nextcloud/apps/dav/lib/Upload/AssemblyStream.php

266 lines
5.9 KiB
PHP

<?php
/**
* @copyright Copyright (c) 2016, ownCloud, Inc.
*
* @author Lukas Reschke <lukas@statuscode.ch>
* @author Markus Goetz <markus@woboq.com>
* @author Robin Appelman <robin@icewind.nl>
* @author Thomas Müller <thomas.mueller@tmit.eu>
* @author Vincent Petry <pvince81@owncloud.com>
*
* @license AGPL-3.0
*
* This code is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License, version 3,
* along with this program. If not, see <http://www.gnu.org/licenses/>
*
*/
namespace OCA\DAV\Upload;
use Sabre\DAV\IFile;
/**
* Class AssemblyStream
*
* The assembly stream is a virtual stream that wraps multiple chunks.
* Reading from the stream transparently accessed the underlying chunks and
* give a representation as if they were already merged together.
*
* @package OCA\DAV\Upload
*/
class AssemblyStream implements \Icewind\Streams\File {
/** @var resource */
private $context;
/** @var IFile[] */
private $nodes;
/** @var int */
private $pos = 0;
/** @var int */
private $size = 0;
/** @var resource */
private $currentStream = null;
/** @var int */
private $currentNode = 0;
/** @var int */
private $currentNodeRead = 0;
/**
* @param string $path
* @param string $mode
* @param int $options
* @param string &$opened_path
* @return bool
*/
public function stream_open($path, $mode, $options, &$opened_path) {
$this->loadContext('assembly');
$nodes = $this->nodes;
// http://stackoverflow.com/a/10985500
@usort($nodes, function (IFile $a, IFile $b) {
return strnatcmp($a->getName(), $b->getName());
});
$this->nodes = array_values($nodes);
if (count($this->nodes) > 0) {
$this->currentStream = $this->getStream($this->nodes[0]);
}
$this->size = array_reduce($this->nodes, function ($size, IFile $file) {
return $size + $file->getSize();
}, 0);
return true;
}
/**
* @param string $offset
* @param int $whence
* @return bool
*/
public function stream_seek($offset, $whence = SEEK_SET) {
return false;
}
/**
* @return int
*/
public function stream_tell() {
return $this->pos;
}
/**
* @param int $count
* @return string
*/
public function stream_read($count) {
if (is_null($this->currentStream)) {
return '';
}
do {
$data = fread($this->currentStream, $count);
$read = strlen($data);
$this->currentNodeRead += $read;
if (feof($this->currentStream)) {
fclose($this->currentStream);
$currentNodeSize = $this->nodes[$this->currentNode]->getSize();
if ($this->currentNodeRead < $currentNodeSize) {
throw new \Exception('Stream from assembly node shorter than expected, got ' . $this->currentNodeRead . ' bytes, expected ' . $currentNodeSize);
}
$this->currentNode++;
$this->currentNodeRead = 0;
if ($this->currentNode < count($this->nodes)) {
$this->currentStream = $this->getStream($this->nodes[$this->currentNode]);
} else {
$this->currentStream = null;
}
}
// if no data read, try again with the next node because
// returning empty data can make the caller think there is no more
// data left to read
} while ($read === 0 && !is_null($this->currentStream));
// update position
$this->pos += $read;
return $data;
}
/**
* @param string $data
* @return int
*/
public function stream_write($data) {
return false;
}
/**
* @param int $option
* @param int $arg1
* @param int $arg2
* @return bool
*/
public function stream_set_option($option, $arg1, $arg2) {
return false;
}
/**
* @param int $size
* @return bool
*/
public function stream_truncate($size) {
return false;
}
/**
* @return array
*/
public function stream_stat() {
return [];
}
/**
* @param int $operation
* @return bool
*/
public function stream_lock($operation) {
return false;
}
/**
* @return bool
*/
public function stream_flush() {
return false;
}
/**
* @return bool
*/
public function stream_eof() {
return $this->pos >= $this->size || $this->currentStream === null;
}
/**
* @return bool
*/
public function stream_close() {
return true;
}
/**
* Load the source from the stream context and return the context options
*
* @param string $name
* @return array
* @throws \Exception
*/
protected function loadContext($name) {
$context = stream_context_get_options($this->context);
if (isset($context[$name])) {
$context = $context[$name];
} else {
throw new \BadMethodCallException('Invalid context, "' . $name . '" options not set');
}
if (isset($context['nodes']) and is_array($context['nodes'])) {
$this->nodes = $context['nodes'];
} else {
throw new \BadMethodCallException('Invalid context, nodes not set');
}
return $context;
}
/**
* @param IFile[] $nodes
* @return resource
*
* @throws \BadMethodCallException
*/
public static function wrap(array $nodes) {
$context = stream_context_create([
'assembly' => [
'nodes' => $nodes
]
]);
stream_wrapper_register('assembly', self::class);
try {
$wrapped = fopen('assembly://', 'r', null, $context);
} catch (\BadMethodCallException $e) {
stream_wrapper_unregister('assembly');
throw $e;
}
stream_wrapper_unregister('assembly');
return $wrapped;
}
/**
* @param IFile $node
* @return resource
*/
private function getStream(IFile $node) {
$data = $node->get();
if (is_resource($data)) {
return $data;
} else {
$tmp = fopen('php://temp', 'w+');
fwrite($tmp, $data);
rewind($tmp);
return $tmp;
}
}
}