+ /**
+ * Start loading a file into memory; when complete, pass it as a
+ * data URL to the callback function. If the callbackBinary is set it will
+ * first be read as binary and afterwards as data URL. Useful if you want
+ * to do preprocessing on the binary data first.
+ *
+ * @param {File} file
+ * @param {Function} callback
+ * @param {Function} callbackBinary
+ */
+ function fetchPreview( file, callback, callbackBinary ) {
+ var reader = new FileReader();
+ if ( callbackBinary && 'readAsBinaryString' in reader ) {
+ // To fetch JPEG metadata we need a binary string; start there.
+ // TODO
+ reader.onload = function () {
+ callbackBinary( reader.result );
+
+ // Now run back through the regular code path.
+ fetchPreview( file, callback );
+ };
+ reader.readAsBinaryString( file );
+ } else if ( callbackBinary && 'readAsArrayBuffer' in reader ) {
+ // readAsArrayBuffer replaces readAsBinaryString
+ // However, our JPEG metadata library wants a string.
+ // So, this is going to be an ugly conversion.
+ reader.onload = function () {
+ var i,
+ buffer = new Uint8Array( reader.result ),
+ string = '';
+ for ( i = 0; i < buffer.byteLength; i++ ) {
+ string += String.fromCharCode( buffer[ i ] );
+ }
+ callbackBinary( string );
+
+ // Now run back through the regular code path.
+ fetchPreview( file, callback );
+ };
+ reader.readAsArrayBuffer( file );
+ } else if ( 'URL' in window && 'createObjectURL' in window.URL ) {
+ // Supported in Firefox 4.0 and above <https://developer.mozilla.org/en/DOM/window.URL.createObjectURL>
+ // WebKit has it in a namespace for now but that's ok. ;)
+ //
+ // Lifetime of this URL is until document close, which is fine
+ // for Special:Upload -- if this code gets used on longer-running
+ // pages, add a revokeObjectURL() when it's no longer needed.
+ //
+ // Prefer this over readAsDataURL for Firefox 7 due to bug reading
+ // some SVG files from data URIs <https://bugzilla.mozilla.org/show_bug.cgi?id=694165>
+ callback( window.URL.createObjectURL( file ) );
+ } else {
+ // This ends up decoding the file to base-64 and back again, which
+ // feels horribly inefficient.
+ reader.onload = function () {
+ callback( reader.result );
+ };
+ reader.readAsDataURL( file );
+ }
+ }
+
+ /**
+ * Clear the file upload preview area.
+ */
+ function clearPreview() {
+ $( '#mw-upload-thumbnail' ).remove();
+ }
+