architect.js

( // Module boilerplate to support node.js and AMD.
  (typeof module !== "undefined" && function (m) { module.exports = m(require('events')); }) ||
  (typeof define === "function" && function (m) { define(["events"], m); })
)(function (events) {
"use strict";
var EventEmitter = events.EventEmitter;

var exports = {};

var DEBUG = typeof location != "undefined" && location.href.match(/debug=[123]/) ? true : false;

// Only define Node-style usage using sync I/O if in node.
if (typeof module === "object") (function () {
    var dirname = require('path').dirname;
    var resolve = require('path').resolve;
    var existsSync = require('fs').existsSync || require('path').existsSync;
    var realpathSync = require('fs').realpathSync;
    var exists = require('fs').exists || require('path').exists;
    var realpath = require('fs').realpath;
    var packagePathCache = {};
    var basePath;

    exports.loadConfig = loadConfig;
    exports.resolveConfig = resolveConfig;

    // This is assumed to be used at startup and uses sync I/O as well as can
    // throw exceptions.  It loads and parses a config file.
    function loadConfig(configPath, callback) {
      var config = require(configPath);
      var base = dirname(configPath);

      return resolveConfig(config, base, callback);
    }

    function resolveConfig(config, base, callback) {
        if(typeof base === 'function') {
          // probably being called from loadAdditionalConfig, use saved base
          callback = base;
          base = basePath;
        } else {
          basePath = base;
        }

        if (!callback)
            return resolveConfigSync(config, base);
        else
            resolveConfigAsync(config, base, callback);
    }

    function resolveConfigSync(config, base) {
        config.forEach(function (plugin, index) {
            // Shortcut where string is used for plugin without any options.
            if (typeof plugin === "string") {
                plugin = config[index] = { packagePath: plugin };
            }
            // The plugin is a package on the disk.  We need to load it.
            if (plugin.hasOwnProperty("packagePath") && !plugin.hasOwnProperty("setup")) {
                var defaults = resolveModuleSync(base, plugin.packagePath);
                Object.keys(defaults).forEach(function (key) {
                    if (!plugin.hasOwnProperty(key)) {
                        plugin[key] = defaults[key];
                    }
                });
                plugin.packagePath = defaults.packagePath;
                plugin.setup = require(plugin.packagePath);
            }
        });
        return config;
    }

    function resolveConfigAsync(config, base, callback) {
        function resolveNext(i) {
            if (i >= config.length) {
                return callback(null, config);
            }

            var plugin = config[i];

            // Shortcut where string is used for plugin without any options.
            if (typeof plugin === "string") {
                plugin = config[i] = { packagePath: plugin };
            }
            // The plugin is a package on the disk.  We need to load it.
            if (plugin.hasOwnProperty("packagePath") && !plugin.hasOwnProperty("setup")) {
                resolveModule(base, plugin.packagePath, function(err, defaults) {
                    if (err) return callback(err);

                    Object.keys(defaults).forEach(function (key) {
                        if (!plugin.hasOwnProperty(key)) {
                            plugin[key] = defaults[key];
                        }
                    });
                    plugin.packagePath = defaults.packagePath;
                    try {
                        plugin.setup = require(plugin.packagePath);
                    } catch(e) {
                        return callback(e);
                    }

                    return resolveNext(++i);
                });
                return;
            }

            return resolveNext(++i);
        }

        resolveNext(0);
    }

    // Loads a module, getting metadata from either it's package.json or export
    // object.
    function resolveModuleSync(base, modulePath) {
        var packagePath;
        try {
            packagePath = resolvePackageSync(base, modulePath + "/package.json");
        }
        catch (err) {
            if (err.code !== "ENOENT") throw err;
        }
        var metadata = packagePath && require(packagePath).plugin || {};
        if (packagePath) {
            modulePath = dirname(packagePath);
        } else {
            modulePath = resolvePackageSync(base, modulePath);
        }
        var module = require(modulePath);
        metadata.provides = metadata.provides || module.provides || [];
        metadata.consumes = metadata.consumes || module.consumes || [];
        metadata.packagePath = modulePath;
        return metadata;
    }

    // Loads a module, getting metadata from either it's package.json or export
    // object.
    function resolveModule(base, modulePath, callback) {
        resolvePackage(base, modulePath + "/package.json", function(err, packagePath) {
            //if (err && err.code !== "ENOENT") return callback(err);

            var metadata = {};
            if (!err) {
                try {
                    metadata = packagePath && require(packagePath).plugin || {};
                } catch(e) {
                    return callback(e);
                }
            }

            (function(next) {
                if (err) {
                    //@todo Fabian what is a better way?
                    resolvePackage(base, modulePath + ".js", next);
                }
                else if (packagePath) {
                    next(null, dirname(packagePath));
                } 
                else {
                    resolvePackage(base, modulePath, next);
                }
            })(function(err, modulePath) {
                if (err) return callback(err);

                var module;
                try {
                    module = require(modulePath);
                } catch(e) {
                    return callback(e);
                }

                metadata.provides = metadata.provides || module.provides || [];
                metadata.consumes = metadata.consumes || module.consumes || [];
                metadata.packagePath = modulePath;
                callback(null, metadata);
            });
        });
    }

    // Node style package resolving so that plugins' package.json can be found relative to the config file
    // It's not the full node require system algorithm, but it's the 99% case
    // This throws, make sure to wrap in try..catch
    function resolvePackageSync(base, packagePath) {
        var originalBase = base;
        if (!(base in packagePathCache)) {
            packagePathCache[base] = {};
        }
        var cache = packagePathCache[base];
        if (packagePath in cache) {
            return cache[packagePath];
        }
        var newPath;
        if (packagePath[0] === "." || packagePath[0] === "/") {
            newPath = resolve(base, packagePath);
            if (!existsSync(newPath)) {
                newPath = newPath + ".js";
            }
            if (existsSync(newPath)) {
                newPath = realpathSync(newPath);
                cache[packagePath] = newPath;
                return newPath;
            }
        }
        else {
            while (base) {
                newPath = resolve(base, "node_modules", packagePath);
                if (existsSync(newPath)) {
                    newPath = realpathSync(newPath);
                    cache[packagePath] = newPath;
                    return newPath;
                }
                base = resolve(base, '..');
            }
        }
        var err = new Error("Can't find '" + packagePath + "' relative to '" + originalBase + "'");
        err.code = "ENOENT";
        throw err;
    }

    function resolvePackage(base, packagePath, callback) {
        var originalBase = base;
        if (!packagePathCache.hasOwnProperty(base)) {
            packagePathCache[base] = {};
        }
        var cache = packagePathCache[base];
        if (cache.hasOwnProperty(packagePath)) {
            return callback(null, cache[packagePath]);
        }
        if (packagePath[0] === "." || packagePath[0] === "/") {
            var newPath = resolve(base, packagePath);
            exists(newPath, function(exists) {
                if (exists) {
                    realpath(newPath, function(err, newPath) {
                        if (err) return callback(err);

                        cache[packagePath] = newPath;
                        return callback(null, newPath);
                    });
                } else {
                    var err = new Error("Can't find '" + packagePath + "' relative to '" + originalBase + "'");
                    err.code = "ENOENT";
                    return callback(err);
                }
            });
        }
        else {
            tryNext(base);
        }

        function tryNext(base) {
            if (base == "/") {
                var err = new Error("Can't find '" + packagePath + "' relative to '" + originalBase + "'");
                err.code = "ENOENT";
                return callback(err);
            }

            var newPath = resolve(base, "node_modules", packagePath);
            exists(newPath, function(exists) {
                if (exists) {
                    realpath(newPath, function(err, newPath) {
                        if (err) return callback(err);

                        cache[packagePath] = newPath;
                        return callback(null, newPath);
                    });
                } else {
                    var nextBase = resolve(base, '..');
                    if (nextBase === base)
                        tryNext("/"); // for windows
                    else
                        tryNext(nextBase);
                }
            });
        }
    }


}());

// Otherwise use amd to load modules.
else (function () {
    exports.loadConfig = loadConfig;
    exports.resolveConfig = resolveConfig;

    function loadConfig(path, callback) {
        require([path], function (config) {
            resolveConfig(config, callback);
        });
    }

    function resolveConfig(config, base, callback, errback) {
        if (typeof base == "function")
            return resolveConfig(config, "", arguments[1], arguments[2]);
        
        var paths = [], pluginIndexes = {};
        config.forEach(function (plugin, index) {
            // Shortcut where string is used for plugin without any options.
            if (typeof plugin === "string") {
                plugin = config[index] = { packagePath: plugin };
            }
            // The plugin is a package over the network.  We need to load it.
            if (plugin.hasOwnProperty("packagePath") && !plugin.hasOwnProperty("setup")) {
                paths.push((base || "") + plugin.packagePath);
                pluginIndexes[plugin.packagePath] = index;
            }
        });
        // Mass-Load path-based plugins using amd's require
        require(paths, function () {
            var args = arguments;
            paths.forEach(function (name, i) {
                var module = args[i];
                var plugin = config[pluginIndexes[name]];
                plugin.setup = module;
                plugin.provides = module.provides || plugin.provides || [];
                plugin.consumes = module.consumes || plugin.consumes || [];
            });
            callback(null, config);
        }, errback);
    }
}());

exports.createApp = createApp;
exports.Architect = Architect;

// Check a plugin config list for bad dependencies and throw on error
function checkConfig(config, lookup) {

    // Check for the required fields in each plugin.
    config.forEach(function (plugin) {
        if (plugin.checked) { return; }
        if (!plugin.hasOwnProperty("setup")) {
            throw new Error("Plugin is missing the setup function " + JSON.stringify(plugin));
        }
        if (!plugin.hasOwnProperty("provides")) {
            throw new Error("Plugin is missing the provides array " + JSON.stringify(plugin));
        }
        if (!plugin.hasOwnProperty("consumes")) {
            throw new Error("Plugin is missing the consumes array " + JSON.stringify(plugin));
        }
    });

    return checkCycles(config, lookup);
}

function checkCycles(config, lookup) {
    var plugins = [];
    config.forEach(function(pluginConfig, index) {
        plugins.push({
            packagePath: pluginConfig.packagePath,
            provides: pluginConfig.provides.concat(),
            consumes: pluginConfig.consumes.concat(),
            i: index
        });
    });

    var resolved = {
        hub: true
    };
    var changed = true;
    var sorted = [];

    while(plugins.length && changed) {
        changed = false;

        plugins.concat().forEach(function(plugin) {
            var consumes = plugin.consumes.concat();

            var resolvedAll = true;
            for (var i=0; i<consumes.length; i++) {
                var service = consumes[i];
                if (!resolved[service] && (!lookup || !lookup(service))) {
                    resolvedAll = false;
                } else {
                    plugin.consumes.splice(plugin.consumes.indexOf(service), 1);
                }
            }

            if (!resolvedAll)
                return;

            plugins.splice(plugins.indexOf(plugin), 1);
            plugin.provides.forEach(function(service) {
                resolved[service] = true;
            });
            sorted.push(config[plugin.i]);
            changed = true;
        });
    }

    if (plugins.length) {
        var unresolved = {};
        plugins.forEach(function(plugin) {
            delete plugin.config;
            plugin.consumes.forEach(function(name) {
                if (unresolved[name] === false)
                    return;
                if (!unresolved[name])
                    unresolved[name] = [];
                unresolved[name].push(plugin.packagePath);
            });
            plugin.provides.forEach(function(name) {
                unresolved[name] = false;
            });
        });
        
        Object.keys(unresolved).forEach(function(name) {
            if (unresolved[name] === false)
                delete unresolved[name];
        });

        var unresolvedList = Object.keys(unresolved);
        var resolvedList = Object.keys(resolved);
        var err  = new Error("Could not resolve dependencies\n"
            + (unresolvedList.length ? "Missing services: " + unresolvedList
            : "Config contains cyclic dependencies" // TODO print cycles
            ));
        err.unresolved = unresolvedList;
        err.resolved = resolvedList;
        throw err;
    }

    return sorted;
}

function Architect(config) {
    var app = this;
    app.config = config;
    app.packages = {};
    app.pluginToPackage = {};
    
    var isAdditionalMode;
    var services = app.services = {
        hub: {
            on: function (name, callback) {
                app.on(name, callback);
            }
        }
    };

    // Check the config
    var sortedPlugins = checkConfig(config);

    var destructors = [];
    var recur = 0, callnext, ready;
    function startPlugins(additional) {
        var plugin = sortedPlugins.shift();
        if (!plugin) {
            ready = true;
            return app.emit(additional ? "ready-additional" : "ready", app);
        }

        var imports = {};
        if (plugin.consumes) {
            plugin.consumes.forEach(function (name) {
                imports[name] = services[name];
            });
        }
        
        var m = /^plugins\/([^\/]+)|\/plugins\/[^\/]+\/([^\/]+)/.exec(plugin.packagePath);
        var packageName = m && (m[1] || m[2]);
        if (!app.packages[packageName]) app.packages[packageName] = [];
        
        if (DEBUG) {
            recur++;
            plugin.setup(plugin, imports, register);
            
            while (callnext && recur <= 1) {
                callnext = false;
                startPlugins(additional);
            }
            recur--;
        }
        else {
            try {
                recur++;
                plugin.setup(plugin, imports, register);
            } catch (e) {
                e.plugin = plugin;
                app.emit("error", e);
                throw e;
            } finally {
                while (callnext && recur <= 1) {
                    callnext = false;
                    startPlugins(additional);
                }
                recur--;
            }
        }
        
        function register(err, provided) {
            if (err) { return app.emit("error", err); }
            plugin.provides.forEach(function (name) {
                if (!provided.hasOwnProperty(name)) {
                    var err = new Error("Plugin failed to provide " + name + " service. " + JSON.stringify(plugin));
                    err.plugin = plugin;
                    return app.emit("error", err);
                }
                services[name] = provided[name];
                app.pluginToPackage[name] = {
                    path: plugin.packagePath,
                    package: packageName,
                    version: plugin.version,
                    isAdditionalMode: isAdditionalMode
                };
                app.packages[packageName].push(name);
                
                app.emit("service", name, services[name], plugin);
            });
            if (provided && provided.hasOwnProperty("onDestroy"))
                destructors.push(provided.onDestroy);

            app.emit("plugin", plugin);
            
            if (recur) return (callnext = true);
            startPlugins(additional);
        }
    }

    // Give createApp some time to subscribe to our "ready" event
    (typeof process === "object" ? process.nextTick : setTimeout)(startPlugins);

    this.loadAdditionalPlugins = function(additionalConfig, callback){
        isAdditionalMode = true;
        
        exports.resolveConfig(additionalConfig, function (err, additionalConfig) {
            if (err) return callback(err);
            
            app.once(ready ? "ready-additional" : "ready", function(app){
                callback(null, app);
            }); // What about error state?
            
            // Check the config - hopefully this works
            var _sortedPlugins = checkConfig(additionalConfig, function(name){
                return services[name];
            });
            
            if (ready) {
                sortedPlugins = _sortedPlugins;
                // Start Loading additional plugins
                startPlugins(true);
            }
            else {
                _sortedPlugins.forEach(function(item){
                    sortedPlugins.push(item);
                });
            }
        });
    }

    this.destroy = function() {
        destructors.forEach(function(destroy) {
            destroy();
        });

        destructors = [];
    };
}
Architect.prototype = Object.create(EventEmitter.prototype, {constructor:{value:Architect}});

Architect.prototype.getService = function(name) {
    if (!this.services[name]) {
        throw new Error("Service '" + name + "' not found in architect app!");
    }
    return this.services[name];
};

// Returns an event emitter that represents the app.  It can emit events.
// event: ("service" name, service) emitted when a service is ready to be consumed.
// event: ("plugin", plugin) emitted when a plugin registers.
// event: ("ready", app) emitted when all plugins are ready.
// event: ("error", err) emitted when something goes wrong.
// app.services - a hash of all the services in this app
// app.config - the plugin config that was passed in.
function createApp(config, callback) {
    var app;
    try {
        app = new Architect(config);
    } catch(err) {
        if (!callback) throw err;
        return callback(err, app);
    }
    if (callback) {
        app.on("error", done);
        app.on("ready", onReady);
    }
    return app;

    function onReady(app) {
        done();
    }

    function done(err) {
        if (err) {
            app.destroy();
        }
        app.removeListener("error", done);
        app.removeListener("ready", onReady);
        callback(err, app);
    }

    return app;
}

return exports;

});