Implement PersistentValueMap, a map that stores UniquePersistent values.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index cfffc914b46f56593e5b97b6e6d09063e6118623..27493d9ee8df34a4472bd737379c8d935e5dcf16 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -140,6 +140,7 @@ class ObjectOperationDescriptor;
 class RawOperationDescriptor;
 class CallHandlerHelper;
 class EscapableHandleScope;
+template<typename T> class ReturnValue;
 
 namespace internal {
 class Arguments;
@@ -412,6 +413,7 @@ template <class T> class Local : public Handle<T> {
   template<class F> friend class internal::CustomArguments;
   friend class HandleScope;
   friend class EscapableHandleScope;
+  template<class F1, class F2, class F3> friend class PersistentValueMap;
 
   V8_INLINE static Local<T> New(Isolate* isolate, T* that);
 };
@@ -527,7 +529,11 @@ template <class T> class PersistentBase {
       P* parameter,
       typename WeakCallbackData<S, P>::Callback callback);
 
-  V8_INLINE void ClearWeak();
+  template<typename P>
+  V8_INLINE P* ClearWeak();
+
+  // TODO(dcarney): remove this.
+  V8_INLINE void ClearWeak() { ClearWeak<void>(); }
 
   /**
    * Marks the reference to this object independent. Garbage collector is free
@@ -576,6 +582,7 @@ template <class T> class PersistentBase {
   template<class F> friend class UniquePersistent;
   template<class F> friend class PersistentBase;
   template<class F> friend class ReturnValue;
+  template<class F1, class F2, class F3> friend class PersistentValueMap;
 
   explicit V8_INLINE PersistentBase(T* val) : val_(val) {}
   PersistentBase(PersistentBase& other); // NOLINT
@@ -781,6 +788,7 @@ class UniquePersistent : public PersistentBase<T> {
   template<class S>
   V8_INLINE UniquePersistent& operator=(UniquePersistent<S> rhs) {
     TYPE_CHECK(T, S);
+    this->Reset();
     this->val_ = rhs.val_;
     rhs.val_ = 0;
     return *this;
@@ -800,6 +808,103 @@ class UniquePersistent : public PersistentBase<T> {
 };
 
 
+typedef uintptr_t PersistentContainerValue;
+static const uintptr_t kPersistentContainerNotFound = 0;
+
+/**
+ * A map wrapper that allows using UniquePersistent as a mapped value.
+ * C++11 embedders don't need this class, as they can use UniquePersistent
+ * directly in std containers.
+ **/
+template<class K, class V, class Traits>

[dcarney, 2014/03/11 15:12:05]

need to add some small comments to the functions to explain what they do

[vogelheim, 2014/03/11 16:11:59]

Done. Please let me know if they're helpful.

+class PersistentValueMap {
+ public:
+  V8_INLINE explicit PersistentValueMap(Isolate* isolate) : isolate_(isolate) {}
+
+  V8_INLINE ~PersistentValueMap() { Clear(); }
+
+  V8_INLINE Isolate* GetIsolate() { return isolate_; }
+
+  V8_INLINE size_t Size() { return Traits::Size(&impl_); }
+
+  V8_INLINE Local<V> Get(const K& key) {
+    return Local<V>::New(isolate_, FromVal(Traits::Get(&impl_, key)));
+  }
+
+  V8_INLINE bool Contains(const K& key) {
+    return Traits::Get(&impl_, key) != 0;
+  }
+
+  V8_INLINE bool SetReturnValue(const K& key,
+    ReturnValue<Value>& returnValue);
+
+  V8_INLINE void SetReference(const K& key,
+      const v8::Persistent<v8::Object>& parent) {
+    GetIsolate()->SetReference(
+      reinterpret_cast<internal::Object**>(parent.val_),
+      reinterpret_cast<internal::Object**>(FromVal(Traits::Get(&impl_, key))));
+  }
+
+  UniquePersistent<V> Set(const K& key, Local<V> value) {
+    UniquePersistent<V> persistent(isolate_, value);
+    return SetUnique(key, &persistent);
+  }
+
+  UniquePersistent<V> Set(const K& key, UniquePersistent<V> value) {
+    return SetUnique(key, &value);
+  }
+
+  V8_INLINE UniquePersistent<V> Remove(const K& key) {
+    return Release(Traits::Remove(&impl_, key)).Pass();
+  }
+
+  /**
+  * Traverses the map repeatedly,
+  * in case side effects of disposal cause insertions.
+  **/
+  void Clear();
+
+ private:
+  PersistentValueMap(PersistentValueMap&);
+  void operator=(PersistentValueMap&);
+
+  UniquePersistent<V> SetUnique(const K& key, UniquePersistent<V>* persistent) {
+    if (Traits::kIsWeak) {
+      Local<V> value(Local<V>::New(isolate_, *persistent));
+      persistent->template SetWeak<typename Traits::WeakCallbackDataType>(
+        Traits::WeakCallbackParameter(&impl_, key, value), WeakCallback);
+    }
+    PersistentContainerValue old_value =
+        Traits::Set(&impl_, key, ClearAndLeak(persistent));
+    return Release(old_value).Pass();
+  }
+
+  static void WeakCallback(
+      const WeakCallbackData<V, typename Traits::WeakCallbackDataType>& data);
+  V8_INLINE static V* FromVal(PersistentContainerValue v) {
+    return reinterpret_cast<V*>(v);
+  }
+  V8_INLINE static PersistentContainerValue ClearAndLeak(
+      UniquePersistent<V>* persistent) {
+    V* v = persistent->val_;
+    persistent->val_ = 0;
+    return reinterpret_cast<PersistentContainerValue>(v);
+  }
+  V8_INLINE static UniquePersistent<V> Release(PersistentContainerValue v) {
+    UniquePersistent<V> p;
+    p.val_ = FromVal(v);
+    if (Traits::kIsWeak && !p.IsEmpty()) {
+      Traits::DisposeCallbackData(
+          p.template ClearWeak<typename Traits::WeakCallbackDataType>());
+    }
+    return p.Pass();
+  }
+
+  Isolate* isolate_;
+  typename Traits::Impl impl_;
+};
+
+
  /**
  * A stack-allocated class that governs a number of local handles.
  * After a handle scope has been created, all local handles will be
@@ -1011,12 +1116,16 @@ class V8_EXPORT Script {
    * \param pre_data Pre-parsing data, as obtained by ScriptData::PreCompile()
    *   using pre_data speeds compilation if it's done multiple times.
    *   Owned by caller, no references are kept when New() returns.
+   * \param script_data Arbitrary data associated with script. Using
+   *   this has same effect as calling SetData(), but allows data to be
+   *   available to compile event handlers.
    * \return Compiled script object (context independent; when run it
    *   will use the currently entered context).
    */
   static Local<Script> New(Handle<String> source,
                            ScriptOrigin* origin = NULL,
-                           ScriptData* pre_data = NULL);
+                           ScriptData* pre_data = NULL,
+                           Handle<String> script_data = Handle<String>());
 
   /**
    * Compiles the specified script using the specified file name
@@ -1040,13 +1149,17 @@ class V8_EXPORT Script {
    * \param pre_data Pre-parsing data, as obtained by ScriptData::PreCompile()
    *   using pre_data speeds compilation if it's done multiple times.
    *   Owned by caller, no references are kept when Compile() returns.
+   * \param script_data Arbitrary data associated with script. Using
+   *   this has same effect as calling SetData(), but makes data available
+   *   earlier (i.e. to compile event handlers).
    * \return Compiled script object, bound to the context that was active
    *   when this function was called.  When run it will always use this
    *   context.
    */
   static Local<Script> Compile(Handle<String> source,
                                ScriptOrigin* origin = NULL,
-                               ScriptData* pre_data = NULL);
+                               ScriptData* pre_data = NULL,
+                               Handle<String> script_data = Handle<String>());
 
   /**
    * Compiles the specified script using the specified file name
@@ -1054,12 +1167,16 @@ class V8_EXPORT Script {
    *
    * \param source Script source code.
    * \param file_name File name to use as script's origin
+   * \param script_data Arbitrary data associated with script. Using
+   *   this has same effect as calling SetData(), but makes data available
+   *   earlier (i.e. to compile event handlers).
    * \return Compiled script object, bound to the context that was active
    *   when this function was called.  When run it will always use this
    *   context.
    */
   static Local<Script> Compile(Handle<String> source,
-                               Handle<Value> file_name);
+                               Handle<Value> file_name,
+                               Handle<String> script_data = Handle<String>());
 
   /**
    * Runs the script returning the resulting value.  If the script is
@@ -1076,6 +1193,13 @@ class V8_EXPORT Script {
   int GetId();
 
   /**
+   * Associate an additional data object with the script. This is mainly used
+   * with the debugger as this data object is only available through the
+   * debugger API.
+   */
+  void SetData(Handle<String> data);
+
+  /**
    * Returns the name value of one Script.
    */
   Handle<Value> GetScriptName();
@@ -2370,6 +2494,8 @@ class ReturnValue {
   template<class F> friend class ReturnValue;
   template<class F> friend class FunctionCallbackInfo;
   template<class F> friend class PropertyCallbackInfo;
+  template<class F, class G, class H> friend class PersistentValueMap;
+  V8_INLINE void SetInternal(internal::Object* value) { *value_ = value; }
   V8_INLINE internal::Object* GetDefaultValue();
   V8_INLINE explicit ReturnValue(internal::Object** slot);
   internal::Object** value_;
@@ -4173,6 +4299,8 @@ class V8_EXPORT Isolate {
   void RequestGarbageCollectionForTesting(GarbageCollectionType type);
 
  private:
+  template<class K, class V, class Traits> friend class PersistentValueMap;
+
   Isolate();
   Isolate(const Isolate&);
   ~Isolate();
@@ -4767,7 +4895,7 @@ class V8_EXPORT V8 {
   static void MakeWeak(internal::Object** global_handle,
                        void* data,
                        WeakCallback weak_callback);
-  static void ClearWeak(internal::Object** global_handle);
+  static void* ClearWeak(internal::Object** global_handle);
   static void Eternalize(Isolate* isolate,
                          Value* handle,
                          int* index);
@@ -5395,7 +5523,7 @@ class Internals {
   static const int kNullValueRootIndex = 7;
   static const int kTrueValueRootIndex = 8;
   static const int kFalseValueRootIndex = 9;
-  static const int kEmptyStringRootIndex = 144;
+  static const int kEmptyStringRootIndex = 142;
 
   static const int kNodeClassIdOffset = 1 * kApiPointerSize;
   static const int kNodeFlagsOffset = 1 * kApiPointerSize + 3;
@@ -5680,8 +5808,10 @@ void PersistentBase<T>::SetWeak(
 
 
 template <class T>
-void PersistentBase<T>::ClearWeak() {
-  V8::ClearWeak(reinterpret_cast<internal::Object**>(this->val_));
+template<typename P>
+P* PersistentBase<T>::ClearWeak() {
+  return reinterpret_cast<P*>(
+    V8::ClearWeak(reinterpret_cast<internal::Object**>(this->val_)));
 }
 
 
@@ -5734,6 +5864,44 @@ uint16_t PersistentBase<T>::WrapperClassId() const {
 }
 
 
+template <class K, class V, class Traits>
+bool PersistentValueMap<K, V, Traits>::SetReturnValue(const K& key,
+    ReturnValue<Value>& returnValue) {
+  PersistentContainerValue value = Traits::Get(&impl_, key);
+  bool hasValue = value != 0;
+  if (hasValue) {
+    returnValue.SetInternal(
+        *reinterpret_cast<internal::Object**>(FromVal(value)));
+  }
+  return hasValue;
+}
+
+template <class K, class V, class Traits>
+void PersistentValueMap<K, V, Traits>::Clear() {
+  typedef typename Traits::Iterator It;
+  HandleScope handle_scope(isolate_);
+  // TODO(dcarney): figure out if this swap and loop is necessary.
+  while (!Traits::Empty(&impl_)) {
+    typename Traits::Impl impl;
+    Traits::Swap(impl_, impl);
+    for (It i = Traits::Begin(&impl); i != Traits::End(&impl); ++i) {
+      Traits::Dispose(Release(Traits::Value(i)).Pass(), isolate_, &impl,
+        Traits::Key(i));
+    }
+  }
+}
+
+
+template <class K, class V, class Traits>
+void PersistentValueMap<K, V, Traits>::WeakCallback(
+    const WeakCallbackData<V, typename Traits::WeakCallbackDataType>& data) {
+  typename Traits::Impl* impl = Traits::ImplFromWeakCallbackData(data);
+  K key = Traits::KeyFromWeakCallbackData(data);
+  PersistentContainerValue value = Traits::Remove(impl, key);
+  Traits::Dispose(Release(value).Pass(), data.GetIsolate(), impl, key);

[dcarney, 2014/03/11 15:12:05]

all function which take an isolate parameter have it as the first parameter by
convention

[vogelheim, 2014/03/11 16:11:59]

Done.

+}
+
+
 template<typename T>
 ReturnValue<T>::ReturnValue(internal::Object** slot) : value_(slot) {}
 
@@ -5742,9 +5910,9 @@ template<typename S>
 void ReturnValue<T>::Set(const Persistent<S>& handle) {
   TYPE_CHECK(T, S);
   if (V8_UNLIKELY(handle.IsEmpty())) {
-    *value_ = GetDefaultValue();
+    SetInternal(GetDefaultValue());

[dcarney, 2014/03/11 15:12:05]

not much point in changing this if there's no if(V8_UNLIKELY) ... in SetInternal

[vogelheim, 2014/03/11 16:11:59]

Done.

   } else {
-    *value_ = *reinterpret_cast<internal::Object**>(*handle);
+    SetInternal(*reinterpret_cast<internal::Object**>(*handle));
   }
 }
 
@@ -5753,9 +5921,9 @@ template<typename S>
 void ReturnValue<T>::Set(const Handle<S> handle) {
   TYPE_CHECK(T, S);
   if (V8_UNLIKELY(handle.IsEmpty())) {
-    *value_ = GetDefaultValue();
+    SetInternal(GetDefaultValue());
   } else {
-    *value_ = *reinterpret_cast<internal::Object**>(*handle);
+    SetInternal(*reinterpret_cast<internal::Object**>(*handle));
   }
 }