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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";
module.metadata = {
"stability": "unstable"
};
// The minimum and maximum integers that can be set as preferences.
// The range of valid values is narrower than the range of valid JS values
// because the native preferences code treats integers as NSPR PRInt32s,
// which are 32-bit signed integers on all platforms.
const MAX_INT = 0x7FFFFFFF;
const MIN_INT = -0x80000000;
const {Cc,Ci,Cr} = require("chrome");
const prefService = Cc["@mozilla.org/preferences-service;1"].
getService(Ci.nsIPrefService);
const prefSvc = prefService.getBranch(null);
const defaultBranch = prefService.getDefaultBranch(null);
function Branch(branchName) {
function getPrefKeys() {
return keys(branchName).map(function(key) {
return key.replace(branchName, "");
});
}
return Proxy.create({
get: function(receiver, pref) {
return get(branchName + pref);
},
set: function(receiver, pref, val) {
set(branchName + pref, val);
},
delete: function(pref) {
reset(branchName + pref);
return true;
},
has: function hasPrefKey(pref) {
return has(branchName + pref)
},
getPropertyDescriptor: function(name) {
return {
value: get(branchName + name)
};
},
enumerate: getPrefKeys,
keys: getPrefKeys
}, Branch.prototype);
}
function get(name, defaultValue) {
switch (prefSvc.getPrefType(name)) {
case Ci.nsIPrefBranch.PREF_STRING:
return prefSvc.getComplexValue(name, Ci.nsISupportsString).data;
case Ci.nsIPrefBranch.PREF_INT:
return prefSvc.getIntPref(name);
case Ci.nsIPrefBranch.PREF_BOOL:
return prefSvc.getBoolPref(name);
case Ci.nsIPrefBranch.PREF_INVALID:
return defaultValue;
default:
// This should never happen.
throw new Error("Error getting pref " + name +
"; its value's type is " +
prefSvc.getPrefType(name) +
", which I don't know " +
"how to handle.");
}
}
exports.get = get;
function set(name, value) {
var prefType;
if (typeof value != "undefined" && value != null)
prefType = value.constructor.name;
switch (prefType) {
case "String":
{
var string = Cc["@mozilla.org/supports-string;1"].
createInstance(Ci.nsISupportsString);
string.data = value;
prefSvc.setComplexValue(name, Ci.nsISupportsString, string);
}
break;
case "Number":
// We throw if the number is outside the range or not an integer, since
// the result will not be what the consumer wanted to store.
if (value > MAX_INT || value < MIN_INT)
throw new Error("you cannot set the " + name +
" pref to the number " + value +
", as number pref values must be in the signed " +
"32-bit integer range -(2^31) to 2^31-1. " +
"To store numbers outside that range, store " +
"them as strings.");
if (value % 1 != 0)
throw new Error("cannot store non-integer number: " + value);
prefSvc.setIntPref(name, value);
break;
case "Boolean":
prefSvc.setBoolPref(name, value);
break;
default:
throw new Error("can't set pref " + name + " to value '" + value +
"'; it isn't a string, integer, or boolean");
}
}
exports.set = set;
function has(name) {
return (prefSvc.getPrefType(name) != Ci.nsIPrefBranch.PREF_INVALID);
}
exports.has = has;
function keys(root) {
return prefSvc.getChildList(root);
}
exports.keys = keys;
function isSet(name) {
return (has(name) && prefSvc.prefHasUserValue(name));
}
exports.isSet = isSet;
function reset(name) {
try {
prefSvc.clearUserPref(name);
} catch (e if e.result == Cr.NS_ERROR_UNEXPECTED) {
// The pref service throws NS_ERROR_UNEXPECTED when the caller tries
// to reset a pref that doesn't exist or is already set to its default
// value. This interface fails silently in those cases, so callers
// can unconditionally reset a pref without having to check if it needs
// resetting first or trap exceptions after the fact. It passes through
// other exceptions, however, so callers know about them, since we don't
// know what other exceptions might be thrown and what they might mean.
}
}
exports.reset = reset;
function getLocalized(name, defaultValue) {
let value = null;
try {
value = prefSvc.getComplexValue(name, Ci.nsIPrefLocalizedString).data;
}
finally {
return value || defaultValue;
}
}
exports.getLocalized = getLocalized;
function setLocalized(name, value) {
// We can't use `prefs.set` here as we have to use `getDefaultBranch`
// (instead of `getBranch`) in order to have `mIsDefault` set to true, here:
// http://mxr.mozilla.org/mozilla-central/source/modules/libpref/src/nsPrefBranch.cpp#233
// Otherwise, we do not enter into this expected condition:
// http://mxr.mozilla.org/mozilla-central/source/modules/libpref/src/nsPrefBranch.cpp#244
defaultBranch.setCharPref(name, value);
}
exports.setLocalized = setLocalized;
exports.Branch = Branch;
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