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
|
/* 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/. */
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
generateUUID: "chrome://remote/content/shared/UUID.sys.mjs",
});
/**
* @typedef {object} NodeReferenceDetails
* @property {number} browserId
* @property {number} browsingContextGroupId
* @property {number} browsingContextId
* @property {boolean} isTopBrowsingContext
* @property {WeakRef} nodeWeakRef
*/
/**
* The class provides a mapping between DOM nodes and a unique node references.
* Supported types of nodes are Element and ShadowRoot.
*/
export class NodeCache {
#nodeIdMap;
#seenNodesMap;
constructor() {
// node => node id
this.#nodeIdMap = new WeakMap();
// Reverse map for faster lookup requests of node references. Values do
// not only contain the resolved DOM node but also further details like
// browsing context information.
//
// node id => node details
this.#seenNodesMap = new Map();
}
/**
* Get the number of nodes in the cache.
*/
get size() {
return this.#seenNodesMap.size;
}
/**
* Get or if not yet existent create a unique reference for an Element or
* ShadowRoot node.
*
* @param {Node} node
* The node to be added.
*
* @returns {string}
* The unique node reference for the DOM node.
*/
getOrCreateNodeReference(node) {
if (!Node.isInstance(node)) {
throw new TypeError(`Failed to create node reference for ${node}`);
}
let nodeId;
if (this.#nodeIdMap.has(node)) {
// For already known nodes return the cached node id.
nodeId = this.#nodeIdMap.get(node);
} else {
// Bug 1820734: For some Node types like `CDATA` no `ownerGlobal`
// property is available, and as such they cannot be deserialized
// right now.
const browsingContext = node.ownerGlobal?.browsingContext;
// For not yet cached nodes generate a unique id without curly braces.
nodeId = lazy.generateUUID();
const details = {
browserId: browsingContext?.browserId,
browsingContextGroupId: browsingContext?.group.id,
browsingContextId: browsingContext?.id,
isTopBrowsingContext: browsingContext?.parent === null,
nodeWeakRef: Cu.getWeakReference(node),
};
this.#nodeIdMap.set(node, nodeId);
this.#seenNodesMap.set(nodeId, details);
}
return nodeId;
}
/**
* Clear known DOM nodes.
*
* @param {object=} options
* @param {boolean=} options.all
* Clear all references from any browsing context. Defaults to false.
* @param {BrowsingContext=} options.browsingContext
* Clear all references living in that browsing context.
*/
clear(options = {}) {
const { all = false, browsingContext } = options;
if (all) {
this.#nodeIdMap = new WeakMap();
this.#seenNodesMap.clear();
return;
}
if (browsingContext) {
for (const [nodeId, identifier] of this.#seenNodesMap.entries()) {
const { browsingContextId, nodeWeakRef } = identifier;
const node = nodeWeakRef.get();
if (browsingContextId === browsingContext.id) {
this.#nodeIdMap.delete(node);
this.#seenNodesMap.delete(nodeId);
}
}
return;
}
throw new Error(`Requires "browsingContext" or "all" to be set.`);
}
/**
* Get a DOM node by its unique reference.
*
* @param {BrowsingContext} browsingContext
* The browsing context the node should be part of.
* @param {string} nodeId
* The unique node reference of the DOM node.
*
* @returns {Node|null}
* The DOM node that the unique identifier was generated for or
* `null` if the node does not exist anymore.
*/
getNode(browsingContext, nodeId) {
const nodeDetails = this.getReferenceDetails(nodeId);
// Check that the node reference is known, and is associated with a
// browsing context that shares the same browsing context group.
if (
nodeDetails === null ||
nodeDetails.browsingContextGroupId !== browsingContext.group.id
) {
return null;
}
if (nodeDetails.nodeWeakRef) {
return nodeDetails.nodeWeakRef.get();
}
return null;
}
/**
* Get detailed information for the node reference.
*
* @param {string} nodeId
*
* @returns {NodeReferenceDetails}
* Node details like: browsingContextId
*/
getReferenceDetails(nodeId) {
const details = this.#seenNodesMap.get(nodeId);
return details !== undefined ? details : null;
}
}
|
