implement policies

1 files changed, 46 insertions, 0 deletions

diff --git a/Digitigrade/PolicyManager.php b/Digitigrade/PolicyManager.php
new file mode 100644
index 0000000..24c2c7f
--- /dev/null
+++ b/Digitigrade/PolicyManager.php
@@ -0,0 +1,46 @@
+<?php
+namespace Digitigrade;
+
+use Digitigrade\Model\Actor;
+use Digitigrade\Model\FetchableModel;
+use Digitigrade\Model\Interaction;
+use Digitigrade\Model\Note;
+
+class PolicyManager extends Singleton {
+    /** @var Policy[] */
+    private array $policies = [];
+
+    public function register(Policy $policy) {
+        $this->policies[] = $policy;
+    }
+
+    public function registerAll(Policy ...$policies) {
+        foreach ($policies as $p) {
+            $this->register($p);
+        }
+    }
+
+    /**
+     * Checks if an object is allowed by all policies and possibly alters it.
+     * @param FetchableModel $object the object to check (may be modified in-place)
+     * @return bool true if allowed, false if it should be dropped
+     */
+    public function check(FetchableModel $object): bool {
+        return match ($object::class) {
+            Actor::class => self::arrayAll($this->policies, fn(Policy $p) => $p->checkActor($object)),
+            Interaction::class => self::arrayAll($this->policies, fn(Policy $p) => $p->checkInteraction($object)),
+            Note::class => self::arrayAll($this->policies, fn(Policy $p) => $p->checkNote($object)),
+            default => true
+        };
+    }
+
+    private static function arrayAll(array $arr, callable $test): bool {
+        // i would use array_all but that's php 8.4+ only which i don't have lol
+        foreach ($arr as $item) {
+            if (!$test($item)) {
+                return false;
+            }
+        }
+        return true;
+    }
+}
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