Reland r17907 - Make it possible to add more than one piece of embedder data to isolates"

include/v8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4036 matching lines @@
    */
   void Exit();
 
   /**
    * Disposes the isolate.  The isolate must not be entered by any
    * thread to be disposable.
    */
   void Dispose();
 
   /**
-   * Associate embedder-specific data with the isolate
+   * Associate embedder-specific data with the isolate. This legacy method
+   * puts the data in the 0th slot. It will be deprecated soon.
    */
   V8_INLINE void SetData(void* data);
 
   /**
-   * Retrieve embedder-specific data from the isolate.
+   * Associate embedder-specific data with the isolate. |slot| has to be
+   * between 0 and GetNumberOfDataSlots() - 1.
+   */
+  V8_INLINE void SetData(uint32_t slot, void* data);
+
+  /**
+   * Retrieve embedder-specific data from the isolate. This legacy method
+   * retrieves the data from slot 0. It will be deprecated soon.
    * Returns NULL if SetData has never been called.
    */
   V8_INLINE void* GetData();
 
   /**
+   * Retrieve embedder-specific data from the isolate.
+   * Returns NULL if SetData has never been called for the given |slot|.
+   */
+  V8_INLINE void* GetData(uint32_t slot);
+
+  /**
+   * Returns the maximum number of available embedder data slots. Valid slots
+   * are in the range of 0 - GetNumberOfDataSlots() - 1.
+   */
+  V8_INLINE static uint32_t GetNumberOfDataSlots();
+
+  /**
    * Get statistics about the heap memory usage.
    */
   void GetHeapStatistics(HeapStatistics* heap_statistics);
 
   /**
    * Adjusts the amount of registered external memory. Used to give V8 an
    * indication of the amount of externally allocated memory that is kept alive
    * by JavaScript objects. V8 uses this to decide when to perform global
    * garbage collections. Registering externally allocated memory will trigger
    * global garbage collections more often than it would otherwise in an attempt
@@ skipping 1363 matching lines @@
   static const int kForeignAddressOffset = kApiPointerSize;
   static const int kJSObjectHeaderSize = 3 * kApiPointerSize;
   static const int kFixedArrayHeaderSize = 2 * kApiPointerSize;
   static const int kContextHeaderSize = 2 * kApiPointerSize;
   static const int kContextEmbedderDataIndex = 65;
   static const int kFullStringRepresentationMask = 0x07;
   static const int kStringEncodingMask = 0x4;
   static const int kExternalTwoByteRepresentationTag = 0x02;
   static const int kExternalAsciiRepresentationTag = 0x06;
 
-  static const int kIsolateEmbedderDataOffset = 1 * kApiPointerSize;
-  static const int kIsolateRootsOffset = 3 * kApiPointerSize;
+  static const int kIsolateEmbedderDataOffset = 0 * kApiPointerSize;
+  static const int kIsolateRootsOffset = 5 * kApiPointerSize;
   static const int kUndefinedValueRootIndex = 5;
   static const int kNullValueRootIndex = 7;
   static const int kTrueValueRootIndex = 8;
   static const int kFalseValueRootIndex = 9;
   static const int kEmptyStringRootIndex = 134;
 
   static const int kNodeClassIdOffset = 1 * kApiPointerSize;
   static const int kNodeFlagsOffset = 1 * kApiPointerSize + 3;
   static const int kNodeStateMask = 0xf;
   static const int kNodeStateIsWeakValue = 2;
   static const int kNodeStateIsPendingValue = 3;
   static const int kNodeStateIsNearDeathValue = 4;
   static const int kNodeIsIndependentShift = 4;
   static const int kNodeIsPartiallyDependentShift = 5;
 
   static const int kJSObjectType = 0xb2;
   static const int kFirstNonstringType = 0x80;
   static const int kOddballType = 0x83;
   static const int kForeignType = 0x87;
 
   static const int kUndefinedOddballKind = 5;
   static const int kNullOddballKind = 3;
 
+  static const uint32_t kNumIsolateDataSlots = 4;
+
   V8_EXPORT static void CheckInitializedImpl(v8::Isolate* isolate);
   V8_INLINE static void CheckInitialized(v8::Isolate* isolate) {
 #ifdef V8_ENABLE_CHECKS
     CheckInitializedImpl(isolate);
 #endif
   }
 
   V8_INLINE static bool HasHeapObjectTag(internal::Object* value) {
     return ((reinterpret_cast<intptr_t>(value) & kHeapObjectTagMask) ==
             kHeapObjectTag);
@@ skipping 43 matching lines @@
     uint8_t* addr = reinterpret_cast<uint8_t*>(obj) + kNodeFlagsOffset;
     return *addr & kNodeStateMask;
   }
 
   V8_INLINE static void UpdateNodeState(internal::Object** obj,
                                         uint8_t value) {
     uint8_t* addr = reinterpret_cast<uint8_t*>(obj) + kNodeFlagsOffset;
     *addr = static_cast<uint8_t>((*addr & ~kNodeStateMask) | value);
   }
 
-  V8_INLINE static void SetEmbedderData(v8::Isolate* isolate, void* data) {
-    uint8_t* addr = reinterpret_cast<uint8_t*>(isolate) +
-        kIsolateEmbedderDataOffset;
+  V8_INLINE static void SetEmbedderData(v8::Isolate *isolate,
+                                        uint32_t slot,
+                                        void *data) {
+    uint8_t *addr = reinterpret_cast<uint8_t *>(isolate) +
+                    kIsolateEmbedderDataOffset + slot * kApiPointerSize;
     *reinterpret_cast<void**>(addr) = data;
   }
 
-  V8_INLINE static void* GetEmbedderData(v8::Isolate* isolate) {
+  V8_INLINE static void* GetEmbedderData(v8::Isolate* isolate, uint32_t slot) {
     uint8_t* addr = reinterpret_cast<uint8_t*>(isolate) +
-        kIsolateEmbedderDataOffset;
+        kIsolateEmbedderDataOffset + slot * kApiPointerSize;
     return *reinterpret_cast<void**>(addr);
   }
 
   V8_INLINE static internal::Object** GetRoot(v8::Isolate* isolate,
                                               int index) {
     uint8_t* addr = reinterpret_cast<uint8_t*>(isolate) + kIsolateRootsOffset;
     return reinterpret_cast<internal::Object**>(addr + index * kApiPointerSize);
   }
 
   template <typename T> V8_INLINE static T ReadField(Object* ptr, int offset) {
@@ skipping 905 matching lines @@
   typedef internal::Object* S;
   typedef internal::Internals I;
   I::CheckInitialized(isolate);
   S* slot = I::GetRoot(isolate, I::kFalseValueRootIndex);
   return Handle<Boolean>(reinterpret_cast<Boolean*>(slot));
 }
 
 
 void Isolate::SetData(void* data) {
   typedef internal::Internals I;
-  I::SetEmbedderData(this, data);
+  I::SetEmbedderData(this, 0, data);
 }
 
 
 void* Isolate::GetData() {
   typedef internal::Internals I;
-  return I::GetEmbedderData(this);
+  return I::GetEmbedderData(this, 0);
 }
 
 
+void Isolate::SetData(uint32_t slot, void* data) {
+  typedef internal::Internals I;
+  I::SetEmbedderData(this, slot, data);
+}
+
+
+void* Isolate::GetData(uint32_t slot) {
+  typedef internal::Internals I;
+  return I::GetEmbedderData(this, slot);
+}
+
+
+uint32_t Isolate::GetNumberOfDataSlots() {
+  typedef internal::Internals I;
+  return I::kNumIsolateDataSlots;
+}
+
+
 template<typename T>
 void Isolate::SetObjectGroupId(const Persistent<T>& object,
                                UniqueId id) {
   TYPE_CHECK(Value, T);
   SetObjectGroupId(reinterpret_cast<v8::internal::Object**>(object.val_), id);
 }
 
 
 template<typename T>
 void Isolate::SetReferenceFromGroup(UniqueId id,
@@ skipping 51 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_