heap/HeapRootVisitor.h

   1 /*
   2  * Copyright (C) 2009, 2011 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. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef HeapRootVisitor_h
  27 #define HeapRootVisitor_h
  28
  29 #include "SlotVisitor.h"
  30
  31 namespace JSC {
  32
  33     // Privileged class for marking JSValues directly. It is only safe to use
  34     // this class to mark direct heap roots that are marked during every GC pass.
  35     // All other references should be wrapped in WriteBarriers.
  36     class HeapRootVisitor {
  37     private:
  38         friend class Heap;
  39         HeapRootVisitor(SlotVisitor&);
  40
  41     public:
  42         void visit(JSValue*);
  43         void visit(JSValue*, size_t);
  44         void visit(JSString**);
  45         void visit(JSCell**);
  46
  47         SlotVisitor& visitor();
  48
  49     private:
  50         SlotVisitor& m_visitor;
  51     };
  52
  53     inline HeapRootVisitor::HeapRootVisitor(SlotVisitor& visitor)
  54         : m_visitor(visitor)
  55     {
  56     }
  57
  58     inline void HeapRootVisitor::visit(JSValue* slot)
  59     {
  60         m_visitor.append(slot);
  61     }
  62
  63     inline void HeapRootVisitor::visit(JSValue* slot, size_t count)
  64     {
  65         m_visitor.append(slot, count);
  66     }
  67
  68     inline void HeapRootVisitor::visit(JSString** slot)
  69     {
  70         m_visitor.append(reinterpret_cast<JSCell**>(slot));
  71     }
  72
  73     inline void HeapRootVisitor::visit(JSCell** slot)
  74     {
  75         m_visitor.append(slot);
  76     }
  77
  78     inline SlotVisitor& HeapRootVisitor::visitor()
  79     {
  80         return m_visitor;
  81     }
  82
  83 } // namespace JSC
  84
  85 #endif // HeapRootVisitor_h