Class: FFI::FileProcessor

Inherits:
Object
  • Object
show all
Defined in:
lib/ffi2/generators/file_processor.rb

Overview

Processes a file containing Ruby code with blocks of FFI definitions delimited by @@@. The blocks are replaced with Ruby code produced by running the FFI generators contained in the blocks. For example:

module Something
  @@@
  constants do |c|
    c.include 'somefile.h'

    c.const 'MAX'
    c.const 'MIN'
  end
  @@@
end

would be converted to:

module Something
  MAX = 1
  MIN = 2
end

assuming that

#define MAX 1
#define MIN 2

was contained in the file ‘something.h’.

Instance Method Summary collapse

Constructor Details

#initialize(ffi_name, rb_name) ⇒ FileProcessor

Returns a new instance of FileProcessor.



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# File 'lib/ffi2/generators/file_processor.rb', line 34

def initialize(ffi_name, rb_name)
  @name = File.basename rb_name, '.rb'

  definitions = File.read ffi_name

  replacement = definitions.gsub(/^( *)@@@(.*?)@@@/m) do
    @constants = []
    @structs = []

    indent = $1
    line_count = $2.count("\n") + 1

    instance_eval $2

    lines = []
    @constants.each { |c| lines << c.to_ruby }
    @structs.each { |s| lines << s.generate_layout }

    # expand multiline blocks
    lines = lines.join("\n").split "\n"
    lines = lines.map { |line| indent + line }

    # preserve source line numbers in output
    padding = line_count - lines.length
    lines += [nil] * padding if padding >= 0

    lines.join "\n"
  end

  File.open rb_name, 'wb' do |f|
    f.puts "# This file is generated #{self.class} from #{ffi_name}."
    f.puts
    f.puts replacement
  end
end

Instance Method Details

#constants(options = {}, &block) ⇒ Object 



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# File 'lib/ffi2/generators/file_processor.rb', line 70

def constants(options={}, &block)
  @constants << FFI::ConstGenerator.new(@name, options, &block)
end

#struct(&block) ⇒ Object 



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# File 'lib/ffi2/generators/file_processor.rb', line 74

def struct(&block)
  @structs << FFI::StructGenerator.new(@name, &block)
end

#to_s ⇒ Object

Utility converter for constants



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# File 'lib/ffi2/generators/file_processor.rb', line 81

def to_s
  proc { |obj| obj.to_s.inspect }
end