wp-stateless / lib / Google / vendor / google / cloud-storage / src / ReadStream.php

ReadStream.php in WP-Stateless – Google Cloud Storage 3.0.3, at lib/Google/vendor/google/cloud-storage/src/ReadStream.php

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1	<?php
2	/**
3	* Copyright 2017 Google Inc. All Rights Reserved.
4	*
5	* Licensed under the Apache License, Version 2.0 (the "License");
6	* you may not use this file except in compliance with the License.
7	* You may obtain a copy of the License at
8	*
9	* http://www.apache.org/licenses/LICENSE-2.0
10	*
11	* Unless required by applicable law or agreed to in writing, software
12	* distributed under the License is distributed on an "AS IS" BASIS,
13	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14	* See the License for the specific language governing permissions and
15	* limitations under the License.
16	*/
17
18	namespace Google\Cloud\Storage;
19
20	use GuzzleHttp\Psr7\StreamDecoratorTrait;
21	use Psr\Http\Message\StreamInterface;
22
23	/**
24	* A Stream implementation that wraps a GuzzleHttp download stream to
25	* provide `getSize()` from the response headers.
26	*/
27	class ReadStream implements StreamInterface
28	{
29	use StreamDecoratorTrait;
30
31	private $stream;
32
33	/**
34	* Create a new ReadStream.
35	*
36	* @param StreamInterface $stream The stream interface to wrap
37	*/
38	public function __construct(StreamInterface $stream)
39	{
40	$this->stream = $stream;
41	}
42
43	/**
44	* Return the full size of the buffer. If the underlying stream does
45	* not report it's size, try to fetch the size from the Content-Length
46	* response header.
47	*
48	* @return int The size of the stream.
49	*/
50	public function getSize()
51	{
52	return $this->stream->getSize() ?: $this->getSizeFromMetadata();
53	}
54
55	/**
56	* Attempt to fetch the size from the Content-Length response header.
57	* If we cannot, return 0.
58	*
59	* @return int The Size of the stream
60	*/
61	private function getSizeFromMetadata()
62	{
63	foreach ($this->stream->getMetadata('wrapper_data') as $value) {
64	if (substr($value, 0, 15) == "Content-Length:") {
65	return (int) substr($value, 16);
66	}
67	}
68	return 0;
69	}
70
71	/**
72	* Read bytes from the underlying buffer, retrying until we have read
73	* enough bytes or we cannot read any more. We do this because the
74	* internal C code for filling a buffer does not account for when
75	* we try to read large chunks from a user-land stream that does not
76	* return enough bytes.
77	*
78	* @param int $length The number of bytes to read.
79	* @return string Read bytes from the underlying stream.
80	*/
81	public function read($length)
82	{
83	$data = '';
84	do {
85	$moreData = $this->stream->read($length);
86	$data .= $moreData;
87	$readLength = strlen($moreData);
88	$length -= $readLength;
89	} while ($length > 0 && $readLength > 0);
90
91	return $data;
92	}
93	}
94