lib/librarian/posix.rb
require "open3"
require "rbconfig"
require "librarian/error"
module Librarian
module Posix
module Platform
extend self
def win?
host_os = RbConfig::CONFIG["host_os"].dup.freeze
host_os =~ /mswin|mingw/
end
end
class << self
# Cross-platform way of finding an executable in the $PATH.
#
# which('ruby') #=> /usr/bin/ruby
#
# From:
# https://github.com/defunkt/hub/commit/353031307e704d860826fc756ff0070be5e1b430#L2R173
def which(cmd)
exts = ENV["PATHEXT"] ? ENV["PATHEXT"].split(';') : ['']
ENV["PATH"].split(File::PATH_SEPARATOR).each do |path|
path = File.expand_path(path)
exts.each do |ext|
exe = File.join(path, cmd + ext)
return exe if File.file?(exe) && File.executable?(exe)
end
end
nil
end
def which!(cmd)
which(cmd) or raise Error, "cannot find #{cmd}"
end
end
class CommandFailure < Error
class << self
def raise!(command, status, message)
ex = new(message)
ex.command = command
ex.status = status
ex.set_backtrace caller
raise ex
end
end
attr_accessor :command, :status
end
class << self
def rescuing(*klasses)
begin
yield
rescue *klasses
end
end
# Hacky way to run a program because we need to update our own env and
# working directory before running the command. Useful when we don't have
# either fork or spawn or when we don't have fork and spawn doesn't
# support all the options we need.
def run_popen3!(command, options = { })
out, err = nil, nil
chdir = options[:chdir].to_s if options[:chdir]
env = options[:env] || { }
old_env = Hash[env.keys.map{|k| [k, ENV[k]]}]
out, err, wait = nil, nil, nil
begin
ENV.update env
Dir.chdir(chdir || Dir.pwd) do
IO.popen3(*command) do |i, o, e, w|
rescuing(Errno::EBADF){ i.close } # jruby/1.9 can raise EBADF
out, err, wait = o.read, e.read, w
end
end
ensure
ENV.update old_env
end
s = wait ? wait.value : $? # wait is 1.9+-only
s.success? or CommandFailure.raise! command, s, err
out
end
# Semi-hacky way to run a program because we're just reimplementing spawn.
# Useful when we have fork but we don't have spawn or when we have fork
# but spawn doesn't support all the options we need.
def run_forkexec!(command, options = { })
i, o, e = IO.pipe, IO.pipe, IO.pipe
pid = fork do
$stdin.reopen i[0]
$stdout.reopen o[1]
$stderr.reopen e[1]
[i[1], i[0], o[0], e[0]].each &:close
ENV.update options[:env] || { }
Dir.chdir options[:chdir].to_s if options[:chdir]
exec *command
end
[i[0], i[1], o[1], e[1]].each &:close
Process.waitpid pid
$?.success? or CommandFailure.raise! command, $?, e[0].read
o[0].read
ensure
[i, o, e].flatten(1).each{|io| io.close unless io.closed?}
end
# The sensible way to run a program.
def run_spawn!(command, options = { })
i, o, e = IO.pipe, IO.pipe, IO.pipe
opts = {:in => i[0], :out => o[1], :err => e[1]}
opts[:chdir] = options[:chdir].to_s if options[:chdir]
command = command.dup
command.unshift options[:env] || { }
command.push opts
pid = Process.spawn(*command)
[i[0], i[1], o[1], e[1]].each &:close
Process.waitpid pid
$?.success? or CommandFailure.raise! command, $?, e[0].read
o[0].read
ensure
[i, o, e].flatten(1).each{|io| io.close unless io.closed?}
end
# jruby-1.7.9 can't fork and doesn't have a decent spawn
# windows can't fork and doesn't have a decent spawn
if defined?(JRuby) || Platform.win?
alias_method :run!, :run_popen3!
else
if RUBY_VERSION < "1.9"
alias_method :run!, :run_forkexec!
else
alias_method :run!, :run_spawn!
end
end
end
end
end