Kernel: Split the ProcFS core file into smaller components

Author: https://github.com/supercomputer7
Commit: 3906dd3aa3
Pull-request: https://github.com/SerenityOS/serenity/pull/15771
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/bgianfo

Kernel/FileSystem/ProcFS/ProcessAssociatedInode.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <Kernel/FileSystem/ProcFS/Inode.h>
+#include <Kernel/Forward.h>
+
+namespace Kernel {
+
+class ProcFSProcessAssociatedInode : public ProcFSInode {
+    friend class ProcFS;
+
+protected:
+    ProcFSProcessAssociatedInode(ProcFS const&, ProcessID, InodeIndex);
+    ProcessID associated_pid() const { return m_pid; }
+
+    // ^Inode
+    virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& buffer, OpenFileDescription*) override final;
+
+private:
+    const ProcessID m_pid;
+};
+
+}