117 lines
2.7 KiB
JavaScript
117 lines
2.7 KiB
JavaScript
"use strict";
|
|
|
|
var utils = require("../utils");
|
|
var GenericWorker = require("./GenericWorker");
|
|
|
|
// the size of the generated chunks
|
|
// TODO expose this as a public variable
|
|
var DEFAULT_BLOCK_SIZE = 16 * 1024;
|
|
|
|
/**
|
|
* A worker that reads a content and emits chunks.
|
|
* @constructor
|
|
* @param {Promise} dataP the promise of the data to split
|
|
*/
|
|
function DataWorker(dataP) {
|
|
GenericWorker.call(this, "DataWorker");
|
|
var self = this;
|
|
this.dataIsReady = false;
|
|
this.index = 0;
|
|
this.max = 0;
|
|
this.data = null;
|
|
this.type = "";
|
|
|
|
this._tickScheduled = false;
|
|
|
|
dataP.then(function (data) {
|
|
self.dataIsReady = true;
|
|
self.data = data;
|
|
self.max = data && data.length || 0;
|
|
self.type = utils.getTypeOf(data);
|
|
if(!self.isPaused) {
|
|
self._tickAndRepeat();
|
|
}
|
|
}, function (e) {
|
|
self.error(e);
|
|
});
|
|
}
|
|
|
|
utils.inherits(DataWorker, GenericWorker);
|
|
|
|
/**
|
|
* @see GenericWorker.cleanUp
|
|
*/
|
|
DataWorker.prototype.cleanUp = function () {
|
|
GenericWorker.prototype.cleanUp.call(this);
|
|
this.data = null;
|
|
};
|
|
|
|
/**
|
|
* @see GenericWorker.resume
|
|
*/
|
|
DataWorker.prototype.resume = function () {
|
|
if(!GenericWorker.prototype.resume.call(this)) {
|
|
return false;
|
|
}
|
|
|
|
if (!this._tickScheduled && this.dataIsReady) {
|
|
this._tickScheduled = true;
|
|
utils.delay(this._tickAndRepeat, [], this);
|
|
}
|
|
return true;
|
|
};
|
|
|
|
/**
|
|
* Trigger a tick a schedule an other call to this function.
|
|
*/
|
|
DataWorker.prototype._tickAndRepeat = function() {
|
|
this._tickScheduled = false;
|
|
if(this.isPaused || this.isFinished) {
|
|
return;
|
|
}
|
|
this._tick();
|
|
if(!this.isFinished) {
|
|
utils.delay(this._tickAndRepeat, [], this);
|
|
this._tickScheduled = true;
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Read and push a chunk.
|
|
*/
|
|
DataWorker.prototype._tick = function() {
|
|
|
|
if(this.isPaused || this.isFinished) {
|
|
return false;
|
|
}
|
|
|
|
var size = DEFAULT_BLOCK_SIZE;
|
|
var data = null, nextIndex = Math.min(this.max, this.index + size);
|
|
if (this.index >= this.max) {
|
|
// EOF
|
|
return this.end();
|
|
} else {
|
|
switch(this.type) {
|
|
case "string":
|
|
data = this.data.substring(this.index, nextIndex);
|
|
break;
|
|
case "uint8array":
|
|
data = this.data.subarray(this.index, nextIndex);
|
|
break;
|
|
case "array":
|
|
case "nodebuffer":
|
|
data = this.data.slice(this.index, nextIndex);
|
|
break;
|
|
}
|
|
this.index = nextIndex;
|
|
return this.push({
|
|
data : data,
|
|
meta : {
|
|
percent : this.max ? this.index / this.max * 100 : 0
|
|
}
|
|
});
|
|
}
|
|
};
|
|
|
|
module.exports = DataWorker;
|