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/**
* @license
* Copyright 2022 Google Inc.
* SPDX-License-Identifier: Apache-2.0
*/
import type {Frame} from '../api/Frame.js';
import {Deferred} from '../util/Deferred.js';
/**
* Keeps track of the page frame tree and it's is managed by
* {@link FrameManager}. FrameTree uses frame IDs to reference frame and it
* means that referenced frames might not be in the tree anymore. Thus, the tree
* structure is eventually consistent.
* @internal
*/
export class FrameTree<FrameType extends Frame> {
#frames = new Map<string, FrameType>();
// frameID -> parentFrameID
#parentIds = new Map<string, string>();
// frameID -> childFrameIDs
#childIds = new Map<string, Set<string>>();
#mainFrame?: FrameType;
#isMainFrameStale = false;
#waitRequests = new Map<string, Set<Deferred<FrameType>>>();
getMainFrame(): FrameType | undefined {
return this.#mainFrame;
}
getById(frameId: string): FrameType | undefined {
return this.#frames.get(frameId);
}
/**
* Returns a promise that is resolved once the frame with
* the given ID is added to the tree.
*/
waitForFrame(frameId: string): Promise<FrameType> {
const frame = this.getById(frameId);
if (frame) {
return Promise.resolve(frame);
}
const deferred = Deferred.create<FrameType>();
const callbacks =
this.#waitRequests.get(frameId) || new Set<Deferred<FrameType>>();
callbacks.add(deferred);
return deferred.valueOrThrow();
}
frames(): FrameType[] {
return Array.from(this.#frames.values());
}
addFrame(frame: FrameType): void {
this.#frames.set(frame._id, frame);
if (frame._parentId) {
this.#parentIds.set(frame._id, frame._parentId);
if (!this.#childIds.has(frame._parentId)) {
this.#childIds.set(frame._parentId, new Set());
}
this.#childIds.get(frame._parentId)!.add(frame._id);
} else if (!this.#mainFrame || this.#isMainFrameStale) {
this.#mainFrame = frame;
this.#isMainFrameStale = false;
}
this.#waitRequests.get(frame._id)?.forEach(request => {
return request.resolve(frame);
});
}
removeFrame(frame: FrameType): void {
this.#frames.delete(frame._id);
this.#parentIds.delete(frame._id);
if (frame._parentId) {
this.#childIds.get(frame._parentId)?.delete(frame._id);
} else {
this.#isMainFrameStale = true;
}
}
childFrames(frameId: string): FrameType[] {
const childIds = this.#childIds.get(frameId);
if (!childIds) {
return [];
}
return Array.from(childIds)
.map(id => {
return this.getById(id);
})
.filter((frame): frame is FrameType => {
return frame !== undefined;
});
}
parentFrame(frameId: string): FrameType | undefined {
const parentId = this.#parentIds.get(frameId);
return parentId ? this.getById(parentId) : undefined;
}
}