src/PEAR/Installer.php
function rollbackFileTransaction()
    {
        $n = count($this->file_operations);
        $this->log(2, "rolling back $n file operations");
        foreach ($this->file_operations as $tr) {
            list($type, $data) = $tr;
            switch ($type) {
                case 'backup':
                    if (file_exists($data[0] . '.bak')) {
                        if (file_exists($data[0] && is_writable($data[0]))) {
                            unlink($data[0]);
                        }
                        @copy($data[0] . '.bak', $data[0]);
                        $this->log(3, "+ restore $data[0] from $data[0].bak");
                    }
                    break;
                case 'removebackup':
                    if (file_exists($data[0] . '.bak') && is_writable($data[0] . '.bak')) {
                        unlink($data[0] . '.bak');
                        $this->log(3, "+ rm backup of $data[0] ($data[0].bak)");
                    }
                    break;
                case 'rename':
                    @unlink($data[0]);
                    $this->log(3, "+ rm $data[0]");
                    break;
                case 'mkdir':
                    @rmdir($data[0]);
                    $this->log(3, "+ rmdir $data[0]");
                    break;
                case 'chmod':
                    break;
                case 'delete':
                    break;
                case 'installed_as':
                    $this->pkginfo->setInstalledAs($data[0], false);
                    break;
            }
        }
        $this->pkginfo->resetDirtree();
        $this->file_operations = array();
    }
function rollbackFileTransaction()
    {
        $n = count($this->file_operations);
        $this->log(2, "rolling back $n file operations");
        foreach ($this->file_operations as $tr) {
            list($type, $data) = $tr;
            switch ($type) {
                case 'backup':
                    if (file_exists($data[0] . '.bak')) {
                        if (file_exists($data[0] && is_writable($data[0]))) {
                            unlink($data[0]);
                        }
                        @copy($data[0] . '.bak', $data[0]);
                        $this->log(3, "+ restore $data[0] from $data[0].bak");
                    }
                    break;
                case 'removebackup':
                    if (file_exists($data[0] . '.bak') && is_writable($data[0] . '.bak')) {
                        unlink($data[0] . '.bak');
                        $this->log(3, "+ rm backup of $data[0] ($data[0].bak)");
                    }
                    break;
                case 'rename':
                    @unlink($data[0]);
                    $this->log(3, "+ rm $data[0]");
                    break;
                case 'mkdir':
                    @rmdir($data[0]);
                    $this->log(3, "+ rmdir $data[0]");
                    break;
                case 'chmod':
                    break;
                case 'delete':
                    break;
                case 'installed_as':
                    $this->pkginfo->setInstalledAs($data[0], false);
                    break;
            }
        }
        $this->pkginfo->resetDirtree();
        $this->file_operations = array();
    }
{{{ rollbackFileTransaction()