mirror of
https://github.com/matrix-construct/construct
synced 2024-11-09 11:31:11 +01:00
76 lines
2.6 KiB
C++
76 lines
2.6 KiB
C++
// Matrix Construct
|
|
//
|
|
// Copyright (C) Matrix Construct Developers, Authors & Contributors
|
|
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
|
|
//
|
|
// Permission to use, copy, modify, and/or distribute this software for any
|
|
// purpose with or without fee is hereby granted, provided that the above
|
|
// copyright notice and this permission notice is present in all copies. The
|
|
// full license for this software is available in the LICENSE file.
|
|
|
|
#pragma once
|
|
#define HAVE_IRCD_FS_READ_H
|
|
|
|
namespace ircd::fs
|
|
{
|
|
struct read_op;
|
|
struct read_opts extern const read_opts_default;
|
|
|
|
// Yields ircd::ctx for parallel reads into buffers; total bytes read
|
|
size_t read(const vector_view<read_op> &);
|
|
|
|
// Yields ircd::ctx for read into buffers; returns bytes read
|
|
size_t read(const fd &, const mutable_buffers &, const read_opts & = read_opts_default);
|
|
|
|
// Yields ircd::ctx for read into buffer; returns view of read portion.
|
|
const_buffer read(const fd &, const mutable_buffer &, const read_opts & = read_opts_default);
|
|
|
|
// Yields ircd::ctx for read into allocated string; returns that string
|
|
std::string read(const fd &, const read_opts & = read_opts_default);
|
|
|
|
// Test whether bytes in the specified range are cached and should not block
|
|
bool incore(const fd &, const size_t &, const read_opts & = read_opts_default);
|
|
|
|
// Prefetch data for subsequent read(); offset given in opts (WILLNEED).
|
|
size_t prefetch(const fd &, const size_t &, const read_opts & = read_opts_default);
|
|
|
|
// Evict data which won't be read anymore (DONTNEED).
|
|
size_t evict(const fd &, const size_t &, const read_opts & = read_opts_default);
|
|
}
|
|
|
|
/// Options for a read operation
|
|
struct ircd::fs::read_opts
|
|
:opts
|
|
{
|
|
/// Yields the ircd::ctx until the buffers are full or EOF. This performs
|
|
/// the unix incremental read loop internally. When this option is true,
|
|
/// any return value from a function in the read suite will not be a
|
|
/// partial value requiring another invocation of read.
|
|
bool all {true};
|
|
|
|
/// Whether to propagate an EINTR; otherwise we reinvoke the syscall. For a
|
|
/// read(2) family call this can only happen before any data was read;
|
|
/// an exception will be thrown. We default to true because we have faith
|
|
/// in the useful propagation of an exception for this event.
|
|
bool interruptible {true};
|
|
|
|
read_opts(const off_t & = 0);
|
|
};
|
|
|
|
/// Convenience aggregation for the parallel read() overload.
|
|
struct ircd::fs::read_op
|
|
{
|
|
// request
|
|
const fs::fd *fd {nullptr};
|
|
const read_opts *opts {nullptr};
|
|
mutable_buffers bufs;
|
|
|
|
// result
|
|
std::exception_ptr eptr;
|
|
size_t ret {0};
|
|
};
|
|
|
|
inline
|
|
ircd::fs::read_opts::read_opts(const off_t &offset)
|
|
:opts{offset, op::READ}
|
|
{}
|