Add pending_events function callback

ui/drivers/cocoa/ui_cocoa_application.m

@@ -23,6 +23,14 @@
 #include "cocoa_common.h"
 #include "../../ui_companion_driver.h"
 
+static bool ui_application_cocoa_pending_events(void)
+{
+   NSEvent *event = [NSApp nextEventMatchingMask:NSAnyEventMask untilDate:[NSDate distantPast] inMode:NSDefaultRunLoopMode dequeue:YES];
+   if (!event)
+      return false;
+   return true;
+}
+
 static void ui_application_cocoa_process_events(void)
 {
     while (1)
@@ -37,6 +45,7 @@ static void ui_application_cocoa_process_events(void)
 }
 
 const ui_application_t ui_application_cocoa = {
+   ui_application_cocoa_pending_events,
    ui_application_cocoa_process_events,
    "cocoa"
 };

ui/drivers/null/ui_null_application.c

@@ -21,11 +21,17 @@
 
 #include "../../ui_companion_driver.h"
 
+static bool ui_application_null_pending_events(void)
+{
+   return true;
+}
+
 static void ui_application_null_process_events(void)
 {
 }
 
 const ui_application_t ui_application_null = {
+   ui_application_null_pending_events,
    ui_application_null_process_events,
    "null"
 };

ui/drivers/win32/ui_win32_application.c

@@ -23,23 +23,28 @@
 
 #include "../../ui_companion_driver.h"
 
-static void ui_application_win32_process_events(void)
+static bool ui_application_win32_pending_events(void)
 {
    MSG msg;
+   return PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE);
+}
 
-   while (PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE))
+static void ui_application_win32_process_events(void)
+{
+   while (ui_application_win32_pending_events())
    {
-      MSG msg2;
+      MSG msg;
 
-      if (PeekMessage(&msg2, 0, 0, 0, PM_REMOVE))
+      if (PeekMessage(&msg, 0, 0, 0, PM_REMOVE))
       {
-         TranslateMessage(&msg2);
-         DispatchMessage (&msg2);
+         TranslateMessage(&msg);
+         DispatchMessage (&msg);
       }
    }
 }
 
 const ui_application_t ui_application_win32 = {
+   ui_application_win32_pending_events,
    ui_application_win32_process_events,
    "win32"
 };

ui/ui_companion_driver.h

@@ -33,6 +33,7 @@ RETRO_BEGIN_DECLS
 
 typedef struct ui_application
 {
+   bool (*pending_events)(void);
    void (*process_events)(void);
    const char *ident;
 } ui_application_t;