1 files changed, 161 insertions, 0 deletions
diff --git a/application/service/storage.php b/application/service/storage.php
new file mode 100644
index 000000000..925827d46
--- /dev/null
+++ b/application/service/storage.php
@@ -0,0 +1,161 @@
+<?php
+/*
+ * Copyright 2014 Florian "Bluewind" Pritz <bluewind@server-speed.net>
+ *
+ * Licensed under AGPLv3
+ * (see COPYING for full license text)
+ *
+ */
+
+namespace service;
+
+/**
+ * This class allows to change a temporary file and replace the original one atomically
+ */
+class storage {
+	private $path;
+	private $tempfile = NULL;
+
+	public function __construct($path)
+	{
+		assert(!is_dir($path));
+
+		$this->path = $path;
+	}
+
+	/**
+	 * Create a temp file which can be written to.
+	 *
+	 * Call commit() once you are done writing.
+	 * Call rollback() to remove the file and throw away any data written.
+	 *
+	 * Calling this multiple times will automatically rollback previous calls.
+	 *
+	 * @return temp file path
+	 */
+	public function begin()
+	{
+		if($this->tempfile !== NULL) {
+			$this->rollback();
+		}
+
+		$this->tempfile = $this->create_tempfile();
+
+		return $this->tempfile;
+	}
+
+	/**
+	 * Create a temporary file. You'll need to remove it yourself when no longer needed.
+	 *
+	 * @return path to the temporary file
+	 */
+	private function create_tempfile()
+	{
+		$dir = dirname($this->get_file());
+		$prefix = basename($this->get_file());
+
+		if (!is_dir($dir)) {
+			mkdir($dir, 0777, true);
+		}
+		assert(is_dir($dir));
+
+		return tempnam($dir, $prefix);
+	}
+
+	/**
+	 * Save the temporary file returned by begin() to the permanent path
+	 * (supplied to the constructor) in an atomic fashion.
+	 */
+	public function commit()
+	{
+		$ret = rename($this->tempfile, $this->get_file());
+		if ($ret) {
+			$this->tempfile = NULL;
+		}
+
+		return $ret;
+	}
+
+	public function exists()
+	{
+		return file_exists($this->get_file());
+	}
+
+	public function get_file()
+	{
+		return $this->path;
+	}
+
+	/**
+	 * Throw away any changes made to the temporary file returned by begin()
+	 */
+	public function rollback()
+	{
+		if ($this->tempfile !== NULL) {
+			unlink($this->tempfile);
+			$this->tempfile = NULL;
+		}
+	}
+
+	public function __destruct()
+	{
+		$this->rollback();
+	}
+
+	/**
+	 * GZIPs the temp file
+	 *
+	 * From http://stackoverflow.com/questions/6073397/how-do-you-create-a-gz-file-using-php
+	 * Based on function by Kioob at:
+	 * http://www.php.net/manual/en/function.gzwrite.php#34955
+	 *
+	 * @param string $source Path to file that should be compressed
+	 * @param integer $level GZIP compression level (default: 6)
+	 * @return boolean true if operation succeeds, false on error
+	 */
+	public function gzip_compress($level = 6){
+		if ($this->tempfile === NULL) {
+			return;
+		}
+
+		$source = $this->tempfile;
+		$file = new storage($source);
+		$dest = $file->begin();
+		$mode = 'wb' . $level;
+		$error = false;
+		$chunk_size = 1024*512;
+
+		if ($fp_out = gzopen($dest, $mode)) {
+			if ($fp_in = fopen($source,'rb')) {
+				while (!feof($fp_in)) {
+					gzwrite($fp_out, fread($fp_in, $chunk_size));
+				}
+				fclose($fp_in);
+			} else {
+				$error = true;
+			}
+			gzclose($fp_out);
+		} else {
+			$error = true;
+		}
+
+		if ($error) {
+			return false;
+		} else {
+			$file->commit();
+			return true;
+		}
+	}
+
+	/**
+	 * Delete the file if it exists.
+	 */
+	public function unlink()
+	{
+		if ($this->exists()) {
+			unlink($this->get_file());
+		}
+	}
+}
+
+# vim: set noet: