Merge pull request #11693 from ncteisen/refactor-thread-pool

Make CreateThreadPool Settable

src/cpp/server/create_default_thread_pool.cc

@@ -23,13 +23,22 @@
 #ifndef GRPC_CUSTOM_DEFAULT_THREAD_POOL
 
 namespace grpc {
+namespace {
 
-ThreadPoolInterface* CreateDefaultThreadPool() {
+ThreadPoolInterface* CreateDefaultThreadPoolImpl() {
   int cores = gpr_cpu_num_cores();
   if (!cores) cores = 4;
   return new DynamicThreadPool(cores);
 }
 
+CreateThreadPoolFunc g_ctp_impl = CreateDefaultThreadPoolImpl;
+
+}  // namespace
+
+ThreadPoolInterface* CreateDefaultThreadPool() { return g_ctp_impl(); }
+
+void SetCreateThreadPool(CreateThreadPoolFunc func) { g_ctp_impl = func; }
+
 }  // namespace grpc
 
 #endif  // !GRPC_CUSTOM_DEFAULT_THREAD_POOL

src/cpp/server/thread_pool_interface.h

@@ -32,6 +32,10 @@ class ThreadPoolInterface {
   virtual void Add(const std::function<void()>& callback) = 0;
 };
 
+// Allows different codebases to use their own thread pool impls
+typedef ThreadPoolInterface* (*CreateThreadPoolFunc)(void);
+void SetCreateThreadPool(CreateThreadPoolFunc func);
+
 ThreadPoolInterface* CreateDefaultThreadPool();
 
 }  // namespace grpc