macOS: Better document plain-text code-path in QMacPasteboard::retrieveData

Due to PasteboardCopyItemFlavorData converting newlines to '\r' for some
UTIs we have traditionally had to shortcut these UTIs via NSStringPboardType
instead of the mime converters such as QMacPasteboardMimeUnicodeText.

Let's explain this a bit better for future generations.

Note that public.utf8-plain-text doesn't seem to have this problem
anymore, but it's left in for now to not cause any regressions due
to behavior change.

Change-Id: I7dce80828865c6323ed308780b8ca07b7a3e7c17
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
 
 
 

1 files changed, 6 insertions, 7 deletions

diff --git a/src/plugins/platforms/cocoa/qmacclipboard.mm b/src/plugins/platforms/cocoa/qmacclipboard.mm
index 554fd7c4c1..358a6b49fd 100644
--- a/src/plugins/platforms/cocoa/qmacclipboard.mm
+++ b/src/plugins/platforms/cocoa/qmacclipboard.mm
@@ -489,13 +489,12 @@ QMacPasteboard::retrieveData(const QString &format, QVariant::Type) const
         QMacInternalPasteboardMime *c = mimes.at(mime);
         QString c_flavor = c->flavorFor(format);
         if (!c_flavor.isEmpty()) {
-            // Handle text/plain a little differently. Try handling Unicode first.
-            bool checkForUtf16 = (c_flavor == QLatin1String("com.apple.traditional-mac-plain-text")
-                                  || c_flavor == QLatin1String("public.utf8-plain-text"));
-            if (checkForUtf16 || c_flavor == QLatin1String("public.utf16-plain-text")) {
-                // Try to get the NSStringPboardType from NSPasteboard, newlines are mapped
-                // correctly (as '\n') in this data. The 'public.utf16-plain-text' type
-                // usually maps newlines to '\r' instead.
+            // Converting via PasteboardCopyItemFlavorData below will for some UITs result
+            // in newlines mapping to '\r' instead of '\n'. To work around this we shortcut
+            // the conversion via NSPasteboard's NSStringPboardType if possible.
+            if (c_flavor == QLatin1String("com.apple.traditional-mac-plain-text")
+             || c_flavor == QLatin1String("public.utf8-plain-text")
+             || c_flavor == QLatin1String("public.utf16-plain-text")) {
                 QString str = qt_mac_get_pasteboardString(paste);
                 if (!str.isEmpty())
                     return str;