Viewing file:  BufferStream.php (3.14 KB) -rw-r--r--
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<?php
declare(strict_types=1);
namespace GuzzleHttp\Psr7;
use Psr\Http\Message\StreamInterface;
/**
* Provides a buffer stream that can be written to to fill a buffer, and read
* from to remove bytes from the buffer.
*
* This stream returns a "hwm" metadata value that tells upstream consumers
* what the configured high water mark of the stream is, or the maximum
* preferred size of the buffer.
*/
final class BufferStream implements StreamInterface
{
/** @var int */
private $hwm;
/** @var string */
private $buffer = '';
/**
* @param int $hwm High water mark, representing the preferred maximum
* buffer size. If the size of the buffer exceeds the high
* water mark, then calls to write will continue to succeed
* but will return 0 to inform writers to slow down
* until the buffer has been drained by reading from it.
*/
public function __construct(int $hwm = 16384)
{
$this->hwm = $hwm;
}
public function __toString(): string
{
return $this->getContents();
}
public function getContents(): string
{
$buffer = $this->buffer;
$this->buffer = '';
return $buffer;
}
public function close(): void
{
$this->buffer = '';
}
public function detach()
{
$this->close();
return null;
}
public function getSize(): ?int
{
return strlen($this->buffer);
}
public function isReadable(): bool
{
return true;
}
public function isWritable(): bool
{
return true;
}
public function isSeekable(): bool
{
return false;
}
public function rewind(): void
{
$this->seek(0);
}
public function seek($offset, $whence = SEEK_SET): void
{
throw new \RuntimeException('Cannot seek a BufferStream');
}
public function eof(): bool
{
return strlen($this->buffer) === 0;
}
public function tell(): int
{
throw new \RuntimeException('Cannot determine the position of a BufferStream');
}
/**
* Reads data from the buffer.
*/
public function read($length): string
{
$currentLength = strlen($this->buffer);
if ($length >= $currentLength) {
// No need to slice the buffer because we don't have enough data.
$result = $this->buffer;
$this->buffer = '';
} else {
// Slice up the result to provide a subset of the buffer.
$result = substr($this->buffer, 0, $length);
$this->buffer = substr($this->buffer, $length);
}
return $result;
}
/**
* Writes data to the buffer.
*/
public function write($string): int
{
$this->buffer .= $string;
if (strlen($this->buffer) >= $this->hwm) {
return 0;
}
return strlen($string);
}
/**
* @return mixed
*/
public function getMetadata($key = null)
{
if ($key === 'hwm') {
return $this->hwm;
}
return $key ? null : [];
}
}
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