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>

1 files changed, 185 insertions, 0 deletions

diff --git a/src/libcamera/base/timer.cpp b/src/libcamera/base/timer.cpp
new file mode 100644
index 00000000..9c54352d
--- /dev/null
+++ b/src/libcamera/base/timer.cpp
@@ -0,0 +1,185 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * timer.cpp - Generic timer
+ */
+
+#include <libcamera/base/timer.h>
+
+#include <chrono>
+
+#include <libcamera/base/event_dispatcher.h>
+#include <libcamera/base/log.h>
+#include <libcamera/base/message.h>
+#include <libcamera/base/thread.h>
+#include <libcamera/base/utils.h>
+
+#include <libcamera/camera_manager.h>
+
+/**
+ * \file base/timer.h
+ * \brief Generic timer
+ */
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(Timer)
+
+/**
+ * \class Timer
+ * \brief Single-shot timer interface
+ *
+ * The Timer class models a single-shot timer that is started with start() and
+ * emits the \ref timeout signal when it times out.
+ *
+ * Once started the timer will run until it times out. It can be stopped with
+ * stop(), and once it times out or is stopped, can be started again with
+ * start().
+ *
+ * The timer deadline is specified as either a duration in milliseconds or an
+ * absolute time point. If the deadline is set to the current time or to the
+ * past, the timer will time out immediately when execution returns to the
+ * event loop of the timer's thread.
+ *
+ * Timers run in the thread they belong to, and thus emit the \a ref timeout
+ * signal from that thread. To avoid race conditions they must not be started
+ * or stopped from a different thread, attempts to do so will be rejected and
+ * logged, and may cause undefined behaviour.
+ */
+
+/**
+ * \brief Construct a timer
+ * \param[in] parent The parent Object
+ */
+Timer::Timer(Object *parent)
+	: Object(parent), running_(false)
+{
+}
+
+Timer::~Timer()
+{
+	stop();
+}
+
+/**
+ * \fn Timer::start(unsigned int msec)
+ * \brief Start or restart the timer with a timeout of \a msec
+ * \param[in] msec The timer duration in milliseconds
+ *
+ * If the timer is already running it will be stopped and restarted.
+ *
+ * \context This function is \threadbound.
+ */
+
+/**
+ * \brief Start or restart the timer with a timeout of \a duration
+ * \param[in] duration The timer duration in milliseconds
+ *
+ * If the timer is already running it will be stopped and restarted.
+ *
+ * \context This function is \threadbound.
+ */
+void Timer::start(std::chrono::milliseconds duration)
+{
+	start(utils::clock::now() + duration);
+}
+
+/**
+ * \brief Start or restart the timer with a \a deadline
+ * \param[in] deadline The timer deadline
+ *
+ * If the timer is already running it will be stopped and restarted.
+ *
+ * \context This function is \threadbound.
+ */
+void Timer::start(std::chrono::steady_clock::time_point deadline)
+{
+	if (Thread::current() != thread()) {
+		LOG(Timer, Error) << "Timer can't be started from another thread";
+		return;
+	}
+
+	deadline_ = deadline;
+
+	LOG(Timer, Debug)
+		<< "Starting timer " << this << ": deadline "
+		<< utils::time_point_to_string(deadline_);
+
+	if (isRunning())
+		unregisterTimer();
+
+	registerTimer();
+}
+
+/**
+ * \brief Stop the timer
+ *
+ * After this function returns the timer is guaranteed not to emit the
+ * \ref timeout signal.
+ *
+ * If the timer is not running this function performs no operation.
+ *
+ * \context This function is \threadbound.
+ */
+void Timer::stop()
+{
+	if (!isRunning())
+		return;
+
+	if (Thread::current() != thread()) {
+		LOG(Timer, Error) << "Timer can't be stopped from another thread";
+		return;
+	}
+
+	unregisterTimer();
+}
+
+void Timer::registerTimer()
+{
+	thread()->eventDispatcher()->registerTimer(this);
+	running_ = true;
+}
+
+void Timer::unregisterTimer()
+{
+	running_ = false;
+	thread()->eventDispatcher()->unregisterTimer(this);
+}
+
+/**
+ * \brief Check if the timer is running
+ * \return True if the timer is running, false otherwise
+ */
+bool Timer::isRunning() const
+{
+	return running_;
+}
+
+/**
+ * \fn Timer::deadline()
+ * \brief Retrieve the timer deadline
+ * \return The timer deadline
+ */
+
+/**
+ * \var Timer::timeout
+ * \brief Signal emitted when the timer times out
+ *
+ * The timer pointer is passed as a parameter.
+ */
+
+void Timer::message(Message *msg)
+{
+	if (msg->type() == Message::ThreadMoveMessage) {
+		if (isRunning()) {
+			unregisterTimer();
+			invokeMethod(&Timer::registerTimer,
+				     ConnectionTypeQueued);
+		}
+	}
+
+	Object::message(msg);
+}
+
+} /* namespace libcamera */