libcamera/base: Move extended base functionality

Move the functionality for the following components to the new
base support library:

 - BoundMethod
 - EventDispatcher
 - EventDispatcherPoll
 - Log
 - Message
 - Object
 - Signal
 - Semaphore
 - Thread
 - Timer

While it would be preferable to see these split to move one component
per commit, these components are all interdependent upon each other,
which leaves us with one big change performing the move for all of them.

Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

include/libcamera/base/object.h

@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * object.h - Base object
+ */
+#ifndef __LIBCAMERA_BASE_OBJECT_H__
+#define __LIBCAMERA_BASE_OBJECT_H__
+
+#include <list>
+#include <memory>
+#include <vector>
+
+#include <libcamera/base/bound_method.h>
+
+namespace libcamera {
+
+class Message;
+template<typename... Args>
+class Signal;
+class SignalBase;
+class Thread;
+
+class Object
+{
+public:
+	Object(Object *parent = nullptr);
+	virtual ~Object();
+
+	void deleteLater();
+
+	void postMessage(std::unique_ptr<Message> msg);
+
+	template<typename T, typename R, typename... FuncArgs, typename... Args,
+		 typename std::enable_if_t<std::is_base_of<Object, T>::value> * = nullptr>
+	R invokeMethod(R (T::*func)(FuncArgs...), ConnectionType type,
+		       Args... args)
+	{
+		T *obj = static_cast<T *>(this);
+		auto *method = new BoundMethodMember<T, R, FuncArgs...>(obj, this, func, type);
+		return method->activate(args..., true);
+	}
+
+	Thread *thread() const { return thread_; }
+	void moveToThread(Thread *thread);
+
+	Object *parent() const { return parent_; }
+
+protected:
+	virtual void message(Message *msg);
+
+private:
+	friend class SignalBase;
+	friend class Thread;
+
+	void notifyThreadMove();
+
+	void connect(SignalBase *signal);
+	void disconnect(SignalBase *signal);
+
+	Object *parent_;
+	std::vector<Object *> children_;
+
+	Thread *thread_;
+	std::list<SignalBase *> signals_;
+	unsigned int pendingMessages_;
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_BASE_OBJECT_H__ */