// Copyright 2006-2008 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_HANDLES_INL_H_
#define V8_HANDLES_INL_H_
namespace v8 {
namespace internal {
-template<typename T>
-Handle<T>::Handle(T* obj) {
- location_ = HandleScope::CreateHandle(obj->GetIsolate(), obj);
-}
-
-
-template<typename T>
-Handle<T>::Handle(T* obj, Isolate* isolate) {
- location_ = HandleScope::CreateHandle(isolate, obj);
-}
-
-
-template <typename T>
-inline bool Handle<T>::is_identical_to(const Handle<T> o) const {
- // Dereferencing deferred handles to check object equality is safe.
- SLOW_DCHECK(
- (location_ == NULL || IsDereferenceAllowed(NO_DEFERRED_CHECK)) &&
- (o.location_ == NULL || o.IsDereferenceAllowed(NO_DEFERRED_CHECK)));
- if (location_ == o.location_) return true;
- if (location_ == NULL || o.location_ == NULL) return false;
- return *location_ == *o.location_;
-}
-
-
-template <typename T>
-inline T* Handle<T>::operator*() const {
- SLOW_DCHECK(IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
- return *bit_cast<T**>(location_);
-}
-
-template <typename T>
-inline T** Handle<T>::location() const {
- SLOW_DCHECK(location_ == NULL ||
- IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
- return location_;
-}
-
-#ifdef DEBUG
-template <typename T>
-bool Handle<T>::IsDereferenceAllowed(DereferenceCheckMode mode) const {
- DCHECK(location_ != NULL);
- Object* object = *bit_cast<T**>(location_);
- if (object->IsSmi()) return true;
- HeapObject* heap_object = HeapObject::cast(object);
- Heap* heap = heap_object->GetHeap();
- Object** handle = reinterpret_cast<Object**>(location_);
- Object** roots_array_start = heap->roots_array_start();
- if (roots_array_start <= handle &&
- handle < roots_array_start + Heap::kStrongRootListLength &&
- heap->RootCanBeTreatedAsConstant(
- static_cast<Heap::RootListIndex>(handle - roots_array_start))) {
- return true;
- }
- if (!AllowHandleDereference::IsAllowed()) return false;
- if (mode == INCLUDE_DEFERRED_CHECK &&
- !AllowDeferredHandleDereference::IsAllowed()) {
- // Accessing cells, maps and internalized strings is safe.
- if (heap_object->IsCell()) return true;
- if (heap_object->IsMap()) return true;
- if (heap_object->IsInternalizedString()) return true;
- return !heap->isolate()->IsDeferredHandle(handle);
- }
- return true;
-}
-#endif
-
+HandleBase::HandleBase(Object* object, Isolate* isolate)
+ : location_(HandleScope::CreateHandle(isolate, object)) {}
HandleScope::HandleScope(Isolate* isolate) {
CloseScope(isolate_, prev_next_, prev_limit_);
// Allocate one handle in the parent scope.
DCHECK(current->level > 0);
- Handle<T> result(CreateHandle<T>(isolate_, value));
+ Handle<T> result(value, isolate_);
// Reinitialize the current scope (so that it's ready
// to be used or closed again).
prev_next_ = current->next;
DCHECK(AllowHandleAllocation::IsAllowed());
HandleScopeData* current = isolate->handle_scope_data();
- internal::Object** cur = current->next;
+ Object** cur = current->next;
if (cur == current->limit) cur = Extend(isolate);
// Update the current next field, set the value in the created
// handle, and return the result.
#endif
-} } // namespace v8::internal
+} // namespace internal
+} // namespace v8
#endif // V8_HANDLES_INL_H_
namespace v8 {
namespace internal {
-// A Handle can be converted into a MaybeHandle. Converting a MaybeHandle
-// into a Handle requires checking that it does not point to NULL. This
-// ensures NULL checks before use.
-// Do not use MaybeHandle as argument type.
+// Forward declarations.
+class DeferredHandles;
+class HandleScopeImplementer;
-template<typename T>
-class MaybeHandle {
- public:
- INLINE(MaybeHandle()) : location_(NULL) { }
- // Constructor for handling automatic up casting from Handle.
- // Ex. Handle<JSArray> can be passed when MaybeHandle<Object> is expected.
- template <class S> MaybeHandle(Handle<S> handle) {
-#ifdef DEBUG
- T* a = NULL;
- S* b = NULL;
- a = b; // Fake assignment to enforce type checks.
- USE(a);
-#endif
- this->location_ = reinterpret_cast<T**>(handle.location());
- }
+// ----------------------------------------------------------------------------
+// Base class for Handle instantiations. Don't use directly.
+class HandleBase {
+ public:
+ V8_INLINE explicit HandleBase(Object** location) : location_(location) {}
+ V8_INLINE explicit HandleBase(Object* object, Isolate* isolate);
- // Constructor for handling automatic up casting.
- // Ex. MaybeHandle<JSArray> can be passed when Handle<Object> is expected.
- template <class S> MaybeHandle(MaybeHandle<S> maybe_handle) {
-#ifdef DEBUG
- T* a = NULL;
- S* b = NULL;
- a = b; // Fake assignment to enforce type checks.
- USE(a);
-#endif
- location_ = reinterpret_cast<T**>(maybe_handle.location_);
+ // Check if this handle refers to the exact same object as the other handle.
+ V8_INLINE bool is_identical_to(const HandleBase that) const {
+ // Dereferencing deferred handles to check object equality is safe.
+ SLOW_DCHECK((this->location_ == NULL ||
+ this->IsDereferenceAllowed(NO_DEFERRED_CHECK)) &&
+ (that.location_ == NULL ||
+ that.IsDereferenceAllowed(NO_DEFERRED_CHECK)));
+ if (this->location_ == that.location_) return true;
+ if (this->location_ == NULL || that.location_ == NULL) return false;
+ return *this->location_ == *that.location_;
}
- INLINE(void Assert() const) { DCHECK(location_ != NULL); }
- INLINE(void Check() const) { CHECK(location_ != NULL); }
-
- INLINE(Handle<T> ToHandleChecked()) const {
- Check();
- return Handle<T>(location_);
- }
+ V8_INLINE bool is_null() const { return location_ == nullptr; }
- // Convert to a Handle with a type that can be upcasted to.
- template <class S>
- V8_INLINE bool ToHandle(Handle<S>* out) const {
- if (location_ == NULL) {
- *out = Handle<T>::null();
- return false;
- } else {
- *out = Handle<T>(location_);
- return true;
- }
+ protected:
+ // Provides the C++ dereference operator.
+ V8_INLINE Object* operator*() const {
+ SLOW_DCHECK(IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
+ return *location_;
}
- bool is_null() const { return location_ == NULL; }
-
- template <typename S>
- bool operator==(MaybeHandle<S> that) const {
- return this->location_ == that.location_;
- }
- template <typename S>
- bool operator!=(MaybeHandle<S> that) const {
- return !(*this == that);
+ // Returns the address to where the raw pointer is stored.
+ V8_INLINE Object** location() const {
+ SLOW_DCHECK(location_ == NULL ||
+ IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
+ return location_;
}
+ enum DereferenceCheckMode { INCLUDE_DEFERRED_CHECK, NO_DEFERRED_CHECK };
+#ifdef DEBUG
+ bool IsDereferenceAllowed(DereferenceCheckMode mode) const;
+#else
+ V8_INLINE
+ bool IsDereferenceAllowed(DereferenceCheckMode mode) const { return true; }
+#endif // DEBUG
- protected:
- T** location_;
-
- // MaybeHandles of different classes are allowed to access each
- // other's location_.
- template<class S> friend class MaybeHandle;
- template <typename S>
- friend size_t hash_value(MaybeHandle<S>);
+ Object** location_;
};
-template <typename S>
-inline size_t hash_value(MaybeHandle<S> maybe_handle) {
- return bit_cast<size_t>(maybe_handle.location_);
-}
-
// ----------------------------------------------------------------------------
// A Handle provides a reference to an object that survives relocation by
// the garbage collector.
// Handles are only valid within a HandleScope.
// When a handle is created for an object a cell is allocated in the heap.
-
-template<typename T>
-class Handle {
+template <typename T>
+class Handle final : public HandleBase {
public:
- INLINE(explicit Handle(T** location)) { location_ = location; }
- INLINE(explicit Handle(T* obj));
- INLINE(Handle(T* obj, Isolate* isolate));
-
- // TODO(yangguo): Values that contain empty handles should be declared as
- // MaybeHandle to force validation before being used as handles.
- INLINE(Handle()) : location_(NULL) { }
+ V8_INLINE explicit Handle(T** location = nullptr)
+ : HandleBase(reinterpret_cast<Object**>(location)) {
+ Object* a = nullptr;
+ T* b = nullptr;
+ a = b; // Fake assignment to enforce type checks.
+ USE(a);
+ }
+ V8_INLINE explicit Handle(T* object) : Handle(object, object->GetIsolate()) {}
+ V8_INLINE Handle(T* object, Isolate* isolate) : HandleBase(object, isolate) {}
// Constructor for handling automatic up casting.
// Ex. Handle<JSFunction> can be passed when Handle<Object> is expected.
- template <class S> Handle(Handle<S> handle) {
-#ifdef DEBUG
- T* a = NULL;
- S* b = NULL;
+ template <typename S>
+ V8_INLINE Handle(Handle<S> handle)
+ : HandleBase(handle) {
+ T* a = nullptr;
+ S* b = nullptr;
a = b; // Fake assignment to enforce type checks.
USE(a);
-#endif
- location_ = reinterpret_cast<T**>(handle.location_);
}
- INLINE(T* operator->() const) { return operator*(); }
-
- // Check if this handle refers to the exact same object as the other handle.
- INLINE(bool is_identical_to(const Handle<T> other) const);
+ V8_INLINE T* operator->() const { return operator*(); }
// Provides the C++ dereference operator.
- INLINE(T* operator*() const);
+ V8_INLINE T* operator*() const {
+ return reinterpret_cast<T*>(HandleBase::operator*());
+ }
// Returns the address to where the raw pointer is stored.
- INLINE(T** location() const);
+ V8_INLINE T** location() const {
+ return reinterpret_cast<T**>(HandleBase::location());
+ }
- template <class S> static Handle<T> cast(Handle<S> that) {
+ template <typename S>
+ static const Handle<T> cast(Handle<S> that) {
T::cast(*reinterpret_cast<T**>(that.location_));
return Handle<T>(reinterpret_cast<T**>(that.location_));
}
// TODO(yangguo): Values that contain empty handles should be declared as
// MaybeHandle to force validation before being used as handles.
- static Handle<T> null() { return Handle<T>(); }
- bool is_null() const { return location_ == NULL; }
-
- // Closes the given scope, but lets this handle escape. See
- // implementation in api.h.
- inline Handle<T> EscapeFrom(v8::EscapableHandleScope* scope);
-
-#ifdef DEBUG
- enum DereferenceCheckMode { INCLUDE_DEFERRED_CHECK, NO_DEFERRED_CHECK };
-
- bool IsDereferenceAllowed(DereferenceCheckMode mode) const;
-#endif // DEBUG
+ static const Handle<T> null() { return Handle<T>(); }
private:
- T** location_;
-
// Handles of different classes are allowed to access each other's location_.
- template<class S> friend class Handle;
+ template <typename>
+ friend class Handle;
+ // MaybeHandle is allowed to access location_.
+ template <typename>
+ friend class MaybeHandle;
};
+template <typename T>
+V8_INLINE Handle<T> handle(T* object, Isolate* isolate) {
+ return Handle<T>(object, isolate);
+}
-// Convenience wrapper.
-template<class T>
-inline Handle<T> handle(T* t, Isolate* isolate) {
- return Handle<T>(t, isolate);
+template <typename T>
+V8_INLINE Handle<T> handle(T* object) {
+ return Handle<T>(object);
}
-// Convenience wrapper.
-template<class T>
-inline Handle<T> handle(T* t) {
- return Handle<T>(t, t->GetIsolate());
-}
+// ----------------------------------------------------------------------------
+// A Handle can be converted into a MaybeHandle. Converting a MaybeHandle
+// into a Handle requires checking that it does not point to NULL. This
+// ensures NULL checks before use.
+// Do not use MaybeHandle as argument type.
+template <typename T>
+class MaybeHandle final {
+ public:
+ V8_INLINE MaybeHandle() {}
+ V8_INLINE ~MaybeHandle() {}
+ // Constructor for handling automatic up casting from Handle.
+ // Ex. Handle<JSArray> can be passed when MaybeHandle<Object> is expected.
+ template <typename S>
+ V8_INLINE MaybeHandle(Handle<S> handle)
+ : location_(reinterpret_cast<T**>(handle.location_)) {
+ T* a = nullptr;
+ S* b = nullptr;
+ a = b; // Fake assignment to enforce type checks.
+ USE(a);
+ }
-class DeferredHandles;
-class HandleScopeImplementer;
+ // Constructor for handling automatic up casting.
+ // Ex. MaybeHandle<JSArray> can be passed when Handle<Object> is expected.
+ template <typename S>
+ V8_INLINE MaybeHandle(MaybeHandle<S> maybe_handle)
+ : location_(reinterpret_cast<T**>(maybe_handle.location_)) {
+ T* a = nullptr;
+ S* b = nullptr;
+ a = b; // Fake assignment to enforce type checks.
+ USE(a);
+ }
+
+ V8_INLINE void Assert() const { DCHECK_NOT_NULL(location_); }
+ V8_INLINE void Check() const { CHECK_NOT_NULL(location_); }
+
+ V8_INLINE Handle<T> ToHandleChecked() const {
+ Check();
+ return Handle<T>(location_);
+ }
+
+ // Convert to a Handle with a type that can be upcasted to.
+ template <typename S>
+ V8_INLINE bool ToHandle(Handle<S>* out) const {
+ if (location_ == nullptr) {
+ *out = Handle<T>::null();
+ return false;
+ } else {
+ *out = Handle<T>(location_);
+ return true;
+ }
+ }
+
+ bool is_null() const { return location_ == nullptr; }
+
+ template <typename S>
+ V8_INLINE bool operator==(MaybeHandle<S> that) const {
+ return this->location_ == that.location_;
+ }
+ template <typename S>
+ V8_INLINE bool operator!=(MaybeHandle<S> that) const {
+ return this->location_ != that.location_;
+ }
+
+ protected:
+ T** location_ = nullptr;
+
+ // MaybeHandles of different classes are allowed to access each
+ // other's location_.
+ template <typename>
+ friend class MaybeHandle;
+ // Utility functions are allowed to access location_.
+ template <typename S>
+ friend size_t hash_value(MaybeHandle<S>);
+};
+
+template <typename T>
+V8_INLINE size_t hash_value(MaybeHandle<T> maybe_handle) {
+ uintptr_t v = bit_cast<uintptr_t>(maybe_handle.location_);
+ DCHECK_EQ(0u, v & ((1u << kPointerSizeLog2) - 1));
+ return v >> kPointerSizeLog2;
+}
// A stack-allocated class that governs a number of local handles.
Object** prev_limit);
// Extend the handle scope making room for more handles.
- static internal::Object** Extend(Isolate* isolate);
+ static Object** Extend(Isolate* isolate);
#ifdef ENABLE_HANDLE_ZAPPING
// Zaps the handles in the half-open interval [start, end).
#endif
friend class v8::HandleScope;
- friend class v8::internal::DeferredHandles;
- friend class v8::internal::HandleScopeImplementer;
- friend class v8::internal::Isolate;
+ friend class DeferredHandles;
+ friend class HandleScopeImplementer;
+ friend class Isolate;
};
-class DeferredHandles;
-
-
-class DeferredHandleScope {
+class DeferredHandleScope final {
public:
explicit DeferredHandleScope(Isolate* isolate);
// The DeferredHandles object returned stores the Handles created
// Seal off the current HandleScope so that new handles can only be created
// if a new HandleScope is entered.
-class SealHandleScope BASE_EMBEDDED {
+class SealHandleScope final {
public:
#ifndef DEBUG
explicit SealHandleScope(Isolate* isolate) {}
#endif
};
-struct HandleScopeData {
- internal::Object** next;
- internal::Object** limit;
+
+struct HandleScopeData final {
+ Object** next;
+ Object** limit;
int level;
void Initialize() {
}
};
-} } // namespace v8::internal
+} // namespace internal
+} // namespace v8
#endif // V8_HANDLES_H_
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