Class: Cod::Select

Inherits:
Object
  • Object
show all
Defined in:
lib/cod/select.rb

Overview

Performs an IO.select on a list of file descriptors and Cod channels. Construct this like so:

Select.new(
  0.1,                    # timeout
  foo: single_fd,         # a single named FD
  bar: [one, two, three], # a group of FDs.
)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(timeout, groups) ⇒ Select

Returns a new instance of Select.



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# File 'lib/cod/select.rb', line 27

def initialize(timeout, groups)
  @timeout = timeout
  @groups = SelectGroup.new(groups)
end

Instance Attribute Details

#groups ⇒ Object (readonly)

Returns the value of attribute groups.



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# File 'lib/cod/select.rb', line 25

def groups
  @groups
end

#timeout ⇒ Object (readonly)

Returns the value of attribute timeout.



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# File 'lib/cod/select.rb', line 24

def timeout
  @timeout
end

Instance Method Details

#do ⇒ Hash, ...

Performs the IO.select and returns a thinned out version of that initial groups, containing only FDs and channels that are ready for reading.

Returns:



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# File 'lib/cod/select.rb', line 37

def do
  fds = groups.values { |e| to_read_fds(e) }.compact
  
  # Perform select  
  r,w,e = IO.select(fds, nil, nil, timeout)

  # Nothing is ready if r is nil
  return groups.empty unless r
  
  # Prepare a return value: The original hash, where the fds are ready.
  groups.
    keep_if { |e| to_read_fds(e).
      any? { |fd| r.include?(fd) } }.
    unpack
end