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ObservableArrayProxyHandler.h (4706B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
      5 * You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef mozilla_dom_ObservableArrayProxyHandler_h
      8 #define mozilla_dom_ObservableArrayProxyHandler_h
      9 
     10 #include "js/TypeDecls.h"
     11 #include "js/Wrapper.h"
     12 
     13 namespace mozilla::dom {
     14 
     15 /**
     16 * Proxy handler for observable array exotic object.
     17 *
     18 * The indexed properties are stored in the backing list object in reserved slot
     19 * of the proxy object with special treatment intact.
     20 *
     21 * The additional properties are stored in the proxy target object.
     22 */
     23 
     24 class ObservableArrayProxyHandler : public js::ForwardingProxyHandler {
     25 public:
     26  explicit constexpr ObservableArrayProxyHandler()
     27      : js::ForwardingProxyHandler(&family) {}
     28 
     29  // Implementations of methods that can be implemented in terms of
     30  // other lower-level methods.
     31  bool defineProperty(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     32                      JS::Handle<JS::PropertyKey> aId,
     33                      JS::Handle<JS::PropertyDescriptor> aDesc,
     34                      JS::ObjectOpResult& aResult) const override;
     35 
     36  bool delete_(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     37               JS::Handle<JS::PropertyKey> aId,
     38               JS::ObjectOpResult& aResult) const override;
     39 
     40  bool get(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     41           JS::Handle<JS::Value> aReceiver, JS::Handle<JS::PropertyKey> aId,
     42           JS::MutableHandle<JS::Value> aVp) const override;
     43 
     44  bool getOwnPropertyDescriptor(
     45      JSContext* aCx, JS::Handle<JSObject*> aProxy,
     46      JS::Handle<JS::PropertyKey> aId,
     47      JS::MutableHandle<Maybe<JS::PropertyDescriptor>> aDesc) const override;
     48 
     49  bool has(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     50           JS::Handle<JS::PropertyKey> aId, bool* aBp) const override;
     51 
     52  bool ownPropertyKeys(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     53                       JS::MutableHandleVector<jsid> aProps) const override;
     54 
     55  bool preventExtensions(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     56                         JS::ObjectOpResult& aResult) const override;
     57 
     58  bool set(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     59           JS::Handle<JS::PropertyKey> aId, JS::Handle<JS::Value> aV,
     60           JS::Handle<JS::Value> aReceiver,
     61           JS::ObjectOpResult& aResult) const override;
     62 
     63  bool SetLength(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     64                 uint32_t aLength) const;
     65 
     66  static const char family;
     67 
     68 protected:
     69  bool GetBackingListObject(
     70      JSContext* aCx, JS::Handle<JSObject*> aProxy,
     71      JS::MutableHandle<JSObject*> aBackingListObject) const;
     72 
     73  bool GetBackingListLength(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     74                            uint32_t* aLength) const;
     75 
     76  bool SetLength(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     77                 JS::Handle<JSObject*> aBackingList, uint32_t aLength,
     78                 JS::ObjectOpResult& aResult) const;
     79 
     80  bool SetLength(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     81                 JS::Handle<JSObject*> aBackingList,
     82                 JS::Handle<JS::Value> aValue,
     83                 JS::ObjectOpResult& aResult) const;
     84 
     85  // Hook for subclasses to invoke the setting the indexed value steps which
     86  // would invoke DeleteAlgorithm/SetAlgorithm defined and implemented per
     87  // interface. Returns false and throw exception on failure.
     88  virtual bool SetIndexedValue(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     89                               JS::Handle<JSObject*> aBackingList,
     90                               uint32_t aIndex, JS::Handle<JS::Value> aValue,
     91                               JS::ObjectOpResult& aResult) const = 0;
     92 
     93  // Hook for subclasses to invoke the DeleteAlgorithm defined and implemented
     94  // per interface. Returns false and throw exception on failure.
     95  virtual bool OnDeleteItem(JSContext* aCx, JS::Handle<JSObject*> aProxy,
     96                            JS::Handle<JS::Value> aValue,
     97                            uint32_t aIndex) const = 0;
     98 };
     99 
    100 inline bool IsObservableArrayProxy(JSObject* obj) {
    101  return js::IsProxy(obj) && js::GetProxyHandler(obj)->family() ==
    102                                 &ObservableArrayProxyHandler::family;
    103 }
    104 
    105 inline const ObservableArrayProxyHandler* GetObservableArrayProxyHandler(
    106    JSObject* obj) {
    107  MOZ_ASSERT(IsObservableArrayProxy(obj));
    108  return static_cast<const ObservableArrayProxyHandler*>(
    109      js::GetProxyHandler(obj));
    110 }
    111 
    112 }  // namespace mozilla::dom
    113 
    114 #endif /* mozilla_dom_ObservableArrayProxyHandler_h */