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install.js
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install.js
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makeInstaller = function (options) {
"use strict";
options = options || {};
// These file extensions will be appended to required module identifiers
// if they do not exactly match an installed module.
var defaultExtensions = options.extensions || [".js", ".json"];
// If defined, the options.fallback function will be called when no
// installed module is found for a required module identifier. Often
// options.fallback will be implemented in terms of the native Node
// require function, which has the ability to load binary modules.
var fallback = options.fallback;
// List of fields to look for in package.json files to determine the
// main entry module of the package. The first field listed here whose
// value is a string will be used to resolve the entry module.
var mainFields = options.mainFields ||
// If options.mainFields is absent and options.browser is truthy,
// package resolution will prefer the "browser" field of package.json
// files to the "main" field. Note that this only supports
// string-valued "browser" fields for now, though in the future it
// might make sense to support the object version, a la browserify.
(options.browser ? ["browser", "main"] : ["main"]);
var hasOwn = {}.hasOwnProperty;
function strictHasOwn(obj, key) {
return isObject(obj) && isString(key) && hasOwn.call(obj, key);
}
// Cache for looking up File objects given absolute module identifiers.
// Invariants:
// filesByModuleId[module.id] === fileAppendId(root, module.id)
// filesByModuleId[module.id].module === module
var filesByModuleId = {};
// The file object representing the root directory of the installed
// module tree.
var root = new File("/", new File("/.."));
var rootRequire = makeRequire(root);
// Merges the given tree of directories and module factory functions
// into the tree of installed modules and returns a require function
// that behaves as if called from a module in the root directory.
function install(tree, options) {
if (isObject(tree)) {
fileMergeContents(root, tree, options);
}
return rootRequire;
}
// Replace this function to enable Module.prototype.prefetch.
install.fetch = function (ids) {
throw new Error("fetch not implemented");
};
// This constructor will be used to instantiate the module objects
// passed to module factory functions (i.e. the third argument after
// require and exports), and is exposed as install.Module in case the
// caller of makeInstaller wishes to modify Module.prototype.
function Module(id) {
this.id = id;
// The Node implementation of module.children unfortunately includes
// only those child modules that were imported for the first time by
// this parent module (i.e., child.parent === this).
this.children = [];
// This object is an install.js extension that includes all child
// modules imported by this module, even if this module is not the
// first to import them.
this.childrenById = {};
}
// Used to keep module.prefetch promise resolutions well-ordered.
var lastPrefetchPromise;
// May be shared by multiple sequential calls to module.prefetch.
// Initialized to {} only when necessary.
var missing;
Module.prototype.prefetch = function (id) {
var module = this;
var parentFile = getOwn(filesByModuleId, module.id);
lastPrefetchPromise = lastPrefetchPromise || Promise.resolve();
var previousPromise = lastPrefetchPromise;
function walk(module) {
var file = getOwn(filesByModuleId, module.id);
if (fileIsDynamic(file) && ! file.pending) {
file.pending = true;
missing = missing || {};
// These are the data that will be exposed to the install.fetch
// callback, so it's worth documenting each item with a comment.
missing[module.id] = {
// The CommonJS module object that will be exposed to this
// dynamic module when it is evaluated. Note that install.fetch
// could decide to populate module.exports directly, instead of
// fetching anything. In that case, install.fetch should omit
// this module from the tree that it produces.
module: file.module,
// List of module identifier strings imported by this module.
// Note that the missing object already contains all available
// dependencies (including transitive dependencies), so
// install.fetch should not need to traverse these dependencies
// in most cases; however, they may be useful for other reasons.
// Though the strings are unique, note that two different
// strings could resolve to the same module.
deps: Object.keys(file.deps),
// The options (if any) that were passed as the second argument
// to the install(tree, options) function when this stub was
// first registered. Typically contains options.extensions, but
// could contain any information appropriate for the entire tree
// as originally installed. These options will be automatically
// inherited by the newly fetched modules, so install.fetch
// should not need to modify them.
options: file.options,
// Any stub data included in the array notation from the
// original entry for this dynamic module. Typically contains
// "main" and/or "browser" fields for package.json files, and is
// otherwise undefined.
stub: file.stub
};
each(file.deps, function (parentId, id) {
fileResolve(file, id);
});
each(module.childrenById, walk);
}
}
return lastPrefetchPromise = new Promise(function (resolve) {
var absChildId = module.resolve(id);
each(module.childrenById, walk);
resolve(absChildId);
}).then(function (absChildId) {
// Grab the current missing object and fetch its contents.
var toBeFetched = missing;
missing = null;
function clearPending() {
if (toBeFetched) {
Object.keys(toBeFetched).forEach(function (id) {
getOwn(filesByModuleId, id).pending = false;
});
}
}
return new Promise(function (resolve) {
// The install.fetch function takes an object mapping missing
// dynamic module identifiers to options objects, and should
// return a Promise that resolves to a module tree that can be
// installed. As an optimization, if there were no missing dynamic
// modules, then we can skip calling install.fetch entirely.
resolve(toBeFetched && install.fetch(toBeFetched));
}).then(function (tree) {
function both() {
install(tree);
clearPending();
return absChildId;
}
// Although we want multiple install.fetch calls to run in
// parallel, it is important that the promises returned by
// module.prefetch are resolved in the same order as the original
// calls to module.prefetch, because previous fetches may include
// modules assumed to exist by more recent module.prefetch calls.
// Whether previousPromise was resolved or rejected, carry on with
// the installation regardless.
return previousPromise.then(both, both);
}, function (error) {
// Fixes https://github.com/meteor/meteor/issues/10182.
clearPending();
throw error;
});
});
};
install.Module = Module;
function getOwn(obj, key) {
return strictHasOwn(obj, key) && obj[key];
}
function isObject(value) {
return value !== null && typeof value === "object";
}
function isFunction(value) {
return typeof value === "function";
}
function isString(value) {
return typeof value === "string";
}
function makeMissingError(id) {
return new Error("Cannot find module '" + id + "'");
}
Module.prototype.resolve = function (id) {
var file = fileResolve(filesByModuleId[this.id], id);
if (file) return file.module.id;
var error = makeMissingError(id);
if (fallback && isFunction(fallback.resolve)) {
return fallback.resolve(id, this.id, error);
}
throw error;
};
Module.prototype.require = function require(id) {
var result = fileResolve(filesByModuleId[this.id], id);
if (result) {
return fileEvaluate(result, this);
}
var error = makeMissingError(id);
if (isFunction(fallback)) {
return fallback(
id, // The missing module identifier.
this.id, // ID of the parent module.
error // The error we would have thrown.
);
}
throw error;
};
function makeRequire(file) {
var module = file.module;
function require(id) {
return module.require(id);
}
require.extensions = fileGetExtensions(file).slice(0);
require.resolve = function resolve(id) {
return module.resolve(id);
};
return require;
}
// File objects represent either directories or modules that have been
// installed. When a `File` respresents a directory, its `.contents`
// property is an object containing the names of the files (or
// directories) that it contains. When a `File` represents a module, its
// `.contents` property is a function that can be invoked with the
// appropriate `(require, exports, module)` arguments to evaluate the
// module. If the `.contents` property is a string, that string will be
// resolved as a module identifier, and the exports of the resulting
// module will provide the exports of the original file. The `.parent`
// property of a File is either a directory `File` or `null`. Note that
// a child may claim another `File` as its parent even if the parent
// does not have an entry for that child in its `.contents` object.
// This is important for implementing anonymous files, and preventing
// child modules from using `../relative/identifier` syntax to examine
// unrelated modules.
function File(moduleId, parent) {
var file = this;
// Link to the parent file.
file.parent = parent = parent || null;
// The module object for this File, which will eventually boast an
// .exports property when/if the file is evaluated.
file.module = new Module(moduleId);
filesByModuleId[moduleId] = file;
// The .contents of the file can be either (1) an object, if the file
// represents a directory containing other files; (2) a factory
// function, if the file represents a module that can be imported; (3)
// a string, if the file is an alias for another file; or (4) null, if
// the file's contents are not (yet) available.
file.contents = null;
// Set of module identifiers imported by this module. Note that this
// set is not necessarily complete, so don't rely on it unless you
// know what you're doing.
file.deps = {};
}
function fileEvaluate(file, parentModule) {
var module = file.module;
const runSettersAndReturn = () => {
// The module.runModuleSetters method will be deprecated in favor of
// just module.runSetters: https://github.com/benjamn/reify/pull/160
var runSetters = module.runSetters || module.runModuleSetters;
if (isFunction(runSetters)) {
runSetters.call(module);
}
return module.exports;
}
if (! strictHasOwn(module, "exports")) {
var contents = file.contents;
if (! contents) {
// If this file was installed with array notation, and the array
// contained one or more objects but no functions, then the combined
// properties of the objects are treated as a temporary stub for
// file.module.exports. This is particularly important for partial
// package.json modules, so that the resolution logic can know the
// value of the "main" and/or "browser" fields, at least, even if
// the rest of the package.json file is not (yet) available.
if (file.stub) {
return file.stub;
}
throw makeMissingError(module.id);
}
if (parentModule) {
module.parent = parentModule;
var children = parentModule.children;
if (Array.isArray(children)) {
children.push(module);
}
}
// We don't need to do anything fancy. When importing an async module, we need to wait for it
// to evaluate, and then evaluate the rest like usual.
if (contents.constructor.name === "AsyncFunction") {
return contents(
makeRequire(file),
// If the file had a .stub, reuse the same object for exports.
module.exports = file.stub || {},
module,
file.module.id,
file.parent.module.id
).then(() => {
module.loaded = true;
return runSettersAndReturn();
})
}
contents(
makeRequire(file),
// If the file had a .stub, reuse the same object for exports.
module.exports = file.stub || {},
module,
file.module.id,
file.parent.module.id
);
module.loaded = true;
}
return runSettersAndReturn();
}
function fileIsDirectory(file) {
return file && isObject(file.contents);
}
function fileIsDynamic(file) {
return file && file.contents === null;
}
function fileMergeContents(file, contents, options) {
if (Array.isArray(contents)) {
contents.forEach(function (item) {
if (isString(item)) {
file.deps[item] = file.module.id;
} else if (isFunction(item)) {
contents = item;
} else if (isObject(item)) {
file.stub = file.stub || {};
each(item, function (value, key) {
file.stub[key] = value;
});
}
});
if (! isFunction(contents)) {
// If the array did not contain a function, merge nothing.
contents = null;
}
} else if (! isFunction(contents) &&
! isString(contents) &&
! isObject(contents)) {
// If contents is neither an array nor a function nor a string nor
// an object, just give up and merge nothing.
contents = null;
}
if (contents) {
file.contents = file.contents || (isObject(contents) ? {} : contents);
if (isObject(contents) && fileIsDirectory(file)) {
each(contents, function (value, key) {
if (key === "..") {
child = file.parent;
} else {
var child = getOwn(file.contents, key);
if (! child) {
child = file.contents[key] = new File(
file.module.id.replace(/\/*$/, "/") + key,
file
);
child.options = options;
}
}
fileMergeContents(child, value, options);
});
}
}
}
function each(obj, callback, context) {
Object.keys(obj).forEach(function (key) {
callback.call(this, obj[key], key);
}, context);
}
function fileGetExtensions(file) {
return file.options
&& file.options.extensions
|| defaultExtensions;
}
function fileAppendIdPart(file, part, extensions) {
// Always append relative to a directory.
while (file && ! fileIsDirectory(file)) {
file = file.parent;
}
if (! file || ! part || part === ".") {
return file;
}
if (part === "..") {
return file.parent;
}
var exactChild = getOwn(file.contents, part);
// Only consider multiple file extensions if this part is the last
// part of a module identifier and not equal to `.` or `..`, and there
// was no exact match or the exact match was a directory.
if (extensions && (! exactChild || fileIsDirectory(exactChild))) {
for (var e = 0; e < extensions.length; ++e) {
var child = getOwn(file.contents, part + extensions[e]);
if (child && ! fileIsDirectory(child)) {
return child;
}
}
}
return exactChild;
}
function fileAppendId(file, id, extensions) {
var parts = id.split("/");
// Use `Array.prototype.every` to terminate iteration early if
// `fileAppendIdPart` returns a falsy value.
parts.every(function (part, i) {
return file = i < parts.length - 1
? fileAppendIdPart(file, part)
: fileAppendIdPart(file, part, extensions);
});
return file;
}
function recordChild(parentModule, childFile) {
var childModule = childFile && childFile.module;
if (parentModule && childModule) {
parentModule.childrenById[childModule.id] = childModule;
}
}
function fileResolve(file, id, parentModule, seenDirFiles) {
var parentModule = parentModule || file.module;
var extensions = fileGetExtensions(file);
file =
// Absolute module identifiers (i.e. those that begin with a `/`
// character) are interpreted relative to the root directory, which
// is a slight deviation from Node, which has access to the entire
// file system.
id.charAt(0) === "/" ? fileAppendId(root, id, extensions) :
// Relative module identifiers are interpreted relative to the
// current file, naturally.
id.charAt(0) === "." ? fileAppendId(file, id, extensions) :
// Top-level module identifiers are interpreted as referring to
// packages in `node_modules` directories.
nodeModulesLookup(file, id, extensions);
// If the identifier resolves to a directory, we use the same logic as
// Node to find an `index.js` or `package.json` file to evaluate.
while (fileIsDirectory(file)) {
seenDirFiles = seenDirFiles || [];
// If the "main" field of a `package.json` file resolves to a
// directory we've already considered, then we should not attempt to
// read the same `package.json` file again. Using an array as a set
// is acceptable here because the number of directories to consider
// is rarely greater than 1 or 2. Also, using indexOf allows us to
// store File objects instead of strings.
if (seenDirFiles.indexOf(file) < 0) {
seenDirFiles.push(file);
var pkgJsonFile = fileAppendIdPart(file, "package.json");
var pkg = pkgJsonFile && fileEvaluate(pkgJsonFile, parentModule);
var mainFile, resolved = pkg && mainFields.some(function (name) {
var main = pkg[name];
if (isString(main)) {
// The "main" field of package.json does not have to begin
// with ./ to be considered relative, so first we try
// simply appending it to the directory path before
// falling back to a full fileResolve, which might return
// a package from a node_modules directory.
return mainFile = fileAppendId(file, main, extensions) ||
fileResolve(file, main, parentModule, seenDirFiles);
}
});
if (resolved && mainFile) {
file = mainFile;
recordChild(parentModule, pkgJsonFile);
// The fileAppendId call above may have returned a directory,
// so continue the loop to make sure we resolve it to a
// non-directory file.
continue;
}
}
// If we didn't find a `package.json` file, or it didn't have a
// resolvable `.main` property, the only possibility left to
// consider is that this directory contains an `index.js` module.
// This assignment almost always terminates the while loop, because
// there's very little chance `fileIsDirectory(file)` will be true
// for `fileAppendIdPart(file, "index", extensions)`. However, in
// principle it is remotely possible that a file called `index.js`
// could be a directory instead of a file.
file = fileAppendIdPart(file, "index", extensions);
}
if (file && isString(file.contents)) {
file = fileResolve(file, file.contents, parentModule, seenDirFiles);
}
recordChild(parentModule, file);
return file;
};
function nodeModulesLookup(file, id, extensions) {
for (var resolved; file && ! resolved; file = file.parent) {
resolved = fileIsDirectory(file) &&
fileAppendId(file, "node_modules/" + id, extensions);
}
return resolved;
}
return install;
};
if (typeof exports === "object") {
exports.makeInstaller = makeInstaller;
}