Kernel: Split the ISO9660FileSystem.{cpp,h} files to smaller components

Kernel/FileSystem/ISO9660FS/DirectoryEntry.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+#include <Kernel/KBuffer.h>
+
+namespace Kernel {
+
+struct ISO9660FSDirectoryEntry final : public AtomicRefCounted<ISO9660FSDirectoryEntry> {
+    u32 extent { 0 };
+    u32 length { 0 };
+
+    // NOTE: This can never be empty if we read the directory successfully.
+    //       We need it as an OwnPtr to default-construct this struct.
+    OwnPtr<KBuffer> blocks;
+
+    static ErrorOr<NonnullLockRefPtr<ISO9660FSDirectoryEntry>> try_create(u32 extent, u32 length, OwnPtr<KBuffer> blocks)
+    {
+        return adopt_nonnull_lock_ref_or_enomem(new (nothrow) ISO9660FSDirectoryEntry(extent, length, move(blocks)));
+    }
+
+private:
+    ISO9660FSDirectoryEntry(u32 extent, u32 length, OwnPtr<KBuffer> blocks)
+        : extent(extent)
+        , length(length)
+        , blocks(move(blocks))
+    {
+    }
+};
+
+struct ISO9660FSDirectoryState {
+    LockRefPtr<ISO9660FSDirectoryEntry> entry;
+    u32 offset { 0 };
+};
+
+}