Deprecate non-RAII init()

Summary: RAII version has been around for a while and where adopted it has simplified shutdown management, let's deprecate the old function.

Reviewed By: yfeldblum, luciang

Differential Revision: D46561311

fbshipit-source-id: 53e8068e26206e1b2ee51df535356e5187dfaa52

folly/init/Init.cpp

@@ -41,11 +41,7 @@ const unsigned long kAllFatalSignals =
 
 InitOptions::InitOptions() noexcept : fatal_signals(kAllFatalSignals) {}
 
-void init(int* argc, char*** argv, bool removeFlags) {
-  InitOptions options;
-  options.removeFlags(removeFlags);
-  init(argc, argv, options);
-}
+namespace {
 
 #if FOLLY_USE_SYMBOLIZER
 // Newer versions of glog require the function passed to InstallFailureFunction
@@ -65,7 +61,7 @@ wrapped_abort() {
 }
 #endif
 
-void init(int* argc, char*** argv, InitOptions options) {
+void initImpl(int* argc, char*** argv, InitOptions options) {
 #if !defined(_WIN32)
   // Install the handler now, to trap errors received during startup.
   // The callbacks, if any, can be installed later
@@ -104,15 +100,26 @@ void init(int* argc, char*** argv, InitOptions options) {
   folly::enable_hazptr_thread_pool_executor();
 }
 
+} // namespace
+
 Init::Init(int* argc, char*** argv, bool removeFlags) {
-  init(argc, argv, removeFlags);
+  initImpl(argc, argv, InitOptions{}.removeFlags(removeFlags));
 }
 
 Init::Init(int* argc, char*** argv, InitOptions options) {
-  init(argc, argv, options);
+  initImpl(argc, argv, options);
 }
 
 Init::~Init() {
   SingletonVault::singleton()->destroyInstancesFinal();
 }
+
+void init(int* argc, char*** argv, bool removeFlags) {
+  initImpl(argc, argv, InitOptions{}.removeFlags(removeFlags));
+}
+
+void init(int* argc, char*** argv, InitOptions options) {
+  initImpl(argc, argv, options);
+}
+
 } // namespace folly

folly/init/Init.h

@@ -17,7 +17,7 @@
 #pragma once
 #include <bitset>
 
-#include <folly/CPortability.h>
+#include <folly/Portability.h>
 
 namespace folly {
 class InitOptions {
@@ -51,35 +51,26 @@ class InitOptions {
   }
 };
 
-/*
- * Calls common init functions in the necessary order
- * Among other things, this ensures that folly::Singletons are initialized
- * correctly and installs signal handlers for a superior debugging experience.
- * It also initializes gflags and glog.
- *
- * @param argc, argv   arguments to your main
- * @param removeFlags  if true, will update argc,argv to remove recognized
- *                     gflags passed on the command line
- * @param options      options
- */
-
-void init(int* argc, char*** argv, bool removeFlags = true);
-
-void init(int* argc, char*** argv, InitOptions options);
-
 /*
  * An RAII object to be constructed at the beginning of main() and destructed
  * implicitly at the end of main().
  *
- * The constructor performs the same setup as folly::init(), including
- * initializing singletons managed by folly::Singleton.
+ * The constructor calls common init functions in the necessary order
+ * Among other things, this ensures that folly::Singletons are initialized
+ * correctly and installs signal handlers for a superior debugging experience.
+ * It also initializes gflags and glog.
  *
  * The destructor destroys all singletons managed by folly::Singleton, yielding
  * better shutdown behavior when performed at the end of main(). In particular,
  * this guarantees that all singletons managed by folly::Singleton are destroyed
  * before all Meyers singletons are destroyed.
+ *
+ * @param argc, argv   arguments to your main
+ * @param removeFlags  if true, will update argc,argv to remove recognized
+ *                     gflags passed on the command line
+ * @param options      options
  */
-class Init {
+class FOLLY_NODISCARD Init {
  public:
   // Force ctor & dtor out of line for better stack traces even with LTO.
   FOLLY_NOINLINE Init(int* argc, char*** argv, bool removeFlags = true);
@@ -94,4 +85,9 @@ class Init {
   Init& operator=(Init&&) = delete;
 };
 
+[[deprecated("Use the RAII version Init")]] void init(
+    int* argc, char*** argv, bool removeFlags = true);
+[[deprecated("Use the RAII version Init")]] void init(
+    int* argc, char*** argv, InitOptions options);
+
 } // namespace folly