Added optimized algorithm for batch addition of new aliases via

configure(). The algorithm suitable for single alias addition showed up
to be utterly slow (because of the immense cost of array_intersect).

Removed double parethesis.

Author: fhein

src/ServiceManager.php

@@ -21,7 +21,6 @@
 use Zend\ServiceManager\Exception\ServiceNotCreatedException;
 use Zend\ServiceManager\Exception\ServiceNotFoundException;
 
-use function \array_keys;
 use function \array_merge;
 use function \array_merge_recursive;
 use function \class_exists;
@@ -222,7 +221,7 @@ public function get($name)
         $object = $this->doCreate($resolvedName);
 
         // Cache the object for later, if it is supposed to be shared.
-        if (($sharedService)) {
+        if ($sharedService) {
             $this->services[$resolvedName] = $object;
         }
 
@@ -334,8 +333,8 @@ public function getAllowOverride()
     public function configure(array $config)
     {
         // This is a bulk update/initial configuration
-        // So we check all definitions
-        $this->validateServiceNameConfig($config);
+        // So we check all definitions upfront
+        $this->validateServiceNames($config);
 
         if (isset($config['services'])) {
             $this->services = $config['services'] + $this->services;
@@ -368,16 +367,15 @@ public function configure(array $config)
             $this->shared = $config['shared'] + $this->shared;
         }
 
-        $aliases = [];
         if (isset($config['aliases'])) {
+            // @todo: Shouldn't that be $config['aliases'] + $this->aliases (or array_merge?)
+            // Will have to examine.
             $aliases = $config['aliases'];
         } elseif (! $this->configured && ! empty($this->aliases)) {
             $aliases = $this->aliases;
         }
         if (! empty($aliases)) {
-            foreach ($aliases as $alias => $target) {
-                $this->mapAliasToTarget($alias, $target);
-            }
+            $this->mapAliasesToTargets($aliases);
         }
 
         if (isset($config['shared_by_default'])) {
@@ -418,8 +416,11 @@ public function configure(array $config)
      */
     public function setAlias($alias, $target)
     {
-        $this->validateServiceName($alias);
-        $this->mapAliasToTarget($alias, $target);
+        if (! isset($this->services[$alias]) || $this->allowOverride) {
+            $this->mapAliasToTarget($alias, $target);
+            return;
+        }
+        throw new ContainerModificationsNotAllowedException($alias);
     }
 
     /**
@@ -443,8 +444,11 @@ public function setInvokableClass($name, $class = null)
      */
     public function setFactory($name, $factory)
     {
-        $this->validateServiceName($name);
-        $this->factories[$name] = $factory;
+        if (! isset($this->services[$name]) || $this->allowOverride) {
+            $this->factories[$name] = $factory;
+            return;
+        }
+        throw new ContainerModificationsNotAllowedException($name);
     }
 
     /**
@@ -499,8 +503,11 @@ public function addInitializer($initializer)
      */
     public function setService($name, $service)
     {
-        $this->validateServiceName($name);
-        $this->services[$name] = $service;
+        if (! isset($this->services[$name]) || $this->allowOverride) {
+            $this->services[$name] = $service;
+            return;
+        }
+        throw new ContainerModificationsNotAllowedException($name);
     }
 
     /**
@@ -511,8 +518,11 @@ public function setService($name, $service)
      */
     public function setShared($name, $flag)
     {
-        $this->validateServiceName($name);
-        $this->shared[$name] = (bool) $flag;
+        if (! isset($this->services[$name]) || $this->allowOverride) {
+            $this->shared[$name] = (bool) $flag;
+            return;
+        }
+        throw new ContainerModificationsNotAllowedException($name);
     }
 
     /**
@@ -537,8 +547,8 @@ private function resolveInitializer($initializer)
 
         if (is_string($initializer)) {
             throw new InvalidArgumentException(sprintf(
-                'An invalid initializer was registered; resolved to class or function "%s" ' 
-                . 'which does not exist; please provide a valid function name or class ' 
+                'An invalid initializer was registered; resolved to class or function "%s" '
+                . 'which does not exist; please provide a valid function name or class '
                 . 'name resolving to an implementation of %s',
                 $initializer,
                 Initializer\InitializerInterface::class
@@ -547,8 +557,8 @@ private function resolveInitializer($initializer)
 
         // Otherwise, we have an invalid type.
         throw new InvalidArgumentException(sprintf(
-            'An invalid initializer was registered. Expected a callable, or an instance of ' 
-            . '(or string class name resolving to) "%s", ' 
+            'An invalid initializer was registered. Expected a callable, or an instance of '
+            . '(or string class name resolving to) "%s", '
             . 'but "%s" was received',
             Initializer\InitializerInterface::class,
             (is_object($initializer) ? get_class($initializer) : gettype($initializer))
@@ -793,61 +803,6 @@ private function createFactoriesForInvokables(array $invokables)
         return $factories;
     }
 
-    /**
-     * Determine if a service instance for a given name already exists,
-     * and if it exists, determine if is it allowed to get overriden.
-     *
-     * Validation in the context of this class means, that for
-     * a given service name we do not have a service instance
-     * in the cache OR override is explicitly allowed.
-     *
-     * @param string $service
-     * @throws ContainerModificationsNotAllowedException if the
-     *     provided service name is invalid.
-     */
-    private function validateServiceName($service)
-    {
-        // Important: Next three lines must kept equal to the three
-        // lines of validateServiceNameArray (see below) which are marked as code
-        // duplicate!
-        if (! isset($this->services[$service]) || $this->allowOverride) {
-            return;
-        }
-        throw new ContainerModificationsNotAllowedException($service);
-    }
-
-    /**
-     * Determine if a service instance for any of the provided array's
-     * keys already exists, and if it exists, determine if is it allowed
-     * to get overriden.
-     *
-     * Validation in the context of this class means, that for
-     * a given service name we do not have a service instance
-     * in the cache OR override is explicitly allowed.
-     *
-     * @param string[] $services
-     * @param string $type Type of service being checked.
-     * @throws ContainerModificationsNotAllowedException if any
-     *     array keys is invalid.
-     */
-    private function validateServiceNameArray(array $services)
-    {
-        foreach (array_keys($services) as $service) {
-            // This is a code duplication from validateServiceName (see above).
-            // validateServiceName is almost a one liner, so we reproduce it
-            // here for the sake of performance of aggregated service
-            // manager configurations (we save the overhead the function
-            // call would produce)
-            //
-            // Important: Next three lines MUST kept equal to the first
-            // three lines of validateServiceName!
-            if (! isset($this->services[$service]) ?: $this->allowOverride) {
-                return;
-            }
-            throw new ContainerModificationsNotAllowedException($service);
-        }
-    }
-
     /**
      * Determine if a service for any name provided by a service
      * manager configuration(services, aliases, factories, ...)
@@ -862,22 +817,73 @@ private function validateServiceNameArray(array $services)
      * @throws ContainerModificationsNotAllowedException if any
      *     service key is invalid.
      */
-    private function validateServiceNameConfig(array $config)
+    private function validateServiceNames(array $config)
     {
         if ($this->allowOverride || ! $this->configured) {
             return;
         }
 
-        $sections = ['services', 'aliases', 'invokables', 'factories', 'delegators', 'shared'];
+        if (isset($config['services'])) {
+            foreach ($config['services'] as $service => $_) {
+                if (! isset($this->services[$service]) || $this->allowOverride) {
+                    continue;
+                }
+                throw new ContainerModificationsNotAllowedException($service);
+            }
+        }
+
+        if (isset($config['aliases'])) {
+            foreach ($config['aliases'] as $service => $_) {
+                if (! isset($this->services[$service]) || $this->allowOverride) {
+                    continue;
+                }
+                throw new ContainerModificationsNotAllowedException($service);
+            }
+        }
 
-        foreach ($sections as $section) {
-            if (isset($config[$section])) {
-                $this->validateServiceNameArray($config[$section]);
+        if (isset($config['invokables'])) {
+            foreach ($config['invokables'] as $service => $_) {
+                if (! isset($this->services[$service]) || $this->allowOverride) {
+                    continue;
+                }
+                throw new ContainerModificationsNotAllowedException($service);
+            }
+        }
+
+        if (isset($config['factories'])) {
+            foreach ($config['factories'] as $service => $_) {
+                if (! isset($this->services[$service]) || $this->allowOverride) {
+                    continue;
+                }
+                throw new ContainerModificationsNotAllowedException($service);
+            }
+        }
+
+        if (isset($config['delegators'])) {
+            foreach ($config['delegators'] as $service => $_) {
+                if (! isset($this->services[$service]) || $this->allowOverride) {
+                    continue;
+                }
+                throw new ContainerModificationsNotAllowedException($service);
+            }
+        }
+
+        if (isset($config['shared'])) {
+            foreach ($config['shared'] as $service => $_) {
+                if (! isset($this->services[$service]) || $this->allowOverride) {
+                    continue;
+                }
+                throw new ContainerModificationsNotAllowedException($service);
             }
         }
 
         if (isset($config['lazy_services']['class_map'])) {
-            $this->validateServiceNameArray($config['lazy_services']['class_map']);
+            foreach ($config['lazy_services']['class_map'] as $service => $_) {
+                if (! isset($this->services[$service]) || $this->allowOverride) {
+                    continue;
+                }
+                throw new ContainerModificationsNotAllowedException($service);
+            }
         }
     }
 
@@ -909,6 +915,40 @@ private function mapAliasToTarget($alias, $target)
         }
     }
 
+    /**
+     * Assuming that all provided alias keys are valid resolve them.
+     *
+     * This as an adaptation of Tarjan's strongly connected components
+     * algorithm. We detect cycles as well reduce the graph so that
+     * each alias key gets associated with the resolved service.
+     *
+     * @param string[][] array of alias definitions
+     */
+    private function mapAliasesToTargets($aliases)
+    {
+        $tagged = [];
+        foreach ($aliases as $alias => $target) {
+            if (! isset($tagged[$alias])) {
+                $tCursor = $aliases[$alias];
+                $aCursor = $alias;
+                $stack = [];
+                while (isset($aliases[$tCursor])) {
+                    $stack[] = $aCursor;
+                    $aCursor = $tCursor;
+                    if (isset($tagged[$aCursor])) {
+                        throw CyclicAliasException::fromCyclicAlias($alias, $aliases);
+                    }
+                    $tagged[$aCursor] = true;
+                    $tCursor = $aliases[$tCursor];
+                }
+                foreach ($stack as $alias) {
+                    $aliases[$alias] = $tCursor;
+                }
+            }
+        }
+        $this->aliases = $aliases;
+    }
+
     /**
      * Instantiate abstract factories in order to avoid checks during service construction.
      *
@@ -938,8 +978,8 @@ private function resolveAbstractFactoryInstance($abstractFactory)
         // If we still have a string, we have a class name that does not resolve
         if (is_string($abstractFactory)) {
             throw new InvalidArgumentException(sprintf(
-                'An invalid abstract factory was registered; resolved to class "%s" ' 
-                . 'which does not exist; please provide a valid class name resolving ' 
+                'An invalid abstract factory was registered; resolved to class "%s" '
+                . 'which does not exist; please provide a valid class name resolving '
                 . 'to an implementation of %s',
                 $abstractFactory,
                 AbstractFactoryInterface::class
@@ -948,7 +988,7 @@ private function resolveAbstractFactoryInstance($abstractFactory)
 
         // Otherwise, we have an invalid type.
         throw new InvalidArgumentException(sprintf(
-            'An invalid abstract factory was registered. Expected an instance of "%s", ' 
+            'An invalid abstract factory was registered. Expected an instance of "%s", '
             . 'but "%s" was received',
             AbstractFactoryInterface::class,
             (is_object($abstractFactory) ? get_class($abstractFactory) : gettype($abstractFactory))