FEATURE: prototype of local theme directory watcher

(note this will be documented a bit late)

lib/theme_store/tgz_importer.rb

@@ -0,0 +1,47 @@
+module ThemeStore; end
+
+class ThemeStore::TgzImporter
+
+  attr_reader :url
+
+  def initialize(filename)
+    @temp_folder = "#{Pathname.new(Dir.tmpdir).realpath}/discourse_theme_#{SecureRandom.hex}"
+    @filename = filename
+  end
+
+  def import!
+    FileUtils.mkdir(@temp_folder)
+    Dir.chdir(@temp_folder) do
+      Discourse::Utils.execute_command("tar", "-xzvf", @filename, "--strip", "1")
+    end
+  end
+
+  def cleanup!
+    FileUtils.rm_rf(@temp_folder)
+  end
+
+  def version
+    ""
+  end
+
+  def real_path(relative)
+    fullpath = "#{@temp_folder}/#{relative}"
+    return nil unless File.exist?(fullpath)
+
+    # careful to handle symlinks here, don't want to expose random data
+    fullpath = Pathname.new(fullpath).realpath.to_s
+
+    if fullpath && fullpath.start_with?(@temp_folder)
+      fullpath
+    else
+      nil
+    end
+  end
+
+  def [](value)
+    fullpath = real_path(value)
+    return nil unless fullpath
+    File.read(fullpath)
+  end
+
+end