1  /*
 2   * Copyright (C) 2018 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  #include "config.h"
27  #include "JSImmutableButterfly.h"
28  
29  #include "ButterflyInlines.h"
30  
31  namespace JSC {
32  
33  const ClassInfo JSImmutableButterfly::s_info = { "Immutable Butterfly", nullptr, nullptr, nullptr, CREATE_METHOD_TABLE(JSImmutableButterfly) };
34  
35  void JSImmutableButterfly::visitChildren(JSCell* cell, SlotVisitor& visitor)
36  {
37      ASSERT_GC_OBJECT_INHERITS(cell, info());
38      Base::visitChildren(cell, visitor);
39      if (!hasContiguous(cell->indexingType())) {
40          ASSERT(hasDouble(cell->indexingType()) || hasInt32(cell->indexingType()));
41          return;
42      }
43  
44      Butterfly* butterfly = jsCast<JSImmutableButterfly*>(cell)->toButterfly();
45      visitor.appendValuesHidden(butterfly->contiguous().data(), butterfly->publicLength());
46  }
47  
48  void JSImmutableButterfly::copyToArguments(JSGlobalObject*, JSValue* firstElementDest, unsigned offset, unsigned length)
49  {
50      for (unsigned i = 0; i < length; ++i) {
51          if ((i + offset) < publicLength())
52              firstElementDest[i] = get(i + offset);
53          else
54              firstElementDest[i] = jsUndefined();
55      }
56  }
57  
58  static_assert(JSImmutableButterfly::offsetOfData() == sizeof(JSImmutableButterfly), "m_header needs to be adjacent to Data");
59  
60  } // namespace JSC