<?php
namespace Aws;
use GuzzleHttp\Psr7\StreamDecoratorTrait;
use Psr\Http\Message\StreamInterface;
/**
* Stream decorator that calculates a rolling hash of the stream as it is read.
*/
class HashingStream implements StreamInterface
{
use StreamDecoratorTrait;
/** @var HashInterface */
private $hash;
/** @var callable|null */
private $callback;
/**
* @param StreamInterface $stream Stream that is being read.
* @param HashInterface $hash Hash used to calculate checksum.
* @param callable $onComplete Optional function invoked when the
* hash calculation is completed.
*/
public function __construct(
StreamInterface $stream,
HashInterface $hash,
callable $onComplete = null
) {
$this->stream = $stream;
$this->hash = $hash;
$this->callback = $onComplete;
}
public function read($length)
{
$data = $this->stream->read($length);
$this->hash->update($data);
if ($this->eof()) {
$result = $this->hash->complete();
if ($this->callback) {
call_user_func($this->callback, $result);
}
}
return $data;
}
public function seek($offset, $whence = SEEK_SET)
{
if ($offset === 0) {
$this->hash->reset();
return $this->stream->seek($offset);
} else {
// Seeking arbitrarily is not supported.
return false;
}
}
}
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