Backport more common classes

src/common/lru_cache.h

@@ -16,7 +16,10 @@ class LRUCache
   using MapType = std::map<K, Item>;
 
 public:
-  LRUCache(std::size_t max_capacity = 16) : m_max_capacity(max_capacity) {}
+  LRUCache(std::size_t max_capacity = 16, bool manual_evict = false)
+    : m_max_capacity(max_capacity), m_manual_evict(manual_evict)
+  {
+  }
   ~LRUCache() = default;
 
   std::size_t GetSize() const { return m_items.size(); }
@@ -31,7 +34,8 @@ public:
       Evict(m_items.size() - m_max_capacity);
   }
 
-  V* Lookup(const K& key)
+  template<typename KeyT>
+  V* Lookup(const KeyT& key)
   {
     auto iter = m_items.find(key);
     if (iter == m_items.end())
@@ -41,7 +45,7 @@ public:
     return &iter->second.value;
   }
 
-  V* Insert(const K& key, V value)
+  V* Insert(K key, V value)
   {
     ShrinkForNewItem();
 
@@ -57,7 +61,7 @@ public:
       Item it;
       it.last_access = ++m_last_counter;
       it.value = std::move(value);
-      auto ip = m_items.emplace(key, std::move(it));
+      auto ip = m_items.emplace(std::move(key), std::move(it));
       return &ip.first->second.value;
     }
   }
@@ -76,7 +80,8 @@ public:
     }
   }
 
-  bool Remove(const K& key)
+  template<typename KeyT>
+  bool Remove(const KeyT& key)
   {
     auto iter = m_items.find(key);
     if (iter == m_items.end())
@@ -86,6 +91,20 @@ public:
     return true;
   }
 
+  void SetManualEvict(bool block)
+  {
+    m_manual_evict = block;
+    if (!m_manual_evict)
+      ManualEvict();
+  }
+
+  void ManualEvict()
+  {
+    // evict if we went over
+    while (m_items.size() > m_max_capacity)
+      Evict(m_items.size() - (m_max_capacity - 1));
+  }
+
 private:
   void ShrinkForNewItem()
   {
@@ -98,4 +117,5 @@ private:
   MapType m_items;
   CounterType m_last_counter = 0;
   std::size_t m_max_capacity = 0;
+  bool m_manual_evict = false;
 };