summaryrefslogtreecommitdiffstats
path: root/dom/svg/SVGNumberList.h
blob: b6845ffd55c127c3b655dc7d08c5b27680b3567d (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
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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_SVGNUMBERLIST_H__
#define MOZILLA_SVGNUMBERLIST_H__

#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsIContent.h"
#include "nsINode.h"
#include "nsIWeakReferenceUtils.h"
#include "nsSVGElement.h"
#include "nsTArray.h"

namespace mozilla {

/**
 * ATTENTION! WARNING! WATCH OUT!!
 *
 * Consumers that modify objects of this type absolutely MUST keep the DOM
 * wrappers for those lists (if any) in sync!! That's why this class is so
 * locked down.
 *
 * The DOM wrapper class for this class is DOMSVGNumberList.
 */
class SVGNumberList
{
  friend class SVGAnimatedNumberList;
  friend class DOMSVGNumberList;
  friend class DOMSVGNumber;

public:

  SVGNumberList(){}
  ~SVGNumberList(){}

  // Only methods that don't make/permit modification to this list are public.
  // Only our friend classes can access methods that may change us.

  /// This may return an incomplete string on OOM, but that's acceptable.
  void GetValueAsString(nsAString& aValue) const;

  bool IsEmpty() const {
    return mNumbers.IsEmpty();
  }

  uint32_t Length() const {
    return mNumbers.Length();
  }

  const float& operator[](uint32_t aIndex) const {
    return mNumbers[aIndex];
  }

  bool operator==(const SVGNumberList& rhs) const {
    return mNumbers == rhs.mNumbers;
  }

  bool SetCapacity(uint32_t size) {
    return mNumbers.SetCapacity(size, fallible);
  }

  void Compact() {
    mNumbers.Compact();
  }

  // Access to methods that can modify objects of this type is deliberately
  // limited. This is to reduce the chances of someone modifying objects of
  // this type without taking the necessary steps to keep DOM wrappers in sync.
  // If you need wider access to these methods, consider adding a method to
  // SVGAnimatedNumberList and having that class act as an intermediary so it
  // can take care of keeping DOM wrappers in sync.

protected:

  /**
   * This may fail on OOM if the internal capacity needs to be increased, in
   * which case the list will be left unmodified.
   */
  nsresult CopyFrom(const SVGNumberList& rhs);

  float& operator[](uint32_t aIndex) {
    return mNumbers[aIndex];
  }

  /**
   * This may fail (return false) on OOM if the internal capacity is being
   * increased, in which case the list will be left unmodified.
   */
  bool SetLength(uint32_t aNumberOfItems) {
    return mNumbers.SetLength(aNumberOfItems, fallible);
  }

private:

  // Marking the following private only serves to show which methods are only
  // used by our friend classes (as opposed to our subclasses) - it doesn't
  // really provide additional safety.

  nsresult SetValueFromString(const nsAString& aValue);

  void Clear() {
    mNumbers.Clear();
  }

  bool InsertItem(uint32_t aIndex, const float &aNumber) {
    if (aIndex >= mNumbers.Length()) {
      aIndex = mNumbers.Length();
    }
    return !!mNumbers.InsertElementAt(aIndex, aNumber, fallible);
  }

  void ReplaceItem(uint32_t aIndex, const float &aNumber) {
    MOZ_ASSERT(aIndex < mNumbers.Length(),
               "DOM wrapper caller should have raised INDEX_SIZE_ERR");
    mNumbers[aIndex] = aNumber;
  }

  void RemoveItem(uint32_t aIndex) {
    MOZ_ASSERT(aIndex < mNumbers.Length(),
               "DOM wrapper caller should have raised INDEX_SIZE_ERR");
    mNumbers.RemoveElementAt(aIndex);
  }

  bool AppendItem(float aNumber) {
    return !!mNumbers.AppendElement(aNumber, fallible);
  }

protected:

  /* See SVGLengthList for the rationale for using FallibleTArray<float> instead
   * of FallibleTArray<float, 1>.
   */
  FallibleTArray<float> mNumbers;
};


/**
 * This SVGNumberList subclass is used by the SMIL code when a number list
 * is to be stored in an nsISMILValue instance. Since nsISMILValue objects may
 * be cached, it is necessary for us to hold a strong reference to our element
 * so that it doesn't disappear out from under us if, say, the element is
 * removed from the DOM tree.
 */
class SVGNumberListAndInfo : public SVGNumberList
{
public:

  SVGNumberListAndInfo()
    : mElement(nullptr)
  {}

  explicit SVGNumberListAndInfo(nsSVGElement *aElement)
    : mElement(do_GetWeakReference(static_cast<nsINode*>(aElement)))
  {}

  void SetInfo(nsSVGElement *aElement) {
    mElement = do_GetWeakReference(static_cast<nsINode*>(aElement));
  }

  nsSVGElement* Element() const {
    nsCOMPtr<nsIContent> e = do_QueryReferent(mElement);
    return static_cast<nsSVGElement*>(e.get());
  }

  nsresult CopyFrom(const SVGNumberListAndInfo& rhs) {
    mElement = rhs.mElement;
    return SVGNumberList::CopyFrom(rhs);
  }

  // Instances of this special subclass do not have DOM wrappers that we need
  // to worry about keeping in sync, so it's safe to expose any hidden base
  // class methods required by the SMIL code, as we do below.

  /**
   * Exposed so that SVGNumberList baseVals can be copied to
   * SVGNumberListAndInfo objects. Note that callers should also call
   * SetInfo() when using this method!
   */
  nsresult CopyFrom(const SVGNumberList& rhs) {
    return SVGNumberList::CopyFrom(rhs);
  }
  const float& operator[](uint32_t aIndex) const {
    return SVGNumberList::operator[](aIndex);
  }
  float& operator[](uint32_t aIndex) {
    return SVGNumberList::operator[](aIndex);
  }
  bool SetLength(uint32_t aNumberOfItems) {
    return SVGNumberList::SetLength(aNumberOfItems);
  }

private:
  // We must keep a weak reference to our element because we may belong to a
  // cached baseVal nsSMILValue. See the comments starting at:
  // https://bugzilla.mozilla.org/show_bug.cgi?id=515116#c15
  // See also https://bugzilla.mozilla.org/show_bug.cgi?id=653497
  nsWeakPtr mElement;
};

} // namespace mozilla

#endif // MOZILLA_SVGNUMBERLIST_H__