From 5634b8856de22158d8da0f71ab315e3e51bc4be2 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Fri, 5 Jul 2013 11:07:02 -0400
Subject: [PATCH] add initial Cache class

---
 lib/rscons.rb             |  1 +
 lib/rscons/cache.rb       | 41 +++++++++++++++++++++++++++++++++++++++
 lib/rscons/environment.rb |  2 ++
 3 files changed, 44 insertions(+)
 create mode 100644 lib/rscons/cache.rb

diff --git a/lib/rscons.rb b/lib/rscons.rb
index c543e0d..90e4dba 100644
--- a/lib/rscons.rb
+++ b/lib/rscons.rb
@@ -1,4 +1,5 @@
 require "rscons/builder"
+require "rscons/cache"
 require "rscons/environment"
 require "rscons/version"
 
diff --git a/lib/rscons/cache.rb b/lib/rscons/cache.rb
new file mode 100644
index 0000000..65ea184
--- /dev/null
+++ b/lib/rscons/cache.rb
@@ -0,0 +1,41 @@
+require 'yaml'
+require 'fileutils'
+require 'digest/md5'
+
+module Rscons
+  class Cache
+    # Constants
+    CACHE_FILE = '.rsconscache'
+
+    # Class Methods
+    def self.clear
+      FileUtils.rm_f(CACHE_FILE)
+    end
+
+    # Instance Methods
+    def initialize
+      @cache = YAML.load(File.read(CACHE_FILE)) rescue {}
+    end
+
+    def write
+      File.open(CACHE_FILE, 'w') do |fh|
+        fh.puts(YAML.dump(@cache))
+      end
+    end
+
+    def up_to_date?(file, deps = nil)
+      # TODO
+    end
+
+    def register_build(target, deps)
+      # TODO
+    end
+
+    # Private Instance Methods
+    private
+
+    def calculate_checksum(file)
+      Digest::MD5.hexdigest(File.read(file)).encode(__ENCODING__)
+    end
+  end
+end
diff --git a/lib/rscons/environment.rb b/lib/rscons/environment.rb
index 750b13d..5098d6e 100644
--- a/lib/rscons/environment.rb
+++ b/lib/rscons/environment.rb
@@ -57,6 +57,8 @@ module Rscons
     end
 
     def process
+      cache = Cache.new
+      cache.write
     end
 
     alias_method :orig_method_missing, :method_missing