660148 - Emulate WebKit behavior for File objects whose underlying file changes

Status: NEW

(Core :: DOM: File, enhancement)

Description

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

WebKit observes files on the disk and changes the File object (AIUI, to a zero-length File) if the file changes on the disk.  We should do the same.

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

This is about nsIDOMFile, not nsIFile, right?
If we implement such behavior, I hope it gets specified in File API.

Comment 2

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

Right, this is about nsIDOMFile.

Comment 3

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Just gotta be careful to maintain run-to-completion semantics. I.e file.size == file.size should always return true.

In fact, I wonder if we should ever touch the size at all and instead add a .invalid member. And make reads fail (asynchronously) when that member is true.

Comment 4

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

I think this is a duplicate of something baku is working on.

Comment 5

[Andrea Marchesini [:baku]]

I and Jonas already discussed this. File API doesn't support the changing of size and lastModified attributes.
I want to see the spec changes before touching our code. Annevk, can you help me with this?

A couple of months ago I was working on a nsIFileWatcherService: a service able to detect OS file changes.  The plan was to invalidate Blob/Files. But we can use the same component for updating size/lastModified attributes instead.

Comment 6

[Anne (:annevk)]

I filed https://github.com/w3c/FileAPI/issues/47.