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// 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_
#include "src/handles.h"
#include "src/isolate.h"
#include "src/msan.h"
namespace v8 {
namespace internal {
HandleBase::HandleBase(Address object, Isolate* isolate)
: location_(HandleScope::GetHandle(isolate, object)) {}
// Allocate a new handle for the object, do not canonicalize.
template <typename T>
Handle<T> Handle<T>::New(T object, Isolate* isolate) {
return Handle(HandleScope::CreateHandle(isolate, object.ptr()));
}
template <typename T>
template <typename S>
const Handle<T> Handle<T>::cast(Handle<S> that) {
T::cast(*FullObjectSlot(that.location()));
return Handle<T>(that.location_);
}
HandleScope::HandleScope(Isolate* isolate) {
HandleScopeData* data = isolate->handle_scope_data();
isolate_ = isolate;
prev_next_ = data->next;
prev_limit_ = data->limit;
data->level++;
}
template <typename T>
Handle<T>::Handle(T object, Isolate* isolate)
: HandleBase(object.ptr(), isolate) {}
template <typename T>
V8_INLINE Handle<T> handle(T object, Isolate* isolate) {
return Handle<T>(object, isolate);
}
template <typename T>
inline std::ostream& operator<<(std::ostream& os, Handle<T> handle) {
return os << Brief(*handle);
}
HandleScope::~HandleScope() {
#ifdef DEBUG
if (FLAG_check_handle_count) {
int before = NumberOfHandles(isolate_);
CloseScope(isolate_, prev_next_, prev_limit_);
int after = NumberOfHandles(isolate_);
DCHECK_LT(after - before, kCheckHandleThreshold);
DCHECK_LT(before, kCheckHandleThreshold);
} else {
#endif // DEBUG
CloseScope(isolate_, prev_next_, prev_limit_);
#ifdef DEBUG
}
#endif // DEBUG
}
void HandleScope::CloseScope(Isolate* isolate, Address* prev_next,
Address* prev_limit) {
HandleScopeData* current = isolate->handle_scope_data();
std::swap(current->next, prev_next);
current->level--;
Address* limit = prev_next;
if (current->limit != prev_limit) {
current->limit = prev_limit;
limit = prev_limit;
DeleteExtensions(isolate);
}
#ifdef ENABLE_HANDLE_ZAPPING
ZapRange(current->next, limit);
#endif
MSAN_ALLOCATED_UNINITIALIZED_MEMORY(
current->next,
static_cast<size_t>(reinterpret_cast<Address>(limit) -
reinterpret_cast<Address>(current->next)));
}
template <typename T>
Handle<T> HandleScope::CloseAndEscape(Handle<T> handle_value) {
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.
DCHECK(current->level > current->sealed_level);
Handle<T> result(value, isolate_);
// 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;
}
Address* HandleScope::CreateHandle(Isolate* isolate, Address value) {
DCHECK(AllowHandleAllocation::IsAllowed());
HandleScopeData* data = isolate->handle_scope_data();
Address* result = data->next;
if (result == data->limit) {
result = Extend(isolate);
}
// Update the current next field, set the value in the created handle,
// and return the result.
DCHECK_LT(reinterpret_cast<Address>(result),
reinterpret_cast<Address>(data->limit));
data->next = reinterpret_cast<Address*>(reinterpret_cast<Address>(result) +
sizeof(Address));
*result = value;
return result;
}
Address* HandleScope::GetHandle(Isolate* isolate, Address value) {
DCHECK(AllowHandleAllocation::IsAllowed());
HandleScopeData* data = isolate->handle_scope_data();
CanonicalHandleScope* canonical = data->canonical_scope;
return canonical ? canonical->Lookup(value) : CreateHandle(isolate, value);
}
#ifdef DEBUG
inline SealHandleScope::SealHandleScope(Isolate* isolate) : isolate_(isolate) {
// Make sure the current thread is allowed to create handles to begin with.
DCHECK(AllowHandleAllocation::IsAllowed());
HandleScopeData* current = isolate_->handle_scope_data();
// Shrink the current handle scope to make it impossible to do
// handle allocations without an explicit handle scope.
prev_limit_ = current->limit;
current->limit = current->next;
prev_sealed_level_ = current->sealed_level;
current->sealed_level = current->level;
}
inline SealHandleScope::~SealHandleScope() {
// Restore state in current handle scope to re-enable handle
// allocations.
HandleScopeData* current = isolate_->handle_scope_data();
DCHECK_EQ(current->next, current->limit);
current->limit = prev_limit_;
DCHECK_EQ(current->level, current->sealed_level);
current->sealed_level = prev_sealed_level_;
}
#endif
} // namespace internal
} // namespace v8
#endif // V8_HANDLES_INL_H_
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