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, 109 insertions, 0 deletions

diff --git a/src/libcamera/base/bound_method.cpp b/src/libcamera/base/bound_method.cpp
new file mode 100644
index 00000000..3ecec51c
--- /dev/null
+++ b/src/libcamera/base/bound_method.cpp
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * bound_method.cpp - Method bind and invocation
+ */
+
+#include <libcamera/base/bound_method.h>
+#include <libcamera/base/message.h>
+#include <libcamera/base/semaphore.h>
+#include <libcamera/base/thread.h>
+
+/**
+ * \file base/bound_method.h
+ * \brief Method bind and invocation
+ */
+
+namespace libcamera {
+
+/**
+ * \enum ConnectionType
+ * \brief Connection type for asynchronous communication
+ *
+ * This enumeration describes the possible types of asynchronous communication
+ * between a sender and a receiver. It applies to Signal::emit() and
+ * Object::invokeMethod().
+ *
+ * \var ConnectionTypeAuto
+ * \brief If the sender and the receiver live in the same thread,
+ * ConnectionTypeDirect is used. Otherwise ConnectionTypeQueued is used.
+ *
+ * \var ConnectionTypeDirect
+ * \brief The receiver is invoked immediately and synchronously in the sender's
+ * thread.
+ *
+ * \var ConnectionTypeQueued
+ * \brief The receiver is invoked asynchronously
+ *
+ * Invoke the receiver asynchronously in its thread when control returns to the
+ * thread's event loop. The sender proceeds without waiting for the invocation
+ * to complete.
+ *
+ * \var ConnectionTypeBlocking
+ * \brief The receiver is invoked synchronously
+ *
+ * If the sender and the receiver live in the same thread, this is equivalent to
+ * ConnectionTypeDirect. Otherwise, the receiver is invoked asynchronously in
+ * its thread when control returns to the thread's event loop. The sender
+ * blocks until the receiver signals the completion of the invocation.
+ */
+
+/**
+ * \brief Invoke the bound method with packed arguments
+ * \param[in] pack Packed arguments
+ * \param[in] deleteMethod True to delete \a this bound method instance when
+ * method invocation completes
+ *
+ * The bound method stores its return value, if any, in the arguments \a pack.
+ * For direct and blocking invocations, this is performed synchronously, and
+ * the return value contained in the pack may be used. For queued invocations,
+ * the return value is stored at an undefined point of time and shall thus not
+ * be used by the caller.
+ *
+ * \return True if the return value contained in the \a pack may be used by the
+ * caller, false otherwise
+ */
+bool BoundMethodBase::activatePack(std::shared_ptr<BoundMethodPackBase> pack,
+				   bool deleteMethod)
+{
+	ConnectionType type = connectionType_;
+	if (type == ConnectionTypeAuto) {
+		if (Thread::current() == object_->thread())
+			type = ConnectionTypeDirect;
+		else
+			type = ConnectionTypeQueued;
+	} else if (type == ConnectionTypeBlocking) {
+		if (Thread::current() == object_->thread())
+			type = ConnectionTypeDirect;
+	}
+
+	switch (type) {
+	case ConnectionTypeDirect:
+	default:
+		invokePack(pack.get());
+		if (deleteMethod)
+			delete this;
+		return true;
+
+	case ConnectionTypeQueued: {
+		std::unique_ptr<Message> msg =
+			std::make_unique<InvokeMessage>(this, pack, nullptr, deleteMethod);
+		object_->postMessage(std::move(msg));
+		return false;
+	}
+
+	case ConnectionTypeBlocking: {
+		Semaphore semaphore;
+
+		std::unique_ptr<Message> msg =
+			std::make_unique<InvokeMessage>(this, pack, &semaphore, deleteMethod);
+		object_->postMessage(std::move(msg));
+
+		semaphore.acquire();
+		return true;
+	}
+	}
+}
+
+} /* namespace libcamera */