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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/api.h"
#include "src/handles.h"
#include "src/heap/heap.h"
#include "src/isolate.h"
namespace v8 {
namespace internal {
HandleBase::HandleBase(Object* object, Isolate* isolate)
: location_(HandleScope::GetHandle(isolate, object)) {}
template <typename T>
// Allocate a new handle for the object, do not canonicalize.
Handle<T> Handle<T>::New(T* object, Isolate* isolate) {
return Handle(
reinterpret_cast<T**>(HandleScope::CreateHandle(isolate, object)));
}
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>
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(after - before < kCheckHandleThreshold);
DCHECK(before < kCheckHandleThreshold);
} else {
#endif // DEBUG
CloseScope(isolate_, prev_next_, prev_limit_);
#ifdef DEBUG
}
#endif // DEBUG
}
void HandleScope::CloseScope(Isolate* isolate,
Object** prev_next,
Object** prev_limit) {
HandleScopeData* current = isolate->handle_scope_data();
std::swap(current->next, prev_next);
current->level--;
if (current->limit != prev_limit) {
current->limit = prev_limit;
DeleteExtensions(isolate);
#ifdef ENABLE_HANDLE_ZAPPING
ZapRange(current->next, prev_limit);
} else {
ZapRange(current->next, prev_next);
#endif
}
}
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;
}
Object** HandleScope::CreateHandle(Isolate* isolate, Object* value) {
DCHECK(AllowHandleAllocation::IsAllowed());
HandleScopeData* data = isolate->handle_scope_data();
Object** 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(result < data->limit);
data->next = result + 1;
*result = value;
return result;
}
Object** HandleScope::GetHandle(Isolate* isolate, Object* 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.
CHECK(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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