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
|
// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "core/resize_observer/ResizeObserver.h"
#include "bindings/core/v8/v8_resize_observer_callback.h"
#include "core/dom/Element.h"
#include "core/frame/LocalFrameView.h"
#include "core/layout/AdjustForAbsoluteZoom.h"
#include "core/layout/LayoutObject.h"
#include "core/resize_observer/ResizeObservation.h"
#include "core/resize_observer/ResizeObserverController.h"
#include "core/resize_observer/ResizeObserverEntry.h"
namespace blink {
ResizeObserver* ResizeObserver::Create(Document& document,
V8ResizeObserverCallback* callback) {
return new ResizeObserver(callback, document);
}
ResizeObserver* ResizeObserver::Create(Document& document, Delegate* delegate) {
return new ResizeObserver(delegate, document);
}
ResizeObserver::ResizeObserver(V8ResizeObserverCallback* callback,
Document& document)
: callback_(callback),
skipped_observations_(false),
element_size_changed_(false) {
DCHECK(callback_);
controller_ = &document.EnsureResizeObserverController();
controller_->AddObserver(*this);
}
ResizeObserver::ResizeObserver(Delegate* delegate, Document& document)
: delegate_(delegate),
skipped_observations_(false),
element_size_changed_(false) {
DCHECK(delegate_);
controller_ = &document.EnsureResizeObserverController();
controller_->AddObserver(*this);
}
void ResizeObserver::observe(Element* target) {
auto& observer_map = target->EnsureResizeObserverData();
if (observer_map.Contains(this))
return; // Already registered.
auto observation = new ResizeObservation(target, this);
observations_.insert(observation);
observer_map.Set(this, observation);
if (LocalFrameView* frame_view = target->GetDocument().View())
frame_view->ScheduleAnimation();
}
void ResizeObserver::unobserve(Element* target) {
auto observer_map = target ? target->ResizeObserverData() : nullptr;
if (!observer_map)
return;
auto observation = observer_map->find(this);
if (observation != observer_map->end()) {
observations_.erase((*observation).value);
observer_map->erase(observation);
}
}
void ResizeObserver::disconnect() {
ObservationList observations;
observations_.Swap(observations);
for (auto& observation : observations) {
Element* target = (*observation).Target();
if (target)
target->EnsureResizeObserverData().erase(this);
}
ClearObservations();
}
size_t ResizeObserver::GatherObservations(size_t deeper_than) {
DCHECK(active_observations_.IsEmpty());
size_t min_observed_depth = ResizeObserverController::kDepthBottom;
if (!element_size_changed_)
return min_observed_depth;
for (auto& observation : observations_) {
if (!observation->ObservationSizeOutOfSync())
continue;
auto depth = observation->TargetDepth();
if (depth > deeper_than) {
active_observations_.push_back(*observation);
min_observed_depth = std::min(min_observed_depth, depth);
} else {
skipped_observations_ = true;
}
}
return min_observed_depth;
}
void ResizeObserver::DeliverObservations() {
// We can only clear this flag after all observations have been
// broadcast.
element_size_changed_ = skipped_observations_;
if (active_observations_.size() == 0)
return;
HeapVector<Member<ResizeObserverEntry>> entries;
for (auto& observation : active_observations_) {
// In case that the observer and the target belong to different execution
// contexts and the target's execution context is already gone, then skip
// such a target.
ExecutionContext* execution_context =
observation->Target()->GetExecutionContext();
if (!execution_context || execution_context->IsContextDestroyed())
continue;
LayoutPoint location = observation->ComputeTargetLocation();
LayoutSize size = observation->ComputeTargetSize();
observation->SetObservationSize(size);
LayoutRect content_rect(location, size);
if (observation->Target()->GetLayoutObject()) {
// Must adjust for zoom in order to report non-zoomed size.
const ComputedStyle& style =
observation->Target()->GetLayoutObject()->StyleRef();
content_rect.SetX(
AdjustForAbsoluteZoom::AdjustLayoutUnit(content_rect.X(), style));
content_rect.SetY(
AdjustForAbsoluteZoom::AdjustLayoutUnit(content_rect.Y(), style));
content_rect.SetWidth(
AdjustForAbsoluteZoom::AdjustLayoutUnit(content_rect.Width(), style));
content_rect.SetHeight(AdjustForAbsoluteZoom::AdjustLayoutUnit(
content_rect.Height(), style));
}
auto entry = new ResizeObserverEntry(observation->Target(), content_rect);
entries.push_back(entry);
}
if (entries.size() == 0) {
// No entry to report.
// Note that, if |active_observations_| is not empty but |entries| is empty,
// it means that it's possible that no target element is making |callback_|
// alive. In this case, we must not touch |callback_|.
ClearObservations();
return;
}
DCHECK(callback_ || delegate_);
if (callback_)
callback_->InvokeAndReportException(this, entries, this);
if (delegate_)
delegate_->OnResize(entries);
ClearObservations();
}
void ResizeObserver::ClearObservations() {
active_observations_.clear();
skipped_observations_ = false;
}
void ResizeObserver::ElementSizeChanged() {
element_size_changed_ = true;
if (controller_)
controller_->ObserverChanged();
}
void ResizeObserver::Trace(blink::Visitor* visitor) {
visitor->Trace(callback_);
visitor->Trace(delegate_);
visitor->Trace(observations_);
visitor->Trace(active_observations_);
visitor->Trace(controller_);
ScriptWrappable::Trace(visitor);
}
void ResizeObserver::TraceWrappers(
const ScriptWrappableVisitor* visitor) const {
visitor->TraceWrappers(callback_);
ScriptWrappable::TraceWrappers(visitor);
}
} // namespace blink
|
