78 lines
2.0 KiB
JavaScript
Executable File
78 lines
2.0 KiB
JavaScript
Executable File
/**
|
|
* Web Worker to load large amounts of data without locking up the UI.
|
|
*
|
|
* @author n1474335 [n1474335@gmail.com]
|
|
* @copyright Crown Copyright 2017
|
|
* @license Apache-2.0
|
|
*/
|
|
|
|
self.port = null;
|
|
self.id = null;
|
|
|
|
|
|
self.handleMessage = function(e) {
|
|
const r = e.data;
|
|
log.debug(`LoaderWorker receiving command '${r.action}'`);
|
|
|
|
switch (r.action) {
|
|
case "loadInput":
|
|
self.loadFile(r.data.file, r.data.inputNum);
|
|
break;
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Respond to message from parent thread.
|
|
*/
|
|
self.addEventListener("message", function(e) {
|
|
const r = e.data;
|
|
if (r.hasOwnProperty("file") && (r.hasOwnProperty("inputNum"))) {
|
|
self.loadFile(r.file, r.inputNum);
|
|
} else if (r.hasOwnProperty("file")) {
|
|
self.loadFile(r.file, "");
|
|
} else if (r.hasOwnProperty("id")) {
|
|
self.id = r.id;
|
|
}
|
|
});
|
|
|
|
|
|
/**
|
|
* Loads a file object into an ArrayBuffer, then transfers it back to the parent thread.
|
|
*
|
|
* @param {File} file
|
|
* @param {string} inputNum
|
|
*/
|
|
self.loadFile = function(file, inputNum) {
|
|
const reader = new FileReader();
|
|
if (file.size >= 256*256*256*128) {
|
|
self.postMessage({"error": "File size too large.", "inputNum": inputNum, "id": self.id});
|
|
return;
|
|
}
|
|
const data = new Uint8Array(file.size);
|
|
let offset = 0;
|
|
const CHUNK_SIZE = 10485760; // 10MiB
|
|
|
|
const seek = function() {
|
|
if (offset >= file.size) {
|
|
self.postMessage({"fileBuffer": data.buffer, "inputNum": inputNum, "id": self.id}, [data.buffer]);
|
|
return;
|
|
}
|
|
self.postMessage({"progress": Math.round(offset / file.size * 100), "inputNum": inputNum});
|
|
const slice = file.slice(offset, offset + CHUNK_SIZE);
|
|
reader.readAsArrayBuffer(slice);
|
|
};
|
|
|
|
reader.onload = function(e) {
|
|
data.set(new Uint8Array(reader.result), offset);
|
|
offset += CHUNK_SIZE;
|
|
seek();
|
|
};
|
|
|
|
reader.onerror = function(e) {
|
|
self.postMessage({"error": reader.error.message, "inputNum": inputNum});
|
|
};
|
|
|
|
seek();
|
|
};
|