From 1a4f628e405661c042dcaa5f62c076a9c328719e Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Mon, 21 Sep 2020 15:36:41 +0200
Subject: [PATCH] Make radio button navigation functions const

This requires adding a couple of const_cast<>s in their implementation
in order to still allow them returning non-const wxRadioButton pointers,
but this seems preferable to not being able to call them on a const
wxRadioButton in the first place.
---
 include/wx/radiobut.h   | 24 ++++++++++++------------
 interface/wx/radiobut.h |  8 ++++----
 src/common/containr.cpp | 16 ++++++++--------
 3 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/include/wx/radiobut.h b/include/wx/radiobut.h
index d68ac4a665..d999800efb 100644
--- a/include/wx/radiobut.h
+++ b/include/wx/radiobut.h
@@ -36,10 +36,10 @@ class WXDLLIMPEXP_FWD_CORE wxRadioButton;
 
 namespace wxPrivate
 {
-    WXDLLIMPEXP_CORE wxRadioButton* wxGetNextButtonInGroup(wxRadioButton *btn);
-    WXDLLIMPEXP_CORE wxRadioButton* wxGetPreviousButtonInGroup(wxRadioButton *btn);
-    WXDLLIMPEXP_CORE wxRadioButton* wxGetFirstButtonInGroup(wxRadioButton *btn);
-    WXDLLIMPEXP_CORE wxRadioButton* wxGetLastButtonInGroup(wxRadioButton *btn);
+    WXDLLIMPEXP_CORE wxRadioButton* wxGetNextButtonInGroup(const wxRadioButton *btn);
+    WXDLLIMPEXP_CORE wxRadioButton* wxGetPreviousButtonInGroup(const wxRadioButton *btn);
+    WXDLLIMPEXP_CORE wxRadioButton* wxGetFirstButtonInGroup(const wxRadioButton *btn);
+    WXDLLIMPEXP_CORE wxRadioButton* wxGetLastButtonInGroup(const wxRadioButton *btn);
 } // namespace wxPrivate
 
 template <class W>
@@ -50,24 +50,24 @@ public:
 
     wxRadioButtonBase() { }
 
-    wxRadioButton* GetFirstInGroup()
+    wxRadioButton* GetFirstInGroup() const
     {
-        return wxPrivate::wxGetFirstButtonInGroup( static_cast<wxRadioButton*>(this));
+        return wxPrivate::wxGetFirstButtonInGroup(static_cast<const wxRadioButton*>(this));
     }
 
-    wxRadioButton* GetLastInGroup()
+    wxRadioButton* GetLastInGroup() const
     {
-        return wxPrivate::wxGetLastButtonInGroup( static_cast<wxRadioButton*>(this));
+        return wxPrivate::wxGetLastButtonInGroup(static_cast<const wxRadioButton*>(this));
     }
 
-    wxRadioButton* GetPreviousInGroup()
+    wxRadioButton* GetPreviousInGroup() const
     {
-        return wxPrivate::wxGetPreviousButtonInGroup( static_cast<wxRadioButton*>(this));
+        return wxPrivate::wxGetPreviousButtonInGroup(static_cast<const wxRadioButton*>(this));
     }
 
-    wxRadioButton* GetNextInGroup() 
+    wxRadioButton* GetNextInGroup() const
     {
-        return wxPrivate::wxGetNextButtonInGroup( static_cast<wxRadioButton*>(this));
+        return wxPrivate::wxGetNextButtonInGroup(static_cast<const wxRadioButton*>(this));
     }
 
 private:
diff --git a/interface/wx/radiobut.h b/interface/wx/radiobut.h
index 2bf6b22261..9094b23fde 100644
--- a/interface/wx/radiobut.h
+++ b/interface/wx/radiobut.h
@@ -139,7 +139,7 @@ public:
 
         @since 3.1.5
     */
-    wxRadioButton* GetFirstInGroup();
+    wxRadioButton* GetFirstInGroup() const;
 
    /**
         Returns the last radio button of the @c wxRB_GROUP this instance is in.
@@ -150,7 +150,7 @@ public:
 
         @since 3.1.5
     */
-    wxRadioButton* GetLastInGroup();
+    wxRadioButton* GetLastInGroup() const;
 
    /**
         Returns the previous radio button of the @c wxRB_GROUP this instance is in.
@@ -162,7 +162,7 @@ public:
 
         @since 3.1.5
     */
-    wxRadioButton* GetPreviousInGroup();
+    wxRadioButton* GetPreviousInGroup() const;
 
    /**
         Returns the next radio button of the @c wxRB_GROUP this instance is in.
@@ -174,6 +174,6 @@ public:
 
         @since 3.1.5
     */
-    wxRadioButton* GetNextInGroup();
+    wxRadioButton* GetNextInGroup() const;
 };
 
diff --git a/src/common/containr.cpp b/src/common/containr.cpp
index 93245b674d..52b808a29f 100644
--- a/src/common/containr.cpp
+++ b/src/common/containr.cpp
@@ -246,7 +246,7 @@ void wxControlContainer::SetLastFocus(wxWindow *win)
 namespace wxPrivate
 {
 
-wxRadioButton* wxGetPreviousButtonInGroup(wxRadioButton *btn)
+wxRadioButton* wxGetPreviousButtonInGroup(const wxRadioButton *btn)
 {
     if ( btn->HasFlag(wxRB_GROUP) || btn->HasFlag(wxRB_SINGLE) )
         return NULL;
@@ -276,7 +276,7 @@ wxRadioButton* wxGetPreviousButtonInGroup(wxRadioButton *btn)
     return prevBtn;
 }
 
-wxRadioButton* wxGetNextButtonInGroup(wxRadioButton *btn)
+wxRadioButton* wxGetNextButtonInGroup(const wxRadioButton *btn)
 {
     if (btn->HasFlag(wxRB_SINGLE))
         return NULL;
@@ -306,35 +306,35 @@ wxRadioButton* wxGetNextButtonInGroup(wxRadioButton *btn)
     return nextBtn;
 }
 
-wxRadioButton* wxGetFirstButtonInGroup(wxRadioButton *btn)
+wxRadioButton* wxGetFirstButtonInGroup(const wxRadioButton *btn)
 {
     while (true)
     {
         wxRadioButton* prevBtn = wxGetPreviousButtonInGroup(btn);
         if (!prevBtn)
-            return btn;
+            return const_cast<wxRadioButton*>(btn);
 
         btn = prevBtn;
     }
 }
 
-wxRadioButton* wxGetLastButtonInGroup(wxRadioButton *btn)
+wxRadioButton* wxGetLastButtonInGroup(const wxRadioButton *btn)
 {
     while (true)
     {
         wxRadioButton* nextBtn = wxGetNextButtonInGroup(btn);
         if (!nextBtn)
-            return btn;
+            return const_cast<wxRadioButton*>(btn);
 
         btn = nextBtn;
     }
 }
 
-wxRadioButton* wxGetSelectedButtonInGroup(wxRadioButton *btn)
+wxRadioButton* wxGetSelectedButtonInGroup(const wxRadioButton *btn)
 {
     // Find currently selected button
     if (btn->GetValue())
-        return btn;
+        return const_cast<wxRadioButton*>(btn);
 
     if (btn->HasFlag(wxRB_SINGLE))
         return NULL;