- From: Eric U <ericu@google.com>
- Date: Thu, 5 Apr 2012 08:32:42 -0700
On Wed, Apr 4, 2012 at 9:36 PM, Kinuko Yasuda <kinuko at chromium.org> wrote: > A follow up about this proposal: > > Based on the feedbacks we got on this list we've implemented the following > API to do experiments in Chrome: > ?DataTransferItem.getAsEntry(in EntryCallback callback) > > which takes a callback that returns FileEntry or DirectoryEntry if it's for > drop event and the item's kind is 'file'. > Right now it's prefixed therefore its actual name in Chrome is > 'webkitGetAsEntry'. > We use kind=='file' in a broader definition here (i.e. a file path which > can be either regular file or directory file) and didn't add a specific > kind for directories. > (Btw we've also implemented DataTransferItem.getAsFile(), so apps can call > either getAsFile or webkitGetAsEntry for kind=='file' item) > > As for lifetime and toURL() issue, which was the biggest concern in the > past discussion, we decided not to support toURL/resolveURL on ?Entries for > drag-and-drop, so that it won't leak reference or expose GC period. ?A > dragged file can be accessed only while the script has the Entry instance > (as well as we do for File object). ?We eventually aim to support > structured cloning of Entries but it's not there yet. > > Each Entry returned by this API has following properties: > * is read-only. > * has the dropped file/directory name (not a full path) in its > Entry.name, which must also match with the basename of Entry.fullPath. > * should not expose the actual platform path, but how exactly its fullPath > should look is implementation dependent. (In our implementation it always > appears as a top-level path, e.g. '/foo' for a file/directory 'foo') > > Example: > If we drop multiple files/directories like following: > ?/User/kinuko/Photos/travel/thailand/ > ?/User/kinuko/Photos/holiday2012/ > ?/User/kinuko/Photos/photos.txt > > We'll get three kind=='file' items in dataTransfer.items, and > calling getAsEntry (webkitGetAsEntry) on each item allow us to get > FileEntry or DirectoryEntry and to recursively traverse its child > files/subdirectories with full control if it's directory. "full control" still doesn't include modification, though, right? It's read-only all the way down? > ?var items = e.dataTransfer.items; > ?for (var i = 0; i < items.length; ++i) { > ? ?if (items[i].kind == 'file') { > ? ? ?items[i].webkitGetAsEntry(function(entry) { > ? ? ? ?displayEntry(entry.name + (entry.isDirectory ? ' [dir]' : '')); > ? ? ? ?... > ? ? ?}); > ? ?} > ?} > > As for <input type="file"> support I am thinking about adding "AsEntries" > attribute (so that we do not need to do the automatic recursive > files/directories retrieval when the attribute is specified) and "entries" > field, but haven't done anything yet. ?(Open to further suggestions) > > I hope we can get valuable user feedbacks (as well as from yours) based on > the implementation. > > > On Sat, Nov 19, 2011 at 7:37 AM, Glenn Maynard <glenn at zewt.org> wrote: > >> On Fri, Nov 18, 2011 at 1:36 AM, Kinuko Yasuda <kinuko at chromium.org>wrote: >> >>> I would say the approach has a bloating per-page bookkeeping problem but >>> not a 'leak'. >> >> >> It's a reference leak: an object which remains referenced after it's no >> longer needed. ?I'm not aware of anything standardized in the platform with >> this problem. ?Also, a lot of toURL use cases would simply not work with >> drag-and-dropped files (being able to modify the URL to access neighboring >> files; storing the URL for access in a future session). >> >> Anyway, do you still agree that having Entry structured clonable is a good >> idea? ?I'm only really worried about toURL if it causes structured cloning >> of Entry to not happen, since I think the latter is a much more solid and >> useful approach, and more consistent with what we already have. >> (Half-solutions make me nervous, because they have a tendency to delay full >> solutions.) >> >> -- >> Glenn Maynard >> >>
Received on Thursday, 5 April 2012 08:32:42 UTC