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25 lines
570 B
Ruby
25 lines
570 B
Ruby
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# The goal of this is to use a synthetic (non-IO) reader
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# to trigger the read/write loop of IO.copy_stream,
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# bypassing in-kernel mechanisms like sendfile for zero copy,
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# so we wrap the /dev/zero IO object:
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class Zero
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def initialize
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@n = 100000
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@in = File.open('/dev/zero', 'rb')
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end
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def read(len, buf)
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return if (@n -= 1) == 0
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@in.read(len, buf)
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end
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end
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begin
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src = Zero.new
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dst = File.open(IO::NULL, 'wb')
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n = IO.copy_stream(src, dst)
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rescue Errno::ENOENT
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# not *nix
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end if IO.respond_to?(:copy_stream) && IO.const_defined?(:NULL)
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