to preload the DB into the cache. See the
  * IDL and sqlite3.h

storage/test/unit/test_storage_connection.js

@@ -37,6 +37,8 @@
 
 // This file tests the functions of mozIStorageConnection
 
+const BACKUP_FILE_NAME = "test_storage.sqlite.backup";
+
 function test_connectionReady()
 {
   // there doesn't seem to be a way for the connection to not be ready
@@ -171,6 +173,42 @@ function test_set_schemaVersion_negative()
   do_check_eq(version, msc.schemaVersion);
 }
 
+function test_backup_not_new_filename()
+{
+  var msc = getOpenedDatabase();
+  const fname = getTestDB().leafName;
+
+  var backup = msc.backupDB(fname);
+  do_check_neq(fname, backup.leafName);
+
+  backup.remove(false);
+}
+
+function test_backup_new_filename()
+{
+  var msc = getOpenedDatabase();
+
+  var backup = msc.backupDB(BACKUP_FILE_NAME);
+  do_check_eq(BACKUP_FILE_NAME, backup.leafName);
+  
+  backup.remove(false);
+}
+
+function test_backup_new_folder()
+{
+  var msc = getOpenedDatabase();
+  var parentDir = getTestDB().parent;
+  parentDir.append("test_storage_temp");
+  parentDir.create(Ci.nsIFile.DIRECTORY_TYPE, 0600);
+  do_check_true(parentDir.exists());
+
+  var backup = msc.backupDB(BACKUP_FILE_NAME, parentDir);
+  do_check_eq(BACKUP_FILE_NAME, backup.leafName);
+  do_check_true(parentDir.equals(backup.parent));
+
+  parentDir.remove(true);
+}
+
 var tests = [test_connectionReady, test_databaseFile,
              test_tableExists_not_created, test_indexExists_not_created,
              test_createTable_not_created, test_indexExists_created,
@@ -179,7 +217,9 @@ var tests = [test_connectionReady, test_databaseFile,
              test_commitTransaction_no_transaction,
              test_rollbackTransaction_no_transaction,
              test_get_schemaVersion_not_set, test_set_schemaVersion,
-             test_set_schemaVersion_same, test_set_schemaVersion_negative];
+             test_set_schemaVersion_same, test_set_schemaVersion_negative,
+             test_backup_not_new_filename, test_backup_new_filename,
+             test_backup_new_folder];
 
 function run_test()
 {