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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
/**
* @typedef {import("./@types/ExperimentManager").Enrollment} Enrollment
* @typedef {import("./@types/ExperimentManager").FeatureConfig} FeatureConfig
*/
const EXPORTED_SYMBOLS = ["ExperimentStore"];
const { SharedDataMap } = ChromeUtils.import(
"resource://messaging-system/lib/SharedDataMap.jsm"
);
const { XPCOMUtils } = ChromeUtils.import(
"resource://gre/modules/XPCOMUtils.jsm"
);
const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
const IS_MAIN_PROCESS =
Services.appinfo.processType === Services.appinfo.PROCESS_TYPE_DEFAULT;
const SYNC_DATA_PREF = "messaging-system.syncdatastore.data";
let tryJSONParse = data => {
try {
return JSON.parse(data);
} catch (e) {}
return {};
};
XPCOMUtils.defineLazyPreferenceGetter(
this,
"syncDataStore",
SYNC_DATA_PREF,
{},
// aOnUpdate
(data, prev, latest) => tryJSONParse(latest),
// aTransform
tryJSONParse
);
const DEFAULT_STORE_ID = "ExperimentStoreData";
// Experiment feature configs that should be saved to prefs for
// fast access on startup.
const SYNC_ACCESS_FEATURES = ["newtab", "aboutwelcome"];
class ExperimentStore extends SharedDataMap {
constructor(sharedDataKey, options = { isParent: IS_MAIN_PROCESS }) {
super(sharedDataKey || DEFAULT_STORE_ID, options);
}
/**
* Given a feature identifier, find an active experiment that matches that feature identifier.
* This assumes, for now, that there is only one active experiment per feature per browser.
*
* @param {string} featureId
* @returns {Enrollment|undefined} An active experiment if it exists
* @memberof ExperimentStore
*/
getExperimentForFeature(featureId) {
return this.getAllActive().find(
experiment => experiment.branch.feature?.featureId === featureId
);
}
/**
* Return FeatureConfig from first active experiment where it can be found
* @param {{slug: string, featureId: string, sendExposurePing: bool}}
* @returns {Branch | null}
*/
activateBranch({ slug, featureId, sendExposurePing = true }) {
for (let experiment of this.getAllActive()) {
if (
experiment?.branch.feature.featureId === featureId ||
experiment.slug === slug
) {
if (sendExposurePing) {
this._emitExperimentExposure({
experimentSlug: experiment.slug,
branchSlug: experiment.branch.slug,
featureId,
});
}
// Default to null for feature-less experiments where we're only
// interested in exposure.
return experiment?.branch || null;
}
}
return null;
}
/**
* Check if an active experiment already exists for a feature
*
* @param {string} featureId
* @returns {boolean} Does an active experiment exist for that feature?
* @memberof ExperimentStore
*/
hasExperimentForFeature(featureId) {
if (!featureId) {
return false;
}
if (this.activateBranch({ featureId })?.feature.featureId === featureId) {
return true;
}
return false;
}
/**
* @returns {Enrollment[]}
*/
getAll() {
if (!this._data) {
return Object.values(syncDataStore);
}
return Object.values(this._data);
}
/**
* @returns {Enrollment[]}
*/
getAllActive() {
return this.getAll().filter(experiment => experiment.active);
}
_emitExperimentUpdates(experiment) {
this.emit(`update:${experiment.slug}`, experiment);
if (experiment.branch.feature) {
this.emit(`update:${experiment.branch.feature.featureId}`, experiment);
}
}
/**
* @param {{featureId: string, experimentSlug: string, branchSlug: string}} experimentData
*/
_emitExperimentExposure(experimentData) {
this.emit("exposure", experimentData);
}
/**
* @param {Enrollment} experiment
*/
_updateSyncStore(experiment) {
if (SYNC_ACCESS_FEATURES.includes(experiment.branch.feature?.featureId)) {
if (!experiment.active) {
// Remove experiments on un-enroll, otherwise nothing to do
if (syncDataStore[experiment.slug]) {
delete syncDataStore[experiment.slug];
}
} else {
syncDataStore[experiment.slug] = experiment;
}
Services.prefs.setStringPref(
SYNC_DATA_PREF,
JSON.stringify(syncDataStore)
);
}
}
/**
* Add an experiment. Short form for .set(slug, experiment)
* @param {Enrollment} experiment
*/
addExperiment(experiment) {
if (!experiment || !experiment.slug) {
throw new Error(
`Tried to add an experiment but it didn't have a .slug property.`
);
}
this.set(experiment.slug, experiment);
this._emitExperimentUpdates(experiment);
this._updateSyncStore(experiment);
}
/**
* Merge new properties into the properties of an existing experiment
* @param {string} slug
* @param {Partial<Enrollment>} newProperties
*/
updateExperiment(slug, newProperties) {
const oldProperties = this.get(slug);
if (!oldProperties) {
throw new Error(
`Tried to update experiment ${slug} bug it doesn't exist`
);
}
const updatedExperiment = { ...oldProperties, ...newProperties };
this.set(slug, updatedExperiment);
this._emitExperimentUpdates(updatedExperiment);
this._updateSyncStore(updatedExperiment);
}
}
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