1/*
2 * Copyright (C) 2011 Google 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 are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "config.h"
32#include "core/dom/MutationObserver.h"
33
34#include "bindings/core/v8/ExceptionState.h"
35#include "core/dom/ExceptionCode.h"
36#include "core/dom/Microtask.h"
37#include "core/dom/MutationCallback.h"
38#include "core/dom/MutationObserverInit.h"
39#include "core/dom/MutationObserverRegistration.h"
40#include "core/dom/MutationRecord.h"
41#include "core/dom/Node.h"
42#include "core/inspector/InspectorInstrumentation.h"
43#include "wtf/MainThread.h"
44#include <algorithm>
45
46namespace blink {
47
48static unsigned s_observerPriority = 0;
49
50struct MutationObserver::ObserverLessThan {
51    bool operator()(const RefPtrWillBeMember<MutationObserver>& lhs, const RefPtrWillBeMember<MutationObserver>& rhs)
52    {
53        return lhs->m_priority < rhs->m_priority;
54    }
55};
56
57PassRefPtrWillBeRawPtr<MutationObserver> MutationObserver::create(PassOwnPtr<MutationCallback> callback)
58{
59    ASSERT(isMainThread());
60    return adoptRefWillBeNoop(new MutationObserver(callback));
61}
62
63MutationObserver::MutationObserver(PassOwnPtr<MutationCallback> callback)
64    : m_callback(callback)
65    , m_priority(s_observerPriority++)
66{
67}
68
69MutationObserver::~MutationObserver()
70{
71#if !ENABLE(OILPAN)
72    ASSERT(m_registrations.isEmpty());
73#endif
74    if (!m_records.isEmpty())
75        InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
76}
77
78void MutationObserver::observe(Node* node, const MutationObserverInit& observerInit, ExceptionState& exceptionState)
79{
80    if (!node) {
81        exceptionState.throwDOMException(NotFoundError, "The provided node was null.");
82        return;
83    }
84
85    MutationObserverOptions options = 0;
86
87    if (observerInit.hasAttributeOldValue() && observerInit.attributeOldValue())
88        options |= AttributeOldValue;
89
90    HashSet<AtomicString> attributeFilter;
91    if (observerInit.hasAttributeFilter()) {
92        const Vector<String>& sequence = observerInit.attributeFilter();
93        for (unsigned i = 0; i < sequence.size(); ++i)
94            attributeFilter.add(AtomicString(sequence[i]));
95        options |= AttributeFilter;
96    }
97
98    bool attributes = observerInit.hasAttributes() && observerInit.attributes();
99    if (attributes || (!observerInit.hasAttributes() && (observerInit.hasAttributeOldValue() || observerInit.hasAttributeFilter())))
100        options |= Attributes;
101
102    if (observerInit.hasCharacterDataOldValue() && observerInit.characterDataOldValue())
103        options |= CharacterDataOldValue;
104
105    bool characterData = observerInit.hasCharacterData() && observerInit.characterData();
106    if (characterData || (!observerInit.hasCharacterData() && observerInit.hasCharacterDataOldValue()))
107        options |= CharacterData;
108
109    if (observerInit.childList())
110        options |= ChildList;
111
112    if (observerInit.subtree())
113        options |= Subtree;
114
115    if (!(options & Attributes)) {
116        if (options & AttributeOldValue) {
117            exceptionState.throwTypeError("The options object may only set 'attributeOldValue' to true when 'attributes' is true or not present.");
118            return;
119        }
120        if (options & AttributeFilter) {
121            exceptionState.throwTypeError("The options object may only set 'attributeFilter' when 'attributes' is true or not present.");
122            return;
123        }
124    }
125    if (!((options & CharacterData) || !(options & CharacterDataOldValue))) {
126        exceptionState.throwTypeError("The options object may only set 'characterDataOldValue' to true when 'characterData' is true or not present.");
127        return;
128    }
129
130    if (!(options & (Attributes | CharacterData | ChildList))) {
131        exceptionState.throwTypeError("The options object must set at least one of 'attributes', 'characterData', or 'childList' to true.");
132        return;
133    }
134
135    node->registerMutationObserver(*this, options, attributeFilter);
136}
137
138MutationRecordVector MutationObserver::takeRecords()
139{
140    MutationRecordVector records;
141    records.swap(m_records);
142    InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
143    return records;
144}
145
146void MutationObserver::disconnect()
147{
148    m_records.clear();
149    InspectorInstrumentation::didClearAllMutationRecords(m_callback->executionContext(), this);
150    MutationObserverRegistrationSet registrations(m_registrations);
151    for (MutationObserverRegistrationSet::iterator iter = registrations.begin(); iter != registrations.end(); ++iter)
152        (*iter)->unregister();
153    ASSERT(m_registrations.isEmpty());
154}
155
156void MutationObserver::observationStarted(MutationObserverRegistration* registration)
157{
158    ASSERT(!m_registrations.contains(registration));
159    m_registrations.add(registration);
160}
161
162void MutationObserver::observationEnded(MutationObserverRegistration* registration)
163{
164    ASSERT(m_registrations.contains(registration));
165    m_registrations.remove(registration);
166}
167
168static MutationObserverSet& activeMutationObservers()
169{
170    DEFINE_STATIC_LOCAL(OwnPtrWillBePersistent<MutationObserverSet>, activeObservers, (adoptPtrWillBeNoop(new MutationObserverSet())));
171    return *activeObservers;
172}
173
174static MutationObserverSet& suspendedMutationObservers()
175{
176    DEFINE_STATIC_LOCAL(OwnPtrWillBePersistent<MutationObserverSet>, suspendedObservers, (adoptPtrWillBeNoop(new MutationObserverSet())));
177    return *suspendedObservers;
178}
179
180static void activateObserver(PassRefPtrWillBeRawPtr<MutationObserver> observer)
181{
182    if (activeMutationObservers().isEmpty())
183        Microtask::enqueueMicrotask(WTF::bind(&MutationObserver::deliverMutations));
184
185    activeMutationObservers().add(observer);
186}
187
188void MutationObserver::enqueueMutationRecord(PassRefPtrWillBeRawPtr<MutationRecord> mutation)
189{
190    ASSERT(isMainThread());
191    m_records.append(mutation);
192    activateObserver(this);
193    InspectorInstrumentation::didEnqueueMutationRecord(m_callback->executionContext(), this);
194}
195
196void MutationObserver::setHasTransientRegistration()
197{
198    ASSERT(isMainThread());
199    activateObserver(this);
200}
201
202WillBeHeapHashSet<RawPtrWillBeMember<Node> > MutationObserver::getObservedNodes() const
203{
204    WillBeHeapHashSet<RawPtrWillBeMember<Node> > observedNodes;
205    for (MutationObserverRegistrationSet::const_iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter)
206        (*iter)->addRegistrationNodesToSet(observedNodes);
207    return observedNodes;
208}
209
210bool MutationObserver::canDeliver()
211{
212    return !m_callback->executionContext()->activeDOMObjectsAreSuspended();
213}
214
215void MutationObserver::deliver()
216{
217    ASSERT(canDeliver());
218
219    // Calling clearTransientRegistrations() can modify m_registrations, so it's necessary
220    // to make a copy of the transient registrations before operating on them.
221    WillBeHeapVector<RawPtrWillBeMember<MutationObserverRegistration>, 1> transientRegistrations;
222    for (MutationObserverRegistrationSet::iterator iter = m_registrations.begin(); iter != m_registrations.end(); ++iter) {
223        if ((*iter)->hasTransientRegistrations())
224            transientRegistrations.append(*iter);
225    }
226    for (size_t i = 0; i < transientRegistrations.size(); ++i)
227        transientRegistrations[i]->clearTransientRegistrations();
228
229    if (m_records.isEmpty())
230        return;
231
232    MutationRecordVector records;
233    records.swap(m_records);
234
235    InspectorInstrumentation::willDeliverMutationRecords(m_callback->executionContext(), this);
236    m_callback->call(records, this);
237    InspectorInstrumentation::didDeliverMutationRecords(m_callback->executionContext());
238}
239
240void MutationObserver::resumeSuspendedObservers()
241{
242    ASSERT(isMainThread());
243    if (suspendedMutationObservers().isEmpty())
244        return;
245
246    MutationObserverVector suspended;
247    copyToVector(suspendedMutationObservers(), suspended);
248    for (size_t i = 0; i < suspended.size(); ++i) {
249        if (suspended[i]->canDeliver()) {
250            suspendedMutationObservers().remove(suspended[i]);
251            activateObserver(suspended[i]);
252        }
253    }
254}
255
256void MutationObserver::deliverMutations()
257{
258    ASSERT(isMainThread());
259    MutationObserverVector observers;
260    copyToVector(activeMutationObservers(), observers);
261    activeMutationObservers().clear();
262    std::sort(observers.begin(), observers.end(), ObserverLessThan());
263    for (size_t i = 0; i < observers.size(); ++i) {
264        if (observers[i]->canDeliver())
265            observers[i]->deliver();
266        else
267            suspendedMutationObservers().add(observers[i]);
268    }
269}
270
271void MutationObserver::trace(Visitor* visitor)
272{
273#if ENABLE(OILPAN)
274    visitor->trace(m_records);
275    visitor->trace(m_registrations);
276#endif
277}
278
279} // namespace blink
280