1  /*
 2   * Copyright (C) 2013 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  #pragma once
27  
28  #include "Handle.h"
29  #include "TypedArrayController.h"
30  #include "WeakHandleOwner.h"
31  
32  namespace JSC {
33  
34  // The default controller used for managing the relationship between
35  // array buffers and their wrappers in JavaScriptCore. This isn't what
36  // WebCore uses, but it is what JSC uses when running standalone. This
37  // is pretty simple:
38  //
39  // - If the JSArrayBuffer is live, then the ArrayBuffer stays alive.
40  //
41  // - If there is a JSArrayBufferView that is holding an ArrayBuffer
42  //   then any existing wrapper for that ArrayBuffer will be kept
43  //   alive.
44  //
45  // - If you ask an ArrayBuffer for a JSArrayBuffer after one had
46  //   already been created and it didn't die, then you get the same
47  //   one.
48  
49  class SimpleTypedArrayController final : public TypedArrayController {
50  public:
51      JS_EXPORT_PRIVATE SimpleTypedArrayController(bool allowAtomicsWait = true);
52      ~SimpleTypedArrayController() final;
53      
54      JSArrayBuffer* toJS(JSGlobalObject*, JSGlobalObject*, ArrayBuffer*) final;
55      void registerWrapper(JSGlobalObject*, ArrayBuffer*, JSArrayBuffer*) final;
56      bool isAtomicsWaitAllowedOnCurrentThread() final;
57  
58  private:
59      class JSArrayBufferOwner final : public WeakHandleOwner {
60      public:
61          bool isReachableFromOpaqueRoots(JSC::Handle<JSC::Unknown>, void* context, SlotVisitor&, const char** reason) final;
62          void finalize(JSC::Handle<JSC::Unknown>, void* context) final;
63      };
64  
65      JSArrayBufferOwner m_owner;
66      bool m_allowAtomicsWait { false };
67  };
68  
69  } // namespace JSC