1 files changed, 289 insertions, 0 deletions
diff --git a/apps/dav/lib/Upload/AssemblyStream.php b/apps/dav/lib/Upload/AssemblyStream.php
new file mode 100644
index 00000000000..642a8604b17
--- /dev/null
+++ b/apps/dav/lib/Upload/AssemblyStream.php
@@ -0,0 +1,289 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+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 = $this->nodes;
+		usort($nodes, function (IFile $a, IFile $b) {
+			return strnatcmp($a->getName(), $b->getName());
+		});
+		$this->nodes = array_values($nodes);
+		$this->size = array_reduce($this->nodes, function ($size, IFile $file) {
+			return $size + $file->getSize();
+		}, 0);
+
+		return true;
+	}
+
+	/**
+	 * @param int $offset
+	 * @param int $whence
+	 * @return bool
+	 */
+	public function stream_seek($offset, $whence = SEEK_SET) {
+		if ($whence === SEEK_CUR) {
+			$offset = $this->stream_tell() + $offset;
+		} elseif ($whence === SEEK_END) {
+			$offset = $this->size + $offset;
+		}
+
+		if ($offset === $this->pos) {
+			return true;
+		}
+
+		if ($offset > $this->size) {
+			return false;
+		}
+
+		$nodeIndex = 0;
+		$nodeStart = 0;
+		while (true) {
+			if (!isset($this->nodes[$nodeIndex + 1])) {
+				break;
+			}
+			$node = $this->nodes[$nodeIndex];
+			if ($nodeStart + $node->getSize() > $offset) {
+				break;
+			}
+			$nodeIndex++;
+			$nodeStart += $node->getSize();
+		}
+
+		$stream = $this->getStream($this->nodes[$nodeIndex]);
+		$nodeOffset = $offset - $nodeStart;
+		if ($nodeOffset > 0 && fseek($stream, $nodeOffset) === -1) {
+			return false;
+		}
+		$this->currentNode = $nodeIndex;
+		$this->currentNodeRead = $nodeOffset;
+		$this->currentStream = $stream;
+		$this->pos = $offset;
+
+		return true;
+	}
+
+	/**
+	 * @return int
+	 */
+	public function stream_tell() {
+		return $this->pos;
+	}
+
+	/**
+	 * @param int $count
+	 * @return string
+	 */
+	public function stream_read($count) {
+		if (is_null($this->currentStream)) {
+			if ($this->currentNode < count($this->nodes)) {
+				$this->currentStream = $this->getStream($this->nodes[$this->currentNode]);
+			} else {
+				return '';
+			}
+		}
+
+		$collectedData = '';
+		// read data until we either got all the data requested or there is no more stream left
+		while ($count > 0 && !is_null($this->currentStream)) {
+			$data = fread($this->currentStream, $count);
+			$read = strlen($data);
+
+			$count -= $read;
+			$collectedData .= $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;
+				}
+			}
+		}
+
+		// update position
+		$this->pos += strlen($collectedData);
+		return $collectedData;
+	}
+
+	/**
+	 * @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 [
+			'size' => $this->size,
+		];
+	}
+
+	/**
+	 * @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->currentNode >= count($this->nodes) && $this->currentNode === null);
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function stream_close() {
+		return true;
+	}
+
+
+	/**
+	 * Load the source from the stream context and return the context options
+	 *
+	 * @param string $name
+	 * @return array
+	 * @throws \BadMethodCallException
+	 */
+	protected function loadContext($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', false, $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;
+		}
+	}
+}