1<?php
2
3/**
4 * Copyright (c) 2006- Facebook
5 * Distributed under the Thrift Software License
6 *
7 * See accompanying file LICENSE or visit the Thrift site at:
8 * http://developers.facebook.com/thrift/
9 *
10 * @package thrift.transport
11 * @author Mark Slee <mcslee@facebook.com>
12 */
13
14/**
15 * Framed transport. Writes and reads data in chunks that are stamped with
16 * their length.
17 *
18 * @package thrift.transport
19 * @author Mark Slee <mcslee@facebook.com>
20 */
21class TFramedTransport extends TTransport {
22
23  /**
24   * Underlying transport object.
25   *
26   * @var TTransport
27   */
28  private $transport_;
29
30  /**
31   * Buffer for read data.
32   *
33   * @var string
34   */
35  private $rBuf_;
36
37  /**
38   * Buffer for queued output data
39   *
40   * @var string
41   */
42  private $wBuf_;
43
44  /**
45   * Whether to frame reads
46   *
47   * @var bool
48   */
49  private $read_;
50
51  /**
52   * Whether to frame writes
53   *
54   * @var bool
55   */
56  private $write_;
57
58  /**
59   * Constructor.
60   *
61   * @param TTransport $transport Underlying transport
62   */
63  public function __construct($transport=null, $read=true, $write=true) {
64    $this->transport_ = $transport;
65    $this->read_ = $read;
66    $this->write_ = $write;
67  }
68
69  public function isOpen() {
70    return $this->transport_->isOpen();
71  }
72
73  public function open() {
74    $this->transport_->open();
75  }
76
77  public function close() {
78    $this->transport_->close();
79  }
80
81  /**
82   * Reads from the buffer. When more data is required reads another entire
83   * chunk and serves future reads out of that.
84   *
85   * @param int $len How much data
86   */
87  public function read($len) {
88    if (!$this->read_) {
89      return $this->transport_->read($len);
90    }
91
92    if (strlen($this->rBuf_) === 0) {
93      $this->readFrame();
94    }
95
96    // Just return full buff
97    if ($len >= strlen($this->rBuf_)) {
98      $out = $this->rBuf_;
99      $this->rBuf_ = null;
100      return $out;
101    }
102
103    // Return substr
104    $out = substr($this->rBuf_, 0, $len);
105    $this->rBuf_ = substr($this->rBuf_, $len);
106    return $out;
107  }
108
109  /**
110   * Put previously read data back into the buffer
111   *
112   * @param string $data data to return
113   */
114  public function putBack($data) {
115    if (strlen($this->rBuf_) === 0) {
116      $this->rBuf_ = $data;
117    } else {
118      $this->rBuf_ = ($data . $this->rBuf_);
119    }
120  }
121
122  /**
123   * Reads a chunk of data into the internal read buffer.
124   */
125  private function readFrame() {
126    $buf = $this->transport_->readAll(4);
127    $val = unpack('N', $buf);
128    $sz = $val[1];
129
130    $this->rBuf_ = $this->transport_->readAll($sz);
131  }
132
133  /**
134   * Writes some data to the pending output buffer.
135   *
136   * @param string $buf The data
137   * @param int    $len Limit of bytes to write
138   */
139  public function write($buf, $len=null) {
140    if (!$this->write_) {
141      return $this->transport_->write($buf, $len);
142    }
143
144    if ($len !== null && $len < strlen($buf)) {
145      $buf = substr($buf, 0, $len);
146    }
147    $this->wBuf_ .= $buf;
148  }
149
150  /**
151   * Writes the output buffer to the stream in the format of a 4-byte length
152   * followed by the actual data.
153   */
154  public function flush() {
155    if (!$this->write_) {
156      return $this->transport_->flush();
157    }
158
159    $out = pack('N', strlen($this->wBuf_));
160    $out .= $this->wBuf_;
161
162    // Note that we clear the internal wBuf_ prior to the underlying write
163    // to ensure we're in a sane state (i.e. internal buffer cleaned)
164    // if the underlying write throws up an exception
165    $this->wBuf_ = '';
166    $this->transport_->write($out);
167    $this->transport_->flush();
168  }
169
170}
171