Changeset 51566 in webkit for trunk/JavaScriptCore/wtf/HashMap.h

Timestamp:

Dec 1, 2009, 4:05:30 PM (15 years ago)

Author:

[email protected]

Message:

JavaScriptCore: Added variants of find/contains/add that allow a foreign key type to be used.
This will allow AtomicString-keyed maps to be queried by C string without
having to create a temporary AtomicString (see HTTPHeaderMap.)
The code for this is adapted from the equivalent in HashSet.h.

WebCore: Add convenience methods to Element and QualifiedName that take
char* instead of AtomicString, in preparation for removing the
implicit conversion between the two types (30187).
​https://bugs.webkit.org/show_bug.cgi?id=31749

Reviewed by Darin Adler.

File:

• trunk/JavaScriptCore/wtf/HashMap.h (modified) (4 diffs)

trunk/JavaScriptCore/wtf/HashMap.h

@@ -84 +84 @@
         MappedType take(const KeyType&); // 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 T, typename HashTranslator> iterator find(const T&);
+        template<typename T, typename HashTranslator> const_iterator find(const T&) const;
+        template<typename T, typename HashTranslator> bool contains(const T&) const;
+
+        // An alternate version of add() that finds the object by hashing and comparing
+        // with some other type, to avoid the cost of type conversion if the object is already
+        // in the table. HashTranslator must have the following function members:
+        //   static unsigned hash(const T&);
+        //   static bool equal(const ValueType&, const T&);
+        //   static translate(ValueType&, const T&, unsigned hashCode);
+        template<typename T, typename HashTranslator> pair<iterator, bool> add(const T&, const MappedType&);
+
     private:
         pair<iterator, bool> inlineAdd(const KeyType&, const MappedType&);
@@ -108 +125 @@
     };
 
+    template<typename ValueType, typename ValueTraits, typename T, typename Translator>
+    struct HashMapTranslatorAdapter {
+        typedef typename ValueType::first_type KeyType;
+        typedef typename ValueType::second_type MappedType;
+
+        static unsigned hash(const T& key) { return Translator::hash(key); }
+        static bool equal(const KeyType& a, const T& b) { return Translator::equal(a, b); }
+        static void translate(ValueType& location, const T& key, const MappedType&, unsigned hashCode)
+        {
+            Translator::translate(location.first, key, hashCode);
+        }
+    };
+
     template<typename T, typename U, typename V, typename W, typename X>
     inline void HashMap<T, U, V, W, X>::swap(HashMap& other)
@@ -172 +202 @@
     {
         return m_impl.contains(key);
+    }
+
+    template<typename T, typename U, typename V, typename W, typename X>
+    template<typename TYPE, typename HashTranslator>
+    inline typename HashMap<T, U, V, W, X>::iterator
+    HashMap<T, U, V, W, X>::find(const TYPE& value)
+    {
+        typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
+        return m_impl.template find<TYPE, Adapter>(value);
+    }
+
+    template<typename T, typename U, typename V, typename W, typename X>
+    template<typename TYPE, typename HashTranslator>
+    inline typename HashMap<T, U, V, W, X>::const_iterator 
+    HashMap<T, U, V, W, X>::find(const TYPE& value) const
+    {
+        typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
+        return m_impl.template find<TYPE, Adapter>(value);
+    }
+
+    template<typename T, typename U, typename V, typename W, typename X>
+    template<typename TYPE, typename HashTranslator>
+    inline bool
+    HashMap<T, U, V, W, X>::contains(const TYPE& value) const
+    {
+        typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
+        return m_impl.template contains<TYPE, Adapter>(value);
     }
 
@@ -192 +249 @@
         }
         return result;
+    }
+
+    template<typename T, typename U, typename V, typename W, typename X>
+    template<typename TYPE, typename HashTranslator>
+    pair<typename HashMap<T, U, V, W, X>::iterator, bool>
+    HashMap<T, U, V, W, X>::add(const TYPE& key, const MappedType& value)
+    {
+        typedef HashMapTranslatorAdapter<ValueType, ValueTraits, TYPE, HashTranslator> Adapter;
+        return m_impl.template addPassingHashCode<TYPE, MappedType, Adapter>(key, value);
     }