Utilities: Add function to format DOM elements

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@933 44740490-163a-0410-bde0-09ae8108e29a

lib/SimpleSAML/Utilities.php

@@ -1541,6 +1541,90 @@ class SimpleSAML_Utilities {
 		return $ret;
 	}
 
+
+	/**
+	 * Format a DOM element.
+	 *
+	 * This function takes in a DOM element, and inserts whitespace to make it more
+	 * readable. Note that whitespace added previously will be removed.
+	 *
+	 * @param DOMElement $root  The root element which should be formatted.
+	 * @param string $indentBase  The indentation this element should be assumed to
+	 *                         have. Default is an empty string.
+	 */
+	public static function formatDOMElement(DOMElement $root, $indentBase = '') {
+		assert(is_string($indentBase));
+
+		/* Check what this element contains. */
+		$fullText = ''; /* All text in this element. */
+		$textNodes = array(); /* Text nodes which should be deleted. */
+		$childNodes = array(); /* Other child nodes. */
+		for ($i = 0; $i < $root->childNodes->length; $i++) {
+			$child = $root->childNodes->item($i);
+
+			if($child instanceof DOMText) {
+				$textNodes[] = $child;
+				$fullText .= $child->wholeText;
+
+			} elseif ($child instanceof DOMComment || $child instanceof DOMElement) {
+				$childNodes[] = $child;
+
+			} else {
+				/* Unknown node type. We don't know how to format this. */
+				return;
+			}
+		}
+
+		$fullText = trim($fullText);
+		if (strlen($fullText) > 0) {
+			/* We contain text. */
+			$hasText = TRUE;
+		} else {
+			$hasText = FALSE;
+		}
+
+		$hasChildNode = (count($childNodes) > 0);
+
+		if ($hasText && $hasChildNode) {
+			/* Element contains both text and child nodes - we don't know how to format this one. */
+			return;
+		}
+
+		/* Remove text nodes. */
+		foreach ($textNodes as $node) {
+			$root->removeChild($node);
+		}
+
+		if ($hasText) {
+			/* Only text - add a single text node to the element with the full text. */
+			$root->appendChild(new DOMText($fullText));
+			return;
+
+		}
+
+		if (!$hasChildNode) {
+			/* Empty node. Nothing to do. */
+			return;
+		}
+
+		/* Element contains only child nodes - add indentation before each one, and
+		 * format child elements.
+		 */
+		$childIndentation = $indentBase . '  ';
+		foreach ($childNodes as $node) {
+			/* Add indentation before node. */
+			$root->insertBefore(new DOMText("\n" . $childIndentation), $node);
+
+			/* Format child elements. */
+			if ($node instanceof DOMElement) {
+				self::formatDOMElement($node, $childIndentation);
+			}
+		}
+
+		/* Add indentation before closing tag. */
+		$root->appendChild(new DOMText("\n" . $indentBase));
+	}
+
 }
 
 ?>
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