class Vagrant::Util::IO

Constants

READ_CHUNK_SIZE

The chunk size for reading from subprocess IO.

Public Class Methods

read_until_block(io) click to toggle source

Reads data from an IO object while it can, returning the data it reads. When it encounters a case when it can’t read anymore, it returns the data.

@return [String]

# File lib/vagrant/util/io.rb, line 14
def self.read_until_block(io)
  data = ""

  while true
    begin
      if Platform.windows?
        # Windows doesn't support non-blocking reads on
        # file descriptors or pipes so we have to get
        # a bit more creative.

        # Check if data is actually ready on this IO device.
        # We have to do this since `readpartial` will actually block
        # until data is available, which can cause blocking forever
        # in some cases.
        results = ::IO.select([io], nil, nil, 1.0)
        break if !results || results[0].empty?

        # Read!
        data << io.readpartial(READ_CHUNK_SIZE).encode(
          "UTF-8", Encoding.default_external,
          invalid: :replace,
          undef: :replace
        )
      else
        # Do a simple non-blocking read on the IO object
        data << io.read_nonblock(READ_CHUNK_SIZE)
      end
    rescue EOFError, Errno::EAGAIN, ::IO::WaitReadable
      break
    end
  end

  data
end