Kernel: start work on ram file system

kernel/include/kernel/FS/RamFS/FileSystem.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <BAN/HashMap.h>
+#include <kernel/FS/FileSystem.h>
+#include <kernel/SpinLock.h>
+
+namespace Kernel
+{
+	
+	class RamInode;
+
+	class RamFileSystem final : public FileSystem
+	{
+	public:
+		static BAN::ErrorOr<RamFileSystem*> create(size_t size, mode_t, uid_t, gid_t);
+		~RamFileSystem() = default;
+
+		virtual BAN::RefPtr<Inode> root_inode() override { return m_inodes[m_root_inode]; }
+
+		BAN::ErrorOr<void> add_inode(BAN::RefPtr<RamInode>);
+		BAN::ErrorOr<BAN::RefPtr<RamInode>> get_inode(ino_t);
+
+		blksize_t blksize() const { return m_blksize; }
+		ino_t next_ino() { return m_next_ino++; }
+
+	private:
+		RamFileSystem() = default;
+
+	private:
+		SpinLock m_lock;
+		size_t m_size { 0 };
+
+		BAN::HashMap<ino_t, BAN::RefPtr<RamInode>> m_inodes;
+		ino_t m_root_inode;
+
+		const blksize_t m_blksize = PAGE_SIZE;
+		ino_t m_next_ino { 1 };
+	};
+
+}

kernel/include/kernel/FS/RamFS/Inode.h

@@ -0,0 +1,95 @@
+#pragma once
+
+#include <kernel/FS/Inode.h>
+
+#include <limits.h>
+
+namespace Kernel
+{
+
+	class RamFileSystem;
+
+	class RamInode : public Inode
+	{
+	public:
+		virtual ~RamInode() = default;
+	
+		virtual ino_t		ino()		const override { return m_inode_info.ino; }
+		virtual Mode		mode()		const override { return { m_inode_info.mode }; }
+		virtual nlink_t		nlink()		const override { return m_inode_info.nlink; }
+		virtual uid_t		uid()		const override { return m_inode_info.uid; }
+		virtual gid_t		gid()		const override { return m_inode_info.gid; }
+		virtual off_t		size()		const override { return m_inode_info.size; }
+		virtual timespec	atime()		const override { return m_inode_info.atime; }
+		virtual timespec	mtime()		const override { return m_inode_info.mtime; }
+		virtual timespec	ctime()		const override { return m_inode_info.ctime; }
+		virtual blksize_t	blksize()	const override { return m_inode_info.blksize; }
+		virtual blkcnt_t	blocks()	const override { return m_inode_info.blocks; }
+		virtual dev_t		dev()		const override { return m_inode_info.dev; }
+		virtual dev_t		rdev()		const override { return m_inode_info.rdev; }
+
+		virtual BAN::StringView name() const override { ASSERT_NOT_REACHED(); }
+
+		void add_link() { m_inode_info.nlink++; }
+
+	protected:
+		RamInode(RamFileSystem& fs, mode_t, uid_t, gid_t);
+		static BAN::ErrorOr<BAN::RefPtr<RamInode>> create(RamFileSystem&, mode_t, uid_t, gid_t);
+
+	protected:
+		struct FullInodeInfo
+		{
+			ino_t		ino;
+			mode_t		mode;
+			nlink_t		nlink;
+			uid_t		uid;
+			gid_t		gid;
+			off_t		size;
+			timespec	atime;
+			timespec	mtime;
+			timespec	ctime;
+			blksize_t	blksize;
+			blkcnt_t	blocks;
+			dev_t		dev;
+			dev_t		rdev;
+		};
+
+	protected:
+		RamFileSystem& m_fs;
+		FullInodeInfo m_inode_info;
+
+		BAN::Vector<uint8_t> m_data;
+
+		friend class RamFileSystem;
+	};
+
+	class RamDirectoryInode final : public RamInode
+	{
+	public:
+		~RamDirectoryInode() = default;
+
+		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find_inode(BAN::StringView) override;
+		virtual BAN::ErrorOr<void> directory_read_next_entries(off_t, DirectoryEntryList*, size_t) override;
+		virtual BAN::ErrorOr<void> create_file(BAN::StringView, mode_t)	override;
+
+	private:
+		RamDirectoryInode(RamFileSystem&, ino_t parent, mode_t, uid_t, gid_t);
+		static BAN::ErrorOr<BAN::RefPtr<RamDirectoryInode>> create(RamFileSystem&, ino_t parent, mode_t, uid_t, gid_t);
+	
+	private:
+		static constexpr size_t m_name_max = NAME_MAX;
+		struct Entry
+		{
+			char name[m_name_max + 1];
+			size_t name_len = 0;
+			ino_t ino;
+		};
+
+	private:
+		BAN::Vector<Entry> m_entries;
+		ino_t m_parent;
+
+		friend class RamFileSystem;
+	};
+
+}