Module: SubSpawn::Internal

Defined in:
lib/subspawn/fd_parse.rb,
lib/subspawn/fd_types.rb,
lib/subspawn/graph_helper.rb

Defined Under Namespace

Classes: BiNode, Bigraph, FdSource

Class Method Summary collapse

Class Method Details

.graph_order(fds) ⇒ Object

convert an unordered list of FdSource’s into an ordered list with appropriate temporaries for a correct swap



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# File 'lib/subspawn/fd_parse.rb', line 96

def self.graph_order(fds)
	# Note that we keep all dests together. It may be smarter to break dests apart to avoid 
	# temporaries, but that is left as an excercise to the reader
	next_temp = [fds.map(&:max).max || 2, 2].max + 1
	graph = Bigraph.new
	# build graphs
	fds.each do |fd|
		from = fd.heads || [Object.new]
		to = fd.tails || [Object.new]
		from.zip(to) do |h, t|
			graph.insert(h, t, fd)
		end
	end
	#puts graph.to_dot
	# find and break cycles
	while point = graph.find_cycle
		# we probably could find the least-cost fd, but this will do for now
		items = graph.delete_outgoing(point)
		#p items
		temp = FdSource::Temp.new([next_temp], point.to_i)
		close = FdSource::Close.new([next_temp])
		items = [temp, *items.map{|x|x.temp_source(next_temp)}, close]
		#p items
		# reinsert
		items.each do |fd|
			from = fd.heads || [Object.new]
			to = fd.tails || [Object.new]
			from.zip(to) do |h, t|
				graph.insert(h, t, fd)
			end
		end
		#puts graph.to_dot
	end
	#puts "removed all cycles, hopeuflly"
	elts = graph.ordered_kahn.reverse # execute in the opposite order of dependencies
	#puts graph.to_dot
	elts
end

.guess_mode(d) ⇒ Object

mode conversion



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# File 'lib/subspawn/fd_parse.rb', line 27

def self.guess_mode(d)
	read = d.include? 0 # stdin
	write = (d.include? 1 or d.include? 2) # stdout
	if read && write
		raise ArgumentError, "Invalid FD source specification: ambiguious mode (r & w)"
	elsif read
		:read
	elsif write
		:write
	else
		raise ArgumentError, "Invalid FD source specification: ambiguious mode (stdio missing)"
	end
end

.parse_fd(fd, allow_pty = false) ⇒ Object

argument value to int (or :tty)



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# File 'lib/subspawn/fd_parse.rb', line 7

def self.parse_fd(fd, allow_pty=false)
	# fd = if fd.respond_to? :to_path
	# fd = if fd.respond_to? :to_file
	# fd = if fd.respond_to? :to_file
	case fd
	when Integer then fd
	when IO then fd.fileno
	when :in, :input, :stdin then 0
	when :out, :output, :stdout then 1
	when :err, :error, :stderr then 2
	else
		if allow_pty and %i{pty tty}.include? fd
			:tty
		else
			raise ArgumentError, "Unknown FD type: #{fd.inspect}"
		end
	end
end

.parse_fd_opts(fds, &settty) ⇒ Object

make FdSource objects of each redirection



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# File 'lib/subspawn/fd_parse.rb', line 42

def self.parse_fd_opts(fds, &settty)
	child_lookup = {}
	fds.map do |dests, src|
		d = dests.map{|x| parse_fd(x, true)} # TODO: configurable
		src = case src
		when Array
			case src.first
			when String # file
				#raise ArgumentError, "Invalid :child FD source specification" unless src.length == 2
				# TODO: validate
				FdSource::File.new(d, *src)
			when :child
				raise ArgumentError, "Invalid :child FD source specification" unless src.length == 2
				# {a => c, b => [child, a]} is the same as {[a, b] => c}
				# so we can transform the former into the latter
				newfd = parse_fd(src.last)
				# TODO: this isn't an error, create a new one
				raise ArgumentError, "Invalid :child FD source specification" unless child_lookup[newfd]
				child_lookup[newfd].tap{|child|
					# add our destinations to the source's redirection
					d.each { |di| child.dests << di }
				}
			else
				raise ArgumentError, "Invalid FD source specification"
			end
		when String
			FdSource::File.new d, src, ({read: IO::RDONLY, write: IO::WRONLY | IO::CREAT | IO::TRUNC}[guess_mode(d)])
		when :close
			FdSource::Close.new d
		when :pty, :tty
			FdSource::PTY.new d
		when :pipe
			FdSource::Pipe.new d, guess_mode(d)
		when :pipe_r
			FdSource::Pipe.new d, :read # TODO: ensure pipe direction is sensical
		when :pipe_w
			FdSource::Pipe.new d, :read
		else
			if d.include? :tty and src.is_a? File # TODO: is this redundant?
				settty.call(src.path)
				d.delete(:tty)
			end
			FdSource::Basic.new d, parse_fd(src)
		end
		# save redirected fds so we can sneak a child reference in
		src.tap{|x| d.each{|c|
			raise ArgumentError, "Invalid FD source specification: duplicate FDs" if child_lookup[c]
			child_lookup[c] = x
			} }
	end.reject(&:nil?)
end

.which(cmd, env) ⇒ Object

I’d love to use this method, but it doesn’t accept env def self.which_jruby(cmd) require ‘jruby’ org.jruby.util.ShellLauncher.findPathExecutable(JRuby.runtime, cmd)&.absolute_path end



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# File 'lib/subspawn/fd_parse.rb', line 141

def self.which(cmd, env)
	return nil if cmd.nil? or cmd.to_str == ""
	SubSpawn::Platform. 
		expand_which(cmd, env).
		lazy.
		find {|x|!File.directory? x and File.executable? x}
end