stockpack / vendor / guzzlehttp / psr7 / src / CachingStream.php

CachingStream.php in StockPack – Stock photos and AI images from Unsplash, Adobe Stock, Freepik and more 2.5.2, at vendor/guzzlehttp/psr7/src/CachingStream.php

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1	<?php
2	namespace GuzzleHttp\Psr7;
3
4	use Psr\Http\Message\StreamInterface;
5
6	/**
7	* Stream decorator that can cache previously read bytes from a sequentially
8	* read stream.
9	*/
10	class CachingStream implements StreamInterface
11	{
12	use StreamDecoratorTrait;
13
14	/** @var StreamInterface Stream being wrapped */
15	private $remoteStream;
16
17	/** @var int Number of bytes to skip reading due to a write on the buffer */
18	private $skipReadBytes = 0;
19
20	/**
21	* We will treat the buffer object as the body of the stream
22	*
23	* @param StreamInterface $stream Stream to cache
24	* @param StreamInterface $target Optionally specify where data is cached
25	*/
26	public function __construct(
27	StreamInterface $stream,
28	StreamInterface $target = null
29	) {
30	$this->remoteStream = $stream;
31	$this->stream = $target ?: new Stream(fopen('php://temp', 'r+'));
32	}
33
34	public function getSize()
35	{
36	return max($this->stream->getSize(), $this->remoteStream->getSize());
37	}
38
39	public function rewind()
40	{
41	$this->seek(0);
42	}
43
44	public function seek($offset, $whence = SEEK_SET)
45	{
46	if ($whence == SEEK_SET) {
47	$byte = $offset;
48	} elseif ($whence == SEEK_CUR) {
49	$byte = $offset + $this->tell();
50	} elseif ($whence == SEEK_END) {
51	$size = $this->remoteStream->getSize();
52	if ($size === null) {
53	$size = $this->cacheEntireStream();
54	}
55	$byte = $size + $offset;
56	} else {
57	throw new \InvalidArgumentException('Invalid whence');
58	}
59
60	$diff = $byte - $this->stream->getSize();
61
62	if ($diff > 0) {
63	// Read the remoteStream until we have read in at least the amount
64	// of bytes requested, or we reach the end of the file.
65	while ($diff > 0 && !$this->remoteStream->eof()) {
66	$this->read($diff);
67	$diff = $byte - $this->stream->getSize();
68	}
69	} else {
70	// We can just do a normal seek since we've already seen this byte.
71	$this->stream->seek($byte);
72	}
73	}
74
75	public function read($length)
76	{
77	// Perform a regular read on any previously read data from the buffer
78	$data = $this->stream->read($length);
79	$remaining = $length - strlen($data);
80
81	// More data was requested so read from the remote stream
82	if ($remaining) {
83	// If data was written to the buffer in a position that would have
84	// been filled from the remote stream, then we must skip bytes on
85	// the remote stream to emulate overwriting bytes from that
86	// position. This mimics the behavior of other PHP stream wrappers.
87	$remoteData = $this->remoteStream->read(
88	$remaining + $this->skipReadBytes
89	);
90
91	if ($this->skipReadBytes) {
92	$len = strlen($remoteData);
93	$remoteData = substr($remoteData, $this->skipReadBytes);
94	$this->skipReadBytes = max(0, $this->skipReadBytes - $len);
95	}
96
97	$data .= $remoteData;
98	$this->stream->write($remoteData);
99	}
100
101	return $data;
102	}
103
104	public function write($string)
105	{
106	// When appending to the end of the currently read stream, you'll want
107	// to skip bytes from being read from the remote stream to emulate
108	// other stream wrappers. Basically replacing bytes of data of a fixed
109	// length.
110	$overflow = (strlen($string) + $this->tell()) - $this->remoteStream->tell();
111	if ($overflow > 0) {
112	$this->skipReadBytes += $overflow;
113	}
114
115	return $this->stream->write($string);
116	}
117
118	public function eof()
119	{
120	return $this->stream->eof() && $this->remoteStream->eof();
121	}
122
123	/**
124	* Close both the remote stream and buffer stream
125	*/
126	public function close()
127	{
128	$this->remoteStream->close() && $this->stream->close();
129	}
130
131	private function cacheEntireStream()
132	{
133	$target = new FnStream(['write' => 'strlen']);
134	copy_to_stream($this, $target);
135
136	return $this->tell();
137	}
138	}
139