// Copyright 2012 The Chromium Authors // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. import type * as PlatformApi from '../../core/platform/api/api.js'; import * as Platform from '../../core/platform/platform.js'; import * as TextUtils from '../../models/text_utils/text_utils.js'; import {type HeapSnapshotHeader, HeapSnapshotProgress, JSHeapSnapshot, type Profile} from './HeapSnapshot.js'; import type {HeapSnapshotWorkerDispatcher} from './HeapSnapshotWorkerDispatcher.js'; export class HeapSnapshotLoader { readonly #progress: HeapSnapshotProgress; #buffer: string[]; #dataCallback: ((value: string|PromiseLike) => void)|null; #done: boolean; // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration) // eslint-disable-next-line @typescript-eslint/no-explicit-any #snapshot?: Record; #array!: Platform.TypedArrayUtilities.BigUint32Array|null; #arrayIndex!: number; #json = ''; parsingComplete: Promise; constructor(dispatcher: HeapSnapshotWorkerDispatcher) { this.#reset(); this.#progress = new HeapSnapshotProgress(dispatcher); this.#buffer = []; this.#dataCallback = null; this.#done = false; this.parsingComplete = this.#parseInput(); } dispose(): void { this.#reset(); } #reset(): void { this.#json = ''; this.#snapshot = undefined; } close(): void { this.#done = true; if (this.#dataCallback) { this.#dataCallback(''); } } async buildSnapshot(secondWorker: PlatformApi.HostRuntime.WorkerMessagePort): Promise { await this.parsingComplete; this.#snapshot = this.#snapshot || {}; this.#progress.updateStatus('Processing snapshot…'); const result = new JSHeapSnapshot((this.#snapshot as Profile), this.#progress); await result.initialize(secondWorker); this.#reset(); return result; } #parseUintArray(): boolean { let index = 0; const char0 = '0'.charCodeAt(0); const char9 = '9'.charCodeAt(0); const closingBracket = ']'.charCodeAt(0); const length = this.#json.length; while (true) { while (index < length) { const code = this.#json.charCodeAt(index); if (char0 <= code && code <= char9) { break; } else if (code === closingBracket) { this.#json = this.#json.slice(index + 1); return false; } ++index; } if (index === length) { this.#json = ''; return true; } let nextNumber = 0; const startIndex = index; while (index < length) { const code = this.#json.charCodeAt(index); if (char0 > code || code > char9) { break; } nextNumber *= 10; nextNumber += (code - char0); ++index; } if (index === length) { this.#json = this.#json.slice(startIndex); return true; } if (!this.#array) { throw new Error('Array not instantiated'); } this.#array.setValue(this.#arrayIndex++, nextNumber); } } #parseStringsArray(): void { this.#progress.updateStatus('Parsing strings…'); const closingBracketIndex = this.#json.lastIndexOf(']'); if (closingBracketIndex === -1) { throw new Error('Incomplete JSON'); } this.#json = this.#json.slice(0, closingBracketIndex + 1); if (!this.#snapshot) { throw new Error('No snapshot in parseStringsArray'); } this.#snapshot.strings = JSON.parse(this.#json); } write(chunk: string): void { this.#buffer.push(chunk); if (!this.#dataCallback) { return; } this.#dataCallback(this.#buffer.shift() as string); this.#dataCallback = null; } #fetchChunk(): Promise { // This method shoudln't be entered more than once since parsing happens // sequentially. This means it's fine to stash away a single #dataCallback // instead of an array of them. if (this.#buffer.length > 0) { return Promise.resolve(this.#buffer.shift() as string); } const {promise, resolve} = Promise.withResolvers(); this.#dataCallback = resolve; return promise; } async #findToken(token: string, startIndex?: number): Promise { while (true) { const pos = this.#json.indexOf(token, startIndex || 0); if (pos !== -1) { return pos; } startIndex = this.#json.length - token.length + 1; this.#json += await this.#fetchChunk(); } } async #parseArray(name: string, title: string, length?: number): Promise { const nameIndex = await this.#findToken(name); const bracketIndex = await this.#findToken('[', nameIndex); this.#json = this.#json.slice(bracketIndex + 1); this.#array = length === undefined ? Platform.TypedArrayUtilities.createExpandableBigUint32Array() : Platform.TypedArrayUtilities.createFixedBigUint32Array(length); this.#arrayIndex = 0; while (this.#parseUintArray()) { if (length) { this.#progress.updateProgress(title, this.#arrayIndex, this.#array.length); } else { this.#progress.updateStatus(title); } this.#json += await this.#fetchChunk(); } const result = this.#array; this.#array = null; return result; } async #parseInput(): Promise { const snapshotToken = '"snapshot"'; const snapshotTokenIndex = await this.#findToken(snapshotToken); if (snapshotTokenIndex === -1) { throw new Error('Snapshot token not found'); } this.#progress.updateStatus('Loading snapshot info…'); const json = this.#json.slice(snapshotTokenIndex + snapshotToken.length + 1); let jsonTokenizerDone = false; const jsonTokenizer = new TextUtils.TextUtils.BalancedJSONTokenizer(metaJSON => { this.#json = jsonTokenizer.remainder(); jsonTokenizerDone = true; this.#snapshot = this.#snapshot || {}; this.#snapshot.snapshot = (JSON.parse(metaJSON) as HeapSnapshotHeader); }); jsonTokenizer.write(json); while (!jsonTokenizerDone) { jsonTokenizer.write(await this.#fetchChunk()); } this.#snapshot = this.#snapshot || {}; const nodes = await this.#parseArray( '"nodes"', 'Loading nodes… {PH1}%', this.#snapshot.snapshot.meta.node_fields.length * this.#snapshot.snapshot.node_count); this.#snapshot.nodes = nodes; const edges = await this.#parseArray( '"edges"', 'Loading edges… {PH1}%', this.#snapshot.snapshot.meta.edge_fields.length * this.#snapshot.snapshot.edge_count); this.#snapshot.edges = edges; if (this.#snapshot.snapshot.trace_function_count) { const traceFunctionInfos = await this.#parseArray( '"trace_function_infos"', 'Loading allocation traces… {PH1}%', this.#snapshot.snapshot.meta.trace_function_info_fields.length * this.#snapshot.snapshot.trace_function_count); this.#snapshot.trace_function_infos = traceFunctionInfos.asUint32ArrayOrFail(); const thisTokenEndIndex = await this.#findToken(':'); const nextTokenIndex = await this.#findToken('"', thisTokenEndIndex); const openBracketIndex = this.#json.indexOf('['); const closeBracketIndex = this.#json.lastIndexOf(']', nextTokenIndex); this.#snapshot.trace_tree = JSON.parse(this.#json.substring(openBracketIndex, closeBracketIndex + 1)); this.#json = this.#json.slice(closeBracketIndex + 1); } if (this.#snapshot.snapshot.meta.sample_fields) { const samples = await this.#parseArray('"samples"', 'Loading samples…'); this.#snapshot.samples = samples.asArrayOrFail(); } if (this.#snapshot.snapshot.meta['location_fields']) { const locations = await this.#parseArray('"locations"', 'Loading locations…'); this.#snapshot.locations = locations.asArrayOrFail(); } else { this.#snapshot.locations = []; } this.#progress.updateStatus('Loading strings…'); const stringsTokenIndex = await this.#findToken('"strings"'); const bracketIndex = await this.#findToken('[', stringsTokenIndex); this.#json = this.#json.slice(bracketIndex); while (this.#buffer.length > 0 || !this.#done) { this.#json += await this.#fetchChunk(); } this.#parseStringsArray(); } }