121 lines
4.4 KiB
Nim
121 lines
4.4 KiB
Nim
#
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# Chronos SendFile
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# (c) Copyright 2018-Present
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# Status Research & Development GmbH
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#
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# Licensed under either of
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# Apache License, version 2.0, (LICENSE-APACHEv2)
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# MIT license (LICENSE-MIT)
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## This module provides cross-platform wrapper for ``sendfile()`` syscall.
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{.push raises: [].}
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when defined(nimdoc):
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proc sendfile*(outfd, infd: int, offset: int, count: var int): int =
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## Copies data between file descriptor ``infd`` and ``outfd``. Because this
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## copying is done within the kernel, ``sendfile()`` is more efficient than
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## the combination of ``read(2)`` and ``write(2)``, which would require
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## transferring data to and from user space.
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##
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## ``infd`` should be a file descriptor opened for reading and
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## ``outfd`` should be a descriptor opened for writing.
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##
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## The ``infd`` argument must correspond to a file which supports
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## ``mmap(2)``-like operations (i.e., it cannot be a socket).
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##
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## ``offset`` the file offset from which ``sendfile()`` will start reading
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## data from ``infd``.
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##
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## ``count`` is the number of bytes to copy between the file descriptors.
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## On exit ``count`` will hold number of bytes actually transferred between
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## file descriptors. May be >0 even in the case of error return, if some
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## bytes were sent before the error occurred.
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##
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## If the transfer was successful, the number of bytes written to ``outfd``
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## is stored in ``count``, and ``0`` returned. Note that a successful call
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## to ``sendfile()`` may write fewer bytes than requested; the caller should
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## be prepared to retry the call if there were unsent bytes.
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##
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## On error, ``-1`` is returned.
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elif defined(emscripten):
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proc sendfile*(outfd, infd: int, offset: int, count: var int): int =
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raiseAssert "sendfile() is not implemented yet"
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elif (defined(linux) or defined(android)) and not(defined(emscripten)):
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proc osSendFile*(outfd, infd: cint, offset: ptr int, count: int): int
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{.importc: "sendfile", header: "<sys/sendfile.h>".}
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proc sendfile*(outfd, infd: int, offset: int, count: var int): int =
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var o = offset
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let res = osSendFile(cint(outfd), cint(infd), addr o, count)
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if res >= 0:
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count = res
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0
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else:
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count = 0
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-1
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elif defined(freebsd) or defined(openbsd) or defined(netbsd) or
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defined(dragonflybsd):
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import oserrno
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type
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SendfileHeader* {.importc: "struct sf_hdtr",
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header: """#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/uio.h>""",
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pure, final.} = object
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proc osSendFile*(outfd, infd: cint, offset: uint, size: uint,
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hdtr: ptr SendfileHeader, sbytes: ptr uint,
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flags: int): int {.importc: "sendfile",
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header: """#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/uio.h>""".}
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proc sendfile*(outfd, infd: int, offset: int, count: var int): int =
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var o = 0'u
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let res = osSendFile(cint(infd), cint(outfd), uint(offset), uint(count),
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nil, addr o, 0)
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if res >= 0:
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count = int(o)
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0
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else:
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let err = osLastError()
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count =
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if err == EAGAIN: int(o)
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else: 0
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-1
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elif defined(macosx):
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import oserrno
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type
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SendfileHeader* {.importc: "struct sf_hdtr",
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header: """#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/uio.h>""",
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pure, final.} = object
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proc osSendFile*(fd, s: cint, offset: int, size: ptr int,
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hdtr: ptr SendfileHeader,
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flags: int): int {.importc: "sendfile",
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header: """#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/uio.h>""".}
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proc sendfile*(outfd, infd: int, offset: int, count: var int): int =
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var o = count
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let res = osSendFile(cint(infd), cint(outfd), offset, addr o, nil, 0)
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if res >= 0:
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count = int(o)
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0
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else:
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let err = osLastError()
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count =
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if err == EAGAIN: int(o)
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else: 0
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-1
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