From 557ef577085017887cfbc8bcc8445b719a78cf95 Mon Sep 17 00:00:00 2001
From: kballou <kballou@devnulllabs.io>
Date: Wed, 8 Feb 2017 19:48:24 -0700
Subject: WIP: initial packfile parser

---
 lib/exgit/packfile.ex                     |  13 +++++++++++++
 test/exgit/packfile_test.exs              |  24 ++++++++++++++++++++++++
 test/fixtures/packfiles/pack-simple.idx   | Bin 0 -> 1156 bytes
 test/fixtures/packfiles/pack-simple.pack  | Bin 0 -> 210 bytes
 test/fixtures/packfiles/pack-simple3.pack | Bin 0 -> 210 bytes
 5 files changed, 37 insertions(+)
 create mode 100644 test/fixtures/packfiles/pack-simple.idx
 create mode 100644 test/fixtures/packfiles/pack-simple.pack
 create mode 100644 test/fixtures/packfiles/pack-simple3.pack

diff --git a/lib/exgit/packfile.ex b/lib/exgit/packfile.ex
index 4fda345..3823259 100644
--- a/lib/exgit/packfile.ex
+++ b/lib/exgit/packfile.ex
@@ -2,4 +2,17 @@ defmodule Exgit.Packfile do
   @moduledoc """
   Module for parsing Git Packfiles
   """
+
+  @spec parse_header(binary) :: {:pack, 2|3, integer}
+  def parse_header(packfile) do
+    <<"PACK" :: utf8, 2 :: size(32), n :: size(32)>> <> rest = packfile
+    {:pack, 2, n, rest}
+  end
+
+  @spec parse_objects(integer, binary) :: [{:commit|:blob|:tree,
+                                            binary,
+                                            binary}]
+  def parse_objects(n, pack) do
+    nil
+  end
 end
diff --git a/test/exgit/packfile_test.exs b/test/exgit/packfile_test.exs
index fd49787..a3c5d4c 100644
--- a/test/exgit/packfile_test.exs
+++ b/test/exgit/packfile_test.exs
@@ -1,4 +1,28 @@
 defmodule Exgit.Packfile.Test do
   use ExUnit.Case
+  import Exgit.Packfile
+
   doctest Exgit.Packfile
+
+  @fixtures_dir "test/fixtures/packfiles/"
+
+  describe "can parse header information" do
+    test "header with version 2" do
+      filename = Path.join(@fixtures_dir, "pack-simple.pack")
+      packfile = File.read!(filename)
+      assert {:pack, 2, 3, _} = parse_header(packfile)
+    end
+  end
+
+  describe "parse objects from pack" do
+    test "can return all objects from pack" do
+      filename = Path.join(@fixtures_dir, "pack-simple.pack")
+      packfile = File.read!(filename)
+      {:pack, 2, 3, rest} = parse_header(packfile)
+      assert [{:commit, "ca5bae75ae512b3e3a3d86f6009452d24cc3873f", },
+              {:blob, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391", _},
+              {:tree, "4d5fcadc293a348e88f777dc0920f11e7d71441c", _}] =
+             parse_objects(3, rest)
+    end
+  end
 end
diff --git a/test/fixtures/packfiles/pack-simple.idx b/test/fixtures/packfiles/pack-simple.idx
new file mode 100644
index 0000000..0bd43fd
Binary files /dev/null and b/test/fixtures/packfiles/pack-simple.idx differ
diff --git a/test/fixtures/packfiles/pack-simple.pack b/test/fixtures/packfiles/pack-simple.pack
new file mode 100644
index 0000000..58a2362
Binary files /dev/null and b/test/fixtures/packfiles/pack-simple.pack differ
diff --git a/test/fixtures/packfiles/pack-simple3.pack b/test/fixtures/packfiles/pack-simple3.pack
new file mode 100644
index 0000000..58a2362
Binary files /dev/null and b/test/fixtures/packfiles/pack-simple3.pack differ
-- 
cgit v1.2.1