Re: New draft of FileWriter API posted

On Wed, Mar 24, 2010 at 9:26 AM, Eric Uhrhane <ericu@google.com> wrote:

> On Tue, Mar 23, 2010 at 8:20 PM, Kinuko Yasuda <kinuko@chromium.org>
> wrote:
> > On Mon, Mar 8, 2010 at 7:01 PM, Eric Uhrhane <ericu@google.com> wrote:
> >>
> >> > Thanks for posting this.  Some questions:
> >> > 1-  What is the proposed way to get a FileWriter from an <INPUT
> >> > type="saveas"> element?
> >>
> >> I was thinking of something like:
> >>
> >> var writer = document.forms['downloadData']['fileChooser'].fileWriter;
> >>
> >> If we make it parallel to the file reader API, that would be an array
> >> rather than a single FileWriter, but it's not clear to me that you'll
> >> ever actually want to browse for more than one save location in a
> >> single operation.
> >
> > Hi Eric,
> > I've come up with another question...how do you plan about how to obtain
> a
> > FileWriterSync instance in a worker context?
>
> That's a good question.  I'd mainly put the sync API in there to
> support uses from the FileSystem API [I haven't posted the full spec
> yet, but the basic idea is at [1]].
>
> > As for obtaining a FileWriter in a worker context, probably what user
> should
> > do is get an instance from the document's SaveAs input element and send
> it
> > to the worker by calling postMessage()?
>
> That seems quite reasonable.  At that point it might also make sense
> to be able to create a FileWriterSync from a FileWriter, if you're a
> worker.  I'll try to think of a clean way to do that.
>
> We'll probably want to invalidate the FileWriter passed in this
> manner, though, to keep the same underlying file handle from being
> used in multiple places at once.
> [1]
> http://lists.w3.org/Archives/Public/public-device-apis/2010Jan/0229.html


I see, thanks.  So the real usage will come with the FileSystem API.  I'll
move things forward with a loose assumption that we may have some transient
way to obtain FileWriterSync from a FileWriter for now.