includes/Rest/StringStream.php

   1 <?php
   2
   3 namespace MediaWiki\Rest;
   4
   5 /**
   6  * A stream class which uses a string as the underlying storage. Surprisingly,
   7  * Guzzle does not appear to have one of these. BufferStream does not do what
   8  * we want.
   9  *
  10  * The normal use of this class should be to first write to the stream, then
  11  * rewind, then read back the whole buffer with getContents().
  12  *
  13  * Seeking is supported, however seeking past the end of the string does not
  14  * fill with null bytes as in a real file, it throws an exception instead.
  15  */
  16 class StringStream implements CopyableStreamInterface {
  17         private $contents = '';
  18         private $offset = 0;
  19
  20         /**
  21          * Construct a StringStream with the given contents.
  22          *
  23          * The offset will start at 0, ready for reading. If appending to the
  24          * given string is desired, you should first seek to the end.
  25          *
  26          * @param string $contents
  27          */
  28         public function __construct( $contents = '' ) {
  29                 $this->contents = $contents;
  30         }
  31
  32         public function copyToStream( $stream ) {
  33                 if ( $this->offset !== 0 ) {
  34                         $block = substr( $this->contents, $this->offset );
  35                 } else {
  36                         $block = $this->contents;
  37                 }
  38                 fwrite( $stream, $block );
  39         }
  40
  41         public function __toString() {
  42                 return $this->contents;
  43         }
  44
  45         public function close() {
  46         }
  47
  48         public function detach() {
  49                 return null;
  50         }
  51
  52         public function getSize() {
  53                 return strlen( $this->contents );
  54         }
  55
  56         public function tell() {
  57                 return $this->offset;
  58         }
  59
  60         public function eof() {
  61                 return $this->offset >= strlen( $this->contents );
  62         }
  63
  64         public function isSeekable() {
  65                 return true;
  66         }
  67
  68         public function seek( $offset, $whence = SEEK_SET ) {
  69                 switch ( $whence ) {
  70                         case SEEK_SET:
  71                                 $this->offset = $offset;
  72                                 break;
  73
  74                         case SEEK_CUR:
  75                                 $this->offset += $offset;
  76                                 break;
  77
  78                         case SEEK_END:
  79                                 $this->offset = strlen( $this->contents ) + $offset;
  80                                 break;
  81
  82                         default:
  83                                 throw new \InvalidArgumentException( "Invalid value for \$whence" );
  84                 }
  85                 if ( $this->offset > strlen( $this->contents ) ) {
  86                         throw new \InvalidArgumentException( "Cannot seek beyond the end of a StringStream" );
  87                 }
  88                 if ( $this->offset < 0 ) {
  89                         throw new \InvalidArgumentException( "Cannot seek before the start of a StringStream" );
  90                 }
  91         }
  92
  93         public function rewind() {
  94                 $this->offset = 0;
  95         }
  96
  97         public function isWritable() {
  98                 return true;
  99         }
 100
 101         public function write( $string ) {
 102                 if ( $this->offset === strlen( $this->contents ) ) {
 103                         $this->contents .= $string;
 104                 } else {
 105                         $this->contents = substr_replace( $this->contents, $string,
 106                                 $this->offset, strlen( $string ) );
 107                 }
 108                 $this->offset += strlen( $string );
 109                 return strlen( $string );
 110         }
 111
 112         public function isReadable() {
 113                 return true;
 114         }
 115
 116         public function read( $length ) {
 117                 if ( $this->offset === 0 && $length >= strlen( $this->contents ) ) {
 118                         $ret = $this->contents;
 119                 } else {
 120                         $ret = substr( $this->contents, $this->offset, $length );
 121                 }
 122                 $this->offset += strlen( $ret );
 123                 return $ret;
 124         }
 125
 126         public function getContents() {
 127                 if ( $this->offset === 0 ) {
 128                         $ret = $this->contents;
 129                 } else {
 130                         $ret = substr( $this->contents, $this->offset );
 131                 }
 132                 $this->offset = strlen( $this->contents );
 133                 return $ret;
 134         }
 135
 136         public function getMetadata( $key = null ) {
 137                 return null;
 138         }
 139 }