Add findEntry() methods to HashMap and TreeMap.

c++/src/kj/map.h

@@ -87,6 +87,14 @@ public:
   // Like find() but if the key isn't present then call createEntry() to create the corresponding
   // entry and insert it. createEntry() must return type `Entry`.
 
+  template <typename KeyLike>
+  kj::Maybe<Entry&> findEntry(KeyLike&& key);
+  template <typename KeyLike>
+  kj::Maybe<const Entry&> findEntry(KeyLike&& key) const;
+  template <typename KeyLike, typename Func>
+  Entry& findOrCreateEntry(KeyLike&& key, Func&& createEntry);
+  // Sometimes you need to see the whole matching Entry, not just the Value.
+
   template <typename KeyLike>
   bool erase(KeyLike&& key);
   // Erase the entry with the matching key.
@@ -176,6 +184,14 @@ public:
   // Like find() but if the key isn't present then call createEntry() to create the corresponding
   // entry and insert it. createEntry() must return type `Entry`.
 
+  template <typename KeyLike>
+  kj::Maybe<Entry&> findEntry(KeyLike&& key);
+  template <typename KeyLike>
+  kj::Maybe<const Entry&> findEntry(KeyLike&& key) const;
+  template <typename KeyLike, typename Func>
+  Entry& findOrCreateEntry(KeyLike&& key, Func&& createEntry);
+  // Sometimes you need to see the whole matching Entry, not just the Value.
+
   template <typename K1, typename K2>
   auto range(K1&& k1, K2&& k2);
   template <typename K1, typename K2>
@@ -353,6 +369,25 @@ Value& HashMap<Key, Value>::findOrCreate(KeyLike&& key, Func&& createEntry) {
   return table.findOrCreate(key, kj::fwd<Func>(createEntry)).value;
 }
 
+template <typename Key, typename Value>
+template <typename KeyLike>
+kj::Maybe<typename HashMap<Key, Value>::Entry&>
+HashMap<Key, Value>::findEntry(KeyLike&& key) {
+  return table.find(kj::fwd<KeyLike>(key));
+}
+template <typename Key, typename Value>
+template <typename KeyLike>
+kj::Maybe<const typename HashMap<Key, Value>::Entry&>
+HashMap<Key, Value>::findEntry(KeyLike&& key) const {
+  return table.find(kj::fwd<KeyLike>(key));
+}
+template <typename Key, typename Value>
+template <typename KeyLike, typename Func>
+typename HashMap<Key, Value>::Entry&
+HashMap<Key, Value>::findOrCreateEntry(KeyLike&& key, Func&& createEntry) {
+  return table.findOrCreate(kj::fwd<KeyLike>(key), kj::fwd<Func>(createEntry));
+}
+
 template <typename Key, typename Value>
 template <typename KeyLike>
 bool HashMap<Key, Value>::erase(KeyLike&& key) {
@@ -445,6 +480,25 @@ Value& TreeMap<Key, Value>::findOrCreate(KeyLike&& key, Func&& createEntry) {
   return table.findOrCreate(key, kj::fwd<Func>(createEntry)).value;
 }
 
+template <typename Key, typename Value>
+template <typename KeyLike>
+kj::Maybe<typename TreeMap<Key, Value>::Entry&>
+TreeMap<Key, Value>::findEntry(KeyLike&& key) {
+  return table.find(kj::fwd<KeyLike>(key));
+}
+template <typename Key, typename Value>
+template <typename KeyLike>
+kj::Maybe<const typename TreeMap<Key, Value>::Entry&>
+TreeMap<Key, Value>::findEntry(KeyLike&& key) const {
+  return table.find(kj::fwd<KeyLike>(key));
+}
+template <typename Key, typename Value>
+template <typename KeyLike, typename Func>
+typename TreeMap<Key, Value>::Entry&
+TreeMap<Key, Value>::findOrCreateEntry(KeyLike&& key, Func&& createEntry) {
+  return table.findOrCreate(kj::fwd<KeyLike>(key), kj::fwd<Func>(createEntry));
+}
+
 template <typename Key, typename Value>
 template <typename K1, typename K2>
 auto TreeMap<Key, Value>::range(K1&& k1, K2&& k2) {