Merge branch 'im/clipboard' of https://github.com/imciner2/wxWidgets

Ensure the clipboard contents are stored properly on GTK.

See https://github.com/wxWidgets/wxWidgets/pull/1953

interface/wx/clipbrd.h

@@ -53,6 +53,13 @@
     }
     @endcode
 
+    @note On GTK, the clipboard behavior can vary depending on the configuration of
+          the end-user's machine. In order for the clipboard data to persist after
+          the window closes, a clipboard manager must be installed. Some clipboard
+          managers will automatically flush the clipboard after each new piece of
+          data is added, while others will not. The @Flush() function will force
+          the clipboard manager to flush the data.
+
     @library{wxcore}
     @category{dnd}
 
@@ -99,6 +106,10 @@ public:
         Currently this method is implemented in MSW and GTK and always returns @false
         otherwise.
 
+        @note On GTK, only the non-primary selection can be flushed. Calling this function
+              when the clipboard is using the primary selection will return @false and not
+              make any data available after the program exits.
+
         @return @false if the operation is unsuccessful for any reason.
     */
     virtual bool Flush();

samples/clipboard/clipboard.cpp

@@ -151,7 +151,8 @@ void MyFrame::OnFlush(wxCommandEvent &WXUNUSED(event))
         return;
     }
 
-    if ( !wxTheClipboard->AddData(new wxTextDataObject("Text from wx clipboard sample")) )
+    wxString clipData = wxString::Format("Text from wx clipboard sample at %s" , wxDateTime::Now().Format());
+    if ( !wxTheClipboard->AddData(new wxTextDataObject(clipData)) )
     {
         m_textctrl->AppendText("Failed to put text on clipboard.\n");
         return;

src/gtk/clipbrd.cpp

@@ -41,7 +41,6 @@ typedef wxScopedArray<wxDataFormat> wxDataFormatArray;
 // data
 // ----------------------------------------------------------------------------
 
-static GdkAtom  g_clipboardAtom   = 0;
 static GdkAtom  g_targetsAtom     = 0;
 static GdkAtom  g_timestampAtom   = 0;
 
@@ -231,7 +230,7 @@ selection_clear_clip( GtkWidget *WXUNUSED(widget), GdkEventSelection *event )
 
         kind = wxClipboard::Primary;
     }
-    else if (event->selection == g_clipboardAtom)
+    else if ( event->selection == GDK_SELECTION_CLIPBOARD )
     {
         wxLogTrace(TRACE_CLIPBOARD, wxT("Lost clipboard" ));
 
@@ -306,6 +305,8 @@ selection_handler( GtkWidget *WXUNUSED(widget),
     if ( !size )
         return;
 
+    wxLogTrace(TRACE_CLIPBOARD, "Valid clipboard data found");
+
     wxCharBuffer buf(size - 1); // it adds 1 internally (for NUL)
 
     // text data must be returned in UTF8 if format is wxDF_UNICODETEXT
@@ -469,8 +470,6 @@ wxClipboard::wxClipboard()
                       G_CALLBACK (selection_clear_clip), NULL);
 
     // initialize atoms we use if not done yet
-    if ( !g_clipboardAtom )
-        g_clipboardAtom = gdk_atom_intern( "CLIPBOARD", FALSE );
     if ( !g_targetsAtom )
         g_targetsAtom = gdk_atom_intern ("TARGETS", FALSE);
     if ( !g_timestampAtom )
@@ -492,7 +491,7 @@ wxClipboard::~wxClipboard()
 GdkAtom wxClipboard::GTKGetClipboardAtom() const
 {
     return m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
-                        : g_clipboardAtom;
+                        : (GdkAtom)GDK_SELECTION_CLIPBOARD;
 }
 
 void wxClipboard::GTKClearData(Kind kind)
@@ -595,8 +594,19 @@ void wxClipboard::Clear()
 
 bool wxClipboard::Flush()
 {
-    gtk_clipboard_store( gtk_clipboard_get( GTKGetClipboardAtom() ) );
+    // Only store the non-primary clipboard when flushing. The primary clipboard is a scratch-space
-    return true;
+    // formed using the currently selected text.
+    if ( !m_usePrimary )
+    {
+        GtkClipboard* clipboard = gtk_clipboard_get(GDK_SELECTION_CLIPBOARD);
+
+        gtk_clipboard_set_can_store(clipboard, NULL, 0);
+        gtk_clipboard_store(clipboard);
+
+        return true;
+    }
+
+    return false;
 }
 
 bool wxClipboard::Open()
@@ -762,7 +772,7 @@ wxDataObject* wxClipboard::GTKGetDataObject( GdkAtom atom )
 
         return Data( wxClipboard::Primary );
     }
-    else if ( atom == g_clipboardAtom )
+    else if ( atom == GDK_SELECTION_CLIPBOARD )
     {
         wxLogTrace(TRACE_CLIPBOARD, wxT("Clipboard data requested" ));