From: Jiahao Li <jiahaoli@fb.com>
Date: Fri, 7 Jul 2017 19:22:51 +0000 (-0700)
Subject: Adds `make_mock` to `folly::LeakySingleton`.
X-Git-Tag: v2017.07.10.00~3
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=7f15a179e20b0d61bfb5e872956993b0c6afaa30;p=folly.git

Adds `make_mock` to `folly::LeakySingleton`.

Summary:
Provides a `make_mock` interface to `folly::LeakySingleton` for unit test
mocking.

Reviewed By: andriigrynenko

Differential Revision: D5382003

fbshipit-source-id: 9ab81dd64703f4f02772bfb8c85e020680abcc85
---

diff --git a/folly/Singleton.h b/folly/Singleton.h
index 104054af..64b6f375 100644
--- a/folly/Singleton.h
+++ b/folly/Singleton.h
@@ -669,6 +669,21 @@ class LeakySingleton {
 
   static T& get() { return instance(); }
 
+  static void make_mock(std::nullptr_t /* c */ = nullptr) {
+    make_mock([]() { return new T; });
+  }
+
+  static void make_mock(CreateFunc createFunc) {
+    auto& entry = entryInstance();
+    if (createFunc == nullptr) {
+      throw std::logic_error(
+          "nullptr_t should be passed if you want T to be default constructed");
+    }
+
+    entry.createFunc = createFunc;
+    entry.state = State::Dead;
+  }
+
  private:
   enum class State { NotRegistered, Dead, Living };