[Summary view] [Print] [Text view]

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