XHR XMLHttpRequest() progress

progress

http://www.w3.org/TR/progress-events/

http://www.w3.org/TR/XMLHttpRequest/

https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest

function makeXHR(buf, url, start, end, init_ref, is_init, is_index) {
    dlog(3, "leosu add ....... makeXHR");
  var xhr = new XMLHttpRequest();
  var range = mkrange(start, end);
  var useArg = !!/youtube.com/.exec(url)
  if (range && useArg) {
    url = url.replace(/&range=[^&]*/, '');
    url += '&range=' + range.substring(6);
  }
  xhr.open("GET", url);
  xhr.responseType = 'arraybuffer';
  xhr.startByte = start;
  if (range != null && !useArg) xhr.setRequestHeader('Range', range);
  xhr.addEventListener('load', onXHRLoad);
  if (url == null) throw "Null URL";
  buf.url = url;
  xhr.buf = buf;
  xhr.init = init_ref;
  xhr.is_init = is_init;
  xhr.is_index = is_index;
  buf.xhr = xhr;
  xhr.lastTime = null;
  xhr.lastSize = null;
  xhr.addEventListener('progress', onXHRProgress);
  xhr.send();
  dlog(2, 'Sent XHR: url=' + url + ', range=' + range + 'start=' + start + 'end= ' + end);
  return xhr;
}

function onXHRLoad(evt) {
    dlog(3, "leosu add ....... onXHRLoad");
  var xhr = evt.target;
  var buf = xhr.buf;
  buf.xhr = null;
  var vid = buf.video;

  if (xhr.readyState != xhr.DONE) return;
  if (xhr.status >= 300) {
    log('XHR failure, status=' + xhr.status);
    throw 'TODO: retry XHRs on failure';
  }

  if (xhr.is_init) {
    xhr.init.value = new Uint8Array(xhr.response);
  }

  if (xhr.is_index) {
    var index = new player.dash.SegmentIndex();
    buf.reps[buf.currentRep].index = index;
    if (buf.mime.indexOf('mp4') >= 0) {
      index.parseSidx(xhr.response, xhr.startByte);
    } else {
      index.parseWebM(xhr.init.value.buffer, xhr.response);
    }
    // We need the index before we append the init.
    if (buf.last_init == null) appendInit(buf, xhr.init);
  }

  if (xhr.is_init || xhr.is_index) {
    return;
  }

  if (buf.last_init !== xhr.init) {
    appendInit(buf, xhr.init);
  }

  queueAppend(buf, xhr.response);
  buf.segIdx++;

  if (buf.segIdx >= buf.reps[buf.currentRep].index.getCount()) {
    buf.active = false;
  }

  if (xhr.expected_time != null && !buf.appendBuffer) {
    // The expected time is the start time of the first buffer in this sequence.
    // This check ensures that media data append time is (roughly) reflected in
    // the buffered range.
    range = findRangeForPlaybackTime(buf, xhr.expected_time);
    if (range == null ||
        !(range.start <= xhr.expected_time && range.end >= xhr.expected_time)) {
      log('Media data expected time not reflected in updated buffer range. ' +
          'MSE implementation bug?');
      if (range == null) {
        dlog(2, 'Reason: range is null');
      } else {
        dlog(2, 'Reason: expected time ' + xhr.expected_time + ' not in (' +
              range.start + ', ' + range.end + ')');
      }
    }
  }

}

function onXHRProgress(evt) {
    dlog(3, "leosu add ....... onXHRProgress");
  var xhr = evt.target;
  if (xhr.lastTime != null && evt.timeStamp != xhr.lastTime) {

    var bw = 8000 * (evt.loaded - xhr.lastSize) / (evt.timeStamp - xhr.lastTime);
    globalSlowBandwidth = kSlowEWMACoeff * globalSlowBandwidth + (1 - kSlowEWMACoeff) * bw;
    globalFastBandwidth = kFastEWMACoeff * globalFastBandwidth + (1 - kFastEWMACoeff) * bw;
  }
  xhr.lastTime = evt.timeStamp;
  xhr.lastSize = evt.loaded;
}

4 Interface XMLHttpRequest

[NoInterfaceObject]
interface XMLHttpRequestEventTarget : EventTarget {
  // event handlers
  attribute EventHandler onloadstart;
  attribute EventHandler onprogress;
  attribute EventHandler onabort;
  attribute EventHandler onerror;
  attribute EventHandler onload;
  attribute EventHandler ontimeout;
  attribute EventHandler onloadend;
};

interface XMLHttpRequestUpload : XMLHttpRequestEventTarget {

};

enum XMLHttpRequestResponseType {
  "",
  "arraybuffer",
  "blob",
  "document",
  "json",
  "text"
};

[Constructor]
interface XMLHttpRequest : XMLHttpRequestEventTarget {
  // event handler
  attribute EventHandler onreadystatechange;

  // states
  const unsigned short UNSENT = 0;
  const unsigned short OPENED = 1;
  const unsigned short HEADERS_RECEIVED = 2;
  const unsigned short LOADING = 3;
  const unsigned short DONE = 4;
  readonly attribute unsigned short readyState;

  // request
  void open(ByteString method, [EnsureUTF16] DOMString url);
  void open(ByteString method, [EnsureUTF16] DOMString url, boolean async, optional [EnsureUTF16] DOMString? username = null, optional [EnsureUTF16] DOMString? password = null);
  void setRequestHeader(ByteString header, ByteString value);
           attribute unsigned long timeout;
           attribute boolean withCredentials;
  readonly attribute XMLHttpRequestUpload upload;
  void send(optional (ArrayBufferView or Blob or Document or [EnsureUTF16] DOMString or FormData)? data = null);
  void abort();

  // response
  readonly attribute unsigned short status;
  readonly attribute ByteString statusText;
  ByteString? getResponseHeader(ByteString header);
  ByteString getAllResponseHeaders();
  void overrideMimeType(DOMString mime);
           attribute XMLHttpRequestResponseType responseType;
  readonly attribute any response;
  readonly attribute DOMString responseText;
  readonly attribute Document? responseXML;
};

Each XMLHttpRequest object has a unique, associated XMLHttpRequestUpload object.

4.3 Suggested names for events using the ProgressEvent interface

This section is non-normative.

The suggested type attribute values for use with events using the ProgressEvent interface are summarized in the table below. Specification editors are free to tune the details to their specific scenarios, though are strongly encouraged to discuss their usage with the W3C WebApps Working Group on public-webapps@w3.org to ensure input from people familiar with the subject.

type attribute value	Description	Times	When
loadstart	Progress has begun.	Once.	First.
progress	In progress.	Zero or more.	After loadstart has been dispatched.
error	Progression failed.	Zero or once.	After the last progress has been dispatched, or after loadstart has been dispatched if progress has not been dispatched.
abort	Progression is terminated.	Zero or once.
load	Progression is successful.	Zero or once.
loadend	Progress has stopped.	Once.	After one of error, abort, or load has been dispatched.

The error, abort, and load event types are mutually exclusive.

Throughout the web platform the error, abort, and load event types have their bubbles and cancelable attributes initialized to false, so it is suggested that for consistency all events using the ProgressEvent interface do the same.