138 lines
3.2 KiB
JavaScript
138 lines
3.2 KiB
JavaScript
JSMpeg.Source.AjaxProgressive = (function(){ "use strict";
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var AjaxProgressiveSource = function(url, options) {
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this.url = url;
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this.destination = null;
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this.request = null;
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this.streaming = false;
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this.completed = false;
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this.established = false;
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this.progress = 0;
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this.fileSize = 0;
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this.loadedSize = 0;
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this.chunkSize = options.chunkSize || 1024*1024;
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this.isLoading = false;
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this.loadStartTime = 0;
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this.throttled = options.throttled !== false;
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this.aborted = false;
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this.onEstablishedCallback = options.onSourceEstablished;
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this.onCompletedCallback = options.onSourceCompleted;
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};
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AjaxProgressiveSource.prototype.connect = function(destination) {
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this.destination = destination;
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};
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AjaxProgressiveSource.prototype.start = function() {
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this.request = new XMLHttpRequest();
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this.request.onreadystatechange = function() {
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if (this.request.readyState === this.request.DONE) {
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this.fileSize = parseInt(
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this.request.getResponseHeader("Content-Length")
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);
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this.loadNextChunk();
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}
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}.bind(this);
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this.request.onprogress = this.onProgress.bind(this);
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this.request.open('HEAD', this.url);
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this.request.send();
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};
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AjaxProgressiveSource.prototype.resume = function(secondsHeadroom) {
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if (this.isLoading || !this.throttled) {
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return;
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}
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// Guess the worst case loading time with lots of safety margin. This is
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// somewhat arbitrary...
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var worstCaseLoadingTime = this.loadTime * 8 + 2;
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if (worstCaseLoadingTime > secondsHeadroom) {
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this.loadNextChunk();
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}
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};
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AjaxProgressiveSource.prototype.destroy = function() {
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this.request.abort();
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this.aborted = true;
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};
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AjaxProgressiveSource.prototype.loadNextChunk = function() {
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var start = this.loadedSize,
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end = Math.min(this.loadedSize + this.chunkSize-1, this.fileSize-1);
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if (start >= this.fileSize || this.aborted) {
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this.completed = true;
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if (this.onCompletedCallback) {
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this.onCompletedCallback(this);
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}
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return;
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}
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this.isLoading = true;
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this.loadStartTime = JSMpeg.Now();
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this.request = new XMLHttpRequest();
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this.request.onreadystatechange = function() {
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if (
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this.request.readyState === this.request.DONE &&
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this.request.status >= 200 && this.request.status < 300
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) {
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this.onChunkLoad(this.request.response);
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}
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else if (this.request.readyState === this.request.DONE) {
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// Retry?
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if (this.loadFails++ < 3) {
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this.loadNextChunk();
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}
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}
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}.bind(this);
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if (start === 0) {
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this.request.onprogress = this.onProgress.bind(this);
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}
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this.request.open('GET', this.url+'?'+start+"-"+end);
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this.request.setRequestHeader("Range", "bytes="+start+"-"+end);
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this.request.responseType = "arraybuffer";
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this.request.send();
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};
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AjaxProgressiveSource.prototype.onProgress = function(ev) {
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this.progress = (ev.loaded / ev.total);
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};
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AjaxProgressiveSource.prototype.onChunkLoad = function(data) {
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var isFirstChunk = !this.established;
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this.established = true;
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this.progress = 1;
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this.loadedSize += data.byteLength;
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this.loadFails = 0;
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this.isLoading = false;
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if (isFirstChunk && this.onEstablishedCallback) {
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this.onEstablishedCallback(this);
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}
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if (this.destination) {
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this.destination.write(data);
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}
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this.loadTime = JSMpeg.Now() - this.loadStartTime;
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if (!this.throttled) {
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this.loadNextChunk();
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}
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};
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return AjaxProgressiveSource;
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})();
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