--- /dev/null
+/**
+ * @ngdoc object
+ * @name ui.router.util.$resolve
+ *
+ * @requires $q
+ * @requires $injector
+ *
+ * @description
+ * Manages resolution of (acyclic) graphs of promises.
+ */
+$Resolve.$inject = ['$q', '$injector'];
+function $Resolve( $q, $injector) {
+
+ var VISIT_IN_PROGRESS = 1,
+ VISIT_DONE = 2,
+ NOTHING = {},
+ NO_DEPENDENCIES = [],
+ NO_LOCALS = NOTHING,
+ NO_PARENT = extend($q.when(NOTHING), { $$promises: NOTHING, $$values: NOTHING });
+
+
+ /**
+ * @ngdoc function
+ * @name ui.router.util.$resolve#study
+ * @methodOf ui.router.util.$resolve
+ *
+ * @description
+ * Studies a set of invocables that are likely to be used multiple times.
+ * <pre>
+ * $resolve.study(invocables)(locals, parent, self)
+ * </pre>
+ * is equivalent to
+ * <pre>
+ * $resolve.resolve(invocables, locals, parent, self)
+ * </pre>
+ * but the former is more efficient (in fact `resolve` just calls `study`
+ * internally).
+ *
+ * @param {object} invocables Invocable objects
+ * @return {function} a function to pass in locals, parent and self
+ */
+ this.study = function (invocables) {
+ if (!isObject(invocables)) throw new Error("'invocables' must be an object");
+ var invocableKeys = objectKeys(invocables || {});
+
+ // Perform a topological sort of invocables to build an ordered plan
+ var plan = [], cycle = [], visited = {};
+ function visit(value, key) {
+ if (visited[key] === VISIT_DONE) return;
+
+ cycle.push(key);
+ if (visited[key] === VISIT_IN_PROGRESS) {
+ cycle.splice(0, indexOf(cycle, key));
+ throw new Error("Cyclic dependency: " + cycle.join(" -> "));
+ }
+ visited[key] = VISIT_IN_PROGRESS;
+
+ if (isString(value)) {
+ plan.push(key, [ function() { return $injector.get(value); }], NO_DEPENDENCIES);
+ } else {
+ var params = $injector.annotate(value);
+ forEach(params, function (param) {
+ if (param !== key && invocables.hasOwnProperty(param)) visit(invocables[param], param);
+ });
+ plan.push(key, value, params);
+ }
+
+ cycle.pop();
+ visited[key] = VISIT_DONE;
+ }
+ forEach(invocables, visit);
+ invocables = cycle = visited = null; // plan is all that's required
+
+ function isResolve(value) {
+ return isObject(value) && value.then && value.$$promises;
+ }
+
+ return function (locals, parent, self) {
+ if (isResolve(locals) && self === undefined) {
+ self = parent; parent = locals; locals = null;
+ }
+ if (!locals) locals = NO_LOCALS;
+ else if (!isObject(locals)) {
+ throw new Error("'locals' must be an object");
+ }
+ if (!parent) parent = NO_PARENT;
+ else if (!isResolve(parent)) {
+ throw new Error("'parent' must be a promise returned by $resolve.resolve()");
+ }
+
+ // To complete the overall resolution, we have to wait for the parent
+ // promise and for the promise for each invokable in our plan.
+ var resolution = $q.defer(),
+ result = resolution.promise,
+ promises = result.$$promises = {},
+ values = extend({}, locals),
+ wait = 1 + plan.length/3,
+ merged = false;
+
+ function done() {
+ // Merge parent values we haven't got yet and publish our own $$values
+ if (!--wait) {
+ if (!merged) merge(values, parent.$$values);
+ result.$$values = values;
+ result.$$promises = result.$$promises || true; // keep for isResolve()
+ delete result.$$inheritedValues;
+ resolution.resolve(values);
+ }
+ }
+
+ function fail(reason) {
+ result.$$failure = reason;
+ resolution.reject(reason);
+ }
+
+ // Short-circuit if parent has already failed
+ if (isDefined(parent.$$failure)) {
+ fail(parent.$$failure);
+ return result;
+ }
+
+ if (parent.$$inheritedValues) {
+ merge(values, omit(parent.$$inheritedValues, invocableKeys));
+ }
+
+ // Merge parent values if the parent has already resolved, or merge
+ // parent promises and wait if the parent resolve is still in progress.
+ extend(promises, parent.$$promises);
+ if (parent.$$values) {
+ merged = merge(values, omit(parent.$$values, invocableKeys));
+ result.$$inheritedValues = omit(parent.$$values, invocableKeys);
+ done();
+ } else {
+ if (parent.$$inheritedValues) {
+ result.$$inheritedValues = omit(parent.$$inheritedValues, invocableKeys);
+ }
+ parent.then(done, fail);
+ }
+
+ // Process each invocable in the plan, but ignore any where a local of the same name exists.
+ for (var i=0, ii=plan.length; i<ii; i+=3) {
+ if (locals.hasOwnProperty(plan[i])) done();
+ else invoke(plan[i], plan[i+1], plan[i+2]);
+ }
+
+ function invoke(key, invocable, params) {
+ // Create a deferred for this invocation. Failures will propagate to the resolution as well.
+ var invocation = $q.defer(), waitParams = 0;
+ function onfailure(reason) {
+ invocation.reject(reason);
+ fail(reason);
+ }
+ // Wait for any parameter that we have a promise for (either from parent or from this
+ // resolve; in that case study() will have made sure it's ordered before us in the plan).
+ forEach(params, function (dep) {
+ if (promises.hasOwnProperty(dep) && !locals.hasOwnProperty(dep)) {
+ waitParams++;
+ promises[dep].then(function (result) {
+ values[dep] = result;
+ if (!(--waitParams)) proceed();
+ }, onfailure);
+ }
+ });
+ if (!waitParams) proceed();
+ function proceed() {
+ if (isDefined(result.$$failure)) return;
+ try {
+ invocation.resolve($injector.invoke(invocable, self, values));
+ invocation.promise.then(function (result) {
+ values[key] = result;
+ done();
+ }, onfailure);
+ } catch (e) {
+ onfailure(e);
+ }
+ }
+ // Publish promise synchronously; invocations further down in the plan may depend on it.
+ promises[key] = invocation.promise;
+ }
+
+ return result;
+ };
+ };
+
+ /**
+ * @ngdoc function
+ * @name ui.router.util.$resolve#resolve
+ * @methodOf ui.router.util.$resolve
+ *
+ * @description
+ * Resolves a set of invocables. An invocable is a function to be invoked via
+ * `$injector.invoke()`, and can have an arbitrary number of dependencies.
+ * An invocable can either return a value directly,
+ * or a `$q` promise. If a promise is returned it will be resolved and the
+ * resulting value will be used instead. Dependencies of invocables are resolved
+ * (in this order of precedence)
+ *
+ * - from the specified `locals`
+ * - from another invocable that is part of this `$resolve` call
+ * - from an invocable that is inherited from a `parent` call to `$resolve`
+ * (or recursively
+ * - from any ancestor `$resolve` of that parent).
+ *
+ * The return value of `$resolve` is a promise for an object that contains
+ * (in this order of precedence)
+ *
+ * - any `locals` (if specified)
+ * - the resolved return values of all injectables
+ * - any values inherited from a `parent` call to `$resolve` (if specified)
+ *
+ * The promise will resolve after the `parent` promise (if any) and all promises
+ * returned by injectables have been resolved. If any invocable
+ * (or `$injector.invoke`) throws an exception, or if a promise returned by an
+ * invocable is rejected, the `$resolve` promise is immediately rejected with the
+ * same error. A rejection of a `parent` promise (if specified) will likewise be
+ * propagated immediately. Once the `$resolve` promise has been rejected, no
+ * further invocables will be called.
+ *
+ * Cyclic dependencies between invocables are not permitted and will cause `$resolve`
+ * to throw an error. As a special case, an injectable can depend on a parameter
+ * with the same name as the injectable, which will be fulfilled from the `parent`
+ * injectable of the same name. This allows inherited values to be decorated.
+ * Note that in this case any other injectable in the same `$resolve` with the same
+ * dependency would see the decorated value, not the inherited value.
+ *
+ * Note that missing dependencies -- unlike cyclic dependencies -- will cause an
+ * (asynchronous) rejection of the `$resolve` promise rather than a (synchronous)
+ * exception.
+ *
+ * Invocables are invoked eagerly as soon as all dependencies are available.
+ * This is true even for dependencies inherited from a `parent` call to `$resolve`.
+ *
+ * As a special case, an invocable can be a string, in which case it is taken to
+ * be a service name to be passed to `$injector.get()`. This is supported primarily
+ * for backwards-compatibility with the `resolve` property of `$routeProvider`
+ * routes.
+ *
+ * @param {object} invocables functions to invoke or
+ * `$injector` services to fetch.
+ * @param {object} locals values to make available to the injectables
+ * @param {object} parent a promise returned by another call to `$resolve`.
+ * @param {object} self the `this` for the invoked methods
+ * @return {object} Promise for an object that contains the resolved return value
+ * of all invocables, as well as any inherited and local values.
+ */
+ this.resolve = function (invocables, locals, parent, self) {
+ return this.study(invocables)(locals, parent, self);
+ };
+}
+
+angular.module('ui.router.util').service('$resolve', $Resolve);
+
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