dom/bindings/ObservableArrayProxyHandler.h

   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 */