Merge pull request mailru#86 from wingedfox/master

Smarter upload recovery

Author: RubaXa

lib/FileAPI.Form.js

@@ -113,7 +113,7 @@
  data.params.push(encodeURIComponent(file.name) + "=" + encodeURIComponent(file.blob));
 }
 data.start = -1;
-data.end = -1;
+data.end = data.file.FileAPIReadPosition || -1;
 data.retry = 0;
 });
 },

lib/FileAPI.XHR.js

@@ -70,6 +70,7 @@
 },
 
 _send: function (options, data){
+
 var _this = this, xhr, uid = _this.uid, url = options.url;
 
 api.log('XHR._send:', data);
@@ -193,10 +194,10 @@
 options.pause(data.file, options);
 
 // smart restart if server reports about the last known byte
-var lkb = xhr.getResponseHeader('X-Last-Known-Byte');
+var lkb = parseInt(xhr.getResponseHeader('X-Last-Known-Byte'), 10);
 api.log("X-Last-Known-Byte: " + lkb);
 if (lkb) {
-data.end = parseInt(lkb);
+data.end = lkb;
 } else {
 data.end = data.start - 1;
 }
@@ -217,6 +218,15 @@
 _this.end(xhr.status);
 } else {
 // next chunk
+
+// shift position if server reports about the last known byte
+var lkb = parseInt(xhr.getResponseHeader('X-Last-Known-Byte'), 10);
+api.log("X-Last-Known-Byte: " + lkb);
+if (lkb) {
+data.end = lkb;
+}
+data.file.FileAPIReadPosition = data.end;
+
 setTimeout(function () {
  _this._send(options, data);
 }, 0);