The current implementation of QMacPasteboardMimeUnicodeText
didn't contain any logic to handle unicode text with a byte
order mark (BOM). According to the
docs (*), 'public.utf16-plain-text' can have an optional BOM.
Because of that, Qt would fail encoding UTF-16 text from the
pasteboard if it had a BOM.
Additionally, perhaps because of a bug in iOS 10, UTF-16 text
placed on the pasteboard by Qt ends up being encoded wrong by
native apps, unless the text has a BOM.
Rather than hard-coding UTF-16 encoding/decoding in qmacmime, we
now leave it to QTextCodec. QTextCodec will add a BOM by
default, and can handle decoding of UTF-16 both with, and
without, a BOM.
*: https://developer.apple.com/library/content/documentation/Miscellaneous/Reference/UTIRef/Articles/System-DeclaredUniformTypeIdentifiers.html
Task-number: QTBUG-56229
Change-Id: I3a08deb0262350c67e5622cf23eb3c3a4907ec39
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
4e19615907