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libphutil/src/channel/PhutilPHPObjectProtocolChannel.php
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PhutilPHPObjectProtocolChannel.php
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<?php
/**
* Channel that transmits PHP objects using PHP serialization. This channel
* is binary safe.
*
* @task protocol Protocol Implementation
*/
final class PhutilPHPObjectProtocolChannel extends PhutilProtocolChannel {
const MODE_LENGTH = 'length';
const MODE_OBJECT = 'object';
/**
* Size of the "length" frame of the protocol in bytes.
*/
const SIZE_LENGTH = 4;
private $mode = self::MODE_LENGTH;
private $byteLengthOfNextChunk = self::SIZE_LENGTH;
private $buf = '';
/* -( Protocol Implementation )-------------------------------------------- */
/**
* Encode a message for transmission over the channel. The message should
* be any serializable PHP object. The entire object will be serialized, so
* avoid transmitting objects which connect to large graphs of other objects,
* etc.
*
* This channel can transmit class instances, but the receiving end must be
* running the same version of the code. There are no builtin safeguards
* to protect against versioning problems in object serialization.
*
* Objects are transmitted as:
*
* <len><serialized PHP object>
*
* ...where <len> is a 4-byte unsigned big-endian integer.
*
* @task protocol
*/
protected function encodeMessage($message) {
$message = serialize($message);
$len = pack('N', strlen($message));
return "{$len}{$message}";
}
/**
* Decode a message received from the other end of the channel.
*
* @task protocol
*/
protected function decodeStream($data) {
$this->buf .= $data;
$objects = array();
while (strlen($this->buf) >= $this->byteLengthOfNextChunk) {
switch ($this->mode) {
case self::MODE_LENGTH:
$len = substr($this->buf, 0, self::SIZE_LENGTH);
$this->buf = substr($this->buf, self::SIZE_LENGTH);
$this->mode = self::MODE_OBJECT;
$this->byteLengthOfNextChunk = head(unpack('N', $len));
break;
case self::MODE_OBJECT:
$data = substr($this->buf, 0, $this->byteLengthOfNextChunk);
$this->buf = substr($this->buf, $this->byteLengthOfNextChunk);
$obj = @unserialize($data);
if ($obj === false) {
throw new Exception("Failed to unserialize object: {$data}");
} else {
$objects[] = $obj;
}
$this->mode = self::MODE_LENGTH;
$this->byteLengthOfNextChunk = self::SIZE_LENGTH;
break;
}
}
return $objects;
}
}
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