Fix code for anything-to-string space estimation

[folly.git] / folly / Conv.h

diff --git a/folly/Conv.h b/folly/Conv.h
index 6103849a26e121701a74fa283c4b26198891c7ee..08628a0e44018b943f0a07cfa59f739d8281dc68 100644 (file)
--- a/folly/Conv.h
+++ b/folly/Conv.h
@@ -719,7 +719,9 @@ estimateSpaceNeeded(const Src&) {
 
 namespace detail {
 
-inline size_t estimateSpaceToReserve(size_t sofar) {
+template <class Tgt>
+typename std::enable_if<IsSomeString<Tgt>::value, size_t>::type
+estimateSpaceToReserve(size_t sofar, Tgt*) {
   return sofar;
 }
 
@@ -728,11 +730,6 @@ size_t estimateSpaceToReserve(size_t sofar, const T& v, const Ts&... vs) {
   return estimateSpaceToReserve(sofar + estimateSpaceNeeded(v), vs...);
 }
 
-template<class T>
-size_t estimateSpaceToReserve(size_t sofar, const T& v) {
-  return sofar + estimateSpaceNeeded(v);
-}
-
 template<class...Ts>
 void reserveInTarget(const Ts&...vs) {
   getLastElement(vs...)->reserve(estimateSpaceToReserve(0, vs...));
@@ -741,7 +738,8 @@ void reserveInTarget(const Ts&...vs) {
 template<class Delimiter, class...Ts>
 void reserveInTargetDelim(const Delimiter& d, const Ts&...vs) {
   static_assert(sizeof...(vs) >= 2, "Needs at least 2 args");
-  size_t fordelim = (sizeof...(vs) - 2) * estimateSpaceToReserve(0, d);
+  size_t fordelim = (sizeof...(vs) - 2) *
+      estimateSpaceToReserve(0, d, static_cast<std::string*>(nullptr));
   getLastElement(vs...)->reserve(estimateSpaceToReserve(fordelim, vs...));
 }