v8/src/handles-inl.h

213 lines
6.8 KiB
C
Raw Normal View History

// Copyright 2006-2008 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_HANDLES_INL_H_
#define V8_HANDLES_INL_H_
#include "api.h"
#include "apiutils.h"
#include "handles.h"
#include "isolate.h"
namespace v8 {
namespace internal {
template<typename T>
Handle<T>::Handle(T* obj) {
ASSERT(!obj->IsFailure());
location_ = HandleScope::CreateHandle(obj->GetIsolate(), obj);
}
template<typename T>
Handle<T>::Handle(T* obj, Isolate* isolate) {
ASSERT(!obj->IsFailure());
location_ = HandleScope::CreateHandle(isolate, obj);
}
template <typename T>
inline bool Handle<T>::is_identical_to(const Handle<T> other) const {
ASSERT(location_ == NULL || !(*location_)->IsFailure());
if (location_ == other.location_) return true;
if (location_ == NULL || other.location_ == NULL) return false;
// Dereferencing deferred handles to check object equality is safe.
SLOW_ASSERT(IsDereferenceAllowed(NO_DEFERRED_CHECK) &&
other.IsDereferenceAllowed(NO_DEFERRED_CHECK));
return *location_ == *other.location_;
}
template <typename T>
inline T* Handle<T>::operator*() const {
ASSERT(location_ != NULL && !(*location_)->IsFailure());
SLOW_ASSERT(IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
return *BitCast<T**>(location_);
}
template <typename T>
inline T** Handle<T>::location() const {
ASSERT(location_ == NULL || !(*location_)->IsFailure());
SLOW_ASSERT(location_ == NULL ||
IsDereferenceAllowed(INCLUDE_DEFERRED_CHECK));
return location_;
}
#ifdef DEBUG
template <typename T>
bool Handle<T>::IsDereferenceAllowed(DereferenceCheckMode mode) const {
ASSERT(location_ != NULL);
Object* object = *BitCast<T**>(location_);
if (object->IsSmi()) return true;
HeapObject* heap_object = HeapObject::cast(object);
Isolate* isolate = heap_object->GetIsolate();
Object** handle = reinterpret_cast<Object**>(location_);
Object** roots_array_start = isolate->heap()->roots_array_start();
if (roots_array_start <= handle &&
handle < roots_array_start + Heap::kStrongRootListLength) {
return true;
}
if (!AllowHandleDereference::IsAllowed()) return false;
if (mode == INCLUDE_DEFERRED_CHECK &&
!AllowDeferredHandleDereference::IsAllowed()) {
// Accessing maps and internalized strings is safe.
if (heap_object->IsMap()) return true;
if (heap_object->IsInternalizedString()) return true;
return !isolate->IsDeferredHandle(handle);
}
return true;
}
#endif
HandleScope::HandleScope(Isolate* isolate) {
v8::ImplementationUtilities::HandleScopeData* current =
isolate->handle_scope_data();
isolate_ = isolate;
prev_next_ = current->next;
prev_limit_ = current->limit;
current->level++;
}
HandleScope::~HandleScope() {
CloseScope(isolate_, prev_next_, prev_limit_);
}
void HandleScope::CloseScope(Isolate* isolate,
Object** prev_next,
Object** prev_limit) {
v8::ImplementationUtilities::HandleScopeData* current =
isolate->handle_scope_data();
current->next = prev_next;
current->level--;
if (current->limit != prev_limit) {
current->limit = prev_limit;
DeleteExtensions(isolate);
}
#ifdef ENABLE_EXTRA_CHECKS
ZapRange(prev_next, prev_limit);
#endif
}
template <typename T>
Handle<T> HandleScope::CloseAndEscape(Handle<T> handle_value) {
v8::ImplementationUtilities::HandleScopeData* current =
isolate_->handle_scope_data();
T* value = *handle_value;
// Throw away all handles in the current scope.
CloseScope(isolate_, prev_next_, prev_limit_);
// Allocate one handle in the parent scope.
ASSERT(current->level > 0);
Handle<T> result(CreateHandle<T>(isolate_, value));
// Reinitialize the current scope (so that it's ready
// to be used or closed again).
prev_next_ = current->next;
prev_limit_ = current->limit;
current->level++;
return result;
}
template <typename T>
T** HandleScope::CreateHandle(Isolate* isolate, T* value) {
ASSERT(AllowHandleAllocation::IsAllowed());
v8::ImplementationUtilities::HandleScopeData* current =
isolate->handle_scope_data();
internal::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.
ASSERT(cur < current->limit);
current->next = cur + 1;
T** result = reinterpret_cast<T**>(cur);
*result = value;
return result;
}
#ifdef DEBUG
inline SealHandleScope::SealHandleScope(Isolate* isolate) : isolate_(isolate) {
// Make sure the current thread is allowed to create handles to begin with.
CHECK(AllowHandleAllocation::IsAllowed());
v8::ImplementationUtilities::HandleScopeData* current =
isolate_->handle_scope_data();
// Shrink the current handle scope to make it impossible to do
// handle allocations without an explicit handle scope.
limit_ = current->limit;
current->limit = current->next;
level_ = current->level;
current->level = 0;
}
inline SealHandleScope::~SealHandleScope() {
// Restore state in current handle scope to re-enable handle
// allocations.
v8::ImplementationUtilities::HandleScopeData* current =
isolate_->handle_scope_data();
ASSERT_EQ(0, current->level);
current->level = level_;
ASSERT_EQ(current->next, current->limit);
current->limit = limit_;
}
#endif
} } // namespace v8::internal
#endif // V8_HANDLES_INL_H_