Luna/kernel/src/memory/AddressSpace.h

#pragma once
#include "arch/MMU.h"
#include <luna/LinkedList.h>
#include <luna/OwnedPtr.h>
#include <luna/Result.h>

class VMRegion : LinkedListNode<VMRegion>
{
  public:
    u64 start;
    u64 end;
    usize count;
    bool used { true };
    bool persistent { false };
    int flags { 0 };
    int prot { 0 };
    u64 shmid;

    void cleanup_shared();
};

class AddressSpace
{
  public:
    AddressSpace();
    ~AddressSpace();

    AddressSpace& operator=(AddressSpace&& other);

    Result<u64> alloc_region(usize count, int prot, int flags, u64 shmid = 0, bool persistent = false);

    Result<bool> test_and_alloc_region(u64 address, usize count, int prot, int flags, u64 shmid = 0,
                                       bool persistent = false)
    {
        return set_region(address, count, true, prot, flags, shmid, persistent);
    }

    Result<bool> free_region(u64 address, usize count)
    {
        return set_region(address, count, false, 0, 0, 0, false);
    }

    static Result<OwnedPtr<AddressSpace>> try_create();

    Result<OwnedPtr<AddressSpace>> clone();

    PageDirectory* page_directory() const
    {
        return m_directory;
    }

  private:
    Result<bool> set_region(u64 address, usize count, bool used, int prot, int flags, u64 shmid, bool persistent);
    Result<void> create_default_region();
    Result<void> create_null_region();
    void try_merge_region_with_neighbors(VMRegion* region);
    void merge_contiguous_regions(VMRegion* a, VMRegion* b);
    Result<VMRegion*> split_region(VMRegion* parent, u64 boundary);

    LinkedList<VMRegion> m_regions;
    PageDirectory* m_directory;
};