Fix Client PID encoding in Login7 structure (#180)

lib/tds/binary_utils.ex

@@ -50,7 +50,7 @@ defmodule Tds.BinaryUtils do
   @doc """
   An unsigned 4-byte (32-bit) value. The range when used as a numeric value is 0 to (2^32)- 1.
   """
-  defmacro dword, do: quote(do: unsigned - 32)
+  defmacro dword, do: quote(do: little - unsigned - 32)
 
   @doc """
   An unsigned single byte (8-bit) value representing a character. The range is 0 to 255.

lib/tds/protocol/login7.ex

@@ -197,16 +197,14 @@ defmodule Tds.Protocol.Login7 do
   # Return the current pid
   # If that fails return a "default" pid
   defp pid! do
-    value =
-      self()
-      |> :erlang.pid_to_list()
-      |> to_string()
-      |> String.split(".")
-      |> Enum.at(1)
-      |> String.to_integer()
-
-    <<value::dword()>>
-  rescue
-    _ -> @client_pid
+    System.pid()
+    |> Integer.parse()
+    |> case do
+      {pid, ""} ->
+        <<pid::dword()>>
+
+      _ ->
+        @client_pid
+    end
   end
 end

test/host_id_test.exs

@@ -0,0 +1,13 @@
+defmodule HostIdTest do
+  use ExUnit.Case, async: true
+
+  import Tds.TestHelper, only: [opts: 0]
+
+  test "Check that SELECT HOST_ID() matches System.pid()" do
+    {:ok, conn} = Tds.start_link(opts())
+    {:ok, %Tds.Result{rows: [[host_id]]}} = Tds.query(conn, "SELECT HOST_ID()", [])
+
+    pid = System.pid()
+    assert pid === String.trim(host_id)
+  end
+end