(core) move data engine code to core

Summary:
this moves sandbox/grist to core, and adds a requirements.txt
file for reconstructing the content of sandbox/thirdparty.

Test Plan:
existing tests pass.
Tested core functionality manually.  Tested docker build manually.

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2563

sandbox/grist/test_actions.py

@@ -0,0 +1,79 @@
+import unittest
+
+import actions
+
+class TestActions(unittest.TestCase):
+  action_obj1 = actions.UpdateRecord("foo", 17, {"bar": "baz"})
+  doc_action1 = ["UpdateRecord", "foo", 17, {"bar": "baz"}]
+
+  def test_convert(self):
+    self.assertEqual(actions.get_action_repr(self.action_obj1), self.doc_action1)
+    self.assertEqual(actions.action_from_repr(self.doc_action1), self.action_obj1)
+
+    with self.assertRaises(ValueError) as err:
+      actions.action_from_repr(["Foo", "bar"])
+    self.assertTrue("Foo" in str(err.exception))
+
+  def test_prune_actions(self):
+    # prune_actions is in-place, so we make a new list every time.
+    def alist():
+      return [
+        actions.BulkUpdateRecord("Table1", [1,2,3], {'Foo': [10,20,30]}),
+        actions.BulkUpdateRecord("Table2", [1,2,3], {'Foo': [10,20,30], 'Bar': ['a','b','c']}),
+        actions.UpdateRecord("Table1", 17, {'Foo': 10}),
+        actions.UpdateRecord("Table2", 18, {'Foo': 10, 'Bar': 'a'}),
+        actions.AddRecord("Table1", 17, {'Foo': 10}),
+        actions.BulkAddRecord("Table2", 18, {'Foo': 10, 'Bar': 'a'}),
+        actions.ReplaceTableData("Table2", 18, {'Foo': 10, 'Bar': 'a'}),
+        actions.RemoveRecord("Table1", 17),
+        actions.BulkRemoveRecord("Table2", [17,18]),
+        actions.AddColumn("Table1", "Foo", {"type": "Text"}),
+        actions.RenameColumn("Table1", "Foo", "Bar"),
+        actions.ModifyColumn("Table1", "Foo", {"type": "Text"}),
+        actions.RemoveColumn("Table1", "Foo"),
+        actions.AddTable("THello", [{"id": "Foo"}, {"id": "Bar"}]),
+        actions.RemoveTable("THello"),
+        actions.RenameTable("THello", "TWorld"),
+      ]
+
+    def prune(table_id, col_id):
+      a = alist()
+      actions.prune_actions(a, table_id, col_id)
+      return a
+
+    self.assertEqual(prune('Table1', 'Foo'), [
+      actions.BulkUpdateRecord("Table2", [1,2,3], {'Foo': [10,20,30], 'Bar': ['a','b','c']}),
+      actions.UpdateRecord("Table2", 18, {'Foo': 10, 'Bar': 'a'}),
+      actions.BulkAddRecord("Table2", 18, {'Foo': 10, 'Bar': 'a'}),
+      actions.ReplaceTableData("Table2", 18, {'Foo': 10, 'Bar': 'a'}),
+      actions.RemoveRecord("Table1", 17),
+      actions.BulkRemoveRecord("Table2", [17,18]),
+      # It doesn't do anything with column renames; it can be addressed if needed.
+      actions.RenameColumn("Table1", "Foo", "Bar"),
+      # It doesn't do anything with AddTable, which is expected.
+      actions.AddTable("THello", [{"id": "Foo"}, {"id": "Bar"}]),
+      actions.RemoveTable("THello"),
+      actions.RenameTable("THello", "TWorld"),
+    ])
+
+    self.assertEqual(prune('Table2', 'Foo'), [
+      actions.BulkUpdateRecord("Table1", [1,2,3], {'Foo': [10,20,30]}),
+      actions.BulkUpdateRecord("Table2", [1,2,3], {'Bar': ['a','b','c']}),
+      actions.UpdateRecord("Table1", 17, {'Foo': 10}),
+      actions.UpdateRecord("Table2", 18, {'Bar': 'a'}),
+      actions.AddRecord("Table1", 17, {'Foo': 10}),
+      actions.BulkAddRecord("Table2", 18, {'Bar': 'a'}),
+      actions.ReplaceTableData("Table2", 18, {'Bar': 'a'}),
+      actions.RemoveRecord("Table1", 17),
+      actions.BulkRemoveRecord("Table2", [17,18]),
+      actions.AddColumn("Table1", "Foo", {"type": "Text"}),
+      actions.RenameColumn("Table1", "Foo", "Bar"),
+      actions.ModifyColumn("Table1", "Foo", {"type": "Text"}),
+      actions.RemoveColumn("Table1", "Foo"),
+      actions.AddTable("THello", [{"id": "Foo"}, {"id": "Bar"}]),
+      actions.RemoveTable("THello"),
+      actions.RenameTable("THello", "TWorld"),
+    ])
+
+if __name__ == "__main__":
+  unittest.main()