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63 lines
1.3 KiB
C++
63 lines
1.3 KiB
C++
// SPDX-License-Identifier: BSD-2-Clause
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// author: Max Kellermann <max.kellermann@gmail.com>
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#pragma once
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#include "Operation.hxx"
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#include <cstddef>
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#include <memory>
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#include <sys/uio.h> // for struct iovec
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class FileDescriptor;
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namespace Uring {
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class Queue;
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class ReadHandler {
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public:
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virtual void OnRead(std::unique_ptr<std::byte[]> buffer,
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std::size_t size) noexcept = 0;
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/**
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* @param error an errno value
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*/
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virtual void OnReadError(int error) noexcept = 0;
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};
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/**
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* Read into a newly allocated buffer.
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*
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* Instances of this class must be allocated with `new`, because
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* cancellation will require this object (and the allocated buffer) to
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* persist until the kernel completes the operation.
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*/
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class ReadOperation final : Operation {
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ReadHandler *handler;
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struct iovec iov;
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std::unique_ptr<std::byte[]> buffer;
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public:
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void Start(Queue &queue, FileDescriptor fd, off_t offset,
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std::size_t size, ReadHandler &_handler) noexcept;
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/**
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* Cancel this operation. This instance will be freed using
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* `delete` after the kernel has finished cancellation,
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* i.e. the caller resigns ownership.
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*/
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void Cancel() noexcept {
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handler = nullptr;
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}
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private:
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/* virtual methods from class Operation */
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void OnUringCompletion(int res) noexcept override;
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};
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} // namespace Uring
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