Module asyncfile

This module implements asynchronous file reading and writing.

import asyncfile, asyncdispatch, os

proc main() {.async.} =
  var file = openAsync(getTempDir() / "foobar.txt", fmReadWrite)
  await file.write("test")
  file.setFilePos(0)
  let data = await file.readAll()
  doAssert data == "test"
  file.close()

waitFor main()

Types

AsyncFile = ref object
  fd: AsyncFD
  offset: int64
  Source Edit

Procs

proc openAsync(filename: string; mode = fmRead): AsyncFile {.
raises: [OSError], tags: [ReadDirEffect]
.}
Opens a file specified by the path in filename using the specified mode asynchronously.   Source Edit
proc readBuffer(f: AsyncFile; buf: pointer; size: int): Future[int] {.
raises: [FutureError, Exception], tags: [RootEffect]
.}

Read size bytes from the specified file asynchronously starting at the current position of the file pointer.

If the file pointer is past the end of the file then zero is returned and no bytes are read into buf

  Source Edit
proc read(f: AsyncFile; size: int): Future[string] {.
raises: [Exception, FutureError], tags: [RootEffect]
.}

Read size bytes from the specified file asynchronously starting at the current position of the file pointer.

If the file pointer is past the end of the file then an empty string is returned.

  Source Edit
proc readLine(f: AsyncFile): Future[string] {.
raises: [FutureError], tags: [RootEffect]
.}
Reads a single line from the specified file asynchronously.   Source Edit
proc getFilePos(f: AsyncFile): int64 {.
raises: [], tags: []
.}
Retrieves the current position of the file pointer that is used to read from the specified file. The file's first byte has the index zero.   Source Edit
proc setFilePos(f: AsyncFile; pos: int64) {.
raises: [], tags: []
.}
Sets the position of the file pointer that is used for read/write operations. The file's first byte has the index zero.   Source Edit
proc readAll(f: AsyncFile): Future[string] {.
raises: [FutureError], tags: [RootEffect]
.}
Reads all data from the specified file.   Source Edit
proc writeBuffer(f: AsyncFile; buf: pointer; size: int): Future[void] {.
raises: [FutureError, Exception], tags: [RootEffect]
.}

Writes size bytes from buf to the file specified asynchronously.

The returned Future will complete once all data has been written to the specified file.

  Source Edit
proc write(f: AsyncFile; data: string): Future[void] {.
raises: [Exception, FutureError], tags: [RootEffect]
.}

Writes data to the file specified asynchronously.

The returned Future will complete once all data has been written to the specified file.

  Source Edit
proc close(f: AsyncFile) {.
raises: [OSError], tags: []
.}
Closes the file specified.   Source Edit