[Summary view]

   1  <?php
   2  
   3  declare(strict_types=1);
   4  
   5  namespace GuzzleHttp\Psr7;
   6  
   7  use Psr\Http\Message\StreamInterface;
   8  
   9  /**
  10   * Provides a buffer stream that can be written to to fill a buffer, and read
  11   * from to remove bytes from the buffer.
  12   *
  13   * This stream returns a "hwm" metadata value that tells upstream consumers
  14   * what the configured high water mark of the stream is, or the maximum
  15   * preferred size of the buffer.
  16   */
  17  final class BufferStream implements StreamInterface
  18  {
  19      /** @var int */
  20      private $hwm;
  21  
  22      /** @var string */
  23      private $buffer = '';
  24  
  25      /**
  26       * @param int $hwm High water mark, representing the preferred maximum
  27       *                 buffer size. If the size of the buffer exceeds the high
  28       *                 water mark, then calls to write will continue to succeed
  29       *                 but will return 0 to inform writers to slow down
  30       *                 until the buffer has been drained by reading from it.
  31       */
  32      public function __construct(int $hwm = 16384)
  33      {
  34          $this->hwm = $hwm;
  35      }
  36  
  37      public function __toString(): string
  38      {
  39          return $this->getContents();
  40      }
  41  
  42      public function getContents(): string
  43      {
  44          $buffer = $this->buffer;
  45          $this->buffer = '';
  46  
  47          return $buffer;
  48      }
  49  
  50      public function close(): void
  51      {
  52          $this->buffer = '';
  53      }
  54  
  55      public function detach()
  56      {
  57          $this->close();
  58  
  59          return null;
  60      }
  61  
  62      public function getSize(): ?int
  63      {
  64          return strlen($this->buffer);
  65      }
  66  
  67      public function isReadable(): bool
  68      {
  69          return true;
  70      }
  71  
  72      public function isWritable(): bool
  73      {
  74          return true;
  75      }
  76  
  77      public function isSeekable(): bool
  78      {
  79          return false;
  80      }
  81  
  82      public function rewind(): void
  83      {
  84          $this->seek(0);
  85      }
  86  
  87      public function seek($offset, $whence = SEEK_SET): void
  88      {
  89          throw new \RuntimeException('Cannot seek a BufferStream');
  90      }
  91  
  92      public function eof(): bool
  93      {
  94          return strlen($this->buffer) === 0;
  95      }
  96  
  97      public function tell(): int
  98      {
  99          throw new \RuntimeException('Cannot determine the position of a BufferStream');
 100      }
 101  
 102      /**
 103       * Reads data from the buffer.
 104       */
 105      public function read($length): string
 106      {
 107          $currentLength = strlen($this->buffer);
 108  
 109          if ($length >= $currentLength) {
 110              // No need to slice the buffer because we don't have enough data.
 111              $result = $this->buffer;
 112              $this->buffer = '';
 113          } else {
 114              // Slice up the result to provide a subset of the buffer.
 115              $result = substr($this->buffer, 0, $length);
 116              $this->buffer = substr($this->buffer, $length);
 117          }
 118  
 119          return $result;
 120      }
 121  
 122      /**
 123       * Writes data to the buffer.
 124       */
 125      public function write($string): int
 126      {
 127          $this->buffer .= $string;
 128  
 129          if (strlen($this->buffer) >= $this->hwm) {
 130              return 0;
 131          }
 132  
 133          return strlen($string);
 134      }
 135  
 136      /**
 137       * {@inheritdoc}
 138       *
 139       * @return mixed
 140       */
 141      public function getMetadata($key = null)
 142      {
 143          if ($key === 'hwm') {
 144              return $this->hwm;
 145          }
 146  
 147          return $key ? null : [];
 148      }
 149  }