1 files changed, 73 insertions, 0 deletions
diff --git a/modules/doc/library/Doc/DocSectionFilterIterator.php b/modules/doc/library/Doc/DocSectionFilterIterator.php
new file mode 100644
index 0000000..bac5a67
--- /dev/null
+++ b/modules/doc/library/Doc/DocSectionFilterIterator.php
@@ -0,0 +1,73 @@
+<?php
+/* Icinga Web 2 | (c) 2014 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Module\Doc;
+
+use Countable;
+use RecursiveFilterIterator;
+use Icinga\Data\Tree\TreeNodeIterator;
+
+/**
+ * Recursive filter iterator over sections that are part of a particular chapter
+ *
+ * @method TreeNodeIterator getInnerIterator() {
+ *     {@inheritdoc}
+ * }
+ */
+class DocSectionFilterIterator extends RecursiveFilterIterator implements Countable
+{
+    /**
+     * Chapter to filter for
+     *
+     * @var string
+     */
+    protected $chapter;
+
+    /**
+     * Create a new recursive filter iterator over sections that are part of a particular chapter
+     *
+     * @param TreeNodeIterator  $iterator
+     * @param string            $chapter      The chapter to filter for
+     */
+    public function __construct(TreeNodeIterator $iterator, $chapter)
+    {
+        parent::__construct($iterator);
+        $this->chapter = $chapter;
+    }
+
+    /**
+     * Accept sections that are part of the given chapter
+     *
+     * @return bool Whether the current element of the iterator is acceptable
+     *              through this filter
+     */
+    public function accept(): bool
+    {
+        $section = $this->current();
+        /** @var \Icinga\Module\Doc\DocSection $section */
+        if ($section->getChapter()->getId() === $this->chapter) {
+            return true;
+        }
+        return false;
+    }
+
+    public function getChildren(): self
+    {
+        return new static($this->getInnerIterator()->getChildren(), $this->chapter);
+    }
+
+    public function count(): int
+    {
+        return iterator_count($this);
+    }
+
+    /**
+     * Whether the filter swallowed every section
+     *
+     * @return bool
+     */
+    public function isEmpty()
+    {
+        return $this->count() === 0;
+    }
+}