Debugger: use weak cells to implement ScriptCache.

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 994 matching lines @@
   V(JSGlobalObject)                \
   V(JSBuiltinsObject)              \
   V(JSGlobalProxy)                 \
   V(UndetectableObject)            \
   V(AccessCheckNeeded)             \
   V(Cell)                          \
   V(PropertyCell)                  \
   V(WeakCell)                      \
   V(ObjectHashTable)               \
   V(WeakHashTable)                 \
+  V(WeakValueHashTable)            \
   V(OrderedHashTable)
 
 // Object is the abstract superclass for all classes in the
 // object hierarchy.
 // Object does not use any virtual functions to avoid the
 // allocation of the C++ vtable.
 // Since both Smi and HeapObject are subclasses of Object no
 // data members can be present in Object.
 class Object {
  public:
@@ skipping 2926 matching lines @@
   // Adds (or overwrites) the value associated with the given key.
   static Handle<ObjectHashTable> Put(Handle<ObjectHashTable> table,
                                      Handle<Object> key,
                                      Handle<Object> value);
 
   // Returns an ObjectHashTable (possibly |table|) where |key| has been removed.
   static Handle<ObjectHashTable> Remove(Handle<ObjectHashTable> table,
                                         Handle<Object> key,
                                         bool* was_present);
 
- private:
+ protected:
   friend class MarkCompactCollector;
 
   void AddEntry(int entry, Object* key, Object* value);
   void RemoveEntry(int entry);
 
   // Returns the index to the value of an entry.
   static inline int EntryToValueIndex(int entry) {
     return EntryToIndex(entry) + 1;
   }
 };
@@ skipping 206 matching lines @@
   // Looks up the value associated with the given key. The hole value is
   // returned in case the key is not present.
   Object* Lookup(Handle<HeapObject> key);
 
   // Adds (or overwrites) the value associated with the given key. Mapping a
   // key to the hole value causes removal of the whole entry.
   MUST_USE_RESULT static Handle<WeakHashTable> Put(Handle<WeakHashTable> table,
                                                    Handle<HeapObject> key,
                                                    Handle<HeapObject> value);
 
+  static Handle<FixedArray> GetValues(Handle<WeakHashTable> table);
+
  private:
   friend class MarkCompactCollector;
 
   void AddEntry(int entry, Handle<WeakCell> key, Handle<HeapObject> value);
 
   // Returns the index to the value of an entry.
   static inline int EntryToValueIndex(int entry) {
     return EntryToIndex(entry) + 1;
   }
 };
 
 
+class WeakValueHashTable : public ObjectHashTable {
+ public:
+  DECLARE_CAST(WeakValueHashTable)
+
+#ifdef DEBUG
+  // Looks up the value associated with the given key. The hole value is
+  // returned in case the key is not present.
+  Object* LookupWeak(Handle<Object> key);
+#endif  // DEBUG
+
+  // Adds (or overwrites) the value associated with the given key. Mapping a
+  // key to the hole value causes removal of the whole entry.
+  MUST_USE_RESULT static Handle<WeakValueHashTable> PutWeak(
+      Handle<WeakValueHashTable> table, Handle<Object> key,
+      Handle<HeapObject> value);
+
+  static Handle<FixedArray> GetWeakValues(Handle<WeakValueHashTable> table);
+};
+
+
 // JSFunctionResultCache caches results of some JSFunction invocation.
 // It is a fixed array with fixed structure:
 //   [0]: factory function
 //   [1]: finger index
 //   [2]: current cache size
 //   [3]: dummy field.
 // The rest of array are key/value pairs.
-class JSFunctionResultCache: public FixedArray {
+class JSFunctionResultCache : public FixedArray {
  public:
   static const int kFactoryIndex = 0;
   static const int kFingerIndex = kFactoryIndex + 1;
   static const int kCacheSizeIndex = kFingerIndex + 1;
   static const int kDummyIndex = kCacheSizeIndex + 1;
   static const int kEntriesIndex = kDummyIndex + 1;
 
   static const int kEntrySize = 2;  // key + value
 
   static const int kFactoryOffset = kHeaderSize;
@@ skipping 6912 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_