Core/Dependencies: start working on resolver

components/ILIAS/Core/src/Dependencies/In.php

@@ -43,8 +43,19 @@ public function __toString(): string
         return $this->type->value . ": " . $this->name;
     }
 
+    public function getName(): Name
+    {
+        return $this->name;
+    }
+
+    public function getType(): InType
+    {
+        return $this->type;
+    }
+
     public function addDependant(Out $out)
     {
         $this->dependant[(string) $out] = $out;
+        $out->addDependency($this);
     }
 }

components/ILIAS/Core/src/Dependencies/OfComponent.php

@@ -41,6 +41,20 @@ public function getComponent(): Component
         return $this->component;
     }
 
+    public function getComponentName(): string
+    {
+        return get_class($this->getComponent());
+    }
+
+    public function getInDependencies(): \Iterator
+    {
+        foreach ($this->dependencies as $d) {
+            if ($d instanceof In) {
+                yield $d;
+            }
+        }
+    }
+
     // ArrayAccess
 
     public function offsetExists($dependency_description): bool

components/ILIAS/Core/src/Dependencies/Out.php

@@ -46,4 +46,9 @@ public function __toString(): string
     {
         return $this->type->value . ": " . $this->name;
     }
+
+    public function addDependency(In $in)
+    {
+        $this->dependencies[(string) $in] = $in;
+    }
 }

components/ILIAS/Core/src/Dependencies/Resolver.php

@@ -0,0 +1,79 @@
+<?php
+
+/**
+ * This file is part of ILIAS, a powerful learning management system
+ * published by ILIAS open source e-Learning e.V.
+ *
+ * ILIAS is licensed with the GPL-3.0,
+ * see https://www.gnu.org/licenses/gpl-3.0.en.html
+ * You should have received a copy of said license along with the
+ * source code, too.
+ *
+ * If this is not the case or you just want to try ILIAS, you'll find
+ * us at:
+ * https://www.ilias.de
+ * https://github.com/ILIAS-eLearning
+ *
+ *********************************************************************/
+
+declare(strict_types=1);
+
+namespace ILIAS\Core\Dependencies;
+
+class Resolver
+{
+    /**
+     * @param OfComponent[]
+     * @return OfComponent[]
+     */
+    public function resolveDependencies(OfComponent ...$components): array
+    {
+        foreach ($components as $component) {
+            foreach ($component->getInDependencies() as $d) {
+                switch ($d->getType()) {
+                    case InType::PULL:
+                        $this->resolvePull($d, $components);
+                        break;
+                    case InType::SEEK:
+                        $this->resolveSeek($d, $components);
+                        break;
+                }
+            }
+        }
+
+        return $components;
+    }
+
+    protected function resolvePull(In $in, array &$others): void
+    {
+        $candidate = null;
+
+        foreach ($others as $other) {
+            if ($other->offsetExists("PROVIDE: " . $in->getName())) {
+                if (!is_null($candidate)) {
+                    throw new \LogicException(
+                        "Dependency {$in->getName()} is provided (at least) twice. " .
+                        "Once by {$candidate->getComponentName()} " .
+                        "and by {$other->getComponentName()} "
+                    );
+                }
+                $candidate = $other;
+            }
+        }
+
+        if (is_null($candidate)) {
+            throw new \LogicException("Could not resolve dependency for: " . (string) $in);
+        }
+
+        $in->addDependant($candidate["PROVIDE: " . $in->getName()]);
+    }
+
+    protected function resolveSeek(In $in, array &$others): void
+    {
+        foreach ($others as $other) {
+            if ($other->offsetExists("CONTRIBUTE: " . $in->getName())) {
+                $in->addDependant($other["CONTRIBUTE: " . $in->getName()]);
+            }
+        }
+    }
+}

components/ILIAS/Core/tests/Dependencies/OfComponentTest.php

@@ -0,0 +1,61 @@
+<?php
+
+/**
+ * This file is part of ILIAS, a powerful learning management system
+ * published by ILIAS open source e-Learning e.V.
+ *
+ * ILIAS is licensed with the GPL-3.0,
+ * see https://www.gnu.org/licenses/gpl-3.0.en.html
+ * You should have received a copy of said license along with the
+ * source code, too.
+ *
+ * If this is not the case or you just want to try ILIAS, you'll find
+ * us at:
+ * https://www.ilias.de
+ * https://github.com/ILIAS-eLearning
+ *
+ *********************************************************************/
+
+declare(strict_types=1);
+
+namespace ILIAS\Core\Tests\Dependencies;
+
+use PHPUnit\Framework\TestCase;
+use ILIAS\Core\Component;
+use ILIAS\Core\Dependencies as D;
+
+class OfComponentTest extends TestCase
+{
+    protected Component $component;
+
+    public function setUp(): void
+    {
+        $this->component = $this->createMock(Component::class);
+        $this->of_component = new D\OfComponent(
+            $this->component
+        );
+    }
+
+    public function testGetComponent(): void
+    {
+        $this->assertEquals($this->component, $this->of_component->getComponent());
+    }
+
+    public function testInDependencies(): void
+    {
+        $name = TestInterface::class;
+
+        $out = new D\Out(D\OutType::PROVIDE, $name, []);
+        $in = new D\In(D\InType::PULL, $name);
+
+        $of_component = new D\OfComponent(
+            $this->component,
+            $in,
+            $out
+        );
+
+        $result = iterator_to_array($of_component->getInDependencies());
+
+        $this->assertEquals([$in], $result);
+    }
+}

components/ILIAS/Core/tests/Dependencies/ResolverTest.php

@@ -0,0 +1,143 @@
+<?php
+
+/**
+ * This file is part of ILIAS, a powerful learning management system
+ * published by ILIAS open source e-Learning e.V.
+ *
+ * ILIAS is licensed with the GPL-3.0,
+ * see https://www.gnu.org/licenses/gpl-3.0.en.html
+ * You should have received a copy of said license along with the
+ * source code, too.
+ *
+ * If this is not the case or you just want to try ILIAS, you'll find
+ * us at:
+ * https://www.ilias.de
+ * https://github.com/ILIAS-eLearning
+ *
+ *********************************************************************/
+
+declare(strict_types=1);
+
+namespace ILIAS\Core\Tests\Dependencies;
+
+use PHPUnit\Framework\TestCase;
+use ILIAS\Core\Dependencies\Resolver;
+use ILIAS\Core\Dependencies as D;
+use ILIAS\Core\Component;
+
+class ResolverTest extends TestCase
+{
+    protected Resolver $resolver;
+
+    public function setUp(): void
+    {
+        $this->resolver = new Resolver();
+    }
+
+    public function testEmptyComponentSet(): void
+    {
+        $result = $this->resolver->resolveDependencies();
+
+        $this->assertEquals([], $result);
+    }
+
+    public function testResolvePull(): void
+    {
+        $component = $this->createMock(Component::class);
+
+        $name = TestInterface::class;
+
+        $pull = new D\In(D\InType::PULL, $name);
+        $provide = new D\Out(D\OutType::PROVIDE, $name, []);
+
+        $c1 = new D\OfComponent($component, $pull);
+        $c2 = new D\OfComponent($component, $provide);
+
+        $result = $this->resolver->resolveDependencies($c1, $c2);
+
+        $pull = new D\In(D\InType::PULL, $name);
+        $provide = new D\Out(D\OutType::PROVIDE, $name, [$pull]);
+
+        $c1 = new D\OfComponent($component, $pull);
+        $c2 = new D\OfComponent($component, $provide);
+
+        $this->assertEquals([$c1, $c2], $result);
+    }
+
+    public function testPullFailsNotExistent(): void
+    {
+        $this->expectException(\LogicException::class);
+
+        $component = $this->createMock(Component::class);
+
+        $name = TestInterface::class;
+
+        $pull = new D\In(D\InType::PULL, $name);
+
+        $c1 = new D\OfComponent($component, $pull);
+
+        $this->resolver->resolveDependencies($c1);
+    }
+
+    public function testPullFailsDuplicate(): void
+    {
+        $this->expectException(\LogicException::class);
+
+        $component = $this->createMock(Component::class);
+
+        $name = TestInterface::class;
+
+        $pull = new D\In(D\InType::PULL, $name);
+        $provide1 = new D\Out(D\OutType::PROVIDE, $name, []);
+        $provide2 = new D\Out(D\OutType::PROVIDE, $name, []);
+
+        $c1 = new D\OfComponent($component, $pull);
+        $c2 = new D\OfComponent($component, $provide1);
+        $c3 = new D\OfComponent($component, $provide2);
+
+        $this->resolver->resolveDependencies($c1, $c2, $c3);
+    }
+
+    public function testEmptySeek(): void
+    {
+        $component = $this->createMock(Component::class);
+
+        $name = TestInterface::class;
+
+        $seek = new D\In(D\InType::SEEK, $name);
+
+        $c1 = new D\OfComponent($component, $seek);
+
+        $result = $this->resolver->resolveDependencies($c1);
+
+        $this->assertEquals([$c1], $result);
+    }
+
+    public function testResolveSeek(): void
+    {
+        $component = $this->createMock(Component::class);
+
+        $name = TestInterface::class;
+
+        $seek = new D\In(D\InType::SEEK, $name);
+        $contribute1 = new D\Out(D\OutType::CONTRIBUTE, $name, []);
+        $contribute2 = new D\Out(D\OutType::CONTRIBUTE, $name, []);
+
+        $c1 = new D\OfComponent($component, $seek);
+        $c2 = new D\OfComponent($component, $contribute1);
+        $c3 = new D\OfComponent($component, $contribute2);
+
+        $result = $this->resolver->resolveDependencies($c1, $c2, $c3);
+
+
+        $seek = new D\In(D\InType::SEEK, $name);
+        $contribute1 = new D\Out(D\OutType::CONTRIBUTE, $name, [$seek]);
+        $contribute2 = new D\Out(D\OutType::CONTRIBUTE, $name, [$seek]);
+
+        $c1 = new D\OfComponent($component, $seek);
+        $c2 = new D\OfComponent($component, $contribute1);
+        $c3 = new D\OfComponent($component, $contribute2);
+
+        $this->assertEquals([$c1, $c2, $c3], $result);
+    }
+}