jeanlemotan
54 lines
1.5 KiB
C++
54 lines
1.5 KiB
C++
///////////////////////////////////////////////////////////////////////////////
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// Copyright (c) Lewis Baker
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// Licenced under MIT license. See LICENSE.txt for details.
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///////////////////////////////////////////////////////////////////////////////
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#include <cppcoro/file_read_operation.hpp>
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#if CPPCORO_OS_WINNT
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# ifndef WIN32_LEAN_AND_MEAN
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# define WIN32_LEAN_AND_MEAN
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# endif
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# include <Windows.h>
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bool cppcoro::file_read_operation_impl::try_start(
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cppcoro::detail::win32_overlapped_operation_base& operation) noexcept
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{
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const DWORD numberOfBytesToRead =
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m_byteCount <= 0xFFFFFFFF ?
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static_cast<DWORD>(m_byteCount) : DWORD(0xFFFFFFFF);
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DWORD numberOfBytesRead = 0;
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BOOL ok = ::ReadFile(
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m_fileHandle,
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m_buffer,
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numberOfBytesToRead,
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&numberOfBytesRead,
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operation.get_overlapped());
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const DWORD errorCode = ok ? ERROR_SUCCESS : ::GetLastError();
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if (errorCode != ERROR_IO_PENDING)
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{
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// Completed synchronously.
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//
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// We are assuming that the file-handle has been set to the
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// mode where synchronous completions do not post a completion
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// event to the I/O completion port and thus can return without
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// suspending here.
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operation.m_errorCode = errorCode;
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operation.m_numberOfBytesTransferred = numberOfBytesRead;
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return false;
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}
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return true;
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}
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void cppcoro::file_read_operation_impl::cancel(
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cppcoro::detail::win32_overlapped_operation_base& operation) noexcept
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{
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(void)::CancelIoEx(m_fileHandle, operation.get_overlapped());
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}
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#endif // CPPCORO_OS_WINNT
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