text: // 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
  //       with the distribution.
  //     * Neither the name of Google Inc. nor the names of its
  //       contributors may be used to endorse or promote products derived
  //       from this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #ifndef V8_ARGUMENTS_H_
  #define V8_ARGUMENTS_H_
  
  #include "allocation.h"
  
  namespace v8 {
  namespace internal {
  
  // Arguments provides access to runtime call parameters.
  //
  // It uses the fact that the instance fields of Arguments
  // (length_, arguments_) are "overlayed" with the parameters
  // (no. of parameters, and the parameter pointer) passed so
  // that inside the C++ function, the parameters passed can
  // be accessed conveniently:
  //
  //   Object* Runtime_function(Arguments args) {
  //     ... use args[i] here ...
  //   }
  
  class Arguments BASE_EMBEDDED {
   public:
    Arguments(int length, Object** arguments)
        : length_(length), arguments_(arguments) { }
  
    Object*& operator[] (int index) {
      ASSERT(0 <= index && index < length_);
      return arguments_[-index];
    }
  
    template <class S> Handle<S> at(int index) {
      Object** value = &((*this)[index]);
      // This cast checks that the object we're accessing does indeed have the
      // expected type.
      S::cast(*value);
      return Handle<S>(reinterpret_cast<S**>(value));
    }
  
    int smi_at(int index) {
      return Smi::cast((*this)[index])->value();
    }
  
    double number_at(int index) {
      return (*this)[index]->Number();
    }
  
    // Get the total number of arguments including the receiver.
    int length() const { return length_; }
  
    Object** arguments() { return arguments_; }
  
   private:
    int length_;
    Object** arguments_;
  };
  
  
  // mappings from old property callbacks to new ones
  // F(old name, new name, return value, parameters...)
  //
  // These aren't included in the list as they have duplicate signatures
  // F(NamedPropertyEnumerator, NamedPropertyEnumeratorCallback, ...)
  // F(NamedPropertyGetter, NamedPropertyGetterCallback, ...)
  
  #define FOR_EACH_CALLBACK_TABLE_MAPPING_0(F) \
    F(IndexedPropertyEnumerator, IndexedPropertyEnumeratorCallback, v8::Array) \
  
  #define FOR_EACH_CALLBACK_TABLE_MAPPING_1(F) \
    F(AccessorGetter, AccessorGetterCallback, v8::Value, v8::Local<v8::String>) \
    F(NamedPropertyQuery, \
      NamedPropertyQueryCallback, \
      v8::Integer, \
      v8::Local<v8::String>) \
    F(NamedPropertyDeleter, \
      NamedPropertyDeleterCallback, \
      v8::Boolean, \
      v8::Local<v8::String>) \
    F(IndexedPropertyGetter, \
      IndexedPropertyGetterCallback, \
      v8::Value, \
      uint32_t) \
    F(IndexedPropertyQuery, \
      IndexedPropertyQueryCallback, \
      v8::Integer, \
      uint32_t) \
    F(IndexedPropertyDeleter, \
      IndexedPropertyDeleterCallback, \
      v8::Boolean, \
      uint32_t) \
  
  #define FOR_EACH_CALLBACK_TABLE_MAPPING_2(F) \
    F(NamedPropertySetter, \
      NamedPropertySetterCallback, \
      v8::Value, \
      v8::Local<v8::String>, \
      v8::Local<v8::Value>) \
    F(IndexedPropertySetter, \
      IndexedPropertySetterCallback, \
      v8::Value, \
      uint32_t, \
      v8::Local<v8::Value>) \
  
  #define FOR_EACH_CALLBACK_TABLE_MAPPING_2_VOID_RETURN(F) \
    F(AccessorSetter, \
      AccessorSetterCallback, \
      void, \
      v8::Local<v8::String>, \
      v8::Local<v8::Value>) \
  
  // All property callbacks as well as invocation callbacks
  #define FOR_EACH_CALLBACK_TABLE_MAPPING(F) \
    F(InvocationCallback, FunctionCallback) \
    F(AccessorGetter, AccessorGetterCallback) \
    F(AccessorSetter, AccessorSetterCallback) \
    F(NamedPropertySetter, NamedPropertySetterCallback) \
    F(NamedPropertyQuery, NamedPropertyQueryCallback) \
    F(NamedPropertyDeleter, NamedPropertyDeleterCallback) \
    F(IndexedPropertyGetter, IndexedPropertyGetterCallback) \
    F(IndexedPropertySetter, IndexedPropertySetterCallback) \
    F(IndexedPropertyQuery, IndexedPropertyQueryCallback) \
    F(IndexedPropertyDeleter, IndexedPropertyDeleterCallback) \
    F(IndexedPropertyEnumerator, IndexedPropertyEnumeratorCallback) \
  
  
  // TODO(dcarney): Remove this class when old callbacks are gone.
  class CallbackTable {
   public:
    // TODO(dcarney): Flip this when it makes sense for performance.
    static const bool kStoreVoidFunctions = true;
    static inline bool ReturnsVoid(Isolate* isolate, void* function) {
      CallbackTable* table = isolate->callback_table();
      bool contains =
          table != NULL &&
          table->map_.occupancy() != 0 &&
          table->Contains(function);
      return contains == kStoreVoidFunctions;
    }
  
    STATIC_ASSERT(sizeof(intptr_t) == sizeof(AccessorGetterCallback));
  
    template<typename F>
    static inline void* FunctionToVoidPtr(F function) {
      return reinterpret_cast<void*>(reinterpret_cast<intptr_t>(function));
    }
  
  #define WRITE_REGISTER(OldFunction, NewFunction)                    \
    static OldFunction Register(Isolate* isolate, NewFunction f) {    \
      InsertCallback(isolate, FunctionToVoidPtr(f), true);            \
      return reinterpret_cast<OldFunction>(f);                        \
    }                                                                 \
                                                                      \
    static OldFunction Register(Isolate* isolate, OldFunction f) {    \
      InsertCallback(isolate, FunctionToVoidPtr(f), false);           \
      return f;                                                       \
    }
    FOR_EACH_CALLBACK_TABLE_MAPPING(WRITE_REGISTER)
  #undef WRITE_REGISTER
  
   private:
    CallbackTable();
    bool Contains(void* function);
    static void InsertCallback(Isolate* isolate,
                               void* function,
                               bool returns_void);
    HashMap map_;
    DISALLOW_COPY_AND_ASSIGN(CallbackTable);
  };
  
  
  // Custom arguments replicate a small segment of stack that can be
  // accessed through an Arguments object the same way the actual stack
  // can.
  template<int kArrayLength>
  class CustomArgumentsBase : public Relocatable {
   public:
    virtual inline void IterateInstance(ObjectVisitor* v) {
      v->VisitPointers(values_, values_ + kArrayLength);
    }
   protected:
    inline Object** end() { return values_ + kArrayLength - 1; }
    explicit inline CustomArgumentsBase(Isolate* isolate)
        : Relocatable(isolate) {}
    Object* values_[kArrayLength];
  };
  
  
  template<typename T>
  class CustomArguments : public CustomArgumentsBase<T::kArgsLength> {
   public:
    static const int kReturnValueOffset = T::kReturnValueIndex;
  
    typedef CustomArgumentsBase<T::kArgsLength> Super;
    ~CustomArguments() {
      // TODO(dcarney): create a new zap value for this.
      this->end()[kReturnValueOffset] =
          reinterpret_cast<Object*>(kHandleZapValue);
    }
  
   protected:
    explicit inline CustomArguments(Isolate* isolate) : Super(isolate) {}
  
    template<typename V>
    v8::Handle<V> GetReturnValue(Isolate* isolate);
  
    inline Isolate* isolate() {
      return reinterpret_cast<Isolate*>(this->end()[T::kIsolateIndex]);
    }
  };
  
  
  class PropertyCallbackArguments
      : public CustomArguments<PropertyCallbackInfo<Value> > {
   public:
    typedef PropertyCallbackInfo<Value> T;
    typedef CustomArguments<T> Super;
    static const int kArgsLength = T::kArgsLength;
    static const int kThisIndex = T::kThisIndex;
    static const int kHolderIndex = T::kHolderIndex;
  
    PropertyCallbackArguments(Isolate* isolate,
                              Object* data,
                              Object* self,
                              JSObject* holder)
        : Super(isolate) {
      Object** values = this->end();
      values[T::kThisIndex] = self;
      values[T::kHolderIndex] = holder;
      values[T::kDataIndex] = data;
      values[T::kIsolateIndex] = reinterpret_cast<Object*>(isolate);
      values[T::kReturnValueIndex] = isolate->heap()->the_hole_value();
      ASSERT(values[T::kHolderIndex]->IsHeapObject());
      ASSERT(values[T::kIsolateIndex]->IsSmi());
    }
  
    /*
     * The following Call functions wrap the calling of all callbacks to handle
     * calling either the old or the new style callbacks depending on which one
     * has been registered.
     * For old callbacks which return an empty handle, the ReturnValue is checked
     * and used if it's been set to anything inside the callback.
     * New style callbacks always use the return value.
     */
  #define WRITE_CALL_0(OldFunction, NewFunction, ReturnValue)                  \
    v8::Handle<ReturnValue> Call(OldFunction f);                               \
  
  #define WRITE_CALL_1(OldFunction, NewFunction, ReturnValue, Arg1)            \
    v8::Handle<ReturnValue> Call(OldFunction f, Arg1 arg1);                    \
  
  #define WRITE_CALL_2(OldFunction, NewFunction, ReturnValue, Arg1, Arg2)      \
    v8::Handle<ReturnValue> Call(OldFunction f, Arg1 arg1, Arg2 arg2);         \
  
  #define WRITE_CALL_2_VOID(OldFunction, NewFunction, ReturnValue, Arg1, Arg2) \
    void Call(OldFunction f, Arg1 arg1, Arg2 arg2);                            \
  
  FOR_EACH_CALLBACK_TABLE_MAPPING_0(WRITE_CALL_0)
  FOR_EACH_CALLBACK_TABLE_MAPPING_1(WRITE_CALL_1)
  FOR_EACH_CALLBACK_TABLE_MAPPING_2(WRITE_CALL_2)
  FOR_EACH_CALLBACK_TABLE_MAPPING_2_VOID_RETURN(WRITE_CALL_2_VOID)
  
  #undef WRITE_CALL_0
  #undef WRITE_CALL_1
  #undef WRITE_CALL_2
  #undef WRITE_CALL_2_VOID
  };
  
  
  class FunctionCallbackArguments
      : public CustomArguments<FunctionCallbackInfo<Value> > {
   public:
    typedef FunctionCallbackInfo<Value> T;
    typedef CustomArguments<T> Super;
    static const int kArgsLength = T::kArgsLength;
  
    FunctionCallbackArguments(internal::Isolate* isolate,
        internal::Object* data,
        internal::JSFunction* callee,
        internal::Object* holder,
        internal::Object** argv,
        int argc,
        bool is_construct_call)
          : Super(isolate),
            argv_(argv),
            argc_(argc),
            is_construct_call_(is_construct_call) {
      Object** values = end();
      values[T::kDataIndex] = data;
      values[T::kCalleeIndex] = callee;
      values[T::kHolderIndex] = holder;
      values[T::kIsolateIndex] = reinterpret_cast<internal::Object*>(isolate);
      values[T::kReturnValueIndex] = isolate->heap()->the_hole_value();
      ASSERT(values[T::kCalleeIndex]->IsJSFunction());
      ASSERT(values[T::kHolderIndex]->IsHeapObject());
      ASSERT(values[T::kIsolateIndex]->IsSmi());
    }
  
    /*
     * The following Call function wraps the calling of all callbacks to handle
     * calling either the old or the new style callbacks depending on which one
     * has been registered.
     * For old callbacks which return an empty handle, the ReturnValue is checked
     * and used if it's been set to anything inside the callback.
     * New style callbacks always use the return value.
     */
    v8::Handle<v8::Value> Call(InvocationCallback f);
  
   private:
    internal::Object** argv_;
    int argc_;
    bool is_construct_call_;
  };
  
  
  #define DECLARE_RUNTIME_FUNCTION(Type, Name)    \
  Type Name(int args_length, Object** args_object, Isolate* isolate)
  
  #define RUNTIME_FUNCTION(Type, Name)                                  \
  static Type __RT_impl_##Name(Arguments args, Isolate* isolate);       \
  Type Name(int args_length, Object** args_object, Isolate* isolate) {  \
    Arguments args(args_length, args_object);                           \
    return __RT_impl_##Name(args, isolate);                             \
  }                                                                     \
  static Type __RT_impl_##Name(Arguments args, Isolate* isolate)
  
  #define RUNTIME_ARGUMENTS(isolate, args) \
    args.length(), args.arguments(), isolate
  
  } }  // namespace v8::internal
  
  #endif  // V8_ARGUMENTS_H_
  