gecko-dev/intl/l10n/L10nRegistry.jsm

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JavaScript
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const { AppConstants } = ChromeUtils.import("resource://gre/modules/AppConstants.jsm", {});
const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm", {});
const { MessageContext } = ChromeUtils.import("resource://gre/modules/MessageContext.jsm", {});
ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
XPCOMUtils.defineLazyGlobalGetters(this, ["fetch"]);
/**
* L10nRegistry is a localization resource management system for Gecko.
*
* It manages the list of resource sources provided with the app and allows
* for additional sources to be added and updated.
*
* It's primary purpose is to allow for building an iterator over MessageContext objects
* that will be utilized by a localization API.
*
* The generator creates all possible permutations of locales and sources to allow for
* complete fallbacking.
*
* Example:
*
* FileSource1:
* name: 'app'
* locales: ['en-US', 'de']
* resources: [
* '/browser/menu.ftl',
* '/platform/toolkit.ftl',
* ]
* FileSource2:
* name: 'platform'
* locales: ['en-US', 'de']
* resources: [
* '/platform/toolkit.ftl',
* ]
*
* If the user will request:
* L10nRegistry.generateContexts(['de', 'en-US'], [
* '/browser/menu.ftl',
* '/platform/toolkit.ftl'
* ]);
*
* the generator will return an async iterator over the following contexts:
*
* {
* locale: 'de',
* resources: [
* ['app', '/browser/menu.ftl'],
* ['app', '/platform/toolkit.ftl'],
* ]
* },
* {
* locale: 'de',
* resources: [
* ['app', '/browser/menu.ftl'],
* ['platform', '/platform/toolkit.ftl'],
* ]
* },
* {
* locale: 'en-US',
* resources: [
* ['app', '/browser/menu.ftl'],
* ['app', '/platform/toolkit.ftl'],
* ]
* },
* {
* locale: 'en-US',
* resources: [
* ['app', '/browser/menu.ftl'],
* ['platform', '/platform/toolkit.ftl'],
* ]
* }
*
* This allows the localization API to consume the MessageContext and lazily fallback
* on the next in case of a missing string or error.
*
* If during the life-cycle of the app a new source is added, the generator can be called again
* and will produce a new set of permutations placing the language pack provided resources
* at the top.
*/
const L10nRegistry = {
sources: new Map(),
ctxCache: new Map(),
bootstrap: null,
/**
* Based on the list of requested languages and resource Ids,
* this function returns an lazy iterator over message context permutations.
*
* @param {Array} requestedLangs
* @param {Array} resourceIds
* @returns {AsyncIterator<MessageContext>}
*/
async* generateContexts(requestedLangs, resourceIds) {
if (this.bootstrap !== null) {
await this.bootstrap;
}
const sourcesOrder = Array.from(this.sources.keys()).reverse();
for (const locale of requestedLangs) {
yield * generateContextsForLocale(locale, sourcesOrder, resourceIds);
}
},
/**
* Adds a new resource source to the L10nRegistry.
*
* @param {FileSource} source
*/
registerSource(source) {
if (this.sources.has(source.name)) {
throw new Error(`Source with name "${source.name}" already registered.`);
}
this.sources.set(source.name, source);
Services.locale.setAvailableLocales(this.getAvailableLocales());
},
/**
* Updates an existing source in the L10nRegistry
*
* That will usually happen when a new version of a source becomes
* available (for example, an updated version of a language pack).
*
* @param {FileSource} source
*/
updateSource(source) {
if (!this.sources.has(source.name)) {
throw new Error(`Source with name "${source.name}" is not registered.`);
}
this.sources.set(source.name, source);
this.ctxCache.clear();
Services.locale.setAvailableLocales(this.getAvailableLocales());
},
/**
* Removes a source from the L10nRegistry.
*
* @param {String} sourceId
*/
removeSource(sourceName) {
this.sources.delete(sourceName);
Services.locale.setAvailableLocales(this.getAvailableLocales());
},
/**
* Returns a list of locales for which at least one source
* has resources.
*
* @returns {Array<String>}
*/
getAvailableLocales() {
const locales = new Set();
for (const source of this.sources.values()) {
for (const locale of source.locales) {
locales.add(locale);
}
}
return Array.from(locales);
},
};
/**
* A helper function for generating unique context ID used for caching
* MessageContexts.
*
* @param {String} locale
* @param {Array} sourcesOrder
* @param {Array} resourceIds
* @returns {String}
*/
function generateContextID(locale, sourcesOrder, resourceIds) {
const sources = sourcesOrder.join(",");
const ids = resourceIds.join(",");
return `${locale}|${sources}|${ids}`;
}
/**
* This function generates an iterator over MessageContexts for a single locale
* for a given list of resourceIds for all possible combinations of sources.
*
* This function is called recursively to generate all possible permutations
* and uses the last, optional parameter, to pass the already resolved
* sources order.
*
* @param {String} locale
* @param {Array} sourcesOrder
* @param {Array} resourceIds
* @param {Array} [resolvedOrder]
* @returns {AsyncIterator<MessageContext>}
*/
async function* generateContextsForLocale(locale, sourcesOrder, resourceIds, resolvedOrder = []) {
const resolvedLength = resolvedOrder.length;
const resourcesLength = resourceIds.length;
// Inside that loop we have a list of resources and the sources for them, like this:
// ['test.ftl', 'menu.ftl', 'foo.ftl']
// ['app', 'platform', 'app']
for (const sourceName of sourcesOrder) {
const order = resolvedOrder.concat(sourceName);
// We bail only if the hasFile returns a strict false here,
// because for FileSource it may also return undefined, which means
// that we simply don't know if the source contains the file and we'll
// have to perform the I/O to learn.
if (L10nRegistry.sources.get(sourceName).hasFile(locale, resourceIds[resolvedOrder.length]) === false) {
continue;
}
// If the number of resolved sources equals the number of resources,
// create the right context and return it if it loads.
if (resolvedLength + 1 === resourcesLength) {
const ctx = await generateContext(locale, order, resourceIds);
if (ctx !== null) {
yield ctx;
}
} else if (resolvedLength < resourcesLength) {
// otherwise recursively load another generator that walks over the
// partially resolved list of sources.
yield * generateContextsForLocale(locale, sourcesOrder, resourceIds, order);
}
}
}
const MSG_CONTEXT_OPTIONS = {
// Temporarily disable bidi isolation due to Microsoft not supporting FSI/PDI.
// See bug 1439018 for details.
useIsolating: Services.prefs.getBoolPref("intl.l10n.enable-bidi-marks", false),
functions: {
/**
* PLATFORM is a built-in allowing localizers to differentiate message
* variants depending on the target platform.
*/
PLATFORM: () => {
switch (AppConstants.platform) {
case "linux":
case "android":
return AppConstants.platform;
case "win":
return "windows";
case "macosx":
return "macos";
default:
return "other";
}
}
}
};
/**
* Pseudolocalizations
*
* PSEUDO_STRATEGIES is a dict of strategies to be used to modify a
* context in order to create pseudolocalizations. These can be used by
* developers to test the localizability of their code without having to
* actually speak a foreign language.
*
* Currently, the following pseudolocales are supported:
*
* accented - Ȧȧƈƈḗḗƞŧḗḗḓ Ḗḗƞɠŀīīşħ
*
* In Accented English all Latin letters are replaced by accented
* Unicode counterparts which don't impair the readability of the content.
* This allows developers to quickly test if any given string is being
* correctly displayed in its 'translated' form. Additionally, simple
* heuristics are used to make certain words longer to better simulate the
* experience of international users.
*
* bidi - ɥsıʅƃuƎ ıpıԐ
*
* Bidi English is a fake RTL locale. All words are surrounded by
* Unicode formatting marks forcing the RTL directionality of characters.
* In addition, to make the reversed text easier to read, individual
* letters are flipped.
*
* Note: The name above is hardcoded to be RTL in case code editors have
* trouble with the RLO and PDF Unicode marks. In reality, it should be
* surrounded by those marks as well.
*
* See https://bugzil.la/1450781 for more information.
*
* In this implementation we use code points instead of inline unicode characters
* because the encoding of JSM files mangles them otherwise.
*/
const ACCENTED_MAP = {
// ȦƁƇḒḖƑƓĦĪĴĶĿḾȠǾƤɊŘŞŦŬṼẆẊẎẐ
"caps": [550, 385, 391, 7698, 7702, 401, 403, 294, 298, 308, 310, 319, 7742, 544, 510, 420, 586, 344, 350, 358, 364, 7804, 7814, 7818, 7822, 7824],
// ȧƀƈḓḗƒɠħīĵķŀḿƞǿƥɋřşŧŭṽẇẋẏẑ
"small": [551, 384, 392, 7699, 7703, 402, 608, 295, 299, 309, 311, 320, 7743, 414, 511, 421, 587, 345, 351, 359, 365, 7805, 7815, 7819, 7823, 7825],
};
const FLIPPED_MAP = {
// ∀ԐↃᗡƎℲ⅁HIſӼ⅂WNOԀÒᴚS⊥∩ɅMX⅄Z
"caps": [8704, 1296, 8579, 5601, 398, 8498, 8513, 72, 73, 383, 1276, 8514, 87, 78, 79, 1280, 210, 7450, 83, 8869, 8745, 581, 77, 88, 8516, 90],
// ɐqɔpǝɟƃɥıɾʞʅɯuodbɹsʇnʌʍxʎz
"small": [592, 113, 596, 112, 477, 607, 387, 613, 305, 638, 670, 645, 623, 117, 111, 100, 98, 633, 115, 647, 110, 652, 653, 120, 654, 122],
};
function transformString(map, elongate = false, prefix = "", postfix = "", msg) {
// Exclude access-keys and other single-char messages
if (msg.length === 1) {
return msg;
}
// XML entities (&#x202a;) and XML tags.
const reExcluded = /(&[#\w]+;|<\s*.+?\s*>)/;
const parts = msg.split(reExcluded);
const modified = parts.map((part) => {
if (reExcluded.test(part)) {
return part;
}
return prefix + part.replace(/[a-z]/ig, (ch) => {
let cc = ch.charCodeAt(0);
if (cc >= 97 && cc <= 122) {
const newChar = String.fromCodePoint(map.small[cc - 97]);
// duplicate "a", "e", "o" and "u" to emulate ~30% longer text
if (elongate && (cc === 97 || cc === 101 || cc === 111 || cc === 117)) {
return newChar + newChar;
}
return newChar;
}
if (cc >= 65 && cc <= 90) {
return String.fromCodePoint(map.caps[cc - 65]);
}
return ch;
}) + postfix;
});
return modified.join("");
}
const PSEUDO_STRATEGIES = {
"accented": transformString.bind(null, ACCENTED_MAP, true, "", ""),
"bidi": transformString.bind(null, FLIPPED_MAP, false, "\u202e", "\u202c"),
};
/**
* Generates a single MessageContext by loading all resources
* from the listed sources for a given locale.
*
* The function casts all error cases into a Promise that resolves with
* value `null`.
* This allows the caller to be an async generator without using
* try/catch clauses.
*
* @param {String} locale
* @param {Array} sourcesOrder
* @param {Array} resourceIds
* @returns {Promise<MessageContext>}
*/
function generateContext(locale, sourcesOrder, resourceIds) {
const ctxId = generateContextID(locale, sourcesOrder, resourceIds);
if (L10nRegistry.ctxCache.has(ctxId)) {
return L10nRegistry.ctxCache.get(ctxId);
}
const fetchPromises = resourceIds.map((resourceId, i) => {
return L10nRegistry.sources.get(sourcesOrder[i]).fetchFile(locale, resourceId);
});
const ctxPromise = Promise.all(fetchPromises).then(
dataSets => {
const pseudoNameFromPref = Services.prefs.getStringPref("intl.l10n.pseudo", "");
const ctx = new MessageContext(locale, {
...MSG_CONTEXT_OPTIONS,
transform: PSEUDO_STRATEGIES[pseudoNameFromPref],
});
for (const data of dataSets) {
if (data === null) {
return null;
}
ctx.addMessages(data);
}
return ctx;
},
() => null
);
L10nRegistry.ctxCache.set(ctxId, ctxPromise);
return ctxPromise;
}
/**
* This is a basic Source for L10nRegistry.
* It registers its own locales and a pre-path, and when asked for a file
* it attempts to download and cache it.
*
* The Source caches the downloaded files so any consecutive loads will
* come from the cache.
**/
class FileSource {
/**
* @param {string} name
* @param {Array<string>} locales
* @param {string} prePath
*
* @returns {IndexedFileSource}
*/
constructor(name, locales, prePath) {
this.name = name;
this.locales = locales;
this.prePath = prePath;
this.indexed = false;
// The cache object stores information about the resources available
// in the Source.
//
// It can take one of three states:
// * true - the resource is available but not fetched yet
// * false - the resource is not available
// * Promise - the resource has been fetched
//
// If the cache has no entry for a given path, that means that there
// is no information available about whether the resource is available.
//
// If the `indexed` property is set to `true` it will be treated as the
// resource not being available. Otherwise, the resource may be
// available and we do not have any information about it yet.
this.cache = {};
}
getPath(locale, path) {
// This is a special case for the only not BCP47-conformant locale
// code we have resources for.
if (locale === "ja-JP-macos") {
locale = "ja-JP-mac";
}
return (this.prePath + path).replace(/\{locale\}/g, locale);
}
hasFile(locale, path) {
if (!this.locales.includes(locale)) {
return false;
}
const fullPath = this.getPath(locale, path);
if (!this.cache.hasOwnProperty(fullPath)) {
return this.indexed ? false : undefined;
}
if (this.cache[fullPath] === false) {
return false;
}
if (this.cache[fullPath].then) {
return undefined;
}
return true;
}
fetchFile(locale, path) {
if (!this.locales.includes(locale)) {
return Promise.reject(`The source has no resources for locale "${locale}"`);
}
const fullPath = this.getPath(locale, path);
if (this.cache.hasOwnProperty(fullPath)) {
if (this.cache[fullPath] === false) {
return Promise.reject(`The source has no resources for path "${fullPath}"`);
}
if (this.cache[fullPath].then) {
return this.cache[fullPath];
}
} else if (this.indexed) {
return Promise.reject(`The source has no resources for path "${fullPath}"`);
}
return this.cache[fullPath] = L10nRegistry.load(fullPath).then(
data => {
return this.cache[fullPath] = data;
},
err => {
this.cache[fullPath] = false;
return Promise.reject(err);
}
);
}
}
/**
* This is an extension of the FileSource which should be used
* for sources that can provide the list of files available in the source.
*
* This allows for a faster lookup in cases where the source does not
* contain most of the files that the app will request for (e.g. an addon).
**/
class IndexedFileSource extends FileSource {
/**
* @param {string} name
* @param {Array<string>} locales
* @param {string} prePath
* @param {Array<string>} paths
*
* @returns {IndexedFileSource}
*/
constructor(name, locales, prePath, paths) {
super(name, locales, prePath);
this.indexed = true;
for (const path of paths) {
this.cache[path] = true;
}
}
}
/**
* The low level wrapper around Fetch API. It unifies the error scenarios to
* always produce a promise rejection.
*
* We keep it as a method to make it easier to override for testing purposes.
*
* @param {string} url
*
* @returns {Promise<string>}
*/
L10nRegistry.load = function(url) {
return fetch(url).then(response => {
if (!response.ok) {
return Promise.reject(response.statusText);
}
return response.text();
});
};
this.L10nRegistry = L10nRegistry;
this.FileSource = FileSource;
this.IndexedFileSource = IndexedFileSource;
var EXPORTED_SYMBOLS = ["L10nRegistry", "FileSource", "IndexedFileSource"];