summaryrefslogtreecommitdiffstats
path: root/dom/events/JSEventHandler.h
blob: a301443f07c2e33ede7706cfe50326a23ed2fef8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_JSEventHandler_h_
#define mozilla_JSEventHandler_h_

#include "mozilla/Attributes.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/dom/EventHandlerBinding.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsIAtom.h"
#include "nsIDOMKeyEvent.h"
#include "nsIDOMEventListener.h"
#include "nsIScriptContext.h"

namespace mozilla {

class TypedEventHandler
{
public:
  enum HandlerType
  {
    eUnset = 0,
    eNormal = 0x1,
    eOnError = 0x2,
    eOnBeforeUnload = 0x3,
    eTypeBits = 0x3
  };

  TypedEventHandler()
    : mBits(0)
  {
  }

  explicit TypedEventHandler(dom::EventHandlerNonNull* aHandler)
    : mBits(0)
  {
    Assign(aHandler, eNormal);
  }

  explicit TypedEventHandler(dom::OnErrorEventHandlerNonNull* aHandler)
    : mBits(0)
  {
    Assign(aHandler, eOnError);
  }

  explicit TypedEventHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler)
    : mBits(0)
  {
    Assign(aHandler, eOnBeforeUnload);
  }

  TypedEventHandler(const TypedEventHandler& aOther)
  {
    if (aOther.HasEventHandler()) {
      // Have to make sure we take our own ref
      Assign(aOther.Ptr(), aOther.Type());
    } else {
      mBits = 0;
    }
  }

  ~TypedEventHandler()
  {
    ReleaseHandler();
  }

  HandlerType Type() const
  {
    return HandlerType(mBits & eTypeBits);
  }

  bool HasEventHandler() const
  {
    return !!Ptr();
  }

  void SetHandler(const TypedEventHandler& aHandler)
  {
    if (aHandler.HasEventHandler()) {
      ReleaseHandler();
      Assign(aHandler.Ptr(), aHandler.Type());
    } else {
      ForgetHandler();
    }
  }

  dom::EventHandlerNonNull* NormalEventHandler() const
  {
    MOZ_ASSERT(Type() == eNormal && Ptr());
    return reinterpret_cast<dom::EventHandlerNonNull*>(Ptr());
  }

  void SetHandler(dom::EventHandlerNonNull* aHandler)
  {
    ReleaseHandler();
    Assign(aHandler, eNormal);
  }

  dom::OnBeforeUnloadEventHandlerNonNull* OnBeforeUnloadEventHandler() const
  {
    MOZ_ASSERT(Type() == eOnBeforeUnload);
    return reinterpret_cast<dom::OnBeforeUnloadEventHandlerNonNull*>(Ptr());
  }

  void SetHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler)
  {
    ReleaseHandler();
    Assign(aHandler, eOnBeforeUnload);
  }

  dom::OnErrorEventHandlerNonNull* OnErrorEventHandler() const
  {
    MOZ_ASSERT(Type() == eOnError);
    return reinterpret_cast<dom::OnErrorEventHandlerNonNull*>(Ptr());
  }

  void SetHandler(dom::OnErrorEventHandlerNonNull* aHandler)
  {
    ReleaseHandler();
    Assign(aHandler, eOnError);
  }

  dom::CallbackFunction* Ptr() const
  {
    // Have to cast eTypeBits so we don't have to worry about
    // promotion issues after the bitflip.
    return reinterpret_cast<dom::CallbackFunction*>(mBits &
                                                      ~uintptr_t(eTypeBits));
  }

  void ForgetHandler()
  {
    ReleaseHandler();
    mBits = 0;
  }

  bool operator==(const TypedEventHandler& aOther) const
  {
    return
      Ptr() && aOther.Ptr() &&
      Ptr()->CallbackPreserveColor() == aOther.Ptr()->CallbackPreserveColor();
  }

private:
  void operator=(const TypedEventHandler&) = delete;

  void ReleaseHandler()
  {
    nsISupports* ptr = Ptr();
    NS_IF_RELEASE(ptr);
  }

  void Assign(nsISupports* aHandler, HandlerType aType)
  {
    MOZ_ASSERT(aHandler, "Must have handler");
    NS_ADDREF(aHandler);
    mBits = uintptr_t(aHandler) | uintptr_t(aType);
  }

  uintptr_t mBits;
};

/**
 * Implemented by script event listeners. Used to retrieve the script object
 * corresponding to the event target and the handler itself.
 *
 * Note, mTarget is a raw pointer and the owner of the JSEventHandler object
 * is expected to call Disconnect()!
 */

#define NS_JSEVENTHANDLER_IID \
{ 0x4f486881, 0x1956, 0x4079, \
  { 0x8c, 0xa0, 0xf3, 0xbd, 0x60, 0x5c, 0xc2, 0x79 } }

class JSEventHandler : public nsIDOMEventListener
{
public:
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_JSEVENTHANDLER_IID)

  JSEventHandler(nsISupports* aTarget, nsIAtom* aType,
                 const TypedEventHandler& aTypedHandler);

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  // nsIDOMEventListener interface
  NS_DECL_NSIDOMEVENTLISTENER

  nsISupports* GetEventTarget() const
  {
    return mTarget;
  }

  void Disconnect()
  {
    mTarget = nullptr;
  }

  const TypedEventHandler& GetTypedEventHandler() const
  {
    return mTypedHandler;
  }

  void ForgetHandler()
  {
    mTypedHandler.ForgetHandler();
  }

  nsIAtom* EventName() const
  {
    return mEventName;
  }

  // Set a handler for this event listener.  The handler must already
  // be bound to the right target.
  void SetHandler(const TypedEventHandler& aTypedHandler)
  {
    mTypedHandler.SetHandler(aTypedHandler);
  }
  void SetHandler(dom::EventHandlerNonNull* aHandler)
  {
    mTypedHandler.SetHandler(aHandler);
  }
  void SetHandler(dom::OnBeforeUnloadEventHandlerNonNull* aHandler)
  {
    mTypedHandler.SetHandler(aHandler);
  }
  void SetHandler(dom::OnErrorEventHandlerNonNull* aHandler)
  {
    mTypedHandler.SetHandler(aHandler);
  }

  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
  {
    return 0;

    // Measurement of the following members may be added later if DMD finds it
    // is worthwhile:
    // - mTarget
    //
    // The following members are not measured:
    // - mTypedHandler: may be shared with others
    // - mEventName: shared with others
  }

  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf)
  {
    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
  }

  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_CLASS(JSEventHandler)

  bool IsBlackForCC();

protected:
  virtual ~JSEventHandler();

  nsISupports* mTarget;
  nsCOMPtr<nsIAtom> mEventName;
  TypedEventHandler mTypedHandler;
};

NS_DEFINE_STATIC_IID_ACCESSOR(JSEventHandler, NS_JSEVENTHANDLER_IID)

} // namespace mozilla

/**
 * Factory function.  aHandler must already be bound to aTarget.
 * aContext is allowed to be null if aHandler is already set up.
 */
nsresult NS_NewJSEventHandler(nsISupports* aTarget,
                              nsIAtom* aType,
                              const mozilla::TypedEventHandler& aTypedHandler,
                              mozilla::JSEventHandler** aReturn);

#endif // mozilla_JSEventHandler_h_