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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
/* exported Loader, resolveURI, Module, Require, unload */
const systemPrincipal = Components.Constructor(
"@mozilla.org/systemprincipal;1",
"nsIPrincipal"
)();
const lazy = {};
XPCOMUtils.defineLazyServiceGetter(
lazy,
"resProto",
"@mozilla.org/network/protocol;1?name=resource",
"nsIResProtocolHandler"
);
ChromeUtils.defineESModuleGetters(
lazy,
{
},
{ global: "contextual" }
);
// Define some shortcuts.
function* getOwnIdentifiers(x) {
yield* Object.getOwnPropertyNames(x);
yield* Object.getOwnPropertySymbols(x);
}
function isJSONURI(uri) {
return uri.endsWith(".json");
}
function isSYSMJSURI(uri) {
return uri.endsWith(".sys.mjs");
}
function isJSURI(uri) {
return uri.endsWith(".js");
}
const AbsoluteRegExp = /^(resource|chrome|file|jar):/;
function isAbsoluteURI(uri) {
return AbsoluteRegExp.test(uri);
}
function isRelative(id) {
return id.startsWith(".");
}
function readURI(uri) {
const nsURI = lazy.NetUtil.newURI(uri);
if (nsURI.scheme == "resource") {
// Resolve to a real URI, this will catch any obvious bad paths without
uri = lazy.resProto.resolveURI(nsURI);
}
const stream = lazy.NetUtil.newChannel({
uri: lazy.NetUtil.newURI(uri, "UTF-8"),
loadUsingSystemPrincipal: true,
}).open();
const count = stream.available();
const data = lazy.NetUtil.readInputStreamToString(stream, count, {
charset: "UTF-8",
});
stream.close();
return data;
}
// Combines all arguments into a resolved, normalized path
function join(base, ...paths) {
// If this is an absolute URL, we need to normalize only the path portion,
// or we wind up stripping too many slashes and producing invalid URLs.
const match = /^((?:resource|file|chrome)\:\/\/[^\/]*|jar:[^!]+!)(.*)/.exec(
base
);
if (match) {
return match[1] + normalize([match[2], ...paths].join("/"));
}
return normalize([base, ...paths].join("/"));
}
// Function takes set of options and returns a JS sandbox. Function may be
// passed set of options:
// - `name`: A string value which identifies the sandbox in about:memory. Will
// throw exception if omitted.
// - `prototype`: Ancestor for the sandbox that will be created. Defaults to
// `{}`.
// - `invisibleToDebugger`: True, if the sandbox is part of the debugger
// implementation and should not be tracked by debugger API.
// For more details see:
function Sandbox(options) {
// Normalize options and rename to match `Cu.Sandbox` expectations.
const sandboxOptions = {
// This will allow exposing Components as well as Cu, Ci and Cr.
wantComponents: true,
// By default, Sandbox come with a very limited set of global.
// The list of all available symbol names is available over there:
// Request to expose all meaningful global here:
wantGlobalProperties: [
"AbortController",
"atob",
"btoa",
"Blob",
"crypto",
"ChromeUtils",
"CSS",
"CSSRule",
"CustomStateSet",
"DOMParser",
"Element",
"Event",
"FileReader",
"FormData",
"Headers",
"InspectorCSSParser",
"InspectorUtils",
"MIDIInputMap",
"MIDIOutputMap",
"Node",
"TextDecoder",
"TextEncoder",
"URL",
"URLSearchParams",
"Window",
"XMLHttpRequest",
],
sandboxName: options.name,
sandboxPrototype: "prototype" in options ? options.prototype : {},
invisibleToDebugger:
"invisibleToDebugger" in options ? options.invisibleToDebugger : false,
freshCompartment: options.freshCompartment || false,
};
return Cu.Sandbox(systemPrincipal, sandboxOptions);
}
// This allows defining some modules in AMD format while retaining CommonJS
// compatibility with this loader by allowing the factory function to have
// access to general CommonJS functions, e.g.
//
// define(function(require, exports, module) {
// ... code ...
// });
function define(factory) {
factory(this.require, this.exports, this.module);
}
// Populates `exports` of the given CommonJS `module` object, in the context
// of the given `loader` by evaluating code associated with it.
function load(loader, module) {
const require = Require(loader, module);
// We expose set of properties defined by `CommonJS` specification via
// prototype of the sandbox. Also globals are deeper in the prototype
// chain so that each module has access to them as well.
const properties = {
require,
module,
exports: module.exports,
};
if (loader.supportAMDModules) {
properties.define = define;
}
// Create a new object in the shared global of the loader, that will be used
// as the scope object for this particular module.
const scopeFromSharedGlobal = new loader.sharedGlobal.Object();
Object.assign(scopeFromSharedGlobal, properties);
const originalExports = module.exports;
try {
Services.scriptloader.loadSubScript(module.uri, scopeFromSharedGlobal);
} catch (error) {
// loadSubScript sometime throws string errors, which includes no stack.
// At least provide the current stack by re-throwing a real Error object.
if (typeof error == "string") {
if (
error.startsWith("Error creating URI") ||
error.startsWith("Error opening input stream (invalid filename?)")
) {
throw new Error(
`Module \`${module.id}\` is not found at ${module.uri}`
);
}
throw new Error(
`Error while loading module \`${module.id}\` at ${module.uri}:` +
"\n" +
error
);
}
// Otherwise just re-throw everything else which should have a stack
throw error;
}
// Only freeze the exports object if we created it ourselves. Modules
// which completely replace the exports object and still want it
// frozen need to freeze it themselves.
if (module.exports === originalExports) {
Object.freeze(module.exports);
}
return module;
}
// Utility function to normalize module `uri`s so they have `.js` extension.
function normalizeExt(uri) {
if (isJSURI(uri) || isJSONURI(uri) || isSYSMJSURI(uri)) {
return uri;
}
return uri + ".js";
}
// Utility function to join paths. In common case `base` is a
// `requirer.uri` but in some cases it may be `baseURI`. In order to
// avoid complexity we require `baseURI` with a trailing `/`.
function resolve(id, base) {
if (!isRelative(id)) {
return id;
}
const baseDir = dirname(base);
let resolved;
if (baseDir.includes(":")) {
resolved = join(baseDir, id);
} else {
resolved = normalize(`${baseDir}/${id}`);
}
// Joining and normalizing removes the "./" from relative files.
// We need to ensure the resolution still has the root
if (base.startsWith("./")) {
resolved = "./" + resolved;
}
return resolved;
}
function compileMapping(paths) {
// Make mapping array that is sorted from longest path to shortest path.
const mapping = Object.keys(paths)
.sort((a, b) => b.length - a.length)
.map(path => [path, paths[path]]);
const PATTERN = /([.\\?+*(){}[\]^$])/g;
const escapeMeta = str => str.replace(PATTERN, "\\$1");
const patterns = [];
paths = {};
for (let [path, uri] of mapping) {
// Strip off any trailing slashes to make comparisons simpler
if (path.endsWith("/")) {
path = path.slice(0, -1);
uri = uri.replace(/\/+$/, "");
}
paths[path] = uri;
// We only want to match path segments explicitly. Examples:
// * "foo/bar" matches for "foo/bar"
// * "foo/bar" matches for "foo/bar/baz"
// * "foo/bar" does not match for "foo/bar-1"
// * "foo/bar/" does not match for "foo/bar"
// * "foo/bar/" matches for "foo/bar/baz"
//
// Check for an empty path, an exact match, or a substring match
// with the next character being a forward slash.
if (path == "") {
patterns.push("");
} else {
patterns.push(`${escapeMeta(path)}(?=$|/)`);
}
}
const pattern = new RegExp(`^(${patterns.join("|")})`);
// This will replace the longest matching path mapping at the start of
// the ID string with its mapped value.
return id => {
return id.replace(pattern, (m0, m1) => paths[m1]);
};
}
export function resolveURI(id, mapping) {
// Do not resolve if already a resource URI
if (isAbsoluteURI(id)) {
return normalizeExt(id);
}
return normalizeExt(mapping(id));
}
// Creates version of `require` that will be exposed to the given `module`
// in the context of the given `loader`. Each module gets own limited copy
// of `require` that is allowed to load only a modules that are associated
// with it during link time.
export function Require(loader, requirer) {
const { modules, mapping, mappingCache, requireHook } = loader;
function require(id) {
if (!id) {
// Throw if `id` is not passed.
throw Error(
"You must provide a module name when calling require() from " +
requirer.id,
requirer.uri
);
}
if (requireHook) {
return requireHook(id, _require);
}
return _require(id);
}
function _require(id) {
let { uri, requirement } = getRequirements(id);
let module = null;
// If module is already cached by loader then just use it.
if (uri in modules) {
module = modules[uri];
} else if (isSYSMJSURI(uri)) {
module = modules[uri] = Module(requirement, uri);
module.exports = ChromeUtils.importESModule(uri, {
global: "contextual",
});
} else if (isJSONURI(uri)) {
let data;
// First attempt to load and parse json uri
// ex: `test.json`
// If that doesn"t exist, check for `test.json.js`
// for node parity
try {
data = JSON.parse(readURI(uri));
module = modules[uri] = Module(requirement, uri);
module.exports = data;
} catch (err) {
// If error thrown from JSON parsing, throw that, do not
// attempt to find .json.js file
if (err && /JSON\.parse/.test(err.message)) {
throw err;
}
uri = uri + ".js";
}
}
// If not yet cached, load and cache it.
// We also freeze module to prevent it from further changes
// at runtime.
if (!(uri in modules)) {
// Many of the loader's functionalities are dependent
// on modules[uri] being set before loading, so we set it and
// remove it if we have any errors.
module = modules[uri] = Module(requirement, uri);
try {
Object.freeze(load(loader, module));
} catch (e) {
// Clear out modules cache so we can throw on a second invalid require
delete modules[uri];
throw e;
}
}
return module.exports;
}
// Resolution function taking a module name/path and
// returning a resourceURI and a `requirement` used by the loader.
// Used by both `require` and `require.resolve`.
function getRequirements(id) {
if (!id) {
// Throw if `id` is not passed.
throw Error(
"you must provide a module name when calling require() from " +
requirer.id,
requirer.uri
);
}
let requirement, uri;
if (modules[id]) {
uri = requirement = id;
} else if (requirer) {
// Resolve `id` to its requirer if it's relative.
requirement = resolve(id, requirer.id);
} else {
requirement = id;
}
// Resolves `uri` of module using loaders resolve function.
if (!uri) {
if (mappingCache.has(requirement)) {
uri = mappingCache.get(requirement);
} else {
uri = resolveURI(requirement, mapping);
mappingCache.set(requirement, uri);
}
}
// Throw if `uri` can not be resolved.
if (!uri) {
throw Error(
"Module: Can not resolve '" +
id +
"' module required by " +
requirer.id +
" located at " +
requirer.uri,
requirer.uri
);
}
return { uri, requirement };
}
// Expose the `resolve` function for this `Require` instance
require.resolve = _require.resolve = function (id) {
const { uri } = getRequirements(id);
return uri;
};
// This is like webpack's require.context. It returns a new require
// function that prepends the prefix to any requests.
require.context = prefix => {
return id => {
return require(prefix + id);
};
};
return require;
}
// Makes module object that is made available to CommonJS modules when they
// are evaluated, along with `exports` and `require`.
export function Module(id, uri) {
return Object.create(null, {
id: { enumerable: true, value: id },
exports: {
enumerable: true,
writable: true,
value: Object.create(null),
configurable: true,
},
uri: { value: uri },
});
}
// Takes `loader`, and unload `reason` string and notifies all observers that
// they should cleanup after them-self.
export function unload(loader, reason) {
// subject is a unique object created per loader instance.
// This allows any code to cleanup on loader unload regardless of how
// it was loaded. To handle unload for specific loader subject may be
// asserted against loader.destructor or require("@loader/unload")
// Note: We don not destroy loader's module cache or sandboxes map as
// some modules may do cleanup in subsequent turns of event loop. Destroying
// cache may cause module identity problems in such cases.
const subject = { wrappedJSObject: loader.destructor };
Services.obs.notifyObservers(subject, "devtools:loader:destroy", reason);
}
// Function makes new loader that can be used to load CommonJS modules.
// Loader takes following options:
// - `paths`: Mandatory dictionary of require path mapped to absolute URIs.
// Object keys are path prefix used in require(), values are URIs where each
// prefix should be mapped to.
// - `globals`: Optional map of globals, that all module scopes will inherit
// from. Map is also exposed under `globals` property of the returned loader
// so it can be extended further later. Defaults to `{}`.
// - `sandboxName`: String, name of the sandbox displayed in about:memory.
// - `invisibleToDebugger`: Boolean. Should be true when loading debugger
// modules, in order to ignore them from the Debugger API.
// - `sandboxPrototype`: Object used to define globals on all module's
// sandboxes.
// - `requireHook`: Optional function used to replace native require function
// from loader. This function receive the module path as first argument,
// and native require method as second argument.
export function Loader(options) {
let { paths, globals } = options;
if (!globals) {
globals = {};
}
// We create an identity object that will be dispatched on an unload
// event as subject. This way unload listeners will be able to assert
// which loader is unloaded. Please note that we intentionally don"t
// use `loader` as subject to prevent a loader access leakage through
// observer notifications.
const destructor = Object.create(null);
const mapping = compileMapping(paths);
// Define pseudo modules.
const builtinModuleExports = {
"@loader/unload": destructor,
"@loader/options": options,
};
const modules = {};
for (const id of Object.keys(builtinModuleExports)) {
// We resolve `uri` from `id` since modules are cached by `uri`.
const uri = resolveURI(id, mapping);
const module = Module(id, uri);
// Lazily expose built-in modules in order to
// allow them to be loaded lazily.
Object.defineProperty(module, "exports", {
enumerable: true,
get() {
return builtinModuleExports[id];
},
});
modules[uri] = module;
}
let sharedGlobal;
if (options.sharedGlobal) {
sharedGlobal = options.sharedGlobal;
} else {
// Create the unique sandbox we will be using for all modules,
// so that we prevent creating a new compartment per module.
// The side effect is that all modules will share the same
// global objects.
sharedGlobal = Sandbox({
name: options.sandboxName || "DevTools",
invisibleToDebugger: options.invisibleToDebugger || false,
prototype: options.sandboxPrototype || globals,
freshCompartment: options.freshCompartment,
});
}
if (options.sharedGlobal || options.sandboxPrototype) {
// If we were given a sharedGlobal or a sandboxPrototype, we have to define
// the globals on the shared global directly. Note that this will not work
// for callers who depend on being able to add globals after the loader was
// created.
for (const name of getOwnIdentifiers(globals)) {
Object.defineProperty(
sharedGlobal,
name,
Object.getOwnPropertyDescriptor(globals, name)
);
}
}
// Loader object is just a representation of a environment
// state. We mark its properties non-enumerable
// as they are pure implementation detail that no one should rely upon.
const returnObj = {
destructor: { enumerable: false, value: destructor },
globals: { enumerable: false, value: globals },
mapping: { enumerable: false, value: mapping },
mappingCache: { enumerable: false, value: new Map() },
// Map of module objects indexed by module URIs.
modules: { enumerable: false, value: modules },
sharedGlobal: { enumerable: false, value: sharedGlobal },
supportAMDModules: {
enumerable: false,
value: options.supportAMDModules || false,
},
// Whether the modules loaded should be ignored by the debugger
invisibleToDebugger: {
enumerable: false,
value: options.invisibleToDebugger || false,
},
requireHook: {
enumerable: false,
writable: true,
value: options.requireHook,
},
};
return Object.create(null, returnObj);
}
// NB: These methods are from the UNIX implementation of OS.Path. Refactoring
// this module to not use path methods on stringly-typed URIs is
// non-trivial.
function dirname(path) {
let index = path.lastIndexOf("/");
if (index == -1) {
return ".";
}
while (index >= 0 && path[index] == "/") {
--index;
}
return path.slice(0, index + 1);
}
function normalize(path) {
const stack = [];
let absolute;
if (path.length >= 0 && path[0] == "/") {
absolute = true;
} else {
absolute = false;
}
path.split("/").forEach(function (v) {
switch (v) {
case "":
case ".": // fallthrough
break;
case "..":
if (!stack.length) {
if (absolute) {
throw new Error("Path is ill-formed: attempting to go past root");
} else {
stack.push("..");
}
} else if (stack[stack.length - 1] == "..") {
stack.push("..");
} else {
stack.pop();
}
break;
default:
stack.push(v);
}
});
const string = stack.join("/");
return absolute ? "/" + string : string;
}