Notify Windows shell about file associations changes

This is documented as being required in the MSDN and, in practice, is
necessary for Windows to update the icon cache and show the new icon.

Closes https://github.com/wxWidgets/wxWidgets/pull/195

docs/changes.txt

@@ -198,6 +198,7 @@ wxMSW:
 - Don't send wxActivateEvent for minimized windows (bzcdr).
 - Return correct OS version under Windows 8.1 and later.
 - Fix crash in wxD2DContext when using non-MSVC compiler (iwbnwif).
+- Notify shell about the changes done by wxMimeTypesManager (Maarten Bent).
 
 wxOSX/Cocoa:
 

include/wx/msw/mimetype.h

@@ -5,7 +5,7 @@
 // Modified by:
 // Created:     23.09.98
 // Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
-// Licence:     wxWindows licence (part of wxExtra library)
+// Licence:     wxWidgets licence (part of base library)
 /////////////////////////////////////////////////////////////////////////////
 
 #ifndef _MIMETYPE_IMPL_H
@@ -62,6 +62,20 @@ public:
     // this is called  by Associate
     bool SetDescription (const wxString& desc);
 
+    // This is called by all our own methods modifying the registry to let the
+    // Windows Shell know about the changes.
+    //
+    // It is also called from Associate() and Unassociate() which suppress the
+    // internally generated notifications using the method below, which is why
+    // it has to be public.
+    void MSWNotifyShell();
+
+    // Call before/after performing several registry changes in a row to
+    // temporarily suppress multiple notifications that would be generated for
+    // them and generate a single one at the end using MSWNotifyShell()
+    // explicitly.
+    void MSWSuppressNotifications(bool supress);
+
 private:
     // helper function: reads the command corresponding to the specified verb
     // from the registry (returns an empty string if not found)
@@ -76,6 +90,7 @@ private:
 
     wxString m_strFileType,         // may be empty
              m_ext;
+    bool m_suppressNotify;
 
     // these methods are not publicly accessible (as wxMimeTypesManager
     // doesn't know about them), and should only be called by Unassociate

src/msw/mimetype.cpp

@@ -5,7 +5,7 @@
 // Modified by:
 // Created:     23.09.98
 // Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
-// Licence:     wxWindows licence (part of wxExtra library)
+// Licence:     wxWidgets licence (part of base library)
 /////////////////////////////////////////////////////////////////////////////
 
 // for compilers that support precompilation, includes "wx.h".
@@ -40,6 +40,7 @@
     #include "wx/msw/registry.h"
     #include "wx/msw/private.h"
     #include <shlwapi.h>
+    #include <shlobj.h>
 
     // For MSVC we can link in the required library explicitly, for the other
     // compilers (e.g. MinGW) this needs to be done at makefiles level.
@@ -146,6 +147,8 @@ void wxFileTypeImpl::Init(const wxString& strFileType, const wxString& ext)
     if ( !strFileType ) {
         m_strFileType = m_ext.AfterFirst('.') + wxT("_auto_file");
     }
+
+    m_suppressNotify = false;
 }
 
 wxString wxFileTypeImpl::GetVerbPath(const wxString& verb) const
@@ -210,6 +213,17 @@ size_t wxFileTypeImpl::GetAllCommands(wxArrayString *verbs,
     return count;
 }
 
+void wxFileTypeImpl::MSWNotifyShell()
+{
+    if (!m_suppressNotify)
+        SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST | SHCNF_FLUSHNOWAIT, NULL, NULL);
+}
+
+void wxFileTypeImpl::MSWSuppressNotifications(bool supress)
+{
+    m_suppressNotify = supress;
+}
+
 // ----------------------------------------------------------------------------
 // modify the registry database
 // ----------------------------------------------------------------------------
@@ -676,12 +690,15 @@ wxFileType *wxMimeTypesManagerImpl::Associate(const wxFileTypeInfo& ftInfo)
 
     if (ft)
     {
+        ft->m_impl->MSWSuppressNotifications(true);
         if (! ftInfo.GetOpenCommand ().empty() ) ft->SetCommand (ftInfo.GetOpenCommand (), wxT("open"  ) );
         if (! ftInfo.GetPrintCommand().empty() ) ft->SetCommand (ftInfo.GetPrintCommand(), wxT("print" ) );
         // chris: I don't like the ->m_impl-> here FIX this ??
         if (! ftInfo.GetDescription ().empty() ) ft->m_impl->SetDescription (ftInfo.GetDescription ()) ;
         if (! ftInfo.GetIconFile().empty() ) ft->SetDefaultIcon (ftInfo.GetIconFile(), ftInfo.GetIconIndex() );
 
+        ft->m_impl->MSWSuppressNotifications(false);
+        ft->m_impl->MSWNotifyShell();
     }
 
     return ft;
@@ -702,7 +719,12 @@ bool wxFileTypeImpl::SetCommand(const wxString& cmd,
     // TODO:
     // 1. translate '%s' to '%1' instead of always adding it
     // 2. create DDEExec value if needed (undo GetCommand)
-    return rkey.Create() && rkey.SetValue(wxEmptyString, cmd + wxT(" \"%1\"") );
+    bool result = rkey.Create() && rkey.SetValue(wxEmptyString, cmd + wxT(" \"%1\"") );
+
+    if ( result )
+        MSWNotifyShell();
+
+    return result;
 }
 
 bool wxFileTypeImpl::SetDefaultIcon(const wxString& cmd, int index)
@@ -718,9 +740,14 @@ bool wxFileTypeImpl::SetDefaultIcon(const wxString& cmd, int index)
     wxRegKey rkey(wxRegKey::HKCU,
                   CLASSES_ROOT_KEY + m_strFileType + wxT("\\DefaultIcon"));
 
-    return rkey.Create() &&
+    bool result = rkey.Create() &&
            rkey.SetValue(wxEmptyString,
                          wxString::Format(wxT("%s,%d"), cmd.c_str(), index));
+
+    if ( result )
+        MSWNotifyShell();
+
+    return result;
 }
 
 bool wxFileTypeImpl::SetDescription (const wxString& desc)
@@ -743,6 +770,7 @@ bool wxFileTypeImpl::SetDescription (const wxString& desc)
 
 bool wxFileTypeImpl::Unassociate()
 {
+    MSWSuppressNotifications(true);
     bool result = true;
     if ( !RemoveOpenCommand() )
         result = false;
@@ -753,6 +781,9 @@ bool wxFileTypeImpl::Unassociate()
     if ( !RemoveDescription() )
         result = false;
 
+    MSWSuppressNotifications(false);
+    MSWNotifyShell();
+
     return result;
 }
 
@@ -769,7 +800,12 @@ bool wxFileTypeImpl::RemoveCommand(const wxString& verb)
     wxRegKey rkey(wxRegKey::HKCU, CLASSES_ROOT_KEY + GetVerbPath(verb));
 
     // if the key already doesn't exist, it's a success
-    return !rkey.Exists() || rkey.DeleteSelf();
+    bool result = !rkey.Exists() || rkey.DeleteSelf();
+
+    if ( result )
+        MSWNotifyShell();
+
+    return result;
 }
 
 bool wxFileTypeImpl::RemoveMimeType()
@@ -787,7 +823,12 @@ bool wxFileTypeImpl::RemoveDefaultIcon()
 
     wxRegKey rkey (wxRegKey::HKCU,
                    CLASSES_ROOT_KEY + m_strFileType  + wxT("\\DefaultIcon"));
-    return !rkey.Exists() || rkey.DeleteSelf();
+    bool result = !rkey.Exists() || rkey.DeleteSelf();
+
+    if ( result )
+        MSWNotifyShell();
+
+    return result;
 }
 
 bool wxFileTypeImpl::RemoveDescription()