Class: Vagrant::Util::IO

Inherits:
Object
  • Object
show all
Defined in:
lib/vagrant/util/io.rb

Constant Summary collapse

READ_CHUNK_SIZE =

The chunk size for reading from subprocess IO.

4096

Class Method Summary collapse

Class Method Details

.read_until_block(io) ⇒ String

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.

Returns:

  • (String) 


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# File 'lib/vagrant/util/io.rb', line 17

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