libcamera: Move file_descriptor.h to base/

The FileDescriptor class is a generic helper that matches the criteria
for the base library. Move it there.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

include/libcamera/base/file_descriptor.h

@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * file_descriptor.h - File descriptor wrapper
+ */
+
+#pragma once
+
+#include <memory>
+#include <sys/types.h>
+
+namespace libcamera {
+
+class FileDescriptor final
+{
+public:
+	explicit FileDescriptor(const int &fd = -1);
+	explicit FileDescriptor(int &&fd);
+	FileDescriptor(const FileDescriptor &other);
+	FileDescriptor(FileDescriptor &&other);
+	~FileDescriptor();
+
+	FileDescriptor &operator=(const FileDescriptor &other);
+	FileDescriptor &operator=(FileDescriptor &&other);
+
+	bool isValid() const { return fd_ != nullptr; }
+	int fd() const { return fd_ ? fd_->fd() : -1; }
+	FileDescriptor dup() const;
+
+	ino_t inode() const;
+
+private:
+	class Descriptor
+	{
+	public:
+		Descriptor(int fd, bool duplicate);
+		~Descriptor();
+
+		int fd() const { return fd_; }
+
+	private:
+		int fd_;
+	};
+
+	std::shared_ptr<Descriptor> fd_;
+};
+
+} /* namespace libcamera */

include/libcamera/base/meson.build

@@ -11,6 +11,7 @@ libcamera_base_headers = files([
     'event_dispatcher_poll.h',
     'event_notifier.h',
     'file.h',
+    'file_descriptor.h',
     'flags.h',
     'log.h',
     'message.h',