[whatwg] Drag-and-drop folders/files support with directory structure using DirectoryEntry

Glenn Maynard glenn at zewt.org
Tue Nov 15 15:02:28 PST 2011

On Tue, Nov 15, 2011 at 5:21 PM, Jonas Sicking <jonas at sicking.cc> wrote:

> Adding FileEntry/DirectoryEntry seems confusing since those are
> generally writable in the FileSystem API spec, right? Additionally,
> DirectoryEntry is asynchronous, which makes enumerating the tree more
> painful.
> The way we were planning on exposing this in Gecko is to simply set
> File.name to the full relative path to the folder dropped. So in the
> example above, if the user dropped the "Photos" folder from the
> example above on a page, we'd make .files return a list of 7 Files,
> with names like "Photos/trip/1.jpg", "Photos/trip/2.jpg",
> "Photos/trip/3.jpg", "Photos/halloween/a.jpg", etc.

That requires a full directory traversal in advance to find all of the
files, though; the tree could be very large.  For example, a sharded
directory tree containing hundreds of thousands of files with individual
frames of a video isn't unheard of, and there's no need to read it all in
advance.  Directory trees with tens of thousands of photos, audio clips,
emails (Maildir), etc. aren't uncommon, either.

DirectoryEntry's asynchronous API seems to have the same advantages here as
they do for regular filesystem access.  It would also set the stage for
exposing writable directories down the line (eg. drag an input and output
directory for file processing), after the security issues are figured out.

Glenn Maynard

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