Search moodle.org's
Developer Documentation

See Release Notes

  • Bug fixes for general core bugs in 3.11.x will end 14 Nov 2022 (12 months plus 6 months extension).
  • Bug fixes for security issues in 3.11.x will end 13 Nov 2023 (18 months plus 12 months extension).
  • PHP version: minimum PHP 7.3.0 Note: minimum PHP version has increased since Moodle 3.10. PHP 7.4.x is supported too.

Differences Between: [Versions 311 and 401] [Versions 311 and 402] [Versions 311 and 403]

   1  <?php
   2  declare(strict_types=1);
   3  
   4  namespace ZipStream;
   5  
   6  use Psr\Http\Message\StreamInterface;
   7  use RuntimeException;
   8  
   9  /**
  10   * Describes a data stream.
  11   *
  12   * Typically, an instance will wrap a PHP stream; this interface provides
  13   * a wrapper around the most common operations, including serialization of
  14   * the entire stream to a string.
  15   */
  16  class Stream implements StreamInterface
  17  {
  18      protected $stream;
  19  
  20      public function __construct($stream)
  21      {
  22          $this->stream = $stream;
  23      }
  24  
  25      /**
  26       * Closes the stream and any underlying resources.
  27       *
  28       * @return void
  29       */
  30      public function close(): void
  31      {
  32          if (is_resource($this->stream)) {
  33              fclose($this->stream);
  34          }
  35          $this->detach();
  36      }
  37  
  38      /**
  39       * Separates any underlying resources from the stream.
  40       *
  41       * After the stream has been detached, the stream is in an unusable state.
  42       *
  43       * @return resource|null Underlying PHP stream, if any
  44       */
  45      public function detach()
  46      {
  47          $result = $this->stream;
  48          $this->stream = null;
  49          return $result;
  50      }
  51  
  52      /**
  53       * Reads all data from the stream into a string, from the beginning to end.
  54       *
  55       * This method MUST attempt to seek to the beginning of the stream before
  56       * reading data and read the stream until the end is reached.
  57       *
  58       * Warning: This could attempt to load a large amount of data into memory.
  59       *
  60       * This method MUST NOT raise an exception in order to conform with PHP's
  61       * string casting operations.
  62       *
  63       * @see http://php.net/manual/en/language.oop5.magic.php#object.tostring
  64       * @return string
  65       */
  66      public function __toString(): string
  67      {
  68          try {
  69              $this->seek(0);
  70          } catch (\RuntimeException $e) {}
  71          return (string) stream_get_contents($this->stream);
  72      }
  73  
  74      /**
  75       * Seek to a position in the stream.
  76       *
  77       * @link http://www.php.net/manual/en/function.fseek.php
  78       * @param int $offset Stream offset
  79       * @param int $whence Specifies how the cursor position will be calculated
  80       *     based on the seek offset. Valid values are identical to the built-in
  81       *     PHP $whence values for `fseek()`.  SEEK_SET: Set position equal to
  82       *     offset bytes SEEK_CUR: Set position to current location plus offset
  83       *     SEEK_END: Set position to end-of-stream plus offset.
  84       * @throws \RuntimeException on failure.
  85       */
  86      public function seek($offset, $whence = SEEK_SET): void
  87      {
  88          if (!$this->isSeekable()) {
  89              throw new RuntimeException;
  90          }
  91          if (fseek($this->stream, $offset, $whence) !== 0) {
  92              throw new RuntimeException;
  93          }
  94      }
  95  
  96      /**
  97       * Returns whether or not the stream is seekable.
  98       *
  99       * @return bool
 100       */
 101      public function isSeekable(): bool
 102      {
 103          return (bool)$this->getMetadata('seekable');
 104      }
 105  
 106      /**
 107       * Get stream metadata as an associative array or retrieve a specific key.
 108       *
 109       * The keys returned are identical to the keys returned from PHP's
 110       * stream_get_meta_data() function.
 111       *
 112       * @link http://php.net/manual/en/function.stream-get-meta-data.php
 113       * @param string $key Specific metadata to retrieve.
 114       * @return array|mixed|null Returns an associative array if no key is
 115       *     provided. Returns a specific key value if a key is provided and the
 116       *     value is found, or null if the key is not found.
 117       */
 118      public function getMetadata($key = null)
 119      {
 120          $metadata = stream_get_meta_data($this->stream);
 121          return $key !== null ? @$metadata[$key] : $metadata;
 122      }
 123  
 124      /**
 125       * Get the size of the stream if known.
 126       *
 127       * @return int|null Returns the size in bytes if known, or null if unknown.
 128       */
 129      public function getSize(): ?int
 130      {
 131          $stats = fstat($this->stream);
 132          return $stats['size'];
 133      }
 134  
 135      /**
 136       * Returns the current position of the file read/write pointer
 137       *
 138       * @return int Position of the file pointer
 139       * @throws \RuntimeException on error.
 140       */
 141      public function tell(): int
 142      {
 143          $position = ftell($this->stream);
 144          if ($position === false) {
 145              throw new RuntimeException;
 146          }
 147          return $position;
 148      }
 149  
 150      /**
 151       * Returns true if the stream is at the end of the stream.
 152       *
 153       * @return bool
 154       */
 155      public function eof(): bool
 156      {
 157          return feof($this->stream);
 158      }
 159  
 160      /**
 161       * Seek to the beginning of the stream.
 162       *
 163       * If the stream is not seekable, this method will raise an exception;
 164       * otherwise, it will perform a seek(0).
 165       *
 166       * @see seek()
 167       * @link http://www.php.net/manual/en/function.fseek.php
 168       * @throws \RuntimeException on failure.
 169       */
 170      public function rewind(): void
 171      {
 172          $this->seek(0);
 173      }
 174  
 175      /**
 176       * Write data to the stream.
 177       *
 178       * @param string $string The string that is to be written.
 179       * @return int Returns the number of bytes written to the stream.
 180       * @throws \RuntimeException on failure.
 181       */
 182      public function write($string): int
 183      {
 184          if (!$this->isWritable()) {
 185              throw new RuntimeException;
 186          }
 187          if (fwrite($this->stream, $string) === false) {
 188              throw new RuntimeException;
 189          }
 190          return \mb_strlen($string);
 191      }
 192  
 193      /**
 194       * Returns whether or not the stream is writable.
 195       *
 196       * @return bool
 197       */
 198      public function isWritable(): bool
 199      {
 200          return preg_match('/[waxc+]/', $this->getMetadata('mode')) === 1;
 201      }
 202  
 203      /**
 204       * Read data from the stream.
 205       *
 206       * @param int $length Read up to $length bytes from the object and return
 207       *     them. Fewer than $length bytes may be returned if underlying stream
 208       *     call returns fewer bytes.
 209       * @return string Returns the data read from the stream, or an empty string
 210       *     if no bytes are available.
 211       * @throws \RuntimeException if an error occurs.
 212       */
 213      public function read($length): string
 214      {
 215          if (!$this->isReadable()) {
 216              throw new RuntimeException;
 217          }
 218          $result = fread($this->stream, $length);
 219          if ($result === false) {
 220              throw new RuntimeException;
 221          }
 222          return $result;
 223      }
 224  
 225      /**
 226       * Returns whether or not the stream is readable.
 227       *
 228       * @return bool
 229       */
 230      public function isReadable(): bool
 231      {
 232          return preg_match('/[r+]/', $this->getMetadata('mode')) === 1;
 233      }
 234  
 235      /**
 236       * Returns the remaining contents in a string
 237       *
 238       * @return string
 239       * @throws \RuntimeException if unable to read or an error occurs while
 240       *     reading.
 241       */
 242      public function getContents(): string
 243      {
 244          if (!$this->isReadable()) {
 245              throw new RuntimeException;
 246          }
 247          $result = stream_get_contents($this->stream);
 248          if ($result === false) {
 249              throw new RuntimeException;
 250          }
 251          return $result;
 252      }
 253  }