From 1093c5155bbc196b96d52e1934036e0994f5ac81 Mon Sep 17 00:00:00 2001
From: Sahn Lam <slam@users.noreply.github.com>
Date: Thu, 15 Sep 2022 10:58:12 -0700
Subject: [PATCH] Add valid_send_options/1 (#12)

---
 lib/manifold.ex        | 16 ++++++++++++++++
 mix.exs                |  2 +-
 test/manifold_test.exs | 11 +++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/lib/manifold.ex b/lib/manifold.ex
index 5d2b2bd..10d0d5f 100644
--- a/lib/manifold.ex
+++ b/lib/manifold.ex
@@ -36,6 +36,22 @@ defmodule Manifold do
 
   ## Client
 
+  @spec valid_send_options?(Keyword.t()) :: boolean()
+  def valid_send_options?(options) when is_list(options) do
+    valid_options = [
+      {:send_mode, :offload},
+    ]
+
+    # Keywords could have duplicate keys, in which case the first key wins.
+    Keyword.keys(options)
+    |> Enum.dedup()
+    |> Enum.reduce(true, fn key, acc -> acc and {key, options[key]} in valid_options end)
+  end
+
+  def valid_send_options?(_options) do
+    false
+  end
+
   @spec send([pid | nil] | pid | nil, term, send_mode: :offload) :: :ok
   def send(pid, message, options \\ [])
   def send([pid], message, options), do: __MODULE__.send(pid, message, options)
diff --git a/mix.exs b/mix.exs
index 017d7f9..d5221cd 100644
--- a/mix.exs
+++ b/mix.exs
@@ -4,7 +4,7 @@ defmodule Manifold.Mixfile do
   def project do
     [
       app: :manifold,
-      version: "1.5.0",
+      version: "1.5.1",
       elixir: "~> 1.5",
       build_embedded: Mix.env == :prod,
       start_permanent: Mix.env == :prod,
diff --git a/test/manifold_test.exs b/test/manifold_test.exs
index 64578a3..b8c384a 100644
--- a/test/manifold_test.exs
+++ b/test/manifold_test.exs
@@ -2,6 +2,17 @@ defmodule ManifoldTest do
   use ExUnit.Case
   doctest Manifold
 
+  test "valid_send_options?" do
+    assert Manifold.valid_send_options?([])
+    assert Manifold.valid_send_options?(send_mode: :offload)
+    assert Manifold.valid_send_options?(send_mode: :offload, send_mode: :bad)
+
+    refute Manifold.valid_send_options?(send_mode: :bad, send_mode: :offload)
+    refute Manifold.valid_send_options?(unknown: :bad)
+    refute Manifold.valid_send_options?(:junk)
+    refute Manifold.valid_send_options?({:junk, :junk})
+  end
+
   test "many pids" do
     me = self()
     message = :hello