Added --relative-only option to bat pack command

This makes BAT skip assets that are referred to with an absolute path.
It is assumed that the receiver of the BAT pack can access those assets
at the same path.

tests/test_pack.py

@@ -63,6 +63,7 @@ class PackTest(AbstractPackTest):
             self.assertEqual(self.tpath / pf, act.new_path, 'for %s' % pf)
 
         self.assertEqual({}, self.rewrites(packer))
+        self.assertEqual(len(packed_files), len(packer._actions))
 
     def test_strategise_rewrite(self):
         ppath = self.blendfiles / 'subdir'
@@ -123,6 +124,29 @@ class PackTest(AbstractPackTest):
         self.assertEqual(b'LILib.002', rw_dbllink[1].block_name)
         self.assertEqual(b'//../material_textures.blend', rw_dbllink[1].asset_path)
 
+    def test_strategise_relative_only(self):
+        infile = self.blendfiles / 'absolute_path.blend'
+
+        packer = pack.Packer(infile, self.blendfiles, self.tpath,
+                             relative_only=True)
+        packer.strategise()
+
+        packed_files = (
+            'absolute_path.blend',
+            # Linked with a relative path:
+            'textures/Bricks/brick_dotted_04-color.jpg',
+            # This file links to textures/Textures/Buildings/buildings_roof_04-color.png,
+            # but using an absolute path, so that file should be skipped.
+        )
+        for pf in packed_files:
+            path = self.blendfiles / pf
+            act = packer._actions[path]
+            self.assertEqual(pack.PathAction.KEEP_PATH, act.path_action, 'for %s' % pf)
+            self.assertEqual(self.tpath / pf, act.new_path, 'for %s' % pf)
+
+        self.assertEqual(len(packed_files), len(packer._actions))
+        self.assertEqual({}, self.rewrites(packer))
+
     def test_execute_rewrite_no_touch_origs(self):
         infile, _ = self._pack_with_rewrite()