Merge b4c8636 into a198dd4

lib/xgit/core/file_mode.ex

@@ -86,6 +86,20 @@ defmodule Xgit.Core.FileMode do
 
   @valid_file_modes [0o100644, 0o100755, 0o120000, 0o040000, 0o160000]
 
+  @doc ~S"""
+  Return a rendered version of this file mode as an octal charlist.
+
+  Optimized for the known file modes. Errors out for any other mode.
+  """
+  @spec to_octal(file_mode :: t) :: charlist
+  def to_octal(file_mode)
+
+  def to_octal(0o040000), do: cover('040000')
+  def to_octal(0o120000), do: cover('120000')
+  def to_octal(0o100644), do: cover('100644')
+  def to_octal(0o100755), do: cover('100755')
+  def to_octal(0o160000), do: cover('160000')
+
   @doc ~S"""
   This guard requires the value to be one of the known git file mode values.
   """

test/xgit/core/file_mode_test.exs

@@ -65,6 +65,18 @@ defmodule Xgit.Core.FileModeTest do
     refute FileMode.valid?(FileMode.gitlink() + 1)
   end
 
+  test "to_octal/1" do
+    assert FileMode.to_octal(FileMode.tree()) == '040000'
+    assert FileMode.to_octal(FileMode.symlink()) == '120000'
+    assert FileMode.to_octal(FileMode.regular_file()) == '100644'
+    assert FileMode.to_octal(FileMode.executable_file()) == '100755'
+    assert FileMode.to_octal(FileMode.gitlink()) == '160000'
+
+    assert_raise FunctionClauseError, fn ->
+      FileMode.to_octal(FileMode.gitlink() + 1)
+    end
+  end
+
   @valid_file_modes [0o040000, 0o120000, 0o100644, 0o100755, 0o160000]
 
   defp accepted_file_mode?(t) when is_file_mode(t), do: true