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- 'use strict';
- function Kareem() {
- this._pres = new Map();
- this._posts = new Map();
- }
- Kareem.prototype.execPre = function(name, context, args, callback) {
- if (arguments.length === 3) {
- callback = args;
- args = [];
- }
- var pres = get(this._pres, name, []);
- var numPres = pres.length;
- var numAsyncPres = pres.numAsync || 0;
- var currentPre = 0;
- var asyncPresLeft = numAsyncPres;
- var done = false;
- var $args = args;
- if (!numPres) {
- return process.nextTick(function() {
- callback(null);
- });
- }
- var next = function() {
- if (currentPre >= numPres) {
- return;
- }
- var pre = pres[currentPre];
- if (pre.isAsync) {
- var args = [
- decorateNextFn(_next),
- decorateNextFn(function(error) {
- if (error) {
- if (done) {
- return;
- }
- done = true;
- return callback(error);
- }
- if (--asyncPresLeft === 0 && currentPre >= numPres) {
- return callback(null);
- }
- })
- ];
- callMiddlewareFunction(pre.fn, context, args, args[0]);
- } else if (pre.fn.length > 0) {
- var args = [decorateNextFn(_next)];
- var _args = arguments.length >= 2 ? arguments : [null].concat($args);
- for (var i = 1; i < _args.length; ++i) {
- args.push(_args[i]);
- }
- callMiddlewareFunction(pre.fn, context, args, args[0]);
- } else {
- let error = null;
- let maybePromise = null;
- try {
- maybePromise = pre.fn.call(context);
- } catch (err) {
- error = err;
- }
- if (isPromise(maybePromise)) {
- maybePromise.then(() => _next(), err => _next(err));
- } else {
- if (++currentPre >= numPres) {
- if (asyncPresLeft > 0) {
- // Leave parallel hooks to run
- return;
- } else {
- return process.nextTick(function() {
- callback(error);
- });
- }
- }
- next(error);
- }
- }
- };
- next.apply(null, [null].concat(args));
- function _next(error) {
- if (error) {
- if (done) {
- return;
- }
- done = true;
- return callback(error);
- }
- if (++currentPre >= numPres) {
- if (asyncPresLeft > 0) {
- // Leave parallel hooks to run
- return;
- } else {
- return callback(null);
- }
- }
- next.apply(context, arguments);
- }
- };
- Kareem.prototype.execPreSync = function(name, context, args) {
- var pres = get(this._pres, name, []);
- var numPres = pres.length;
- for (var i = 0; i < numPres; ++i) {
- pres[i].fn.apply(context, args || []);
- }
- };
- Kareem.prototype.execPost = function(name, context, args, options, callback) {
- if (arguments.length < 5) {
- callback = options;
- options = null;
- }
- var posts = get(this._posts, name, []);
- var numPosts = posts.length;
- var currentPost = 0;
- var firstError = null;
- if (options && options.error) {
- firstError = options.error;
- }
- if (!numPosts) {
- return process.nextTick(function() {
- callback.apply(null, [firstError].concat(args));
- });
- }
- var next = function() {
- var post = posts[currentPost].fn;
- var numArgs = 0;
- var argLength = args.length;
- var newArgs = [];
- for (var i = 0; i < argLength; ++i) {
- numArgs += args[i] && args[i]._kareemIgnore ? 0 : 1;
- if (!args[i] || !args[i]._kareemIgnore) {
- newArgs.push(args[i]);
- }
- }
- if (firstError) {
- if (post.length === numArgs + 2) {
- var _cb = decorateNextFn(function(error) {
- if (error) {
- firstError = error;
- }
- if (++currentPost >= numPosts) {
- return callback.call(null, firstError);
- }
- next();
- });
- callMiddlewareFunction(post, context,
- [firstError].concat(newArgs).concat([_cb]), _cb);
- } else {
- if (++currentPost >= numPosts) {
- return callback.call(null, firstError);
- }
- next();
- }
- } else {
- const _cb = decorateNextFn(function(error) {
- if (error) {
- firstError = error;
- return next();
- }
- if (++currentPost >= numPosts) {
- return callback.apply(null, [null].concat(args));
- }
- next();
- });
- if (post.length === numArgs + 2) {
- // Skip error handlers if no error
- if (++currentPost >= numPosts) {
- return callback.apply(null, [null].concat(args));
- }
- return next();
- }
- if (post.length === numArgs + 1) {
- callMiddlewareFunction(post, context, newArgs.concat([_cb]), _cb);
- } else {
- let error;
- let maybePromise;
- try {
- maybePromise = post.apply(context, newArgs);
- } catch (err) {
- error = err;
- firstError = err;
- }
- if (isPromise(maybePromise)) {
- return maybePromise.then(() => _cb(), err => _cb(err));
- }
- if (++currentPost >= numPosts) {
- return callback.apply(null, [error].concat(args));
- }
- next(error);
- }
- }
- };
- next();
- };
- Kareem.prototype.execPostSync = function(name, context, args) {
- const posts = get(this._posts, name, []);
- const numPosts = posts.length;
- for (let i = 0; i < numPosts; ++i) {
- posts[i].fn.apply(context, args || []);
- }
- };
- Kareem.prototype.createWrapperSync = function(name, fn) {
- var kareem = this;
- return function syncWrapper() {
- kareem.execPreSync(name, this, arguments);
- var toReturn = fn.apply(this, arguments);
- kareem.execPostSync(name, this, [toReturn]);
- return toReturn;
- };
- }
- function _handleWrapError(instance, error, name, context, args, options, callback) {
- if (options.useErrorHandlers) {
- var _options = { error: error };
- return instance.execPost(name, context, args, _options, function(error) {
- return typeof callback === 'function' && callback(error);
- });
- } else {
- return typeof callback === 'function' ?
- callback(error) :
- undefined;
- }
- }
- Kareem.prototype.wrap = function(name, fn, context, args, options) {
- const lastArg = (args.length > 0 ? args[args.length - 1] : null);
- const argsWithoutCb = typeof lastArg === 'function' ?
- args.slice(0, args.length - 1) :
- args;
- const _this = this;
- options = options || {};
- const checkForPromise = options.checkForPromise;
- this.execPre(name, context, args, function(error) {
- if (error) {
- const numCallbackParams = options.numCallbackParams || 0;
- const errorArgs = options.contextParameter ? [context] : [];
- for (var i = errorArgs.length; i < numCallbackParams; ++i) {
- errorArgs.push(null);
- }
- return _handleWrapError(_this, error, name, context, errorArgs,
- options, lastArg);
- }
- const end = (typeof lastArg === 'function' ? args.length - 1 : args.length);
- const numParameters = fn.length;
- const ret = fn.apply(context, args.slice(0, end).concat(_cb));
- if (checkForPromise) {
- if (ret != null && typeof ret.then === 'function') {
- // Thenable, use it
- return ret.then(
- res => _cb(null, res),
- err => _cb(err)
- );
- }
- // If `fn()` doesn't have a callback argument and doesn't return a
- // promise, assume it is sync
- if (numParameters < end + 1) {
- return _cb(null, ret);
- }
- }
- function _cb() {
- const args = arguments;
- const argsWithoutError = Array.prototype.slice.call(arguments, 1);
- if (options.nullResultByDefault && argsWithoutError.length === 0) {
- argsWithoutError.push(null);
- }
- if (arguments[0]) {
- // Assume error
- return _handleWrapError(_this, arguments[0], name, context,
- argsWithoutError, options, lastArg);
- } else {
- _this.execPost(name, context, argsWithoutError, function() {
- if (arguments[0]) {
- return typeof lastArg === 'function' ?
- lastArg(arguments[0]) :
- undefined;
- }
- return typeof lastArg === 'function' ?
- lastArg.apply(context, arguments) :
- undefined;
- });
- }
- }
- });
- };
- Kareem.prototype.filter = function(fn) {
- const clone = this.clone();
- const pres = Array.from(clone._pres.keys());
- for (const name of pres) {
- const hooks = this._pres.get(name).
- map(h => Object.assign({}, h, { name: name })).
- filter(fn);
- if (hooks.length === 0) {
- clone._pres.delete(name);
- continue;
- }
- hooks.numAsync = hooks.filter(h => h.isAsync).length;
- clone._pres.set(name, hooks);
- }
- const posts = Array.from(clone._posts.keys());
- for (const name of posts) {
- const hooks = this._posts.get(name).
- map(h => Object.assign({}, h, { name: name })).
- filter(fn);
- if (hooks.length === 0) {
- clone._posts.delete(name);
- continue;
- }
- clone._posts.set(name, hooks);
- }
- return clone;
- };
- Kareem.prototype.hasHooks = function(name) {
- return this._pres.has(name) || this._posts.has(name);
- };
- Kareem.prototype.createWrapper = function(name, fn, context, options) {
- var _this = this;
- if (!this.hasHooks(name)) {
- // Fast path: if there's no hooks for this function, just return the
- // function wrapped in a nextTick()
- return function() {
- process.nextTick(() => fn.apply(this, arguments));
- };
- }
- return function() {
- var _context = context || this;
- var args = Array.prototype.slice.call(arguments);
- _this.wrap(name, fn, _context, args, options);
- };
- };
- Kareem.prototype.pre = function(name, isAsync, fn, error, unshift) {
- let options = {};
- if (typeof isAsync === 'object' && isAsync != null) {
- options = isAsync;
- isAsync = options.isAsync;
- } else if (typeof arguments[1] !== 'boolean') {
- error = fn;
- fn = isAsync;
- isAsync = false;
- }
- const pres = get(this._pres, name, []);
- this._pres.set(name, pres);
- if (isAsync) {
- pres.numAsync = pres.numAsync || 0;
- ++pres.numAsync;
- }
- if (unshift) {
- pres.unshift(Object.assign({}, options, { fn: fn, isAsync: isAsync }));
- } else {
- pres.push(Object.assign({}, options, { fn: fn, isAsync: isAsync }));
- }
- return this;
- };
- Kareem.prototype.post = function(name, options, fn, unshift) {
- const hooks = get(this._posts, name, []);
- if (typeof options === 'function') {
- unshift = !!fn;
- fn = options;
- options = {};
- }
- if (unshift) {
- hooks.unshift(Object.assign({}, options, { fn: fn }));
- } else {
- hooks.push(Object.assign({}, options, { fn: fn }));
- }
- this._posts.set(name, hooks);
- return this;
- };
- Kareem.prototype.clone = function() {
- const n = new Kareem();
- for (let key of this._pres.keys()) {
- const clone = this._pres.get(key).slice();
- clone.numAsync = this._pres.get(key).numAsync;
- n._pres.set(key, clone);
- }
- for (let key of this._posts.keys()) {
- n._posts.set(key, this._posts.get(key).slice());
- }
- return n;
- };
- Kareem.prototype.merge = function(other, clone) {
- clone = arguments.length === 1 ? true : clone;
- var ret = clone ? this.clone() : this;
- for (let key of other._pres.keys()) {
- const sourcePres = get(ret._pres, key, []);
- const deduplicated = other._pres.get(key).
- // Deduplicate based on `fn`
- filter(p => sourcePres.map(_p => _p.fn).indexOf(p.fn) === -1);
- const combined = sourcePres.concat(deduplicated);
- combined.numAsync = sourcePres.numAsync || 0;
- combined.numAsync += deduplicated.filter(p => p.isAsync).length;
- ret._pres.set(key, combined);
- }
- for (let key of other._posts.keys()) {
- const sourcePosts = get(ret._posts, key, []);
- const deduplicated = other._posts.get(key).
- filter(p => sourcePosts.indexOf(p) === -1);
- ret._posts.set(key, sourcePosts.concat(deduplicated));
- }
- return ret;
- };
- function get(map, key, def) {
- if (map.has(key)) {
- return map.get(key);
- }
- return def;
- }
- function callMiddlewareFunction(fn, context, args, next) {
- let maybePromise;
- try {
- maybePromise = fn.apply(context, args);
- } catch (error) {
- return next(error);
- }
- if (isPromise(maybePromise)) {
- maybePromise.then(() => next(), err => next(err));
- }
- }
- function isPromise(v) {
- return v != null && typeof v.then === 'function';
- }
- function decorateNextFn(fn) {
- var called = false;
- var _this = this;
- return function() {
- // Ensure this function can only be called once
- if (called) {
- return;
- }
- called = true;
- // Make sure to clear the stack so try/catch doesn't catch errors
- // in subsequent middleware
- return process.nextTick(() => fn.apply(_this, arguments));
- };
- }
- module.exports = Kareem;
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