From c1be26e5844b71e2e2ce197fa71b88cd36376761 Mon Sep 17 00:00:00 2001
From: Giuseppe Ottaviano <ott@fb.com>
Date: Fri, 11 Sep 2015 17:37:20 -0700
Subject: [PATCH] Add support for std::string in folly::Hash
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Reviewed By: @​liviu

Differential Revision: D2436705
---
 folly/Hash.h            | 6 ++++++
 folly/test/HashTest.cpp | 8 +++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/folly/Hash.h b/folly/Hash.h
index f40f4ec2..07eb5571 100644
--- a/folly/Hash.h
+++ b/folly/Hash.h
@@ -375,6 +375,12 @@ template<> struct hasher<uint64_t> {
   }
 };
 
+template<> struct hasher<std::string> {
+  size_t operator()(const std::string& key) const {
+    return hash::SpookyHashV2::Hash64(key.data(), key.size(), 0);
+  }
+};
+
 template <class T>
 struct hasher<T, typename std::enable_if<std::is_enum<T>::value, void>::type> {
   size_t operator()(T key) const {
diff --git a/folly/test/HashTest.cpp b/folly/test/HashTest.cpp
index bbae4f6f..de12b1e0 100644
--- a/folly/test/HashTest.cpp
+++ b/folly/test/HashTest.cpp
@@ -303,7 +303,7 @@ TEST(Hash, std_tuple_different_hash) {
             std::hash<tuple3>()(t3));
 }
 
-TEST(Range, Hash) {
+TEST(Hash, Strings) {
   using namespace folly;
 
   StringPiece a1 = "10050517", b1 = "51107032",
@@ -329,4 +329,10 @@ TEST(Range, Hash) {
   EXPECT_NE(h2(w1), h2(w2));
   EXPECT_NE(h2(w1), h2(w3));
   EXPECT_NE(h2(w2), h2(w4));
+
+  // Check compatibility with std::string.
+  EXPECT_EQ(h2(a1), h2(a1.str()));
+  EXPECT_EQ(h2(a2), h2(a2.str()));
+  EXPECT_EQ(h2(a3), h2(a3.str()));
+  EXPECT_EQ(h2(a4), h2(a4.str()));
 }
-- 
2.34.1