public function __construct(\stdClass $info, PatchSet $patchSet)
{
$this->info = $info;
$this->patchSet = $patchSet;
$this->checksum = sha1($this->read());
if (isset($this->info->sha1) && $this->info->sha1 !== $this->checksum) {
throw new Exception("Expected checksum '{$this->info->sha1}' but got '{$this->checksum}'");
}
}