mirror of
https://github.com/matrix-construct/construct
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101 lines
4.6 KiB
C++
101 lines
4.6 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_WRITE_H
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namespace ircd::fs
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{
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struct write_opts extern const write_opts_default;
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// Yields ircd::ctx for write from buffers; returns bytes written
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size_t write(const fd &, const const_buffers &, const write_opts & = write_opts_default);
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size_t write(const string_view &path, const const_buffers &, const write_opts & = write_opts_default);
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// Yields ircd::ctx for write from buffer; returns view of written portion
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const_buffer write(const fd &, const const_buffer &, const write_opts & = write_opts_default);
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const_buffer write(const string_view &path, const const_buffer &, const write_opts & = write_opts_default);
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// Yields ircd::ctx to append to file from buffers; returns bytes appended
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size_t append(const fd &, const const_buffers &, const write_opts & = write_opts_default);
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size_t append(const string_view &path, const const_buffers &, const write_opts & = write_opts_default);
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// Yields ircd::ctx to append to file from buffer; returns view of written portion
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const_buffer append(const fd &, const const_buffer &, const write_opts & = write_opts_default);
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const_buffer append(const string_view &path, const const_buffer &, const write_opts & = write_opts_default);
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// Yields ircd::ctx to overwrite (trunc) file from buffers; returns bytes written
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size_t overwrite(const fd &, const const_buffers &, const write_opts & = write_opts_default);
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size_t overwrite(const string_view &path, const const_buffers &, const write_opts & = write_opts_default);
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// Yields ircd::ctx to overwrite (trunc) file from buffer; returns view of written portion
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const_buffer overwrite(const fd &, const const_buffer & = {}, const write_opts & = write_opts_default);
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const_buffer overwrite(const string_view &path, const const_buffer & = {}, const write_opts & = write_opts_default);
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// Truncate file to explicit size
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void truncate(const fd &, const size_t &, const write_opts & = write_opts_default);
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void truncate(const string_view &path, const size_t &, const write_opts & = write_opts_default);
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// Allocate
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void allocate(const fd &, const size_t &size, const write_opts & = write_opts_default);
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}
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/// Options for a write operation
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struct ircd::fs::write_opts
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:opts
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{
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/// Yields the ircd::ctx until the buffers are written. This performs
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/// the unix incremental write loop internally. When this option is true,
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/// any return value from a function in the write() suite will not be a
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/// partial value requiring another invocation of write().
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bool all {true};
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/// Whether to propagate an EINTR; otherwise we reinvoke the syscall. For a
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/// write(2) family call this can only happen before any data was written;
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/// an exception will be thrown. We default to true because we have faith
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/// in the useful propagation of an exception for this event.
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bool interruptible {true};
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/// Whether to update the fd's offset on appends. This happens naturally
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/// when the file is opened in append mode. If not, we get the same per-
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/// write atomic seek behavior if RWF_APPEND is supported. In the latter
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/// case, this option determines whether the fd's offset is affected.
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bool update_offset {true};
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/// Whether to RWF_SYNC or RWF_DSYNC depending on the metadata option. This
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/// is a range-sync, it only covers the offset and size of the write;
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/// perhaps a worthy replacement for sync_file_range(2).
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bool sync {false};
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/// When sync is true: if metadata is true RWF_SYNC (like fsync(2)) is used,
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/// otherwise RWF_DSYNC (like fdsync(2)) is used. This is only if available,
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/// Careful, if it is not available you are responsible for following the
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/// write with fsync(2)/fdsync(2) yourself.
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bool metadata {false};
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/// RWH_WRITE_LIFE integer representation (see fcntl(2) since Linux 4.13) if
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/// supported; otherwise has no effect. As a write_opts option, this is only
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/// meaningful if pwritev2(2) is available and the kernel recognizes the
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/// RWF_WRITE_LIFE flag bits. See also fs::write_life(fd).
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uint8_t write_life {0};
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/// for allocate()
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bool keep_size {true};
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/// for allocate()
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bool punch_hole {false};
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write_opts(const off_t & = 0);
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};
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inline
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ircd::fs::write_opts::write_opts(const off_t &offset)
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:opts{offset, op::WRITE}
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{}
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