From e49575d4bf1bc6408952d6b469d9b80d53729263 Mon Sep 17 00:00:00 2001
From: Qinfan Wu <wqfish@fb.com>
Date: Sun, 28 May 2017 13:49:28 -0700
Subject: [PATCH] Fix tryTo to support conversion to enumerations
Summary:
[Folly] Fix `tryTo` to support conversion to enumerations.
`tryTo` should return `Expected<Tgt, ConversionCode>` instead of `Tgt`.
Reviewed By: yfeldblum
Differential Revision: D5144706
fbshipit-source-id: cd23f3cf75de7c5a26bc569f3cb47fff360f6e2a
---
folly/Conv.h | 2 +-
folly/test/ConvTest.cpp | 12 ++++++++++++
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/folly/Conv.h b/folly/Conv.h
index 22cc8ac4..6cc32705 100644
--- a/folly/Conv.h
+++ b/folly/Conv.h
@@ -1536,7 +1536,7 @@ tryTo(const Src& value) {
template <class Tgt, class Src>
typename std::enable_if<
std::is_enum<Tgt>::value && !std::is_same<Src, Tgt>::value,
- Tgt>::type
+ Expected<Tgt, ConversionCode>>::type
tryTo(const Src& value) {
using I = typename std::underlying_type<Tgt>::type;
return tryTo<I>(value).then([](I i) { return static_cast<Tgt>(i); });
diff --git a/folly/test/ConvTest.cpp b/folly/test/ConvTest.cpp
index 5f33cf48..646f8a13 100644
--- a/folly/test/ConvTest.cpp
+++ b/folly/test/ConvTest.cpp
@@ -1061,6 +1061,18 @@ TEST(Conv, TryStringToInt) {
EXPECT_EQ(rv2.value(), 4711);
}
+TEST(Conv, TryStringToEnum) {
+ enum class A { x = 42, y = 420, z = 65 };
+ auto rv1 = folly::tryTo<A>("1000000000000000000000000000000");
+ EXPECT_FALSE(rv1.hasValue());
+ auto rv2 = folly::tryTo<A>("42");
+ EXPECT_TRUE(rv2.hasValue());
+ EXPECT_EQ(A::x, rv2.value());
+ auto rv3 = folly::tryTo<A>("50");
+ EXPECT_TRUE(rv3.hasValue());
+ EXPECT_EQ(static_cast<A>(50), rv3.value());
+}
+
TEST(Conv, TryStringToFloat) {
auto rv1 = folly::tryTo<float>("");
EXPECT_FALSE(rv1.hasValue());
--
2.34.1