1 files changed, 71 insertions, 10 deletions

diff --git a/application/FileUtils.php b/application/FileUtils.php
index 6cac9825..918cb83b 100644
--- a/application/FileUtils.php
+++ b/application/FileUtils.php
@@ -1,21 +1,82 @@
 <?php
+
+require_once 'exceptions/IOException.php';
+
 /**
- * Exception class thrown when a filesystem access failure happens
+ * Class FileUtils
+ *
+ * Utility class for file manipulation.
  */
-class IOException extends Exception
+class FileUtils
 {
-    private $path;
+    /**
+     * @var string
+     */
+    protected static $phpPrefix = '<?php /* ';
 
     /**
-     * Construct a new IOException
+     * @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.
      *
-     * @param string $path    path to the resource that cannot be accessed
-     * @param string $message Custom exception message.
+     * @return int|bool Number of bytes written or false if it fails.
+     *
+     * @throws IOException The destination file can't be written.
      */
-    public function __construct($path, $message = '')
+    public static function writeFlatDB($file, $content)
     {
-        $this->path = $path;
-        $this->message = empty($message) ? 'Error accessing' : $message;
-        $this->message .= PHP_EOL . $this->path;
+        if (is_file($file) && !is_writeable($file)) {
+            // The datastore exists but is not writeable
+            throw new IOException($file);
+        } else if (!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
+        );
+    }
+
+    /**
+     * Read data from a file containing Shaarli database format content.
+     *
+     * If the file isn't readable or doesn't exist, default data will be returned.
+     *
+     * @param string $file    File path.
+     * @param mixed  $default The default value to return if the file isn't readable.
+     *
+     * @return mixed The content unserialized, or default if the file isn't readable, or false if it fails.
+     */
+    public static function readFlatDB($file, $default = null)
+    {
+        // Note that gzinflate is faster than gzuncompress.
+        // See: http://www.php.net/manual/en/function.gzdeflate.php#96439
+        if (! is_readable($file)) {
+            return $default;
+        }
+
+        $data = file_get_contents($file);
+        if ($data == '') {
+            return $default;
+        }
+
+        return unserialize(
+            gzinflate(
+                base64_decode(
+                    substr($data, strlen(self::$phpPrefix), -strlen(self::$phpSuffix))
+                )
+            )
+        );
     }
 }