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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/. */
import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
LogManager: "resource://normandy/lib/LogManager.sys.mjs",
});
XPCOMUtils.defineLazyGetter(lazy, "log", () => {
return lazy.LogManager.getLogger("preference-experiments");
});
const kPrefBranches = {
user: Services.prefs,
default: Services.prefs.getDefaultBranch(""),
};
export var PrefUtils = {
/**
* Get a preference of any type from the named branch.
* @param {string} pref
* @param {object} [options]
* @param {"default"|"user"} [options.branchName="user"] One of "default" or "user"
* @param {string|boolean|integer|null} [options.defaultValue]
* The value to return if the preference does not exist. Defaults to null.
*/
getPref(pref, { branch = "user", defaultValue = null } = {}) {
const branchObj = kPrefBranches[branch];
if (!branchObj) {
throw new this.UnexpectedPreferenceBranch(
`"${branch}" is not a valid preference branch`
);
}
const type = branchObj.getPrefType(pref);
try {
switch (type) {
case Services.prefs.PREF_BOOL: {
return branchObj.getBoolPref(pref);
}
case Services.prefs.PREF_STRING: {
return branchObj.getStringPref(pref);
}
case Services.prefs.PREF_INT: {
return branchObj.getIntPref(pref);
}
case Services.prefs.PREF_INVALID: {
return defaultValue;
}
}
} catch (e) {
if (branch === "default" && e.result === Cr.NS_ERROR_UNEXPECTED) {
// There is a value for the pref on the user branch but not on the default branch. This is ok.
return defaultValue;
}
// Unexpected error, re-throw it
throw e;
}
// If `type` isn't any of the above, throw an error. Don't do this in a
// default branch of switch so that error handling is easier.
throw new TypeError(`Unknown preference type (${type}) for ${pref}.`);
},
/**
* Set a preference on the named branch
* @param {string} pref
* @param {string|boolean|integer|null} value The value to set.
* @param {object} options
* @param {"user"|"default"} options.branchName The branch to make the change on.
*/
setPref(pref, value, { branch = "user" } = {}) {
if (value === null) {
this.clearPref(pref, { branch });
return;
}
const branchObj = kPrefBranches[branch];
if (!branchObj) {
throw new this.UnexpectedPreferenceBranch(
`"${branch}" is not a valid preference branch`
);
}
switch (typeof value) {
case "boolean": {
branchObj.setBoolPref(pref, value);
break;
}
case "string": {
branchObj.setStringPref(pref, value);
break;
}
case "number": {
branchObj.setIntPref(pref, value);
break;
}
default: {
throw new TypeError(
`Unexpected value type (${typeof value}) for ${pref}.`
);
}
}
},
/**
* Remove a preference from a branch. Note that default branch preferences
* cannot effectively be cleared. If "default" is passed for a branch, an
* error will be logged and nothing else will happen.
*
* @param {string} pref
* @param {object} options
* @param {"user"|"default"} options.branchName The branch to clear
*/
clearPref(pref, { branch = "user" } = {}) {
if (branch === "user") {
kPrefBranches.user.clearUserPref(pref);
} else if (branch === "default") {
lazy.log.warn(
`Cannot reset pref ${pref} on the default branch. Pref will be cleared at next restart.`
);
} else {
throw new this.UnexpectedPreferenceBranch(
`"${branch}" is not a valid preference branch`
);
}
},
UnexpectedPreferenceType: class extends Error {},
UnexpectedPreferenceBranch: class extends Error {},
};
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