core(fr): add computed cache to pass context

lighthouse-core/fraggle-rock/gather/base-gatherer.js

@@ -90,6 +90,9 @@ class FRGatherer {
    * @return {Promise<LH.Gatherer.PhaseResultNonPromise>}
    */
   async afterPass(passContext, loadData) {
+    if ('dependencies' in this.meta) {
+      throw Error('Gatherer with dependencies should override afterPass');
+    }
     await this.stopSensitiveInstrumentation({...passContext, dependencies: {}});
     await this.stopInstrumentation({...passContext, dependencies: {}});
     return this.getArtifact({...passContext, dependencies: {}});

lighthouse-core/fraggle-rock/gather/navigation-runner.js

@@ -137,6 +137,7 @@ async function navigation(options) {
     {
       url: requestedUrl,
       config,
+      computedCache: new Map(),
     }
   );
 }

lighthouse-core/fraggle-rock/gather/runner-helpers.js

@@ -76,6 +76,7 @@ async function collectPhaseArtifacts(options) {
         gatherMode,
         driver,
         dependencies,
+        computedCache: new Map(),
       });
     });
 

lighthouse-core/fraggle-rock/gather/snapshot-runner.js

@@ -45,6 +45,7 @@ async function snapshot(options) {
     {
       url,
       config,
+      computedCache: new Map(),
     }
   );
 }

lighthouse-core/fraggle-rock/gather/timespan-runner.js

@@ -51,6 +51,7 @@ async function startTimespan(options) {
         {
           url: finalUrl,
           config,
+          computedCache: new Map(),
         }
       );
     },

lighthouse-core/gather/gather-runner.js

@@ -8,7 +8,7 @@
 const log = require('lighthouse-logger');
 const LHError = require('../lib/lh-error.js');
 const NetworkAnalyzer = require('../lib/dependency-graph/simulator/network-analyzer.js');
-const NetworkRecorder = require('../lib/network-recorder.js');
+const NetworkRecords = require('../computed/network-records.js');
 const emulation = require('../lib/emulation.js');
 const constants = require('../config/constants.js');
 const i18n = require('../lib/i18n/i18n.js');
@@ -55,6 +55,7 @@ const SLOW_CPU_BENCHMARK_INDEX_THRESHOLD = 1000;
 const str_ = i18n.createMessageInstanceIdFn(__filename, UIStrings);
 
 /** @typedef {import('../gather/driver.js')} Driver */
+/** @typedef {import('../lib/arbitrary-equality-map.js')} ArbitraryEqualityMap */
 
 /**
  * Each entry in each gatherer result array is the output of a gatherer phase:
@@ -480,7 +481,7 @@ class GatherRunner {
     };
     log.time(status);
     const devtoolsLog = driver.endDevtoolsLog();
-    const networkRecords = NetworkRecorder.recordsFromLogs(devtoolsLog);
+    const networkRecords = await NetworkRecords.request(devtoolsLog, passContext);
     log.timeEnd(status);
 
     return {
@@ -710,7 +711,7 @@ class GatherRunner {
 
   /**
    * @param {Array<LH.Config.Pass>} passConfigs
-   * @param {{driver: Driver, requestedUrl: string, settings: LH.Config.Settings}} options
+   * @param {{driver: Driver, requestedUrl: string, settings: LH.Config.Settings, computedCache: Map<string, ArbitraryEqualityMap>}} options
    * @return {Promise<LH.Artifacts>}
    */
   static async run(passConfigs, options) {
@@ -740,6 +741,7 @@ class GatherRunner {
           settings: options.settings,
           passConfig,
           baseArtifacts,
+          computedCache: options.computedCache,
           LighthouseRunWarnings: baseArtifacts.LighthouseRunWarnings,
         };
         const passResults = await GatherRunner.runPass(passContext);

lighthouse-core/gather/gatherers/link-elements.js

@@ -6,10 +6,12 @@
 'use strict';
 
 const LinkHeader = require('http-link-header');
-const Gatherer = require('./gatherer.js');
+const FRGatherer = require('../../fraggle-rock/gather/base-gatherer.js');
 const {URL} = require('../../lib/url-shim.js');
+const NetworkRecords = require('../../computed/network-records.js');
 const NetworkAnalyzer = require('../../lib/dependency-graph/simulator/network-analyzer.js');
 const pageFunctions = require('../../lib/page-functions.js');
+const DevtoolsLog = require('./devtools-log.js');
 
 /* globals HTMLLinkElement getNodeDetails */
 
@@ -79,15 +81,24 @@ function getLinkElementsInDOM() {
 }
 /* c8 ignore stop */
 
-class LinkElements extends Gatherer {
+class LinkElements extends FRGatherer {
+  constructor() {
+    super();
+    /** @type {LH.Gatherer.GathererMeta<'DevtoolsLog'>} */
+    this.meta = {
+      supportedModes: ['timespan', 'navigation'],
+      dependencies: {DevtoolsLog: DevtoolsLog.symbol},
+    };
+  }
+
   /**
-   * @param {LH.Gatherer.PassContext} passContext
+   * @param {LH.Gatherer.FRTransitionalContext} context
    * @return {Promise<LH.Artifacts['LinkElements']>}
    */
-  static getLinkElementsInDOM(passContext) {
+  static getLinkElementsInDOM(context) {
     // We'll use evaluateAsync because the `node.getAttribute` method doesn't actually normalize
     // the values like access from JavaScript does.
-    return passContext.driver.executionContext.evaluate(getLinkElementsInDOM, {
+    return context.driver.executionContext.evaluate(getLinkElementsInDOM, {
       args: [],
       useIsolation: true,
       deps: [
@@ -98,14 +109,13 @@ class LinkElements extends Gatherer {
   }
 
   /**
-   * @param {LH.Gatherer.PassContext} passContext
-   * @param {LH.Gatherer.LoadData} loadData
+   * @param {LH.Gatherer.FRTransitionalContext} context
+   * @param {LH.Artifacts.NetworkRequest[]} networkRecords
    * @return {LH.Artifacts['LinkElements']}
    */
-  static getLinkElementsInHeaders(passContext, loadData) {
-    const finalUrl = passContext.url;
-    const records = loadData.networkRecords;
-    const mainDocument = NetworkAnalyzer.findMainDocument(records, finalUrl);
+  static getLinkElementsInHeaders(context, networkRecords) {
+    const finalUrl = context.url;
+    const mainDocument = NetworkAnalyzer.findMainDocument(networkRecords, finalUrl);
 
     /** @type {LH.Artifacts['LinkElements']} */
     const linkElements = [];
@@ -131,13 +141,13 @@ class LinkElements extends Gatherer {
   }
 
   /**
-   * @param {LH.Gatherer.PassContext} passContext
-   * @param {LH.Gatherer.LoadData} loadData
+   * @param {LH.Gatherer.FRTransitionalContext} context
+   * @param {LH.Artifacts.NetworkRequest[]} networkRecords
    * @return {Promise<LH.Artifacts['LinkElements']>}
    */
-  async afterPass(passContext, loadData) {
-    const fromDOM = await LinkElements.getLinkElementsInDOM(passContext);
-    const fromHeaders = LinkElements.getLinkElementsInHeaders(passContext, loadData);
+  async _getArtifact(context, networkRecords) {
+    const fromDOM = await LinkElements.getLinkElementsInDOM(context);
+    const fromHeaders = LinkElements.getLinkElementsInHeaders(context, networkRecords);
     const linkElements = fromDOM.concat(fromHeaders);
 
     for (const link of linkElements) {
@@ -147,6 +157,24 @@ class LinkElements extends Gatherer {
 
     return linkElements;
   }
+
+  /**
+   * @param {LH.Gatherer.PassContext} context
+   * @param {LH.Gatherer.LoadData} loadData
+   * @return {Promise<LH.Artifacts['LinkElements']>}
+   */
+  async afterPass(context, loadData) {
+    return await this._getArtifact({...context, dependencies: {}}, loadData.networkRecords);
+  }
+
+  /**
+   * @param {LH.Gatherer.FRTransitionalContext<'DevtoolsLog'>} context
+   * @return {Promise<LH.Artifacts['LinkElements']>}
+   */
+  async getArtifact(context) {
+    const records = await NetworkRecords.request(context.dependencies.DevtoolsLog, context);
+    return await this._getArtifact(context, records);
+  }
 }
 
 module.exports = LinkElements;

lighthouse-core/index.js

@@ -41,7 +41,8 @@ async function lighthouse(url, flags = {}, configJSON, userConnection) {
   log.setLevel(flags.logLevel);
 
   const config = generateConfig(configJSON, flags);
-  const options = {url, config};
+  const computedCache = new Map();
+  const options = {url, config, computedCache};
   const connection = userConnection || new ChromeProtocol(flags.port, flags.hostname);
 
   // kick off a lighthouse run

lighthouse-core/runner.js

@@ -22,13 +22,14 @@ const generateReport = require('./report/report-generator.js').generateReport;
 const LHError = require('./lib/lh-error.js');
 
 /** @typedef {import('./gather/connections/connection.js')} Connection */
+/** @typedef {import('./lib/arbitrary-equality-map.js')} ArbitraryEqualityMap */
 /** @typedef {LH.Config.Config} Config */
 
 class Runner {
   /**
    * @template {LH.Config.Config | LH.Config.FRConfig} TConfig
    * @param {(runnerData: {requestedUrl: string, config: TConfig, driverMock?: Driver}) => Promise<LH.Artifacts>} gatherFn
-   * @param {{config: TConfig, url?: string, driverMock?: Driver}} runOpts
+   * @param {{config: TConfig, computedCache: Map<string, ArbitraryEqualityMap>, url?: string, driverMock?: Driver}} runOpts
    * @return {Promise<LH.RunnerResult|undefined>}
    */
   static async run(gatherFn, runOpts) {
@@ -100,7 +101,7 @@ class Runner {
         throw new Error('No audits to evaluate.');
       }
       const auditResultsById = await Runner._runAudits(settings, runOpts.config.audits, artifacts,
-          lighthouseRunWarnings);
+          lighthouseRunWarnings, runOpts.computedCache);
 
       // LHR construction phase
       const resultsStatus = {msg: 'Generating results...', id: 'lh:runner:generate'};
@@ -217,7 +218,7 @@ class Runner {
   /**
    * Establish connection, load page and collect all required artifacts
    * @param {string} requestedUrl
-   * @param {{config: Config, driverMock?: Driver}} runnerOpts
+   * @param {{config: Config, computedCache: Map<string, ArbitraryEqualityMap>, driverMock?: Driver}} runnerOpts
    * @param {Connection} connection
    * @return {Promise<LH.Artifacts>}
    */
@@ -230,6 +231,7 @@ class Runner {
       driver,
       requestedUrl,
       settings: runnerOpts.config.settings,
+      computedCache: runnerOpts.computedCache,
     };
     const artifacts = await GatherRunner.run(runnerOpts.config.passes, gatherOpts);
     return artifacts;
@@ -241,9 +243,10 @@ class Runner {
    * @param {Array<LH.Config.AuditDefn>} audits
    * @param {LH.Artifacts} artifacts
    * @param {Array<string | LH.IcuMessage>} runWarnings
+   * @param {Map<string, ArbitraryEqualityMap>} computedCache
    * @return {Promise<Record<string, LH.RawIcu<LH.Audit.Result>>>}
    */
-  static async _runAudits(settings, audits, artifacts, runWarnings) {
+  static async _runAudits(settings, audits, artifacts, runWarnings, computedCache) {
     const status = {msg: 'Analyzing and running audits...', id: 'lh:runner:auditing'};
     log.time(status);
 
@@ -267,7 +270,7 @@ class Runner {
     // Members of LH.Audit.Context that are shared across all audits.
     const sharedAuditContext = {
       settings,
-      computedCache: new Map(),
+      computedCache,
     };
 
     // Run each audit sequentially