1 files changed, 118 insertions, 0 deletions
diff --git a/public/js/define.js b/public/js/define.js
new file mode 100644
index 0000000..a3ce8c6
--- /dev/null
+++ b/public/js/define.js
@@ -0,0 +1,118 @@
+/*! Icinga Web 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+(function(window) {
+
+    'use strict';
+
+    /**
+     * Provide a reference to be later required by foreign code
+     *
+     * @param {string} name Optional, defaults to the name (and path) of the file
+     * @param {string[]} requirements Optional, list of required references, may be relative if from the same package
+     * @param {function} factory Required, function that accepts as many params as there are requirements and that
+     *                           produces a value to be referenced
+     */
+    var define = function (name, requirements, factory) {
+        define.defines[name] = {
+            requirements: requirements,
+            factory: factory,
+            ref: null
+        }
+
+        define.resolve(name);
+    }
+
+    /**
+     * Return whether the given name references a value
+     *
+     * @param {string} name The absolute name of the reference
+     * @return {boolean}
+     */
+    define.has = function (name) {
+        return name in define.defines && define.defines[name]['ref'] !== null;
+    }
+
+    /**
+     * Get the value of a reference
+     *
+     * @param {string} name The absolute name of the reference
+     * @return {*}
+     */
+    define.get = function (name) {
+        return define.defines[name]['ref'];
+    }
+
+    /**
+     * Set the value of a reference
+     *
+     * @param {string} name The absolute name of the reference
+     * @param {*} ref The value to reference
+     */
+    define.set = function (name, ref) {
+        define.defines[name]['ref'] = ref;
+    }
+
+    /**
+     * Resolve a reference and, if successful, dependent references
+     *
+     * @param {string} name The absolute name of the reference
+     * @return {boolean}
+     */
+    define.resolve = function (name) {
+        var requirements = define.defines[name]['requirements'];
+
+        var exports, ref;
+        var requiredRefs = [];
+        for (var i = 0; i < requirements.length; i++) {
+            if (define.has(requirements[i])) {
+                ref = define.get(requirements[i]);
+            } else if (requirements[i] === 'exports') {
+                exports = ref = {};
+            } else {
+                return false;
+            }
+
+            requiredRefs.push(ref);
+        }
+
+        var factory = define.defines[name]['factory'];
+        var resolved = factory.apply(null, requiredRefs);
+
+        if (typeof exports === 'object') {
+            if (typeof resolved !== 'undefined') {
+                throw new Error('Factory for ' + name + ' returned, although exports were populated');
+            }
+
+            resolved = exports;
+        }
+
+        define.set(name, resolved);
+
+        for (var definedName in define.defines) {
+            if (define.defines[definedName]['requirements'].indexOf(name) >= 0) {
+                define.resolve(definedName);
+            }
+        }
+    }
+
+    /**
+     * Require a reference
+     *
+     * @param {string} name The absolute name of the reference
+     * @return {*}
+     */
+    var require = function(name) {
+        if (define.has(name)) {
+            return define.get(name);
+        }
+
+        throw new ReferenceError(name + ' is not defined');
+    }
+
+    define.icinga = true;
+    define.defines = {};
+
+    window.define = define;
+    window.require = require;
+
+})(window);