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https://github.com/RGBCube/serenity
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aee4786d8e
This singleton simplifies many aspects that we struggled with before: 1. There's no need to make derived classes of Device expose the constructor as public anymore. The singleton is a friend of them, so he can call the constructor. This solves the issue with try_create_device helper neatly, hopefully for good. 2. Getting a reference of the NullDevice is now being done from this singleton, which means that NullDevice no longer needs to use its own singleton, and we can apply the try_create_device helper on it too :) 3. We can now defer registration completely after the Device constructor which means the Device constructor is merely assigning the major and minor numbers of the Device, and the try_create_device helper ensures it calls the after_inserting method immediately after construction. This creates a great opportunity to make registration more OOM-safe.
41 lines
1.3 KiB
C++
41 lines
1.3 KiB
C++
/*
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* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/String.h>
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#include <AK/Types.h>
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#include <Kernel/Devices/CharacterDevice.h>
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#include <Kernel/PhysicalAddress.h>
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namespace Kernel {
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class MemoryDevice final : public CharacterDevice {
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AK_MAKE_ETERNAL
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friend class DeviceManagement;
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public:
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static NonnullRefPtr<MemoryDevice> must_create();
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~MemoryDevice();
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virtual KResultOr<Memory::Region*> mmap(Process&, OpenFileDescription&, Memory::VirtualRange const&, u64 offset, int prot, bool shared) override;
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private:
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MemoryDevice();
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virtual StringView class_name() const override { return "MemoryDevice"; }
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virtual bool can_read(const OpenFileDescription&, size_t) const override { return true; }
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virtual bool can_write(const OpenFileDescription&, size_t) const override { return false; }
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virtual bool is_seekable() const override { return true; }
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virtual KResultOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) override;
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virtual KResultOr<size_t> write(OpenFileDescription&, u64, const UserOrKernelBuffer&, size_t) override { return EINVAL; }
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virtual void did_seek(OpenFileDescription&, off_t) override;
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bool is_allowed_range(PhysicalAddress, Memory::VirtualRange const&) const;
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};
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}
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