@memlab/core
Version:
memlab core libraries
129 lines (128 loc) • 5.11 kB
JavaScript
/**
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @format
* @lightSyntaxTransform
* @oncall memory_lab
*/
;
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const Config_1 = __importDefault(require("./Config"));
const Console_1 = __importDefault(require("./Console"));
const StringLoader_1 = __importDefault(require("./StringLoader"));
const HeapSnapshot_1 = __importDefault(require("./heap-data/HeapSnapshot"));
// ----------- utility and parsing functions -----------
function getSnapshotMetaData(content) {
function getSignatureIndex(signature) {
const idx = content.indexOf(signature);
if (idx < 0) {
throw 'heap parsing: meta data parsing error';
}
return idx;
}
const startSignature = '"snapshot":';
const startIdx = getSignatureIndex(startSignature) + startSignature.length;
const endSignature = '"nodes":';
const endIdx = getSignatureIndex(endSignature);
const metaContent = content.slice(startIdx, endIdx).trim().slice(0, -1);
return JSON.parse(metaContent);
}
const nums = Object.create(null);
for (let i = 0; i < 10; i++) {
nums[`${i}`] = i;
}
function loadSnapshotMetaDataFromFile(file) {
return __awaiter(this, void 0, void 0, function* () {
const content = yield StringLoader_1.default.readFile(file, {
startSignature: '"snapshot":',
endSignature: '"nodes":',
inclusive: true,
});
return getSnapshotMetaData(content);
});
}
function getNodeIdsFromFile(file,
// eslint-disable-next-line @typescript-eslint/no-unused-vars
_options = {}) {
return __awaiter(this, void 0, void 0, function* () {
const snapshotInfo = yield loadSnapshotMetaDataFromFile(file);
const nodes = yield StringLoader_1.default.readFileAndExtractTypedArray(file, 'nodes');
const ids = new Set();
const nodeFields = snapshotInfo.meta.node_fields;
const nodeFieldCount = nodeFields.length;
const idOffset = nodeFields.indexOf('id');
let valueIndex = 0;
while (valueIndex < nodes.length) {
ids.add(nodes[valueIndex + idOffset]);
valueIndex += nodeFieldCount;
}
return ids;
});
}
function parseFile(file) {
return __awaiter(this, void 0, void 0, function* () {
const [nodes, edges, locations, content] = yield Promise.all([
StringLoader_1.default.readFileAndExtractTypedArray(file, 'nodes'),
StringLoader_1.default.readFileAndExtractTypedArray(file, 'edges'),
StringLoader_1.default.readFileAndExtractTypedArray(file, 'locations'),
StringLoader_1.default.readFileAndExcludeTypedArray(file, [
'nodes',
'edges',
'locations',
]),
]);
const snapshot = JSON.parse(content);
snapshot.nodes = nodes;
snapshot.edges = edges;
snapshot.locations = locations;
return snapshot;
});
}
// auto detect and set JS snapshot's engine type
function identifyAndSetEngine(snapshot) {
if (Config_1.default.specifiedEngine) {
if (Config_1.default.verbose) {
Console_1.default.lowLevel(`JS snapshot engine is manually set to be ${Config_1.default.jsEngine}`);
}
return; // skip if engine type is manually set
}
Console_1.default.overwrite('identifying snapshot engine...');
let engine = 'V8';
snapshot.nodes.forEach((node) => {
if (node.type === 'object' && node.name.startsWith('Object(')) {
engine = 'hermes';
return false;
}
});
if (Config_1.default.verbose) {
Console_1.default.lowLevel(`detect and set JS snapshot engine: ${engine}`);
}
Config_1.default.jsEngine = engine;
}
function parse(file, options = {}) {
return __awaiter(this, void 0, void 0, function* () {
const snapshot = yield parseFile(file);
const ret = new HeapSnapshot_1.default(snapshot, options);
identifyAndSetEngine(ret);
return ret;
});
}
exports.default = {
getNodeIdsFromFile,
parse,
};