Add container to store and handle installation requirements

refs #7163

library/Icinga/Web/Setup/Requirements.php

@@ -0,0 +1,159 @@
+<?php
+// {{{ICINGA_LICENSE_HEADER}}}
+// {{{ICINGA_LICENSE_HEADER}}}
+
+namespace Icinga\Web\Setup;
+
+use ArrayIterator;
+use IteratorAggregate;
+
+/**
+ * Container to store and handle requirements
+ */
+class Requirements implements IteratorAggregate
+{
+    /**
+     * Identifier representing the state OK
+     */
+    const STATE_OK = 2;
+
+    /**
+     * Identifier representing the state OPTIONAL
+     */
+    const STATE_OPTIONAL = 1;
+
+    /**
+     * Identifier representing the state MANDATORY
+     */
+    const STATE_MANDATORY = 0;
+
+    /**
+     * The registered requirements
+     *
+     * @var array
+     */
+    protected $requirements = array();
+
+    /**
+     * Register a requirement
+     *
+     * @param   object  $requirement    The requirement to add
+     *
+     * @return  self
+     */
+    public function add($requirement)
+    {
+        $this->requirements[] = $requirement;
+        return $this;
+    }
+
+    /**
+     * Return all registered requirements
+     *
+     * @return  array
+     */
+    public function getAll()
+    {
+        return $this->requirements;
+    }
+
+    /**
+     * Return an iterator of all registered requirements
+     *
+     * @return  ArrayIterator
+     */
+    public function getIterator()
+    {
+        return new ArrayIterator($this->getAll());
+    }
+
+    /**
+     * Register an optional requirement
+     *
+     * @param   string      $title
+     * @param   string      $description
+     * @param   bool        $state
+     * @param   string      $message
+     *
+     * @return  self
+     */
+    public function addOptional($title, $description, $state, $message)
+    {
+        $this->add((object) array(
+            'title'         => $title,
+            'message'       => $message,
+            'description'   => $description,
+            'state'         => (bool) $state ? static::STATE_OK : static::STATE_OPTIONAL
+        ));
+        return $this;
+    }
+
+    /**
+     * Register a mandatory requirement
+     *
+     * @param   string      $title
+     * @param   string      $description
+     * @param   bool        $state
+     * @param   string      $message
+     *
+     * @return  self
+     */
+    public function addMandatory($title, $description, $state, $message)
+    {
+        $this->add((object) array(
+            'title'         => $title,
+            'message'       => $message,
+            'description'   => $description,
+            'state'         => (bool) $state ? static::STATE_OK : static::STATE_MANDATORY
+        ));
+        return $this;
+    }
+
+    /**
+     * Register the given requirements
+     *
+     * @param   Requirements    $requirements   The requirements to register
+     *
+     * @return  self
+     */
+    public function merge(Requirements $requirements)
+    {
+        foreach ($requirements->getAll() as $requirement) {
+            $this->add($requirement);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Make all registered requirements being optional
+     *
+     * @return  self
+     */
+    public function allOptional()
+    {
+        foreach ($this->getAll() as $requirement) {
+            if ($requirement->state === static::STATE_MANDATORY) {
+                $requirement->state = static::STATE_OPTIONAL;
+            }
+        }
+
+        return $this;
+    }
+
+    /**
+     * Return whether all mandatory requirements are fulfilled
+     *
+     * @return  bool
+     */
+    public function fulfilled()
+    {
+        foreach ($this->getAll() as $requirement) {
+            if ($requirement->state === static::STATE_MANDATORY) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}