OSX file dialog extensions (#2592)

Re-introduce OpenSavePanelDelegate for filtering when wildcard is provided (Spotlight search field was not working correctly, if extension was not known)
(and on macOS 10.11 allow programmatically showing the extra panel)

see http://www.github.com/wxWidgets/wxWidgets/pull/2592 and https://trac.wxwidgets.org/ticket/19324

co-authered-by: Jeff Young <jeff at rokeby dot ie>

include/wx/osx/filedlg.h

@@ -95,6 +95,7 @@ protected:
     bool m_useFileTypeFilter;
     int m_firstFileTypeFilter;
     wxArrayString m_currentExtensions;
+    WX_NSObject m_delegate;
 #endif
 
 private:

src/osx/cocoa/filedlg.mm

@@ -41,6 +41,63 @@
 
 #include <mach-o/dyld.h>
 
+// ============================================================================
+// delegate for filtering by wildcard
+// ============================================================================
+
+@interface wxOpenSavePanelDelegate : NSObject<NSOpenSavePanelDelegate>
+
+- (void)setAllowedExtensions:(const wxArrayString &)extensions;
+
+@end
+
+@implementation wxOpenSavePanelDelegate
+{
+    wxArrayString m_extensions;
+}
+
+- (BOOL)panel:(id)sender shouldEnableURL:(NSURL *)url
+{
+    if ( [url isFileURL] )
+    {
+        NSString* filename = [url path];
+        NSString* resolvedLink = [[NSFileManager defaultManager] destinationOfSymbolicLinkAtPath:filename error:nil];
+
+        if ( resolvedLink != nil )
+            filename = resolvedLink;
+
+        BOOL isDir = NO;
+        if( [[NSFileManager defaultManager]
+            fileExistsAtPath:filename isDirectory:&isDir] && isDir )
+        {
+            // allow ordinary folders to be enabled, but for packages apply our extensions check
+
+            if ([[NSWorkspace sharedWorkspace] isFilePackageAtPath:filename] == NO)
+                return YES;    // it's a folder, OK to show
+        }
+
+        if ( m_extensions.GetCount() == 0 )
+            return YES;
+
+        NSString *ext = [filename pathExtension];
+        wxString wxext = wxCFStringRef([ext retain]).AsString().Lower();
+
+        for( const wxString& extension : m_extensions )
+        {
+            if( wxext == extension )
+                return YES;
+        }
+    }
+    return NO;
+}
+
+- (void)setAllowedExtensions:(const wxArrayString &)extensions
+{
+    m_extensions = extensions;
+}
+
+@end
+
 // ============================================================================
 // implementation
 // ============================================================================
@@ -50,6 +107,7 @@ wxIMPLEMENT_CLASS(wxFileDialog, wxFileDialogBase);
 void wxFileDialog::Init()
 {
     m_filterIndex = -1;
+    m_delegate = nil;
     m_filterPanel = NULL;
     m_filterChoice = NULL;
     m_useFileTypeFilter = false;
@@ -114,13 +172,14 @@ NSArray* GetTypesFromExtension( const wxString extensiongroup, wxArrayString& ex
     return types;
 }
 
-NSArray* GetTypesFromFilter( const wxString& filter, wxArrayString& names, wxArrayString& extensiongroups )
+NSArray* GetTypesFromFilter( const wxString& filter, wxArrayString& names, wxArrayString& extensiongroups, wxArrayString& allextensions )
 {
     NSMutableArray* types = nil;
     bool allowAll = false;
 
     names.Clear();
     extensiongroups.Clear();
+    allextensions.Clear();
 
     if ( !filter.empty() )
     {
@@ -159,6 +218,8 @@ NSArray* GetTypesFromFilter( const wxString& filter, wxArrayString& names, wxArr
                         types = [[NSMutableArray alloc] init];
 
                     [types addObjectsFromArray:exttypes];
+                    for( auto const& s : extensions )
+                        allextensions.Add(s);
                 }
             }
             else
@@ -168,6 +229,8 @@ NSArray* GetTypesFromFilter( const wxString& filter, wxArrayString& names, wxArr
                 types = nil;
             }
         }
+        if ( allowAll )
+            allextensions.Clear();
     }
     [types autorelease];
     return types;
@@ -188,7 +251,7 @@ void wxFileDialog::ShowWindowModal()
 
     wxCHECK_RET(parentWindow, "Window modal display requires parent.");
 
-    NSArray* types = GetTypesFromFilter( m_wildCard, m_filterNames, m_filterExtensions ) ;
+    NSArray* types = GetTypesFromFilter( m_wildCard, m_filterNames, m_filterExtensions, m_currentExtensions ) ;
     if ( HasFlag(wxFD_SAVE) )
     {
         NSSavePanel* sPanel = [NSSavePanel savePanel];
@@ -319,7 +382,13 @@ void wxFileDialog::DoOnFilterSelected(int index)
 {
     NSArray* types = GetTypesFromExtension(m_filterExtensions[index],m_currentExtensions);
     NSSavePanel* panel = (NSSavePanel*) GetWXWindow();
-    [panel setAllowedFileTypes:types];
+    if ( m_delegate )
+    {
+        [(wxOpenSavePanelDelegate*)m_delegate setAllowedExtensions:m_currentExtensions];
+        [panel validateVisibleColumns];
+    }
+    else
+        [panel setAllowedFileTypes:types];
 
     m_currentlySelectedFilterIndex = index;
 
@@ -368,6 +437,10 @@ void wxFileDialog::SetupExtraControls(WXWindow nativeWindow)
     {
         [accView removeFromSuperview];
         [panel setAccessoryView:accView];
+        if ([panel respondsToSelector:@selector(setAccessoryViewDisclosed)])
+        {
+            [panel setAccessoryViewDisclosed:YES];
+        }
     }
     else
     {
@@ -431,7 +504,7 @@ int wxFileDialog::ShowModal()
     }
 
 
-    NSArray* types = GetTypesFromFilter( m_wildCard, m_filterNames, m_filterExtensions ) ;
+    NSArray* types = GetTypesFromFilter( m_wildCard, m_filterNames, m_filterExtensions, m_currentExtensions ) ;
 
     m_useFileTypeFilter = m_filterExtensions.GetCount() > 1;
 
@@ -511,7 +584,11 @@ int wxFileDialog::ShowModal()
         NSOpenPanel* oPanel = [NSOpenPanel openPanel];
         
         SetupExtraControls(oPanel);
-                
+
+        wxOpenSavePanelDelegate* del = [[wxOpenSavePanelDelegate alloc]init];
+        [oPanel setDelegate:del];
+        m_delegate = del;
+
         [oPanel setTreatsFilePackagesAsDirectories:NO];
         [oPanel setCanChooseDirectories:NO];
         [oPanel setResolvesAliases:HasFlag(wxFD_NO_FOLLOW) ? NO : YES];
@@ -530,7 +607,10 @@ int wxFileDialog::ShowModal()
         }
         else
         {
-            [oPanel setAllowedFileTypes: types];
+            if ( m_delegate )
+                [(wxOpenSavePanelDelegate*) m_delegate setAllowedExtensions: m_currentExtensions];
+            else
+                [oPanel setAllowedFileTypes: types];
         }
         if ( !m_dir.IsEmpty() )
             [oPanel setDirectoryURL:[NSURL fileURLWithPath:dir.AsNSString() 
@@ -595,6 +675,12 @@ void wxFileDialog::ModalFinishedCallback(void* panel, int returnCode)
             else
                 m_filterIndex = GetMatchingFilterExtension(m_fileName);
         }
+        if ( m_delegate )
+        {
+            [oPanel setDelegate:nil];
+            [m_delegate release];
+            m_delegate = nil;
+        }
     }
     SetReturnCode(result);