1/*
2 * Copyright (C) 2010 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef LocalScope_h
27#define LocalScope_h
28
29#include "HandleStack.h"
30#include "Local.h"
31
32namespace JSC {
33/*
34 A LocalScope is a temporary scope in which Locals are allocated. When a
35 LocalScope goes out of scope, all the Locals created in it are destroyed.
36
37 LocalScope is similar in concept to NSAutoreleasePool.
38*/
39
40class VM;
41
42class LocalScope {
43public:
44 explicit LocalScope(VM&);
45 ~LocalScope();
46
47 template <typename T> Local<T> release(Local<T>); // Destroys all other locals in the scope.
48
49private:
50 HandleStack* m_handleStack;
51 HandleStack::Frame m_lastFrame;
52};
53
54inline LocalScope::LocalScope(VM& vm)
55 : m_handleStack(vm.heap.handleStack())
56{
57 m_handleStack->enterScope(m_lastFrame);
58}
59
60inline LocalScope::~LocalScope()
61{
62 m_handleStack->leaveScope(m_lastFrame);
63}
64
65template <typename T> Local<T> LocalScope::release(Local<T> local)
66{
67 typename Local<T>::ExternalType ptr = local.get();
68
69 m_handleStack->leaveScope(m_lastFrame);
70 HandleSlot slot = m_handleStack->push();
71 m_handleStack->enterScope(m_lastFrame);
72
73 return Local<T>(slot, ptr);
74}
75
76}
77
78#endif
79