Class: NIO::Selector
- Inherits:
-
Object
- Object
- NIO::Selector
- Defined in:
- lib/nio/selector.rb,
ext/nio4r/selector.c
Overview
Selectors monitor IO objects for events of interest
Instance Method Summary collapse
-
#backend ⇒ Object
Return a symbol representing the backend I/O multiplexing mechanism used.
-
#close ⇒ Object
Close this selector and free its resources.
-
#closed? ⇒ Boolean
Is this selector closed?.
-
#deregister(io) ⇒ Object
Deregister the given IO object from the selector.
- #empty? ⇒ Boolean
-
#initialize ⇒ Object
constructor
Methods.
-
#register(io, interest) ⇒ Object
Register interest in an IO object with the selector for the given types of events.
-
#registered?(io) ⇒ Boolean
Is the given IO object registered with the selector?.
-
#select(timeout = nil) ⇒ Object
Select which monitors are ready.
-
#wakeup ⇒ Object
Wake up a thread that’s in the middle of selecting on this selector, if any such thread exists.
Constructor Details
#initialize ⇒ Object
Methods
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# File 'lib/nio/selector.rb', line 9 def initialize @selectables = {} @lock = Mutex.new # Other threads can wake up a selector @wakeup, @waker = IO.pipe @closed = false end |
Instance Method Details
#backend ⇒ Object
Return a symbol representing the backend I/O multiplexing mechanism used. Supported backends are:
-
:ruby - pure Ruby (i.e IO.select)
-
:java - Java NIO on JRuby
-
:epoll - libev w\ Linux epoll
-
:poll - libev w\ POSIX poll
-
:kqueue - libev w\ BSD kqueue
-
:select - libev w\ SysV select
-
:port - libev w\ I/O completion ports
-
:unknown - libev w\ unknown backend
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# File 'lib/nio/selector.rb', line 28 def backend :ruby end |
#close ⇒ Object
Close this selector and free its resources
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# File 'lib/nio/selector.rb', line 133 def close @lock.synchronize do return if @closed begin @wakeup.close rescue IOError end begin @waker.close rescue IOError end @closed = true end end |
#closed? ⇒ Boolean
Is this selector closed?
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# File 'lib/nio/selector.rb', line 152 def closed? @closed end |
#deregister(io) ⇒ Object
Deregister the given IO object from the selector
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# File 'lib/nio/selector.rb', line 54 def deregister(io) @lock.synchronize do monitor = @selectables.delete IO.try_convert(io) monitor.close(false) if monitor && !monitor.closed? monitor end end |
#empty? ⇒ Boolean
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# File 'ext/nio4r/selector.c', line 40 def empty? @selectables.empty? end |
#register(io, interest) ⇒ Object
Register interest in an IO object with the selector for the given types of events. Valid event types for interest are:
-
:r - is the IO readable?
-
:w - is the IO writeable?
-
:rw - is the IO either readable or writeable?
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# File 'lib/nio/selector.rb', line 37 def register(io, interest) io = IO.try_convert(io) @lock.synchronize do raise IOError, "selector is closed" if closed? monitor = @selectables[io] raise ArgumentError, "already registered as #{monitor.interests.inspect}" if monitor monitor = Monitor.new(io, interest, self) @selectables[monitor.io] = monitor monitor end end |
#registered?(io) ⇒ Boolean
Is the given IO object registered with the selector?
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# File 'lib/nio/selector.rb', line 63 def registered?(io) @lock.synchronize { @selectables.key? io } end |
#select(timeout = nil) ⇒ Object
Select which monitors are ready
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# File 'lib/nio/selector.rb', line 68 def select(timeout = nil) selected_monitors = Set.new @lock.synchronize do readers = [@wakeup] writers = [] @selectables.each do |io, monitor| readers << io if monitor.interests == :r || monitor.interests == :rw writers << io if monitor.interests == :w || monitor.interests == :rw monitor.readiness = nil end ready_readers, ready_writers = Kernel.select(readers, writers, [], timeout) return unless ready_readers # timeout ready_readers.each do |io| if io == @wakeup # Clear all wakeup signals we've received by reading them # Wakeups should have level triggered behavior @wakeup.read(@wakeup.stat.size) else monitor = @selectables[io] monitor.readiness = :r selected_monitors << monitor end end ready_writers.each do |io| monitor = @selectables[io] monitor.readiness = monitor.readiness == :r ? :rw : :w selected_monitors << monitor end end if block_given? selected_monitors.each { |m| yield m } selected_monitors.size else selected_monitors.to_a end end |
#wakeup ⇒ Object
Wake up a thread that’s in the middle of selecting on this selector, if any such thread exists.
Invoking this method more than once between two successive select calls has the same effect as invoking it just once. In other words, it provides level-triggered behavior.
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# File 'lib/nio/selector.rb', line 117 def wakeup # Send the selector a signal in the form of writing data to a pipe begin @waker.write_nonblock "\0" rescue IO::WaitWritable # This indicates the wakeup pipe is full, which means the other thread # has already received many wakeup calls, but not processed them yet. # The other thread will completely drain this pipe when it wakes up, # so it's ok to ignore this exception if it occurs: we know the other # thread has already been signaled to wake up end nil end |