add initial checkout handler

lib/svi.rb

@@ -1,3 +1,4 @@
+require_relative "svi/ansi"
 require_relative "svi/cli"
 require_relative "svi/svn_runner"
 require_relative "svi/version"
@@ -7,6 +8,32 @@ module Svi
   class << self
 
     def checkout(url)
+      last_checkout_message = ""
+      clear_message = lambda do
+        if last_checkout_message.size > 0
+          clear = ""
+          lines = (last_checkout_message.size + C.screen_width - 1) / C.screen_width
+          if lines > 1
+            clear += Ansi.cursor_up(lines - 1)
+          end
+          clear += Ansi.cursor_back(999)
+          clear += Ansi.erase_cursor_to_eos
+          $stdout.write(clear)
+          last_checkout_message = ""
+        end
+      end
+      SvnRunner.run_svn("checkout", [url], allow_interactive: true) do |line|
+        if line =~ /^A.{4}(.*)$/
+          path = $1
+          clear_message[]
+          last_checkout_message = "Checking out #{path}..."
+          $stdout.write(last_checkout_message)
+          $stdout.flush
+        else
+          clear_message[]
+          $stdout.puts line
+        end
+      end
       0
     end
 

lib/svi/ansi.rb

@@ -0,0 +1,21 @@
+module Svi
+  module Ansi
+
+    class << self
+
+      def cursor_up(n = 1)
+        "\e[#{n}A"
+      end
+
+      def cursor_back(n = 1)
+        "\e[#{n}D"
+      end
+
+      def erase_cursor_to_eos
+        "\e[J"
+      end
+
+    end
+
+  end
+end