rakefile for C++ source build.

rake-for-cpp

# coding: utf-8
require 'fileutils'

### 定数 ###
COMPILER = "g++"
CPPFLAGS = %w{}
LDFLAGS = %w{}
INC_DIRS = []
LIB_DIRS = []
TARGET = "app"

SRC_ROOT = "."
BUILD_ROOT = "./.build"
OBJ_ROOT = BUILD_ROOT + "/objs"
DEP_ROOT = BUILD_ROOT + "/deps"

EXE_EXT = '.exe'
SRC_EXT = '.cpp'
OBJ_EXT = '.o'
DEP_EXT = '.mf'

SRCS = FileList["#{SRC_ROOT}/**/*#{SRC_EXT}"]
LIBS = FileList[]

### メソッド定義 ###

def CPPFLAGS.to_option_s
  self.join(' ')
end

def LDFLAGS.to_option_s
  self.join(' ')
end

def INC_DIRS.to_option_s
  self.map{|dir| "-I\"#{dir}\""}.join(' ')
end

def LIB_DIRS.to_option_s
  self.map {|dir| "-L\"#{dir}\""}.join(' ')
end

def change_root(path, from, to)
  path.gsub(Regexp.new("\\A" + from), to)
end

# ソースファイル, オブジェクトファイル, 依存情報ファイルのパスを相互変換する
def convert_path(file, to)
  ext = File.extname(file)
  root_dir =
    case ext 
    when SRC_EXT then SRC_ROOT
    when OBJ_EXT then OBJ_ROOT
    when DEP_EXT then DEP_ROOT
    end
  new_root, new_ext =
    case to
    when :source then [SRC_ROOT, SRC_EXT]
    when :object then [OBJ_ROOT, OBJ_EXT]
    when :depend then [DEP_ROOT, DEP_EXT]
    end
  change_root(file, root_dir, new_root).gsub(Regexp.new("\\#{ext}$"), new_ext)
end

def src_path(file)
  convert_path(file, :source)
end

def obj_path(file)
  convert_path(file, :object)
end

def dep_path(file)
  convert_path(file, :depend)
end

def make_depfile(srcfile)
  depfile = dep_path(srcfile)
  objfile = obj_path(srcfile)
  sh "#{COMPILER} #{CPPFLAGS.to_option_s} #{INC_DIRS.to_option_s} -MM -MT #{objfile} #{srcfile} -MF #{depfile}"
end

def load_depfile(depfile)
  line = File.readlines(depfile).shift
  obj, deps = line.split(':', 2)
  deps = deps.split(' ').map{|s| s.strip}
  return obj, deps
end

# 依存情報ファイルから依存ファイルリストを読み込んで返す
def dependencies(objfile)
  depfile = dep_path(objfile)

  # 必要なら依存情報ファイルを生成する
  file(depfile).invoke

  obj, deps = load_depfile(depfile)
  objfile.include?(obj) ? deps : []
end

def cleanup(file_name)
  rm_r file_name if File.exist?(file_name)
end

# オブジェクトファイルのリストを生成
OBJS = FileList[SRCS.map {|src| obj_path(src)}]

### タスク ###

task :default => "build"

desc "Setup build environment."
task :setup do
  Dir.glob("#{SRC_ROOT}/**/").each do |srcdir|
    [OBJ_ROOT, DEP_ROOT].each do |root|
      dir = change_root(srcdir, SRC_ROOT, root)
      FileUtils.mkdir_p(dir) unless Dir.exist?(dir)
    end
  end
end

desc "Build application."
task :build do |t|
  task(:setup).invoke
  task(TARGET).invoke
end

desc "Rebuild application."
task :rebuild do |t|
  task(:clobber).invoke
  task(:build).invoke
end

desc "Remove temporary files."
task :clean do
  ["#{BUILD_ROOT}/**/*#{OBJ_EXT}", "#{BUILD_ROOT}/**/*#{DEP_EXT}"].each do |file_name|
    cleanup(file_name)
  end
end

desc "Remove all generated files."
task :clobber => :clean do
  ["#{TARGET}#{EXE_EXT}", BUILD_ROOT].each do |file_name|
    cleanup(file_name)
  end
end

### 依存関係 ###

file TARGET => [OBJS, LIBS].flatten do |t|
  sh "#{COMPILER} #{LIB_DIRS.to_option_s} #{LDFLAGS.to_option_s} -o #{TARGET} #{t.prerequisites.join(' ')}"
end

rule OBJ_EXT => [proc{|objfile| dependencies(objfile)}] do |r|
  objfile = r.name
  srcfile = src_path(objfile)
  sh "#{COMPILER} #{CPPFLAGS.to_option_s} #{INC_DIRS.to_option_s} -o #{objfile} -c #{srcfile}"
end

rule DEP_EXT do |r|
  make_depfile(src_path(r.name))
end