1  /*
 2   * Copyright (C) 2015-2019 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 "JSSegmentedVariableObject.h"
29  
30  namespace JSC {
31  
32  class JSGlobalLexicalEnvironment final : public JSSegmentedVariableObject {
33  public:
34      using Base = JSSegmentedVariableObject;
35  
36      static constexpr unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot;
37  
38      template<typename CellType, SubspaceAccess mode>
39      static IsoSubspace* subspaceFor(VM& vm)
40      {
41          return &vm.globalLexicalEnvironmentSpace;
42      }
43  
44      static JSGlobalLexicalEnvironment* create(VM& vm, Structure* structure, JSScope* parentScope)
45      {
46          JSGlobalLexicalEnvironment* result =
47              new (NotNull, allocateCell<JSGlobalLexicalEnvironment>(vm.heap)) JSGlobalLexicalEnvironment(vm, structure, parentScope);
48          result->finishCreation(vm);
49          result->symbolTable()->setScopeType(SymbolTable::ScopeType::GlobalLexicalScope);
50          return result;
51      }
52  
53      static bool getOwnPropertySlot(JSObject*, JSGlobalObject*, PropertyName, PropertySlot&);
54      static bool put(JSCell*, JSGlobalObject*, PropertyName, JSValue, PutPropertySlot&);
55  
56      static void destroy(JSCell*);
57      static constexpr bool needsDestruction = true;
58  
59      bool isEmpty() const { return !symbolTable()->size(); }
60      bool isConstVariable(UniquedStringImpl*);
61  
62      DECLARE_INFO;
63  
64      static Structure* createStructure(VM& vm, JSGlobalObject* globalObject)
65      {
66          return Structure::create(vm, globalObject, jsNull(), TypeInfo(GlobalLexicalEnvironmentType, StructureFlags), info());
67      }
68  
69  private:
70      JSGlobalLexicalEnvironment(VM& vm, Structure* structure, JSScope* scope)
71          : Base(vm, structure, scope)
72      {
73      }
74  };
75  
76  } // namespace JSC