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                 $this->offset = strlen( $this->contents );
  39                 fwrite( $stream, $block );
  40         }
  41
  42         public function __toString() {
  43                 return $this->contents;
  44         }
  45
  46         public function close() {
  47         }
  48
  49         public function detach() {
  50                 return null;
  51         }
  52
  53         public function getSize() {
  54                 return strlen( $this->contents );
  55         }
  56
  57         public function tell() {
  58                 return $this->offset;
  59         }
  60
  61         public function eof() {
  62                 return $this->offset >= strlen( $this->contents );
  63         }
  64
  65         public function isSeekable() {
  66                 return true;
  67         }
  68
  69         public function seek( $offset, $whence = SEEK_SET ) {
  70                 switch ( $whence ) {
  71                         case SEEK_SET:
  72                                 $this->offset = $offset;
  73                                 break;
  74
  75                         case SEEK_CUR:
  76                                 $this->offset += $offset;
  77                                 break;
  78
  79                         case SEEK_END:
  80                                 $this->offset = strlen( $this->contents ) + $offset;
  81                                 break;
  82
  83                         default:
  84                                 throw new \InvalidArgumentException( "Invalid value for \$whence" );
  85                 }
  86                 if ( $this->offset > strlen( $this->contents ) ) {
  87                         throw new \InvalidArgumentException( "Cannot seek beyond the end of a StringStream" );
  88                 }
  89                 if ( $this->offset < 0 ) {
  90                         throw new \InvalidArgumentException( "Cannot seek before the start of a StringStream" );
  91                 }
  92         }
  93
  94         public function rewind() {
  95                 $this->offset = 0;
  96         }
  97
  98         public function isWritable() {
  99                 return true;
 100         }
 101
 102         public function write( $string ) {
 103                 if ( $this->offset === strlen( $this->contents ) ) {
 104                         $this->contents .= $string;
 105                 } else {
 106                         $this->contents = substr_replace( $this->contents, $string,
 107                                 $this->offset, strlen( $string ) );
 108                 }
 109                 $this->offset += strlen( $string );
 110                 return strlen( $string );
 111         }
 112
 113         public function isReadable() {
 114                 return true;
 115         }
 116
 117         public function read( $length ) {
 118                 if ( $this->offset === 0 && $length >= strlen( $this->contents ) ) {
 119                         $ret = $this->contents;
 120                 } else {
 121                         $ret = substr( $this->contents, $this->offset, $length );
 122                 }
 123                 $this->offset += strlen( $ret );
 124                 return $ret;
 125         }
 126
 127         public function getContents() {
 128                 if ( $this->offset === 0 ) {
 129                         $ret = $this->contents;
 130                 } else {
 131                         $ret = substr( $this->contents, $this->offset );
 132                 }
 133                 $this->offset = strlen( $this->contents );
 134                 return $ret;
 135         }
 136
 137         public function getMetadata( $key = null ) {
 138                 return null;
 139         }
 140 }