+ /**
+ * @var string
+ */
+ protected static $phpPrefix = '<?php /* ';
+
+ /**
+ * @var string
+ */
+ protected static $phpSuffix = ' */ ?>';
+
+ /**
+ * Write data into a file (Shaarli database format).
+ * The data is stored in a PHP file, as a comment, in compressed base64 format.
+ *
+ * The file will be created if it doesn't exist.
+ *
+ * @param string $file File path.
+ * @param mixed $content Content to write.
+ *
+ * @return int|bool Number of bytes written or false if it fails.
+ *
+ * @throws IOException The destination file can't be written.
+ */
+ public static function writeFlatDB($file, $content)
+ {
+ if (is_file($file) && !is_writeable($file)) {
+ // The datastore exists but is not writeable
+ throw new IOException($file);
+ } elseif (!is_file($file) && !is_writeable(dirname($file))) {
+ // The datastore does not exist and its parent directory is not writeable
+ throw new IOException(dirname($file));
+ }
+
+ return file_put_contents(
+ $file,
+ self::$phpPrefix.base64_encode(gzdeflate(serialize($content))).self::$phpSuffix
+ );
+ }