mirror of
https://github.com/matrix-construct/construct
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72 lines
2.7 KiB
C++
72 lines
2.7 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_FS_SYNC_OPTS_H
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namespace ircd::fs
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{
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struct opts extern const opts_default;
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int reqprio(int) noexcept __attribute__((const));
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}
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/// Options common to all operations
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struct ircd::fs::opts
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{
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static const int highest_priority;
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/// Offset in the file. If this is -1, for writes, it indicates an append
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/// at the end of the file (RWF_APPEND or legacy non-atomic lseek()).
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off_t offset {0};
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/// Request priority. Lower value takes priority over higher. The lowest
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/// possible priority value is special, on supporting platforms (RWF_HIPRI).
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/// One can either simply set the integer minimum or use the extern value.
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int8_t priority {0};
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/// Submits the I/O request immediately rather than allowing IRCd to
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/// queue requests for a few iterations of the ircd::ios event loop.
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/// (only relevant to aio).
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bool nodelay {false};
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/// Setting this to false enables non-blocking behavior. If the operation
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/// would block, EAGAIN is returned. This is only available with RWF_NOWAIT
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/// on newer systems, otherwise this value is ignored and is always true.
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/// This feature makes up for the fact that O_NONBLOCK when opening the
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/// file is ineffective for regular files.
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bool blocking {true};
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/// Determines whether this operation is conducted via AIO/io_uring. If
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/// not, a direct syscall is made. Using AIO will only block one ircd::ctx
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/// while a direct syscall will block the thread (all contexts). If AIO is
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/// not available or not enabled, or doesn't support this operation,
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/// setting this has no effect. If this system supports io_uring this
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/// option is reused to indicate use of io_uring (as AIO and io_uring are
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/// not used simultaneously).
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bool aio {true};
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/// The enumerated operation code to identify the type of request being
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/// made at runtime from any abstract list of requests. This is set by
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/// the fs:: interface call and not the user in most cases. The user
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/// should not rely on this value being preserved if, e.g. they set a read
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/// opcode and then pass the opts structure to write().
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enum op op {op::NOOP};
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opts(const off_t &, const enum op &op);
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opts() = default;
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};
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inline
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ircd::fs::opts::opts(const off_t &offset,
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const enum op &op)
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:offset{offset}
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,op{op}
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{}
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