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                 fwrite( $stream, $this->getContents() );
  34         }
  35
  36         public function __toString() {
  37                 return $this->contents;
  38         }
  39
  40         public function close() {
  41         }
  42
  43         public function detach() {
  44                 return null;
  45         }
  46
  47         public function getSize() {
  48                 return strlen( $this->contents );
  49         }
  50
  51         public function tell() {
  52                 return $this->offset;
  53         }
  54
  55         public function eof() {
  56                 return $this->offset >= strlen( $this->contents );
  57         }
  58
  59         public function isSeekable() {
  60                 return true;
  61         }
  62
  63         public function seek( $offset, $whence = SEEK_SET ) {
  64                 switch ( $whence ) {
  65                         case SEEK_SET:
  66                                 $this->offset = $offset;
  67                                 break;
  68
  69                         case SEEK_CUR:
  70                                 $this->offset += $offset;
  71                                 break;
  72
  73                         case SEEK_END:
  74                                 $this->offset = strlen( $this->contents ) + $offset;
  75                                 break;
  76
  77                         default:
  78                                 throw new \InvalidArgumentException( "Invalid value for \$whence" );
  79                 }
  80                 if ( $this->offset > strlen( $this->contents ) ) {
  81                         throw new \InvalidArgumentException( "Cannot seek beyond the end of a StringStream" );
  82                 }
  83                 if ( $this->offset < 0 ) {
  84                         throw new \InvalidArgumentException( "Cannot seek before the start of a StringStream" );
  85                 }
  86         }
  87
  88         public function rewind() {
  89                 $this->offset = 0;
  90         }
  91
  92         public function isWritable() {
  93                 return true;
  94         }
  95
  96         public function write( $string ) {
  97                 if ( $this->offset === strlen( $this->contents ) ) {
  98                         $this->contents .= $string;
  99                 } else {
 100                         $this->contents = substr_replace( $this->contents, $string,
 101                                 $this->offset, strlen( $string ) );
 102                 }
 103                 $this->offset += strlen( $string );
 104                 return strlen( $string );
 105         }
 106
 107         public function isReadable() {
 108                 return true;
 109         }
 110
 111         public function read( $length ) {
 112                 if ( $this->offset === 0 && $length >= strlen( $this->contents ) ) {
 113                         $ret = $this->contents;
 114                 } elseif ( $this->offset >= strlen( $this->contents ) ) {
 115                         $ret = '';
 116                 } else {
 117                         $ret = substr( $this->contents, $this->offset, $length );
 118                 }
 119                 $this->offset += strlen( $ret );
 120                 return $ret;
 121         }
 122
 123         public function getContents() {
 124                 if ( $this->offset === 0 ) {
 125                         $ret = $this->contents;
 126                 } elseif ( $this->offset >= strlen( $this->contents ) ) {
 127                         $ret = '';
 128                 } else {
 129                         $ret = substr( $this->contents, $this->offset );
 130                 }
 131                 $this->offset = strlen( $this->contents );
 132                 return $ret;
 133         }
 134
 135         public function getMetadata( $key = null ) {
 136                 return null;
 137         }
 138 }