Class: ChildProcess::Tools::Generator

Inherits:
Object
  • Object
show all
Defined in:
lib/childprocess/tools/generator.rb

Constant Summary collapse

EXE_NAME = 
"childprocess-sizeof-generator"
TMP_PROGRAM = 
"childprocess-sizeof-generator.c"
DEFAULT_INCLUDES = 
%w[stdio.h stddef.h]

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Generator

Returns a new instance of Generator.



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# File 'lib/childprocess/tools/generator.rb', line 15

def initialize
  @cc        = ENV['CC'] || 'gcc'
  @out       = File.expand_path("../../unix/platform/#{ChildProcess.platform_name}.rb", __FILE__)
  @sizeof    = {}
  @constants = {}
end

Class Method Details

.generate ⇒ Object 



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# File 'lib/childprocess/tools/generator.rb', line 11

def self.generate
  new.generate
end

Instance Method Details

#execute(src, opts) ⇒ Object 



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# File 'lib/childprocess/tools/generator.rb', line 86

def execute(src, opts)
  program = Array(opts[:define]).map do |key, value|
    <<-SRC
#ifndef #{key}
#define #{key} #{value}
#endif
    SRC
  end.join("\n")
  program << "\n"

  includes = Array(opts[:include]) + DEFAULT_INCLUDES
  program << includes.map { |include| "#include <#{include}>" }.join("\n")
  program << "\n#{src}"

  File.open(TMP_PROGRAM, 'w') do |file|
    file << program
  end

  cmd = "#{@cc} #{TMP_PROGRAM} -o #{EXE_NAME}"
  system cmd
  unless $?.success?
    raise "failed to compile program: #{cmd.inspect}\n#{program}"
  end

  output = `./#{EXE_NAME} 2>&1`

  unless $?.success?
    raise "failed to run program: #{cmd.inspect}\n#{output}"
  end

  output.chomp
ensure
  File.delete TMP_PROGRAM if File.exist?(TMP_PROGRAM)
  File.delete EXE_NAME if File.exist?(EXE_NAME)
end

#fetch_constant(name, opts) ⇒ Object 



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# File 'lib/childprocess/tools/generator.rb', line 69

def fetch_constant(name, opts)
  print "#{name}: "
  src = <<-EOF
int main() {
  printf("%d", (unsigned int)#{name});
  return 0;
}
  EOF

  output = execute(src, opts)
  value  = Integer(output)
  @constants[name] = value

  puts value
end

#fetch_size(type_name, opts = {}) ⇒ Object 



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# File 'lib/childprocess/tools/generator.rb', line 48

def fetch_size(type_name, opts = {})
  print "sizeof(#{type_name}): "
  src = <<-EOF
int main() {
  printf("%d", (unsigned int)sizeof(#{type_name}));
  return 0;
}
  EOF

  output = execute(src, opts)

  if output.to_i < 1
    raise "sizeof(#{type_name}) == #{output.to_i} (output=#{output})"
  end

  size = output.to_i
  @sizeof[type_name] = size

  puts size
end

#generate ⇒ Object 



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# File 'lib/childprocess/tools/generator.rb', line 22

def generate
  fetch_size 'posix_spawn_file_actions_t', :include => "spawn.h"
  fetch_size 'posix_spawnattr_t', :include => "spawn.h"
  fetch_size 'sigset_t', :include => "signal.h"

  fetch_constant 'POSIX_SPAWN_RESETIDS',   :include  => 'spawn.h'
  fetch_constant 'POSIX_SPAWN_SETPGROUP',  :include  => 'spawn.h'
  fetch_constant 'POSIX_SPAWN_SETSIGDEF',  :include  => 'spawn.h'
  fetch_constant 'POSIX_SPAWN_SETSIGMASK', :include  => 'spawn.h'

  if ChildProcess.linux?
    fetch_constant 'POSIX_SPAWN_USEVFORK', :include => 'spawn.h', :define => {'_GNU_SOURCE' => nil}
  end

  write
end

#result ⇒ Object 



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# File 'lib/childprocess/tools/generator.rb', line 122

def result
  if @sizeof.empty?
    raise "no sizes collected, nothing to do"
  end

  out =  ['module ChildProcess::Unix::Platform']
  out << '  SIZEOF = {'

  max = @sizeof.keys.map { |e| e.length }.max
  @sizeof.each_with_index do |(type, size), idx|
    out << "     :#{type.ljust max} => #{size}#{',' unless idx == @sizeof.size - 1}"
  end
  out << '  }'

  max = @constants.keys.map { |e| e.length }.max
  @constants.each do |name, val|
    out << "  #{name.ljust max} = #{val}"
  end
  out << 'end'

  out.join "\n"
end

#write ⇒ Object 



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# File 'lib/childprocess/tools/generator.rb', line 39

def write
  FileUtils.mkdir_p(File.dirname(@out))
  File.open(@out, 'w') do |io|
    io.puts result
  end

  puts "wrote #{@out}"
end