media-cloud-sync / includes / sdk / s3 / Aws / Api / Parser / DecodingEventStreamIterator.php

DecodingEventStreamIterator.php in Media Cloud Sync 1.2.6, at includes/sdk/s3/Aws/Api/Parser/DecodingEventStreamIterator.php

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1	<?php
2
3	namespace Dudlewebs\WPMCS\s3\Aws\Api\Parser;
4
5	use Iterator;
6	use Dudlewebs\WPMCS\s3\Aws\Api\DateTimeResult;
7	use Dudlewebs\WPMCS\s3\GuzzleHttp\Psr7;
8	use Dudlewebs\WPMCS\s3\Psr\Http\Message\StreamInterface;
9	use Dudlewebs\WPMCS\s3\Aws\Api\Parser\Exception\ParserException;
10	/**
11	* @internal Implements a decoder for a binary encoded event stream that will
12	* decode, validate, and provide individual events from the stream.
13	*/
14	class DecodingEventStreamIterator implements Iterator
15	{
16	const HEADERS = 'headers';
17	const PAYLOAD = 'payload';
18	const LENGTH_TOTAL = 'total_length';
19	const LENGTH_HEADERS = 'headers_length';
20	const CRC_PRELUDE = 'prelude_crc';
21	const BYTES_PRELUDE = 12;
22	const BYTES_TRAILING = 4;
23	private static $preludeFormat = [self::LENGTH_TOTAL => 'decodeUint32', self::LENGTH_HEADERS => 'decodeUint32', self::CRC_PRELUDE => 'decodeUint32'];
24	private static $lengthFormatMap = [1 => 'decodeUint8', 2 => 'decodeUint16', 4 => 'decodeUint32', 8 => 'decodeUint64'];
25	private static $headerTypeMap = [0 => 'decodeBooleanTrue', 1 => 'decodeBooleanFalse', 2 => 'decodeInt8', 3 => 'decodeInt16', 4 => 'decodeInt32', 5 => 'decodeInt64', 6 => 'decodeBytes', 7 => 'decodeString', 8 => 'decodeTimestamp', 9 => 'decodeUuid'];
26	/** @var StreamInterface Stream of eventstream shape to parse. */
27	private $stream;
28	/** @var array Currently parsed event. */
29	private $currentEvent;
30	/** @var int Current in-order event key. */
31	private $key;
32	/** @var resource\|\HashContext CRC32 hash context for event validation */
33	private $hashContext;
34	/** @var int $currentPosition */
35	private $currentPosition;
36	/**
37	* DecodingEventStreamIterator constructor.
38	*
39	* @param StreamInterface $stream
40	*/
41	public function __construct(StreamInterface $stream)
42	{
43	$this->stream = $stream;
44	$this->rewind();
45	}
46	private function parseHeaders($headerBytes)
47	{
48	$headers = [];
49	$bytesRead = 0;
50	while ($bytesRead < $headerBytes) {
51	list($key, $numBytes) = $this->decodeString(1);
52	$bytesRead += $numBytes;
53	list($type, $numBytes) = $this->decodeUint8();
54	$bytesRead += $numBytes;
55	$f = self::$headerTypeMap[$type];
56	list($value, $numBytes) = $this->{$f}();
57	$bytesRead += $numBytes;
58	if (isset($headers[$key])) {
59	throw new ParserException('Duplicate key in event headers.');
60	}
61	$headers[$key] = $value;
62	}
63	return [$headers, $bytesRead];
64	}
65	private function parsePrelude()
66	{
67	$prelude = [];
68	$bytesRead = 0;
69	$calculatedCrc = null;
70	foreach (self::$preludeFormat as $key => $decodeFunction) {
71	if ($key === self::CRC_PRELUDE) {
72	$hashCopy = \hash_copy($this->hashContext);
73	$calculatedCrc = \hash_final($this->hashContext, \true);
74	$this->hashContext = $hashCopy;
75	}
76	list($value, $numBytes) = $this->{$decodeFunction}();
77	$bytesRead += $numBytes;
78	$prelude[$key] = $value;
79	}
80	if (\unpack('N', $calculatedCrc)[1] !== $prelude[self::CRC_PRELUDE]) {
81	throw new ParserException('Prelude checksum mismatch.');
82	}
83	return [$prelude, $bytesRead];
84	}
85	private function parseEvent()
86	{
87	$event = [];
88	if ($this->stream->tell() < $this->stream->getSize()) {
89	$this->hashContext = \hash_init('crc32b');
90	$bytesLeft = $this->stream->getSize() - $this->stream->tell();
91	list($prelude, $numBytes) = $this->parsePrelude();
92	if ($prelude[self::LENGTH_TOTAL] > $bytesLeft) {
93	throw new ParserException('Message length too long.');
94	}
95	$bytesLeft -= $numBytes;
96	if ($prelude[self::LENGTH_HEADERS] > $bytesLeft) {
97	throw new ParserException('Headers length too long.');
98	}
99	list($event[self::HEADERS], $numBytes) = $this->parseHeaders($prelude[self::LENGTH_HEADERS]);
100	$event[self::PAYLOAD] = Psr7\Utils::streamFor($this->readAndHashBytes($prelude[self::LENGTH_TOTAL] - self::BYTES_PRELUDE - $numBytes - self::BYTES_TRAILING));
101	$calculatedCrc = \hash_final($this->hashContext, \true);
102	$messageCrc = $this->stream->read(4);
103	if ($calculatedCrc !== $messageCrc) {
104	throw new ParserException('Message checksum mismatch.');
105	}
106	}
107	return $event;
108	}
109	// Iterator Functionality
110	/**
111	* @return array
112	*/
113	#[\ReturnTypeWillChange]
114	public function current()
115	{
116	return $this->currentEvent;
117	}
118	/**
119	* @return int
120	*/
121	#[\ReturnTypeWillChange]
122	public function key()
123	{
124	return $this->key;
125	}
126	#[\ReturnTypeWillChange]
127	public function next()
128	{
129	$this->currentPosition = $this->stream->tell();
130	if ($this->valid()) {
131	$this->key++;
132	$this->currentEvent = $this->parseEvent();
133	}
134	}
135	#[\ReturnTypeWillChange]
136	public function rewind()
137	{
138	$this->stream->rewind();
139	$this->key = 0;
140	$this->currentPosition = 0;
141	$this->currentEvent = $this->parseEvent();
142	}
143	/**
144	* @return bool
145	*/
146	#[\ReturnTypeWillChange]
147	public function valid()
148	{
149	return $this->currentPosition < $this->stream->getSize();
150	}
151	// Decoding Utilities
152	private function readAndHashBytes($num)
153	{
154	$bytes = $this->stream->read($num);
155	\hash_update($this->hashContext, $bytes);
156	return $bytes;
157	}
158	private function decodeBooleanTrue()
159	{
160	return [\true, 0];
161	}
162	private function decodeBooleanFalse()
163	{
164	return [\false, 0];
165	}
166	private function uintToInt($val, $size)
167	{
168	$signedCap = \pow(2, $size - 1);
169	if ($val > $signedCap) {
170	$val -= 2 * $signedCap;
171	}
172	return $val;
173	}
174	private function decodeInt8()
175	{
176	$val = (int) \unpack('C', $this->readAndHashBytes(1))[1];
177	return [$this->uintToInt($val, 8), 1];
178	}
179	private function decodeUint8()
180	{
181	return [\unpack('C', $this->readAndHashBytes(1))[1], 1];
182	}
183	private function decodeInt16()
184	{
185	$val = (int) \unpack('n', $this->readAndHashBytes(2))[1];
186	return [$this->uintToInt($val, 16), 2];
187	}
188	private function decodeUint16()
189	{
190	return [\unpack('n', $this->readAndHashBytes(2))[1], 2];
191	}
192	private function decodeInt32()
193	{
194	$val = (int) \unpack('N', $this->readAndHashBytes(4))[1];
195	return [$this->uintToInt($val, 32), 4];
196	}
197	private function decodeUint32()
198	{
199	return [\unpack('N', $this->readAndHashBytes(4))[1], 4];
200	}
201	private function decodeInt64()
202	{
203	$val = $this->unpackInt64($this->readAndHashBytes(8))[1];
204	return [$this->uintToInt($val, 64), 8];
205	}
206	private function decodeUint64()
207	{
208	return [$this->unpackInt64($this->readAndHashBytes(8))[1], 8];
209	}
210	private function unpackInt64($bytes)
211	{
212	if (\version_compare(\PHP_VERSION, '5.6.3', '<')) {
213	$d = \unpack('N2', $bytes);
214	return [1 => $d[1] << 32 \| $d[2]];
215	}
216	return \unpack('J', $bytes);
217	}
218	private function decodeBytes($lengthBytes = 2)
219	{
220	if (!isset(self::$lengthFormatMap[$lengthBytes])) {
221	throw new ParserException('Undefined variable length format.');
222	}
223	$f = self::$lengthFormatMap[$lengthBytes];
224	list($len, $bytes) = $this->{$f}();
225	return [$this->readAndHashBytes($len), $len + $bytes];
226	}
227	private function decodeString($lengthBytes = 2)
228	{
229	if (!isset(self::$lengthFormatMap[$lengthBytes])) {
230	throw new ParserException('Undefined variable length format.');
231	}
232	$f = self::$lengthFormatMap[$lengthBytes];
233	list($len, $bytes) = $this->{$f}();
234	return [$this->readAndHashBytes($len), $len + $bytes];
235	}
236	private function decodeTimestamp()
237	{
238	list($val, $bytes) = $this->decodeInt64();
239	return [DateTimeResult::createFromFormat('U.u', $val / 1000), $bytes];
240	}
241	private function decodeUuid()
242	{
243	$val = \unpack('H32', $this->readAndHashBytes(16))[1];
244	return [\substr($val, 0, 8) . '-' . \substr($val, 8, 4) . '-' . \substr($val, 12, 4) . '-' . \substr($val, 16, 4) . '-' . \substr($val, 20, 12), 16];
245	}
246	}
247