Open Radar

 
NSFilesPromisePboardType has a note in the documentation:

> On OS X v10.6 and later, use (NSString *)kPasteboardTypeFileURLPromise instead.

In Google Chrome 29 I switched from NSFilesPromisePboardType to kPasteboardTypeFileURLPromise. The complaints about how drag-and-drop broke came pouring in, and I had to revert.

There are four issues I am reporting; this is one of them. I will update this radar with links to the other three when I am done filing them all.

---

There is no documentation for kPasteboardTypeFileURLPromise, but when we look in the header file HIServices/Pasteboard.h we see a list explaining how to use it:

 *    Order of operations on paste or drop
[…]
 *    6) The sender's promise callback for kPasteboardTypeFileURLPromise is called.
 *    7) The sender uses PasteboardCopyPasteLocation to retrieve the paste location, creates the file
 *          and keeps its kPasteboardTypeFileURLPromise promise.

PasteboardCopyPasteLocation takes a PasteboardRef. How do you create one from Cocoa, where you have an NSPasteboard*? NSPasteboard isn't bridged with PasteboardRef, so it takes a ton of boilerplate code. An email from cocoa-dev explained the amount of boilerplate required:

http://lists.apple.com/archives/cocoa-dev/2012/Feb/msg00706.html

The equivalent code in Chrome was twenty lines. Requiring twenty lines of boilerplate code to properly do drag-and-drop is unacceptable. If you want people to use kPasteboardTypeFileURLPromise, you need to provide a Cocoa API, something like:

- (NSURL*)pasteLocation;