depicter / modules / GuzzleHttp / Psr7 / CachingStream.php

CachingStream.php in Depicter — Popup & Slider Builder 1.3.2, at modules/GuzzleHttp/Psr7/CachingStream.php

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1	<?php
2
3	namespace Depicter\GuzzleHttp\Psr7;
4
5	use Depicter\Psr\Http\Message\StreamInterface;
6
7	/**
8	* Stream decorator that can cache previously read bytes from a sequentially
9	* read stream.
10	*
11	* @final
12	*/
13	class CachingStream implements StreamInterface
14	{
15	use StreamDecoratorTrait;
16
17	/** @var StreamInterface Stream being wrapped */
18	private $remoteStream;
19
20	/** @var int Number of bytes to skip reading due to a write on the buffer */
21	private $skipReadBytes = 0;
22
23	/**
24	* We will treat the buffer object as the body of the stream
25	*
26	* @param StreamInterface $stream Stream to cache. The cursor is assumed to be at the beginning of the stream.
27	* @param StreamInterface $target Optionally specify where data is cached
28	*/
29	public function __construct(
30	StreamInterface $stream,
31	StreamInterface $target = null
32	) {
33	$this->remoteStream = $stream;
34	$this->stream = $target ?: new Stream(Utils::tryFopen('php://temp', 'r+'));
35	}
36
37	public function getSize()
38	{
39	$remoteSize = $this->remoteStream->getSize();
40
41	if (null === $remoteSize) {
42	return null;
43	}
44
45	return max($this->stream->getSize(), $remoteSize);
46	}
47
48	public function rewind()
49	{
50	$this->seek(0);
51	}
52
53	public function seek($offset, $whence = SEEK_SET)
54	{
55	if ($whence == SEEK_SET) {
56	$byte = $offset;
57	} elseif ($whence == SEEK_CUR) {
58	$byte = $offset + $this->tell();
59	} elseif ($whence == SEEK_END) {
60	$size = $this->remoteStream->getSize();
61	if ($size === null) {
62	$size = $this->cacheEntireStream();
63	}
64	$byte = $size + $offset;
65	} else {
66	throw new \InvalidArgumentException('Invalid whence');
67	}
68
69	$diff = $byte - $this->stream->getSize();
70
71	if ($diff > 0) {
72	// Read the remoteStream until we have read in at least the amount
73	// of bytes requested, or we reach the end of the file.
74	while ($diff > 0 && !$this->remoteStream->eof()) {
75	$this->read($diff);
76	$diff = $byte - $this->stream->getSize();
77	}
78	} else {
79	// We can just do a normal seek since we've already seen this byte.
80	$this->stream->seek($byte);
81	}
82	}
83
84	public function read($length)
85	{
86	// Perform a regular read on any previously read data from the buffer
87	$data = $this->stream->read($length);
88	$remaining = $length - strlen($data);
89
90	// More data was requested so read from the remote stream
91	if ($remaining) {
92	// If data was written to the buffer in a position that would have
93	// been filled from the remote stream, then we must skip bytes on
94	// the remote stream to emulate overwriting bytes from that
95	// position. This mimics the behavior of other PHP stream wrappers.
96	$remoteData = $this->remoteStream->read(
97	$remaining + $this->skipReadBytes
98	);
99
100	if ($this->skipReadBytes) {
101	$len = strlen($remoteData);
102	$remoteData = substr($remoteData, $this->skipReadBytes);
103	$this->skipReadBytes = max(0, $this->skipReadBytes - $len);
104	}
105
106	$data .= $remoteData;
107	$this->stream->write($remoteData);
108	}
109
110	return $data;
111	}
112
113	public function write($string)
114	{
115	// When appending to the end of the currently read stream, you'll want
116	// to skip bytes from being read from the remote stream to emulate
117	// other stream wrappers. Basically replacing bytes of data of a fixed
118	// length.
119	$overflow = (strlen($string) + $this->tell()) - $this->remoteStream->tell();
120	if ($overflow > 0) {
121	$this->skipReadBytes += $overflow;
122	}
123
124	return $this->stream->write($string);
125	}
126
127	public function eof()
128	{
129	return $this->stream->eof() && $this->remoteStream->eof();
130	}
131
132	/**
133	* Close both the remote stream and buffer stream
134	*/
135	public function close()
136	{
137	$this->remoteStream->close() && $this->stream->close();
138	}
139
140	private function cacheEntireStream()
141	{
142	$target = new FnStream(['write' => 'strlen']);
143	Utils::copyToStream($this, $target);
144
145	return $this->tell();
146	}
147	}
148