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
|
// Copyright 2018 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.
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_SVG_SVG_RESOURCE_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_SVG_SVG_RESOURCE_H_
#include "base/macros.h"
#include "third_party/blink/renderer/platform/heap/handle.h"
#include "third_party/blink/renderer/platform/loader/fetch/resource_client.h"
#include "third_party/blink/renderer/platform/weborigin/kurl.h"
#include "third_party/blink/renderer/platform/wtf/hash_map.h"
#include "third_party/blink/renderer/platform/wtf/text/atomic_string.h"
namespace blink {
class Document;
class Element;
class IdTargetObserver;
class LayoutSVGResourceContainer;
class QualifiedName;
class SVGFilterPrimitiveStandardAttributes;
class SVGResourceClient;
class SVGResourceDocumentContent;
class TreeScope;
// A class tracking a reference to an SVG resource (an element that constitutes
// a paint server, mask, clip-path, filter et.c.)
//
// Elements can be referenced using CSS, for example like:
//
// filter: url(#baz); ("local")
//
// or
//
// filter: url(foo.com/bar.svg#baz); ("external")
//
// SVGResource provide a mechanism to persistently reference an element in such
// cases - regardless of if the element reside in the same document (read: tree
// scope) or in an external (resource) document. Loading events related to the
// external documents case are handled by the SVGResource.
//
// For same document references, changes that could affect the 'id' lookup will
// be tracked, to handle elements being added, removed or having their 'id'
// mutated. (This does not apply for the external document case because it's
// assumed they will not mutate after load, due to scripts not being run etc.)
//
// SVGResources are created, and managed, either by SVGTreeScopeResources
// (local) or CSSURIValue (external), and have SVGResourceClients as a means to
// deliver change notifications. Clients that are interested in change
// notifications hence need to register a SVGResourceClient with the
// SVGResource. Most commonly this registration would take place when the
// computed style changes.
//
// The element is bound either when the SVGResource is created (for local
// resources) or after the referenced resource has completed loading (for
// external resources.)
//
// As content is mutated, clients will get notified via the SVGResource.
//
// <event> -> SVG...Element -> SVGResource -> SVGResourceClient(0..N)
//
class SVGResource : public GarbageCollected<SVGResource> {
public:
virtual ~SVGResource();
virtual void Load(Document&) {}
virtual void LoadWithoutCSP(Document&) {}
Element* Target() const { return target_; }
// Returns the target's LayoutObject (if target exists and is attached to the
// layout tree). Also perform cycle-checking, and may thus return nullptr if
// this SVGResourceClient -> SVGResource reference would start a cycle.
LayoutSVGResourceContainer* ResourceContainer(SVGResourceClient&) const;
// Same as the above, minus the cycle-checking.
LayoutSVGResourceContainer* ResourceContainerNoCycleCheck() const;
// Run cycle-checking for this SVGResourceClient -> SVGResource
// reference. Used internally by the cycle-checking, and shouldn't be called
// directly in general.
bool FindCycle(SVGResourceClient&) const;
void AddClient(SVGResourceClient&);
void RemoveClient(SVGResourceClient&);
virtual void Trace(Visitor*) const;
protected:
SVGResource();
void InvalidateCycleCache();
void NotifyContentChanged();
Member<Element> target_;
enum CycleState {
kNeedCheck,
kPerformingCheck,
kHasCycle,
kNoCycle,
};
struct ClientEntry {
int count = 0;
CycleState cached_cycle_check = kNeedCheck;
};
mutable HeapHashMap<Member<SVGResourceClient>, ClientEntry> clients_;
private:
DISALLOW_COPY_AND_ASSIGN(SVGResource);
};
// Local resource reference (see SVGResource.)
class LocalSVGResource final : public SVGResource {
public:
LocalSVGResource(TreeScope&, const AtomicString& id);
void Unregister();
using SVGResource::NotifyContentChanged;
void NotifyFilterPrimitiveChanged(
SVGFilterPrimitiveStandardAttributes& primitive,
const QualifiedName& attribute);
void Trace(Visitor*) const override;
private:
void TargetChanged(const AtomicString& id);
Member<TreeScope> tree_scope_;
Member<IdTargetObserver> id_observer_;
};
// External resource reference (see SVGResource.)
class ExternalSVGResource final : public SVGResource, public ResourceClient {
public:
explicit ExternalSVGResource(const KURL&);
void Load(Document&) override;
void LoadWithoutCSP(Document&) override;
void Trace(Visitor*) const override;
private:
Element* ResolveTarget();
// ResourceClient implementation
void NotifyFinished(Resource*) override;
String DebugName() const override;
Member<SVGResourceDocumentContent> document_content_;
KURL url_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_SVG_SVG_RESOURCE_H_
|
