X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=blobdiff_plain;f=folly%2FMapUtil.h;h=433489273785a6f2677c6f36563ea2a292d8fb58;hp=d6be57115c7d55d884abf49360f1a7372ec6145b;hb=5277a636b62a8f9c80756012de9bae80358ee30e;hpb=cc84c39c1c042b20af82b8f54d72a6bf65deb58e

diff --git a/folly/MapUtil.h b/folly/MapUtil.h
index d6be5711..43348927 100644
--- a/folly/MapUtil.h
+++ b/folly/MapUtil.h
@@ -18,6 +18,7 @@
 
 #include <folly/Conv.h>
 #include <folly/Optional.h>
+#include <folly/functional/Invoke.h>
 #include <tuple>
 
 namespace folly {
@@ -26,13 +27,21 @@ namespace folly {
  * Given a map and a key, return the value corresponding to the key in the map,
  * or a given default value if the key doesn't exist in the map.
  */
-template <class Map>
-typename Map::mapped_type get_default(
-    const Map& map, const typename Map::key_type& key,
-    const typename Map::mapped_type& dflt =
-    typename Map::mapped_type()) {
+template <typename Map, typename Key>
+typename Map::mapped_type get_default(const Map& map, const Key& key) {
   auto pos = map.find(key);
-  return (pos != map.end() ? pos->second : dflt);
+  return (pos != map.end()) ? (pos->second) : (typename Map::mapped_type{});
+}
+template <
+    class Map,
+    typename Key = typename Map::key_type,
+    typename Value = typename Map::mapped_type,
+    typename std::enable_if<!is_invocable<Value>::value>::type* = nullptr>
+typename Map::mapped_type
+get_default(const Map& map, const Key& key, Value&& dflt) {
+  using M = typename Map::mapped_type;
+  auto pos = map.find(key);
+  return (pos != map.end()) ? (pos->second) : M(std::forward<Value>(dflt));
 }
 
 /**
@@ -41,12 +50,13 @@ typename Map::mapped_type get_default(
  */
 template <
     class Map,
+    typename Key = typename Map::key_type,
     typename Func,
     typename = typename std::enable_if<std::is_convertible<
         typename std::result_of<Func()>::type,
         typename Map::mapped_type>::value>::type>
 typename Map::mapped_type
-get_default(const Map& map, const typename Map::key_type& key, Func&& dflt) {
+get_default(const Map& map, const Key& key, Func&& dflt) {
   auto pos = map.find(key);
   return pos != map.end() ? pos->second : dflt();
 }
@@ -55,10 +65,13 @@ get_default(const Map& map, const typename Map::key_type& key, Func&& dflt) {
  * Given a map and a key, return the value corresponding to the key in the map,
  * or throw an exception of the specified type.
  */
-template <class E = std::out_of_range, class Map>
+template <
+    class E = std::out_of_range,
+    class Map,
+    typename Key = typename Map::key_type>
 const typename Map::mapped_type& get_or_throw(
     const Map& map,
-    const typename Map::key_type& key,
+    const Key& key,
     const std::string& exceptionStrPrefix = std::string()) {
   auto pos = map.find(key);
   if (pos != map.end()) {
@@ -67,10 +80,13 @@ const typename Map::mapped_type& get_or_throw(
   throw E(folly::to<std::string>(exceptionStrPrefix, key));
 }
 
-template <class E = std::out_of_range, class Map>
+template <
+    class E = std::out_of_range,
+    class Map,
+    typename Key = typename Map::key_type>
 typename Map::mapped_type& get_or_throw(
     Map& map,
-    const typename Map::key_type& key,
+    const Key& key,
     const std::string& exceptionStrPrefix = std::string()) {
   auto pos = map.find(key);
   if (pos != map.end()) {
@@ -83,9 +99,10 @@ typename Map::mapped_type& get_or_throw(
  * Given a map and a key, return a Optional<V> if the key exists and None if the
  * key does not exist in the map.
  */
-template <class Map>
+template <class Map, typename Key = typename Map::key_type>
 folly::Optional<typename Map::mapped_type> get_optional(
-    const Map& map, const typename Map::key_type& key) {
+    const Map& map,
+    const Key& key) {
   auto pos = map.find(key);
   if (pos != map.end()) {
     return folly::Optional<typename Map::mapped_type>(pos->second);
@@ -99,9 +116,10 @@ folly::Optional<typename Map::mapped_type> get_optional(
  * key in the map, or the given default reference if the key doesn't exist in
  * the map.
  */
-template <class Map>
+template <class Map, typename Key = typename Map::key_type>
 const typename Map::mapped_type& get_ref_default(
-    const Map& map, const typename Map::key_type& key,
+    const Map& map,
+    const Key& key,
     const typename Map::mapped_type& dflt) {
   auto pos = map.find(key);
   return (pos != map.end() ? pos->second : dflt);
@@ -113,16 +131,16 @@ const typename Map::mapped_type& get_ref_default(
  * The caller must ensure that the default value outlives the reference returned
  * by get_ref_default().
  */
-template <class Map>
+template <class Map, typename Key = typename Map::key_type>
 const typename Map::mapped_type& get_ref_default(
     const Map& map,
-    const typename Map::key_type& key,
+    const Key& key,
     typename Map::mapped_type&& dflt) = delete;
 
-template <class Map>
+template <class Map, typename Key = typename Map::key_type>
 const typename Map::mapped_type& get_ref_default(
     const Map& map,
-    const typename Map::key_type& key,
+    const Key& key,
     const typename Map::mapped_type&& dflt) = delete;
 
 /**
@@ -132,16 +150,15 @@ const typename Map::mapped_type& get_ref_default(
  */
 template <
     class Map,
+    typename Key = typename Map::key_type,
     typename Func,
     typename = typename std::enable_if<std::is_convertible<
         typename std::result_of<Func()>::type,
         const typename Map::mapped_type&>::value>::type,
     typename = typename std::enable_if<
         std::is_reference<typename std::result_of<Func()>::type>::value>::type>
-const typename Map::mapped_type& get_ref_default(
-    const Map& map,
-    const typename Map::key_type& key,
-    Func&& dflt) {
+const typename Map::mapped_type&
+get_ref_default(const Map& map, const Key& key, Func&& dflt) {
   auto pos = map.find(key);
   return (pos != map.end() ? pos->second : dflt());
 }
@@ -150,9 +167,8 @@ const typename Map::mapped_type& get_ref_default(
  * Given a map and a key, return a pointer to the value corresponding to the
  * key in the map, or nullptr if the key doesn't exist in the map.
  */
-template <class Map>
-const typename Map::mapped_type* get_ptr(
-    const Map& map, const typename Map::key_type& key) {
+template <class Map, typename Key = typename Map::key_type>
+const typename Map::mapped_type* get_ptr(const Map& map, const Key& key) {
   auto pos = map.find(key);
   return (pos != map.end() ? &pos->second : nullptr);
 }
@@ -160,9 +176,8 @@ const typename Map::mapped_type* get_ptr(
 /**
  * Non-const overload of the above.
  */
-template <class Map>
-typename Map::mapped_type* get_ptr(
-    Map& map, const typename Map::key_type& key) {
+template <class Map, typename Key = typename Map::key_type>
+typename Map::mapped_type* get_ptr(Map& map, const Key& key) {
   auto pos = map.find(key);
   return (pos != map.end() ? &pos->second : nullptr);
 }
@@ -201,7 +216,7 @@ auto extract_default(const KeysDefault&... keysDefault) ->
     typename DefaultType<KeysDefault...>::type const& {
   return std::get<sizeof...(KeysDefault)-1>(std::tie(keysDefault...));
 }
-}
+} // namespace detail
 
 /**
  * Given a map of maps and a path of keys, return a pointer to the nested value,
@@ -274,4 +289,4 @@ auto get_ref_default(
   }
   return detail::extract_default(keysDefault...);
 }
-}  // namespace folly
+} // namespace folly