Add QPlatformTheme::standardButtonShortcut()

It allows to set shortcuts for the standard buttons in
QDialogButtonBox.

Restore Qt4's behavior for the "Don't Save" button on macOS
by setting a shortcut for it (it was Cmd-D before Lion,
now it's Cmd-Delete).

Change-Id: I6b56f68f37670962178693a8983d9fe550540856
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

5 files changed, 22 insertions, 6 deletions

diff --git a/src/gui/kernel/qplatformtheme.cpp b/src/gui/kernel/qplatformtheme.cpp
index eef8b817fd..931c784d08 100644
--- a/src/gui/kernel/qplatformtheme.cpp
+++ b/src/gui/kernel/qplatformtheme.cpp
@@ -671,6 +671,19 @@ QString QPlatformTheme::standardButtonText(int button) const
     return QPlatformTheme::defaultStandardButtonText(button);
 }
 
+/*!
+   Returns the mnemonic that should be used for a standard \a button.
+
+  \since 5.9
+  \sa QPlatformDialogHelper::StandardButton
+ */
+
+QKeySequence QPlatformTheme::standardButtonShortcut(int button) const
+{
+    Q_UNUSED(button)
+    return QKeySequence();
+}
+
 QString QPlatformTheme::defaultStandardButtonText(int button)
 {
     switch (button) {
diff --git a/src/gui/kernel/qplatformtheme.h b/src/gui/kernel/qplatformtheme.h
index 4135e31517..2ba2f8669f 100644
--- a/src/gui/kernel/qplatformtheme.h
+++ b/src/gui/kernel/qplatformtheme.h
@@ -312,6 +312,7 @@ public:
 #endif
 
     virtual QString standardButtonText(int button) const;
+    virtual QKeySequence standardButtonShortcut(int button) const;
 
     static QVariant defaultThemeHint(ThemeHint hint);
     static QString defaultStandardButtonText(int button);
diff --git a/src/plugins/platforms/cocoa/qcocoatheme.h b/src/plugins/platforms/cocoa/qcocoatheme.h
index d47e620fbb..27c071a8cd 100644
--- a/src/plugins/platforms/cocoa/qcocoatheme.h
+++ b/src/plugins/platforms/cocoa/qcocoatheme.h
@@ -74,6 +74,7 @@ public:
 
     QVariant themeHint(ThemeHint hint) const Q_DECL_OVERRIDE;
     QString standardButtonText(int button) const Q_DECL_OVERRIDE;
+    QKeySequence standardButtonShortcut(int button) const Q_DECL_OVERRIDE;
 
     static const char *name;
 
diff --git a/src/plugins/platforms/cocoa/qcocoatheme.mm b/src/plugins/platforms/cocoa/qcocoatheme.mm
index 4d74c11581..d2345f9abc 100644
--- a/src/plugins/platforms/cocoa/qcocoatheme.mm
+++ b/src/plugins/platforms/cocoa/qcocoatheme.mm
@@ -344,6 +344,12 @@ QString QCocoaTheme::standardButtonText(int button) const
     return button == QPlatformDialogHelper::Discard ? msgDialogButtonDiscard() : QPlatformTheme::standardButtonText(button);
 }
 
+QKeySequence QCocoaTheme::standardButtonShortcut(int button) const
+{
+    return button == QPlatformDialogHelper::Discard ? QKeySequence(Qt::CTRL | Qt::Key_Delete)
+                                                    : QPlatformTheme::standardButtonShortcut(button);
+}
+
 QPlatformMenuItem *QCocoaTheme::createPlatformMenuItem() const
 {
     return new QCocoaMenuItem();
diff --git a/src/widgets/widgets/qdialogbuttonbox.cpp b/src/widgets/widgets/qdialogbuttonbox.cpp
index 23158cf82f..61ef8e8c93 100644
--- a/src/widgets/widgets/qdialogbuttonbox.cpp
+++ b/src/widgets/widgets/qdialogbuttonbox.cpp
@@ -411,12 +411,7 @@ QPushButton *QDialogButtonBoxPrivate::createButton(QDialogButtonBox::StandardBut
     else
         addButton(button, static_cast<QDialogButtonBox::ButtonRole>(role), doLayout);
 
-#if 0 // Used to be included in Qt4 for Q_WS_MAC
-    // Since mnemonics is off by default on Mac, we add a Cmd-D
-    // shortcut here to e.g. make the "Don't Save" button work nativly:
-    if (sbutton == QDialogButtonBox::Discard)
-        button->setShortcut(QKeySequence(QLatin1String("Ctrl+D")));
-#endif
+    button->setShortcut(QGuiApplicationPrivate::platformTheme()->standardButtonShortcut(sbutton));
 
     return button;
 }