initial commit

Signed-off-by: Peter Siegmund <mars3142@noreply.mars3142.dev>

libs/wxWidgets-3.3.1/interface/wx/msgqueue.h

@@ -0,0 +1,121 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        wx/msgqueue.h
+// Purpose:     interface of wxMessageQueue<T>
+// Author:      wxWidgets team
+// Licence:     wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+/**
+    Error codes for wxMessageQueue<> operations.
+
+    This enum contains the possible return value of wxMessageQueue<> methods.
+
+    @since 2.9.0
+    @category{threading}
+ */
+enum wxMessageQueueError
+{
+    /// Indicates that the operation completed successfully.
+    wxMSGQUEUE_NO_ERROR = 0,
+
+    /**
+        Indicates that no messages were received before timeout expired.
+
+        This return value is only used by wxMessageQueue<>::ReceiveTimeout().
+     */
+    wxMSGQUEUE_TIMEOUT,
+
+    /// Some unexpected (and fatal) error has occurred.
+    wxMSGQUEUE_MISC_ERROR
+};
+
+/**
+    wxMessageQueue allows passing messages between threads.
+
+    This class should be typically used to communicate between the main and worker
+    threads. The main thread calls wxMessageQueue::Post and the worker thread
+    calls wxMessageQueue::Receive.
+
+    @tparam T
+        For this class a message is an object of arbitrary type T.
+
+    Notice that often there is a some special message indicating that the thread
+    should terminate as there is no other way to gracefully shutdown a thread
+    waiting on the message queue.
+
+    @since 2.9.0
+
+    @nolibrary
+    @category{threading}
+
+    @see wxThread
+*/
+template <typename T>
+class wxMessageQueue<T>
+{
+public:
+    /**
+        Default and only constructor.
+        Use wxMessageQueue::IsOk to check if the object was successfully initialized.
+    */
+    wxMessageQueue();
+
+    /**
+        Remove all messages from the queue.
+
+        This method is meant to be called from the same thread(s) that call
+        Post() to discard any still pending requests if they became
+        unnecessary.
+
+        @since 2.9.1
+     */
+    wxMessageQueueError Clear();
+
+    /**
+        Returns @true if the object had been initialized successfully, @false
+        if an error occurred.
+    */
+    bool IsOk() const;
+
+    /**
+        Add a message to this queue and signal the threads waiting for messages
+        (i.e. the threads which called wxMessageQueue::Receive or
+        wxMessageQueue::ReceiveTimeout).
+
+        This method is safe to call from multiple threads in parallel.
+    */
+    wxMessageQueueError Post(T const& msg);
+
+    /**
+        Post a message of move-only type.
+
+        This function has the same semantics as the other overload but can be
+        used for non-copyable (but movable) types.
+
+        @since 3.3.0
+     */
+    wxMessageQueueError Post(T&& msg);
+
+    /**
+        Block until a message becomes available in the queue.
+        Waits indefinitely long or until an error occurs.
+
+        The message is returned in @a msg.
+    */
+    wxMessageQueueError Receive(T& msg);
+
+    /**
+        Block until a message becomes available in the queue, but no more than
+        @a timeout milliseconds has elapsed.
+
+        If no message is available after @a timeout milliseconds then returns
+        @b wxMSGQUEUE_TIMEOUT.
+
+        If @a timeout is 0 then checks for any messages present in the queue
+        and returns immediately without waiting.
+
+        The message is returned in @a msg.
+    */
+    wxMessageQueueError ReceiveTimeout(long timeout, T& msg);
+};
+