Class: Async::IO::Stream

Inherits:
Object
  • Object
show all
Defined in:
lib/async/io/stream.rb

Constant Summary collapse

BLOCK_SIZE =

The default block size for IO buffers. BLOCK_SIZE = ENV.fetch(‘BLOCK_SIZE’, 1024*16).to_i

1024*8

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io, block_size: BLOCK_SIZE, sync: true) ⇒ Stream

Returns a new instance of Stream.



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# File 'lib/async/io/stream.rb', line 31

def initialize(io, block_size: BLOCK_SIZE, sync: true)
	@io = io
	@eof = false
	
	# We don't want Ruby to do any IO buffering.
	@io.sync = sync
	
	@block_size = block_size
	
	@read_buffer = Buffer.new
	@write_buffer = Buffer.new
	
	# Used as destination buffer for underlying reads.
	@input_buffer = Buffer.new
end

Instance Attribute Details

#block_size ⇒ Object (readonly)

Returns the value of attribute block_size.



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# File 'lib/async/io/stream.rb', line 48

def block_size
  @block_size
end

#io ⇒ Object (readonly)

Returns the value of attribute io.



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# File 'lib/async/io/stream.rb', line 47

def io
  @io
end

Instance Method Details

#<<(string) ⇒ Object

Writes ‘string` to the stream and returns self.



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# File 'lib/async/io/stream.rb', line 130

def <<(string)
	write(string)
	
	return self
end

#close ⇒ Object

Closes the stream and flushes any unwritten data.



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# File 'lib/async/io/stream.rb', line 165

def close
	return if @io.closed?
	
	begin
		flush
	rescue
		# We really can't do anything here unless we want #close to raise exceptions.
		Async.logger.error(self) {$!}
	ensure
		@io.close
	end
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/async/io/stream.rb', line 160

def closed?
	@io.closed?
end

#connected? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/async/io/stream.rb', line 156

def connected?
	@io.connected?
end

#eof! ⇒ Object

Raises:

  • (EOFError) 


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# File 'lib/async/io/stream.rb', line 187

def eof!
	@read_buffer.clear
	@eof = true
	
	raise EOFError
end

#eof? ⇒ Boolean Also known as: eof

Returns true if the stream is at file which means there is no more data to be read.

Returns:

  • (Boolean) 


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# File 'lib/async/io/stream.rb', line 179

def eof?
	fill_read_buffer if !@eof && @read_buffer.empty?
	
	return @eof && @read_buffer.empty?
end

#flush ⇒ Object

Flushes buffered data to the stream.



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# File 'lib/async/io/stream.rb', line 137

def flush
	unless @write_buffer.empty?
		syswrite(@write_buffer)
		@write_buffer.clear
	end
end

#gets(separator = $/, **options) ⇒ Object 



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# File 'lib/async/io/stream.rb', line 144

def gets(separator = $/, **options)
	read_until(separator, **options)
end

#peek ⇒ Object 



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# File 'lib/async/io/stream.rb', line 104

def peek
	until yield(@read_buffer) or @eof
		fill_read_buffer
	end
end

#puts(*args, separator: $/) ⇒ Object 



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# File 'lib/async/io/stream.rb', line 148

def puts(*args, separator: $/)
	args.each do |arg|
		@write_buffer << arg << separator
	end
	
	flush
end

#read(size = nil) ⇒ Object

Reads ‘size` bytes from the stream. If size is not specified, read until end of file.



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# File 'lib/async/io/stream.rb', line 51

def read(size = nil)
	return '' if size == 0
	
	if size
		until @eof or @read_buffer.size >= size
			# Compute the amount of data we need to read from the underlying stream:
			read_size = size - @read_buffer.bytesize
			
			# Don't read less than @block_size to avoid lots of small reads:
			fill_read_buffer(read_size > @block_size ? read_size : @block_size)
		end
	else
		until @eof
			fill_read_buffer
		end
	end
	
	return consume_read_buffer(size)
end

#read_partial(size = nil) ⇒ Object Also known as: readpartial

Read at most ‘size` bytes from the stream. Will avoid reading from the underlying stream if possible.



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# File 'lib/async/io/stream.rb', line 72

def read_partial(size = nil)
	return '' if size == 0
	
	if @read_buffer.empty? and !@eof
		fill_read_buffer
	end
	
	return consume_read_buffer(size)
end

#read_until(pattern, offset = 0, chomp: true) ⇒ String

Efficiently read data from the stream until encountering pattern.

Parameters:

  • pattern (String) —

    The pattern to match.

Returns:

  • (String) —

    The contents of the stream up until the pattern, which is consumed but not returned.



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# File 'lib/async/io/stream.rb', line 87

def read_until(pattern, offset = 0, chomp: true)
	# We don't want to split on the pattern, so we subtract the size of the pattern.
	split_offset = pattern.bytesize - 1
	
	until index = @read_buffer.index(pattern, offset)
		offset = [0, @read_buffer.size - split_offset].max
		
		return unless fill_read_buffer
	end
	
	@read_buffer.freeze
	matched = @read_buffer.byteslice(0, index+(chomp ? 0 : pattern.bytesize))
	@read_buffer = @read_buffer.byteslice(index+pattern.bytesize, @read_buffer.bytesize)
	
	return matched
end

#write(string) ⇒ Object

Writes ‘string` to the buffer. When the buffer is full or #sync is true the buffer is flushed to the underlying `io`.

Parameters:

  • string —

    the string to write to the buffer.

Returns:

  • the number of bytes appended to the buffer.



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# File 'lib/async/io/stream.rb', line 114

def write(string)
	if @write_buffer.empty? and string.bytesize >= @block_size
		syswrite(string)
	else
		@write_buffer << string
		
		if @write_buffer.size >= @block_size
			syswrite(@write_buffer)
			@write_buffer.clear
		end
	end
	
	return string.bytesize
end