backupping file when change

3 files changed, 23 insertions, 2 deletions

diff --git a/TODO.md b/TODO.md
index 1f83cad..120fec9 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,7 +1,6 @@
 # TODO
 
 * Recursively install a directory
-* Backup of files when changed
 * Support for file deletion
 * Support for file modes (owner, chmod)
 * Support for symlinks
diff --git a/lib/dslkeywords/file.rb b/lib/dslkeywords/file.rb
index b42f223..e83906e 100644
--- a/lib/dslkeywords/file.rb
+++ b/lib/dslkeywords/file.rb
@@ -1,13 +1,32 @@
+require 'digest'
 require 'erb'
 require 'fileutils'
 
 require_relative 'resource'
 
 module RCM
+  # Backup the file on change
+  module FileBackup
+    def backup!(path)
+      return unless ::File.exist?(path)
+
+      backup_dir = "#{::File.dirname(path)}/.rcm"
+      Dir.mkdir(backup_dir) unless ::File.directory?(backup_dir)
+      checksum = Digest::SHA256.file(path).hexdigest
+      backup_path = "#{backup_dir}/#{::File.basename(path)}.#{checksum}"
+      return if ::File.exist?(backup_path)
+
+      info("Backing up #{path} -> #{backup_path}")
+      ::File.rename(path, backup_path)
+    end
+  end
+
   # Managing files
   class File < Resource
     attr_reader :path
 
+    include FileBackup
+
     def initialize(path)
       super(path)
       @path = path
@@ -45,9 +64,10 @@ module RCM
     def write_content!(text)
       create_parent_directory!
       debug text if option :debug
-      info "Creating file #{@path}"
+      info "Managing file #{@path}"
       tmp_path = "#{@path}.tmp"
       ::File.write(tmp_path, text)
+      backup!(@path)
       ::File.rename(tmp_path, @path)
     end
 
diff --git a/lib/dslkeywords/resource.rb b/lib/dslkeywords/resource.rb
index f646030..f665a50 100644
--- a/lib/dslkeywords/resource.rb
+++ b/lib/dslkeywords/resource.rb
@@ -69,6 +69,8 @@ module RCM
 
     class NoSuchResourceObject < StandardError; end
 
+    # TODO: Detect duplicate resource definition
+
     @@resource_find_cache = {}
 
     def self.find(id)