class-inflatereadstream.php — Jetpack – WP Security, Backup, Speed, & Growth 16.1-beta.3

jetpack / vendor / wp-php-toolkit / bytestream / ReadStream / class-inflatereadstream.php

jetpack / vendor / wp-php-toolkit / bytestream / ReadStream Last commit date

class-basebytereadstream.php 1 week ago class-deflatereadstream.php 1 week ago class-filereadstream.php 1 week ago class-inflatereadstream.php 1 week ago class-limitedbytereadstream.php 1 week ago class-transformedreadstream.php 1 week ago interface-bytereadstream.php 1 week ago

class-inflatereadstream.php

151 lines

1	<?php
2
3	namespace WordPress\ByteStream\ReadStream;
4
5	use Exception;
6	use WordPress\ByteStream\ByteStreamException;
7
8	class InflateReadStream extends BaseByteReadStream {
9
10	protected $inflate_context;
11	protected $inflate_encoding;
12	protected $upstream;
13
14	/**
15	* The offset of the underlying reader at the time of the first read
16	* from the InflateReader.
17	*
18	* It's the only way to seek to an earlier offset when reading from
19	* a git-like object that has a plaintext header and gzipped body:
20	*
21	* blob <size>\x00
22	* <gzip-compressed-data>
23	*
24	* If we just seeked to offset=0, we'd start inflating the plaintext,
25	* not the deflated body, and get an error.
26	*
27	* @var int\|null
28	*/
29	protected $delegate_offset_0;
30
31	/**
32	* Ensure properties are defined or inherited.
33	*
34	* @var bool
35	*/
36	protected $is_closed = false;
37	protected $buffer = '';
38	protected $bytes_already_forgotten = 0;
39	protected $offset_in_current_buffer = 0;
40
41	public function __construct( ByteReadStream $upstream, $encoding = ZLIB_ENCODING_DEFLATE ) {
42	$this->inflate_encoding = $encoding;
43	$this->inflate_init();
44	$this->upstream = $upstream;
45	}
46
47	protected function internal_pull( $n ): string {
48	if ( null === $this->delegate_offset_0 ) {
49	$this->delegate_offset_0 = $this->upstream->tell();
50	}
51
52	if ( ! $this->inflate_context ) {
53	return '';
54	}
55
56	if ( $this->upstream->reached_end_of_data() ) {
57	$bytes = inflate_add( $this->inflate_context, '', ZLIB_FINISH );
58	$this->inflate_context = null;
59
60	return $bytes;
61	}
62
63	$n = max( 200, $n );
64	$available = $this->upstream->pull( $n );
65
66	$inflated = inflate_add( $this->inflate_context, $this->upstream->consume( $available ) );
67	if ( false === $inflated ) {
68	throw new ByteStreamException( esc_html( 'Inflate error: ' . $this->get_error_string() ) );
69	}
70
71	return $inflated;
72	}
73
74	public function length(): ?int {
75	return null;
76	}
77
78	protected function internal_close_reading(): void {
79	$this->inflate_context = null;
80	}
81
82	protected function internal_reached_end_of_data(): bool {
83	return null === $this->inflate_context && $this->upstream->reached_end_of_data();
84	}
85
86	public function seek( $offset ): void {
87	if ( null !== $this->length() && $offset > $this->length() ) {
88	throw new ByteStreamException( 'Cannot seek past the available data. Call append_bytes() first.' );
89	}
90
91	if ( $offset < $this->tell() ) {
92	$this->upstream->seek( $this->delegate_offset_0 ?? 0 );
93	$this->buffer = '';
94	$this->bytes_already_forgotten = 0;
95	$this->offset_in_current_buffer = 0;
96
97	$this->inflate_init();
98	}
99
100	while ( $this->tell() < $offset ) {
101	$remaining_bytes = $offset - $this->tell();
102	$next_chunk_size = min( 50 * 1024, $remaining_bytes );
103	$pulled = $this->pull( $next_chunk_size );
104	// Keep skipping bytes until we've consumed enough.
105	$this->consume( min( $remaining_bytes, $pulled ) );
106	}
107	}
108
109	private function inflate_init() {
110	$this->inflate_context = inflate_init( $this->inflate_encoding );
111	if ( ! $this->inflate_context ) {
112	throw new Exception( 'Failed to initialize inflate context' );
113	}
114	}
115
116	protected function get_error_string() {
117	$status = inflate_get_status( $this->inflate_context );
118	switch ( $status ) {
119	case ZLIB_OK:
120	$error_string = 'ZLIB_OK';
121	break;
122	case ZLIB_STREAM_END:
123	$error_string = 'ZLIB_STREAM_END';
124	break;
125	case ZLIB_NEED_DICT:
126	$error_string = 'ZLIB_NEED_DICT';
127	break;
128	case ZLIB_ERRNO:
129	$error_string = 'ZLIB_ERRNO';
130	break;
131	case ZLIB_STREAM_ERROR:
132	$error_string = 'ZLIB_STREAM_ERROR';
133	break;
134	case ZLIB_DATA_ERROR:
135	$error_string = 'ZLIB_DATA_ERROR';
136	break;
137	case ZLIB_BUF_ERROR:
138	$error_string = 'ZLIB_BUF_ERROR';
139	break;
140	case ZLIB_MEM_ERROR:
141	$error_string = 'ZLIB_MEM_ERROR';
142	break;
143	default:
144	$error_string = 'Unknown error';
145	break;
146	}
147
148	return "Error $status: $error_string";
149	}
150	}
151