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
|
/*
* Copyright (C) 2020 Igalia S.L.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "LazyLoadImageObserver.h"
#include "DocumentInlines.h"
#include "HTMLImageElement.h"
#include "IntersectionObserverCallback.h"
#include "IntersectionObserverEntry.h"
#include "LocalFrame.h"
#include <limits>
#include <wtf/TZoneMallocInlines.h>
namespace WebCore {
WTF_MAKE_TZONE_ALLOCATED_IMPL(LazyLoadImageObserver);
class LazyImageLoadIntersectionObserverCallback final : public IntersectionObserverCallback {
public:
static Ref<LazyImageLoadIntersectionObserverCallback> create(Document& document)
{
return adoptRef(*new LazyImageLoadIntersectionObserverCallback(document));
}
private:
LazyImageLoadIntersectionObserverCallback(Document& document)
: IntersectionObserverCallback(&document)
{
}
bool hasCallback() const final { return true; }
CallbackResult<void> handleEvent(IntersectionObserver&, const Vector<Ref<IntersectionObserverEntry>>& entries, IntersectionObserver&) final
{
ASSERT(!entries.isEmpty());
for (auto& entry : entries) {
if (!entry->isIntersecting())
continue;
if (RefPtr element = dynamicDowncast<HTMLImageElement>(entry->target())) {
element->loadDeferredImage();
element->document().lazyLoadImageObserver().unobserve(*element, element->document());
}
}
return { };
}
CallbackResult<void> handleEventRethrowingException(IntersectionObserver& thisObserver, const Vector<Ref<IntersectionObserverEntry>>& entries, IntersectionObserver& observer) final
{
return handleEvent(thisObserver, entries, observer);
}
};
void LazyLoadImageObserver::observe(Element& element)
{
auto& observer = element.document().lazyLoadImageObserver();
auto* intersectionObserver = observer.intersectionObserver(element.protectedDocument());
if (!intersectionObserver)
return;
intersectionObserver->observe(element);
}
void LazyLoadImageObserver::unobserve(Element& element, Document& document)
{
if (auto& observer = document.lazyLoadImageObserver().m_observer)
observer->unobserve(element);
}
IntersectionObserver* LazyLoadImageObserver::intersectionObserver(Document& document)
{
if (!m_observer) {
auto callback = LazyImageLoadIntersectionObserverCallback::create(document);
static NeverDestroyed<const String> lazyLoadingRootMarginFallback(MAKE_STATIC_STRING_IMPL("100%"));
IntersectionObserver::Init options { &document, lazyLoadingRootMarginFallback, { } };
auto observer = IntersectionObserver::create(document, WTFMove(callback), WTFMove(options));
if (observer.hasException())
return nullptr;
m_observer = observer.returnValue().ptr();
}
return m_observer.get();
}
bool LazyLoadImageObserver::isObserved(Element& element) const
{
return m_observer && m_observer->isObserving(element);
}
}
|
