988815 - Memory mapping array buffer for blobs coming from IndexedDB

Status: NEW

(Core :: DOM: Core & HTML, defect)

Description

[Shian-Yow Wu [:swu]]

Follow up from bug 945152 comment 27.

Comment 1

[Shian-Yow Wu [:swu]]

Attachment: (WIP) Patch: Support memory-mapped array buffer for FileReader.

This patch enhances FileReader API to support memory-mapped array buffer when calling .readAsArrayBuffer() from blob, and the blob is a file.

One thing to note:
The FileReader API is asyncronous, but it sends progress event is syncronously.
When the load event is sent quickly, the onload() event will be triggered before the readAsArrayBuffer() finished.

Because memory mapping triggers load event quickly, it caused below error in the mochitest:
Got exception: TypeError: already executing generator

The test case in the patch uses a workaround to avoid such problem.

Comment 2

[Shian-Yow Wu [:swu]]

I am not actively working on this, unassign myself.