Add removeAll method to sets and maps and use them

Source/wtf/HashMap.h

 /*
  * Copyright (C) 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 108 matching lines @@
         AddResult set(KeyPeekInType, MappedPassInType);
 
         // does nothing if key is already present
         // return value is a pair of the iterator to the key location,
         // and a boolean that's true if a new value was actually added
         AddResult add(KeyPeekInType, MappedPassInType);
 
         void remove(KeyPeekInType);
         void remove(iterator);
         void clear();
+        template<typename Collection>
+        void removeAll(const Collection& other);
 
         MappedPassOutType take(KeyPeekInType); // efficient combination of get with remove
 
         // An alternate version of find() that finds the object by hashing and comparing
         // with some other type, to avoid the cost of type conversion. HashTranslator
         // must have the following function members:
         //   static unsigned hash(const T&);
         //   static bool equal(const ValueType&, const T&);
         template<typename HashTranslator, typename T> iterator find(const T&);
         template<typename HashTranslator, typename T> const_iterator find(const T&) const;
@@ skipping 266 matching lines @@
         remove(find(key));
     }
 
     template<typename T, typename U, typename V, typename W, typename X, typename Y>
     inline void HashMap<T, U, V, W, X, Y>::clear()
     {
         m_impl.clear();
     }
 
     template<typename T, typename U, typename V, typename W, typename X, typename Y>
+    template<typename Collection>
+    inline void HashMap<T, U, V, W, X, Y>::removeAll(const Collection& other)

[Mikhail, 2014/04/25 11:02:26]

I'm a bit concerned that this code is repeated at every container, can we
introduce a generic free function (for instance in HashTable.h) that would be
invoked from each of 'removeAll' methods?

[Erik Corry, 2014/04/25 12:00:31]

Done.

+    {
+        if (other.isEmpty() || isEmpty())
+            return;
+        typedef typename Collection::const_iterator CollectionIterator;
+        CollectionIterator otherEnd(other.end());
+        for (CollectionIterator it(other.begin()); it != otherEnd; ++it)
+            remove(*it);
+    }
+
+    template<typename T, typename U, typename V, typename W, typename X, typename Y>
     typename HashMap<T, U, V, W, X, Y>::MappedPassOutType
     HashMap<T, U, V, W, X, Y>::take(KeyPeekInType key)
     {
         iterator it = find(key);
         if (it == end())
             return MappedTraits::passOut(MappedTraits::emptyValue());
         MappedPassOutType result = MappedTraits::passOut(it->value);
         remove(it);
         return result;
     }
@@ skipping 82 matching lines @@
         iterator end = collection.end().values();
         for (unsigned i = 0; it != end; ++it, ++i)
             vector[i] = *it;
     }
 
 } // namespace WTF
 
 using WTF::HashMap;
 
 #endif /* WTF_HashMap_h */