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- // Copyright 2021 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 INCLUDE_V8_FUNCTION_CALLBACK_H_
- #define INCLUDE_V8_FUNCTION_CALLBACK_H_
- #include "v8-local-handle.h" // NOLINT(build/include_directory)
- #include "v8-primitive.h" // NOLINT(build/include_directory)
- #include "v8config.h" // NOLINT(build/include_directory)
- namespace v8 {
- template <typename T>
- class BasicTracedReference;
- template <typename T>
- class Global;
- class Object;
- class Value;
- namespace internal {
- class FunctionCallbackArguments;
- class PropertyCallbackArguments;
- } // namespace internal
- namespace debug {
- class ConsoleCallArguments;
- } // namespace debug
- template <typename T>
- class ReturnValue {
- public:
- template <class S>
- V8_INLINE ReturnValue(const ReturnValue<S>& that) : value_(that.value_) {
- static_assert(std::is_base_of<T, S>::value, "type check");
- }
- // Local setters
- template <typename S>
- V8_INLINE void Set(const Global<S>& handle);
- template <typename S>
- V8_INLINE void Set(const BasicTracedReference<S>& handle);
- template <typename S>
- V8_INLINE void Set(const Local<S> handle);
- // Fast primitive setters
- V8_INLINE void Set(bool value);
- V8_INLINE void Set(double i);
- V8_INLINE void Set(int32_t i);
- V8_INLINE void Set(uint32_t i);
- // Fast JS primitive setters
- V8_INLINE void SetNull();
- V8_INLINE void SetUndefined();
- V8_INLINE void SetEmptyString();
- // Convenience getter for Isolate
- V8_INLINE Isolate* GetIsolate() const;
- // Pointer setter: Uncompilable to prevent inadvertent misuse.
- template <typename S>
- V8_INLINE void Set(S* whatever);
- // Getter. Creates a new Local<> so it comes with a certain performance
- // hit. If the ReturnValue was not yet set, this will return the undefined
- // value.
- V8_INLINE Local<Value> Get() const;
- private:
- 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 PersistentValueMapBase;
- V8_INLINE void SetInternal(internal::Address value) { *value_ = value; }
- V8_INLINE internal::Address GetDefaultValue();
- V8_INLINE explicit ReturnValue(internal::Address* slot);
- internal::Address* value_;
- };
- /**
- * The argument information given to function call callbacks. This
- * class provides access to information about the context of the call,
- * including the receiver, the number and values of arguments, and
- * the holder of the function.
- */
- template <typename T>
- class FunctionCallbackInfo {
- public:
- /** The number of available arguments. */
- V8_INLINE int Length() const;
- /**
- * Accessor for the available arguments. Returns `undefined` if the index
- * is out of bounds.
- */
- V8_INLINE Local<Value> operator[](int i) const;
- /** Returns the receiver. This corresponds to the "this" value. */
- V8_INLINE Local<Object> This() const;
- /**
- * If the callback was created without a Signature, this is the same
- * value as This(). If there is a signature, and the signature didn't match
- * This() but one of its hidden prototypes, this will be the respective
- * hidden prototype.
- *
- * Note that this is not the prototype of This() on which the accessor
- * referencing this callback was found (which in V8 internally is often
- * referred to as holder [sic]).
- */
- V8_INLINE Local<Object> Holder() const;
- /** For construct calls, this returns the "new.target" value. */
- V8_INLINE Local<Value> NewTarget() const;
- /** Indicates whether this is a regular call or a construct call. */
- V8_INLINE bool IsConstructCall() const;
- /** The data argument specified when creating the callback. */
- V8_INLINE Local<Value> Data() const;
- /** The current Isolate. */
- V8_INLINE Isolate* GetIsolate() const;
- /** The ReturnValue for the call. */
- V8_INLINE ReturnValue<T> GetReturnValue() const;
- // This shouldn't be public, but the arm compiler needs it.
- static const int kArgsLength = 6;
- protected:
- friend class internal::FunctionCallbackArguments;
- friend class internal::CustomArguments<FunctionCallbackInfo>;
- friend class debug::ConsoleCallArguments;
- static const int kHolderIndex = 0;
- static const int kIsolateIndex = 1;
- static const int kReturnValueDefaultValueIndex = 2;
- static const int kReturnValueIndex = 3;
- static const int kDataIndex = 4;
- static const int kNewTargetIndex = 5;
- V8_INLINE FunctionCallbackInfo(internal::Address* implicit_args,
- internal::Address* values, int length);
- internal::Address* implicit_args_;
- internal::Address* values_;
- int length_;
- };
- /**
- * The information passed to a property callback about the context
- * of the property access.
- */
- template <typename T>
- class PropertyCallbackInfo {
- public:
- /**
- * \return The isolate of the property access.
- */
- V8_INLINE Isolate* GetIsolate() const;
- /**
- * \return The data set in the configuration, i.e., in
- * `NamedPropertyHandlerConfiguration` or
- * `IndexedPropertyHandlerConfiguration.`
- */
- V8_INLINE Local<Value> Data() const;
- /**
- * \return The receiver. In many cases, this is the object on which the
- * property access was intercepted. When using
- * `Reflect.get`, `Function.prototype.call`, or similar functions, it is the
- * object passed in as receiver or thisArg.
- *
- * \code
- * void GetterCallback(Local<Name> name,
- * const v8::PropertyCallbackInfo<v8::Value>& info) {
- * auto context = info.GetIsolate()->GetCurrentContext();
- *
- * v8::Local<v8::Value> a_this =
- * info.This()
- * ->GetRealNamedProperty(context, v8_str("a"))
- * .ToLocalChecked();
- * v8::Local<v8::Value> a_holder =
- * info.Holder()
- * ->GetRealNamedProperty(context, v8_str("a"))
- * .ToLocalChecked();
- *
- * CHECK(v8_str("r")->Equals(context, a_this).FromJust());
- * CHECK(v8_str("obj")->Equals(context, a_holder).FromJust());
- *
- * info.GetReturnValue().Set(name);
- * }
- *
- * v8::Local<v8::FunctionTemplate> templ =
- * v8::FunctionTemplate::New(isolate);
- * templ->InstanceTemplate()->SetHandler(
- * v8::NamedPropertyHandlerConfiguration(GetterCallback));
- * LocalContext env;
- * env->Global()
- * ->Set(env.local(), v8_str("obj"), templ->GetFunction(env.local())
- * .ToLocalChecked()
- * ->NewInstance(env.local())
- * .ToLocalChecked())
- * .FromJust();
- *
- * CompileRun("obj.a = 'obj'; var r = {a: 'r'}; Reflect.get(obj, 'x', r)");
- * \endcode
- */
- V8_INLINE Local<Object> This() const;
- /**
- * \return The object in the prototype chain of the receiver that has the
- * interceptor. Suppose you have `x` and its prototype is `y`, and `y`
- * has an interceptor. Then `info.This()` is `x` and `info.Holder()` is `y`.
- * The Holder() could be a hidden object (the global object, rather
- * than the global proxy).
- *
- * \note For security reasons, do not pass the object back into the runtime.
- */
- V8_INLINE Local<Object> Holder() const;
- /**
- * \return The return value of the callback.
- * Can be changed by calling Set().
- * \code
- * info.GetReturnValue().Set(...)
- * \endcode
- *
- */
- V8_INLINE ReturnValue<T> GetReturnValue() const;
- /**
- * \return True if the intercepted function should throw if an error occurs.
- * Usually, `true` corresponds to `'use strict'`.
- *
- * \note Always `false` when intercepting `Reflect.set()`
- * independent of the language mode.
- */
- V8_INLINE bool ShouldThrowOnError() const;
- // This shouldn't be public, but the arm compiler needs it.
- static const int kArgsLength = 7;
- protected:
- friend class MacroAssembler;
- friend class internal::PropertyCallbackArguments;
- friend class internal::CustomArguments<PropertyCallbackInfo>;
- static const int kShouldThrowOnErrorIndex = 0;
- static const int kHolderIndex = 1;
- static const int kIsolateIndex = 2;
- static const int kReturnValueDefaultValueIndex = 3;
- static const int kReturnValueIndex = 4;
- static const int kDataIndex = 5;
- static const int kThisIndex = 6;
- V8_INLINE PropertyCallbackInfo(internal::Address* args) : args_(args) {}
- internal::Address* args_;
- };
- using FunctionCallback = void (*)(const FunctionCallbackInfo<Value>& info);
- // --- Implementation ---
- template <typename T>
- ReturnValue<T>::ReturnValue(internal::Address* slot) : value_(slot) {}
- template <typename T>
- template <typename S>
- void ReturnValue<T>::Set(const Global<S>& handle) {
- static_assert(std::is_base_of<T, S>::value, "type check");
- if (V8_UNLIKELY(handle.IsEmpty())) {
- *value_ = GetDefaultValue();
- } else {
- *value_ = *reinterpret_cast<internal::Address*>(*handle);
- }
- }
- template <typename T>
- template <typename S>
- void ReturnValue<T>::Set(const BasicTracedReference<S>& handle) {
- static_assert(std::is_base_of<T, S>::value, "type check");
- if (V8_UNLIKELY(handle.IsEmpty())) {
- *value_ = GetDefaultValue();
- } else {
- *value_ = *reinterpret_cast<internal::Address*>(handle.val_);
- }
- }
- template <typename T>
- template <typename S>
- void ReturnValue<T>::Set(const Local<S> handle) {
- static_assert(std::is_void<T>::value || std::is_base_of<T, S>::value,
- "type check");
- if (V8_UNLIKELY(handle.IsEmpty())) {
- *value_ = GetDefaultValue();
- } else {
- *value_ = *reinterpret_cast<internal::Address*>(*handle);
- }
- }
- template <typename T>
- void ReturnValue<T>::Set(double i) {
- static_assert(std::is_base_of<T, Number>::value, "type check");
- Set(Number::New(GetIsolate(), i));
- }
- template <typename T>
- void ReturnValue<T>::Set(int32_t i) {
- static_assert(std::is_base_of<T, Integer>::value, "type check");
- using I = internal::Internals;
- if (V8_LIKELY(I::IsValidSmi(i))) {
- *value_ = I::IntToSmi(i);
- return;
- }
- Set(Integer::New(GetIsolate(), i));
- }
- template <typename T>
- void ReturnValue<T>::Set(uint32_t i) {
- static_assert(std::is_base_of<T, Integer>::value, "type check");
- // Can't simply use INT32_MAX here for whatever reason.
- bool fits_into_int32_t = (i & (1U << 31)) == 0;
- if (V8_LIKELY(fits_into_int32_t)) {
- Set(static_cast<int32_t>(i));
- return;
- }
- Set(Integer::NewFromUnsigned(GetIsolate(), i));
- }
- template <typename T>
- void ReturnValue<T>::Set(bool value) {
- static_assert(std::is_base_of<T, Boolean>::value, "type check");
- using I = internal::Internals;
- int root_index;
- if (value) {
- root_index = I::kTrueValueRootIndex;
- } else {
- root_index = I::kFalseValueRootIndex;
- }
- *value_ = *I::GetRoot(GetIsolate(), root_index);
- }
- template <typename T>
- void ReturnValue<T>::SetNull() {
- static_assert(std::is_base_of<T, Primitive>::value, "type check");
- using I = internal::Internals;
- *value_ = *I::GetRoot(GetIsolate(), I::kNullValueRootIndex);
- }
- template <typename T>
- void ReturnValue<T>::SetUndefined() {
- static_assert(std::is_base_of<T, Primitive>::value, "type check");
- using I = internal::Internals;
- *value_ = *I::GetRoot(GetIsolate(), I::kUndefinedValueRootIndex);
- }
- template <typename T>
- void ReturnValue<T>::SetEmptyString() {
- static_assert(std::is_base_of<T, String>::value, "type check");
- using I = internal::Internals;
- *value_ = *I::GetRoot(GetIsolate(), I::kEmptyStringRootIndex);
- }
- template <typename T>
- Isolate* ReturnValue<T>::GetIsolate() const {
- // Isolate is always the pointer below the default value on the stack.
- return *reinterpret_cast<Isolate**>(&value_[-2]);
- }
- template <typename T>
- Local<Value> ReturnValue<T>::Get() const {
- using I = internal::Internals;
- if (*value_ == *I::GetRoot(GetIsolate(), I::kTheHoleValueRootIndex))
- return Local<Value>(*Undefined(GetIsolate()));
- return Local<Value>::New(GetIsolate(), reinterpret_cast<Value*>(value_));
- }
- template <typename T>
- template <typename S>
- void ReturnValue<T>::Set(S* whatever) {
- static_assert(sizeof(S) < 0, "incompilable to prevent inadvertent misuse");
- }
- template <typename T>
- internal::Address ReturnValue<T>::GetDefaultValue() {
- // Default value is always the pointer below value_ on the stack.
- return value_[-1];
- }
- template <typename T>
- FunctionCallbackInfo<T>::FunctionCallbackInfo(internal::Address* implicit_args,
- internal::Address* values,
- int length)
- : implicit_args_(implicit_args), values_(values), length_(length) {}
- template <typename T>
- Local<Value> FunctionCallbackInfo<T>::operator[](int i) const {
- // values_ points to the first argument (not the receiver).
- if (i < 0 || length_ <= i) return Local<Value>(*Undefined(GetIsolate()));
- return Local<Value>(reinterpret_cast<Value*>(values_ + i));
- }
- template <typename T>
- Local<Object> FunctionCallbackInfo<T>::This() const {
- // values_ points to the first argument (not the receiver).
- return Local<Object>(reinterpret_cast<Object*>(values_ - 1));
- }
- template <typename T>
- Local<Object> FunctionCallbackInfo<T>::Holder() const {
- return Local<Object>(
- reinterpret_cast<Object*>(&implicit_args_[kHolderIndex]));
- }
- template <typename T>
- Local<Value> FunctionCallbackInfo<T>::NewTarget() const {
- return Local<Value>(
- reinterpret_cast<Value*>(&implicit_args_[kNewTargetIndex]));
- }
- template <typename T>
- Local<Value> FunctionCallbackInfo<T>::Data() const {
- return Local<Value>(reinterpret_cast<Value*>(&implicit_args_[kDataIndex]));
- }
- template <typename T>
- Isolate* FunctionCallbackInfo<T>::GetIsolate() const {
- return *reinterpret_cast<Isolate**>(&implicit_args_[kIsolateIndex]);
- }
- template <typename T>
- ReturnValue<T> FunctionCallbackInfo<T>::GetReturnValue() const {
- return ReturnValue<T>(&implicit_args_[kReturnValueIndex]);
- }
- template <typename T>
- bool FunctionCallbackInfo<T>::IsConstructCall() const {
- return !NewTarget()->IsUndefined();
- }
- template <typename T>
- int FunctionCallbackInfo<T>::Length() const {
- return length_;
- }
- template <typename T>
- Isolate* PropertyCallbackInfo<T>::GetIsolate() const {
- return *reinterpret_cast<Isolate**>(&args_[kIsolateIndex]);
- }
- template <typename T>
- Local<Value> PropertyCallbackInfo<T>::Data() const {
- return Local<Value>(reinterpret_cast<Value*>(&args_[kDataIndex]));
- }
- template <typename T>
- Local<Object> PropertyCallbackInfo<T>::This() const {
- return Local<Object>(reinterpret_cast<Object*>(&args_[kThisIndex]));
- }
- template <typename T>
- Local<Object> PropertyCallbackInfo<T>::Holder() const {
- return Local<Object>(reinterpret_cast<Object*>(&args_[kHolderIndex]));
- }
- template <typename T>
- ReturnValue<T> PropertyCallbackInfo<T>::GetReturnValue() const {
- return ReturnValue<T>(&args_[kReturnValueIndex]);
- }
- template <typename T>
- bool PropertyCallbackInfo<T>::ShouldThrowOnError() const {
- using I = internal::Internals;
- if (args_[kShouldThrowOnErrorIndex] !=
- I::IntToSmi(I::kInferShouldThrowMode)) {
- return args_[kShouldThrowOnErrorIndex] != I::IntToSmi(I::kDontThrow);
- }
- return v8::internal::ShouldThrowOnError(
- reinterpret_cast<v8::internal::Isolate*>(GetIsolate()));
- }
- } // namespace v8
- #endif // INCLUDE_V8_FUNCTION_CALLBACK_H_
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