From b07e4a0a4cd184c15ddb7bc1d137fd7071416a64 Mon Sep 17 00:00:00 2001
From: Jack Lloyd <jack@randombit.net>
Date: Thu, 11 Jul 2024 17:42:40 -0400
Subject: [PATCH] wip

---
 src/lib/utils/thread_utils/thread_pool.h |  7 ----
 src/lib/utils/thread_utils/work_fn.h     | 48 ++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 7 deletions(-)
 create mode 100644 src/lib/utils/thread_utils/work_fn.h

diff --git a/src/lib/utils/thread_utils/thread_pool.h b/src/lib/utils/thread_utils/thread_pool.h
index 9673efebc13..62b028a81b6 100644
--- a/src/lib/utils/thread_utils/thread_pool.h
+++ b/src/lib/utils/thread_utils/thread_pool.h
@@ -38,13 +38,6 @@ class BOTAN_TEST_API Thread_Pool final {
       */
       Thread_Pool(std::optional<size_t> pool_size);
 
-      /**
-      * Initialize a thread pool with some number of threads
-      * @param pool_size number of threads in the pool, if 0
-      *        then some default value is chosen.
-      */
-      Thread_Pool(size_t pool_size = 0) : Thread_Pool(std::optional<size_t>(pool_size)) {}
-
       ~Thread_Pool() { shutdown(); }
 
       void shutdown();
diff --git a/src/lib/utils/thread_utils/work_fn.h b/src/lib/utils/thread_utils/work_fn.h
new file mode 100644
index 00000000000..dbf84338c10
--- /dev/null
+++ b/src/lib/utils/thread_utils/work_fn.h
@@ -0,0 +1,48 @@
+/*
+* (C) 2024 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_WORK_FN_H_
+#define BOTAN_WORK_FN_H_
+
+#include <functional>
+#include <memory>
+
+namespace Botan {
+
+/**
+* A Work Executor is something capable of executing functions
+*
+* The library delegates certain work 
+*/
+class Work_Executor {
+   public:
+      /**
+      * Set the global work executor. This allows for example
+      * providing a custom thread pool.
+      */
+      static void set_global_work_executor(std::shared_ptr<Work_Executor> worker);
+
+      virtual ~Work_Executor() = default;
+
+      /**
+      * The work executor promises to eventually call fn
+      *
+      * The execution may be delayed and in any order
+      */
+      virtual void run_work(const std::function<void()>& fn) = 0;
+
+      /**
+      * Return a best-effort approximation of how much parallelism is
+      * possible
+      */
+      virtual size_t available_parallelism() const = 0;
+
+      worker_count() const { return m_workers.size(); }
+};
+
+}
+
+#endif