summaryrefslogtreecommitdiff
path: root/ext/js/comm/frame-ancestry-handler.js
blob: b1ed71142b069a2021f27e45dbf48ef446892c7a (plain)
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
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
/*
 * Copyright (C) 2021  Yomichan Authors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

/* global
 * api
 */

/**
 * This class is used to return the ancestor frame IDs for the current frame.
 * This is a workaround to using the `webNavigation.getAllFrames` API, which
 * would require an additional permission that is otherwise unnecessary.
 * It is also used to track the correlation between child frame elements and their IDs.
 */
class FrameAncestryHandler {
    /**
     * Creates a new instance.
     * @param frameId The frame ID of the current frame the instance is instantiated in.
     */
    constructor(frameId) {
        this._frameId = frameId;
        this._isPrepared = false;
        this._requestMessageId = 'FrameAncestryHandler.requestFrameInfo';
        this._responseMessageIdBase = `${this._requestMessageId}.response.`;
        this._getFrameAncestryInfoPromise = null;
        this._childFrameMap = new Map();
    }

    /**
     * Gets the frame ID that the instance is instantiated in.
     */
    get frameId() {
        return this._frameId;
    }

    /**
     * Initializes event event listening.
     */
    prepare() {
        if (this._isPrepared) { return; }
        window.addEventListener('message', this._onWindowMessage.bind(this), false);
        this._isPrepared = true;
    }

    /**
     * Returns whether or not this frame is the root frame in the tab.
     * @returns `true` if it is the root, otherwise `false`.
     */
    isRootFrame() {
        return (window === window.parent);
    }

    /**
     * Gets the frame ancestry information for the current frame. If the frame is the
     * root frame, an empty array is returned. Otherwise, an array of frame IDs is returned,
     * starting from the nearest ancestor.
     * @param timeout The maximum time to wait to receive a response to frame information requests.
     * @returns An array of frame IDs corresponding to the ancestors of the current frame.
     */
    async getFrameAncestryInfo() {
        if (this._getFrameAncestryInfoPromise === null) {
            this._getFrameAncestryInfoPromise = this._getFrameAncestryInfo(5000);
        }
        return await this._getFrameAncestryInfoPromise;
    }

    /**
     * Gets the frame element of a child frame given a frame ID.
     * For this function to work, the `getFrameAncestryInfo` function needs to have
     * been invoked previously.
     * @param frameId The frame ID of the child frame to get.
     * @returns The element corresponding to the frame with ID `frameId`, otherwise `null`.
     */
    getChildFrameElement(frameId) {
        const frameInfo = this._childFrameMap.get(frameId);
        if (typeof frameInfo === 'undefined') { return null; }

        let {frameElement} = frameInfo;
        if (typeof frameElement === 'undefined') {
            frameElement = this._findFrameElementWithContentWindow(frameInfo.window);
            frameInfo.frameElement = frameElement;
        }

        return frameElement;
    }

    // Private

    _getFrameAncestryInfo(timeout=5000) {
        return new Promise((resolve, reject) => {
            const targetWindow = window.parent;
            if (window === targetWindow) {
                resolve([]);
                return;
            }

            const uniqueId = generateId(16);
            let nonce = generateId(16);
            const responseMessageId = `${this._responseMessageIdBase}${uniqueId}`;
            const results = [];
            let timer = null;

            const cleanup = () => {
                if (timer !== null) {
                    clearTimeout(timer);
                    timer = null;
                }
                api.crossFrame.unregisterHandler(responseMessageId);
            };
            const onMessage = (params) => {
                if (params.nonce !== nonce) { return null; }

                // Add result
                const {frameId, more} = params;
                results.push(frameId);
                nonce = generateId(16);

                if (!more) {
                    // Cleanup
                    cleanup();

                    // Finish
                    resolve(results);
                }
                return {nonce};
            };
            const onTimeout = () => {
                timer = null;
                cleanup();
                reject(new Error(`Request for parent frame ID timed out after ${timeout}ms`));
            };
            const resetTimeout = () => {
                if (timer !== null) { clearTimeout(timer); }
                timer = setTimeout(onTimeout, timeout);
            };

            // Start
            api.crossFrame.registerHandlers([[responseMessageId, {async: false, handler: onMessage}]]);
            resetTimeout();
            const frameId = this._frameId;
            this._requestFrameInfo(targetWindow, frameId, frameId, uniqueId, nonce);
        });
    }

    _onWindowMessage(event) {
        const {source} = event;
        if (source === window || source.parent !== window) { return; }

        const {data} = event;
        if (
            typeof data === 'object' &&
            data !== null &&
            data.action === this._requestMessageId
        ) {
            this._onRequestFrameInfo(data.params, source);
        }
    }

    async _onRequestFrameInfo(params, source) {
        try {
            let {originFrameId, childFrameId, uniqueId, nonce} = params;
            if (
                !this._isNonNegativeInteger(originFrameId) ||
                typeof uniqueId !== 'string' ||
                typeof nonce !== 'string'
            ) {
                return;
            }

            const frameId = this._frameId;
            const {parent} = window;
            const more = (window !== parent);
            const responseParams = {frameId, nonce, more};
            const responseMessageId = `${this._responseMessageIdBase}${uniqueId}`;

            try {
                const response = await api.crossFrame.invoke(originFrameId, responseMessageId, responseParams);
                if (response === null) { return; }
                nonce = response.nonce;
            } catch (e) {
                return;
            }

            if (!this._childFrameMap.has(childFrameId)) {
                this._childFrameMap.set(childFrameId, {window: source, frameElement: void 0});
            }

            if (more) {
                this._requestFrameInfo(parent, originFrameId, frameId, uniqueId, nonce);
            }
        } catch (e) {
            // NOP
        }
    }

    _requestFrameInfo(targetWindow, originFrameId, childFrameId, uniqueId, nonce) {
        targetWindow.postMessage({
            action: this._requestMessageId,
            params: {originFrameId, childFrameId, uniqueId, nonce}
        }, '*');
    }

    _isNonNegativeInteger(value) {
        return (
            typeof value === 'number' &&
            Number.isFinite(value) &&
            value >= 0 &&
            Math.floor(value) === value
        );
    }

    _findFrameElementWithContentWindow(contentWindow) {
        // Check frameElement, for non-null same-origin frames
        try {
            const {frameElement} = contentWindow;
            if (frameElement !== null) { return frameElement; }
        } catch (e) {
            // NOP
        }

        // Check frames
        const frameTypes = ['iframe', 'frame', 'embed'];
        for (const frameType of frameTypes) {
            for (const frame of document.getElementsByTagName(frameType)) {
                if (frame.contentWindow === contentWindow) {
                    return frame;
                }
            }
        }

        // Check for shadow roots
        const rootElements = [document.documentElement];
        while (rootElements.length > 0) {
            const rootElement = rootElements.shift();
            const walker = document.createTreeWalker(rootElement, NodeFilter.SHOW_ELEMENT);
            while (walker.nextNode()) {
                const element = walker.currentNode;

                if (element.contentWindow === contentWindow) {
                    return element;
                }

                const shadowRoot = (
                    element.shadowRoot ||
                    element.openOrClosedShadowRoot // Available to Firefox 63+ for WebExtensions
                );
                if (shadowRoot) {
                    rootElements.push(shadowRoot);
                }
            }
        }

        // Not found
        return null;
    }
}