You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@cordova.apache.org by "Damian Senn (JIRA)" <ji...@apache.org> on 2016/10/29 09:07:58 UTC
[jira] [Updated] (CB-12085) FileReader#readAsArrayBuffer reads
whole file
[ https://issues.apache.org/jira/browse/CB-12085?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Damian Senn updated CB-12085:
-----------------------------
Description:
Reading a File with
```js
let fr = new FileReader
fr.onload = () => done(fs.result)
fr.readAsArrayBuffer(blob)
```
Is very slow, I'm assuming this is because it reads the whole file, then transfers this via base64 to the JS world, where it is converted to an ArrayBuffer. My use-case involves reading some media metadata in JS-World, this usually involves reading several bytes of 2mb to 50mb files.
I noticed this by profiling via Chrome-DevTools where the most time is being spent in the `atob` function in `cordova/base64.toArrayBuffer`.
So parsing some hundreds of bytes on a 3mb file may take around 3 to 4 seconds on my Samsung Galaxy S4 and around 1 second on my Samsung Galaxy S6. (This is without trying to read the actual metadata from the file).
My guess is that this also has a very negative impact on memory usage and garbage collection.
was:
Reading a File with
```js
let fr = new FileReader
fr.onload = () => done(fs.result)
fr.readAsArrayBuffer(blob)
```
Is very slow, I'm assuming this is because it reads the whole file, then transfers this via base64 to the JS world, where it is converted to an ArrayBuffer. My use-case involves reading some media metadata in JS-World, this usually involves reading several bytes of 2mb to 50mb files.
I noticed this by profiling via Chrome-DevTools where the most time is being spent in the `atob` function in `cordova/base64.toArrayBuffer`.
So parsing some hundreds of bytes on a 3mb file may take around 3 to 4 seconds.
My guess is that this also has a very negative impact on memory usage and garbage collection.
> FileReader#readAsArrayBuffer reads whole file
> ---------------------------------------------
>
> Key: CB-12085
> URL: https://issues.apache.org/jira/browse/CB-12085
> Project: Apache Cordova
> Issue Type: Bug
> Components: Plugin File
> Affects Versions: 4.3.0
> Environment: Android
> Reporter: Damian Senn
> Priority: Critical
> Labels: performance
>
> Reading a File with
> ```js
> let fr = new FileReader
> fr.onload = () => done(fs.result)
> fr.readAsArrayBuffer(blob)
> ```
> Is very slow, I'm assuming this is because it reads the whole file, then transfers this via base64 to the JS world, where it is converted to an ArrayBuffer. My use-case involves reading some media metadata in JS-World, this usually involves reading several bytes of 2mb to 50mb files.
> I noticed this by profiling via Chrome-DevTools where the most time is being spent in the `atob` function in `cordova/base64.toArrayBuffer`.
> So parsing some hundreds of bytes on a 3mb file may take around 3 to 4 seconds on my Samsung Galaxy S4 and around 1 second on my Samsung Galaxy S6. (This is without trying to read the actual metadata from the file).
> My guess is that this also has a very negative impact on memory usage and garbage collection.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@cordova.apache.org
For additional commands, e-mail: issues-help@cordova.apache.org