Rakefile.rb

# coding: utf-8

require "ostruct"
require "fileutils"
require "pp"
require "pathname"
require "rake/loaders/makefile"

### Variables ###

# Project Strcuture
OBJ_ROOT = "build/obj"
SRC_ROOT = {
	"main" => "./src"
}

# Commands of Tools
CXX  = "clang++"
LINK = "clang++ -dynamiclib"

# Flags for Compiler
CXXFLAGS = %w{
	-std=c++1y
}

# Libraries
LIBS = %w{ stdc++ }

# Header Search Paths
INCLUDES = SRC_ROOT.values
INCLUDES.concat(%w(
))

# Final Outputs
ENTRYPOINTS = {
	"build/test.dylib" => ["main/test.cpp"]
}


### Source Files ###

# Collecting all the ".cpp" files in the project.
CXXFILES = {}
SRC_ROOT.each do |name, root|
	base = Pathname.new(root)
	Dir["#{root}/**/*.{cpp,cxx,c}"].map {|e| Pathname.new(e) }.each do |src|
		key = src.relative_path_from(base)
		CXXFILES["#{name}/#{key}"] = OpenStruct.new({
			src: src.to_path,
			obj: "#{OBJ_ROOT}/#{name}/#{key}.o",
			dep: "#{OBJ_ROOT}/#{name}/#{key}.depends.mf",
		})
	end
end

# Copies the directory structure of `SRC_ROOT` into `OBJ_ROOT`.
CXXFILES.values.each do |e|
	FileUtils.mkpath(File.dirname(e.obj))
end


### Top-level Tasks ###

ep_files = ENTRYPOINTS.keys

task :default => ENTRYPOINTS.keys
task :release => ENTRYPOINTS.keys do |t|
	CXXFLAGS.push("-O3")
end

task :debug => ENTRYPOINTS.keys do |t|
	CXXFLAGS.push("-g")
end

task :clean do
	FileUtils.rm_r("build")
	exit
end


### Dependencies among Source Files and Final Outputs ###

cc_opts = []
cc_opts << CXXFLAGS.join(" ")
cc_opts << INCLUDES.map {|e| "-I#{e}" }.join(" ")
cxxflags = cc_opts.join(" ")

CXXFILES.each do |key, sub|
	file sub.dep => sub.obj
	file sub.obj => sub.src do |t|
		sh %Q{#{CXX} #{cxxflags} -c -MD -MF #{sub.dep} -o #{sub.obj} #{sub.src}}
	end
	import sub.dep
end

obj_files_0 = CXXFILES.reject {|key, e| ENTRYPOINTS.values.flatten.include?(key) }.values.map(&:obj)

ENTRYPOINTS.each do |out, keys|
	file out => (CXXFILES.values_at(*keys).map(&:obj) + obj_files_0) do |t|
		sh %Q{#{LINK} -o #{t.name} #{t.prerequisites.join " "} #{LIBS.map {|e| "-l" + e }.join " "}}
	end
end