- From: Eric Uhrhane <ericu@google.com>
- Date: Mon, 8 Mar 2010 19:01:35 -0800
- To: Darin Fisher <darin@chromium.org>
- Cc: public-device-apis@w3.org
On Mon, Mar 8, 2010 at 11:16 AM, Darin Fisher <darin@chromium.org> wrote: > On Fri, Mar 5, 2010 at 6:01 PM, Eric Uhrhane <ericu@google.com> wrote: >> >> I've just posted a new draft of the File Writer API [1], based on the >> version I posted in January [2]. I look forward to your feedback. In >> the mean time, I'll get going on a clean draft of the FileSystem API. >> >> Thanks, >> >> Eric Uhrhane >> ericu@google.com >> >> [1] http://dev.w3.org/2009/dap/file-system/file-writer.html >> [2] >> http://lists.w3.org/Archives/Public/public-device-apis/2010Jan/0228.html >> > > 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. > 2- In the sample, it appears that onwrite is used to signal completion. > But is that called if the write completes with an error as well? Or, is > onwrite only called if successful? Write should be sent only on successful completion. Writeend should be sent on any completion [success or failure]. I'll add that to the write method description and the event descriptions. > 3- How are the onwritestart, onwriteend, and onprogress events defined? > 4- It would be good to document when the "length" and "position" properties > are updated. I'll flesh that out, but basically you get a writestart at some time between argument validation and the first progress event, you then get progress events periodically throughout the write, each of which corresponds to a chunk of bytes being written to the disk and length and position getting updated, and then you get a write and a writeend. > 5- Can seek throw an exception if position > length? Or, is it valid to > seek beyond the end of the file? If you attempt to seek beyond the end of the file, you just get a seek to the end. "If position is greater than length, length is used instead." > 6- Can truncate fail? I would assume so. Yes, truncate should really be asynchronous as well on FileWriter, since it's another kind of write. I'll fix that.
Received on Tuesday, 9 March 2010 03:02:24 UTC