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<?php
namespace Dompdf\Frame;
use DOMDocument;
use DOMNode;
use DOMElement;
use DOMXPath;
use Dompdf\Exception;
use Dompdf\Frame;
/**
* @package dompdf
* @link http://dompdf.github.com/
* @author Benj Carson <benjcarson@digitaljunkies.ca>
* @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
*/
/**
* Represents an entire document as a tree of frames
*
* The FrameTree consists of {@link Frame} objects each tied to specific
* DOMNode objects in a specific DomDocument. The FrameTree has the same
* structure as the DomDocument, but adds additional capabalities for
* styling and layout.
*
* @package dompdf
*/
class FrameTree
{
/**
* Tags to ignore while parsing the tree
*
* @var array
*/
protected static $HIDDEN_TAGS = array(
"area",
"base",
"basefont",
"head",
"style",
"meta",
"title",
"colgroup",
"noembed",
"param",
"#comment"
);
/**
* The main DomDocument
*
* @see http://ca2.php.net/manual/en/ref.dom.php
* @var DOMDocument
*/
protected $_dom;
/**
* The root node of the FrameTree.
*
* @var Frame
*/
protected $_root;
/**
* Subtrees of absolutely positioned elements
*
* @var array of Frames
*/
protected $_absolute_frames;
/**
* A mapping of {@link Frame} objects to DOMNode objects
*
* @var array
*/
protected $_registry;
/**
* Class constructor
*
* @param DOMDocument $dom the main DomDocument object representing the current html document
*/
public function __construct(DomDocument $dom)
{
$this->_dom = $dom;
$this->_root = null;
$this->_registry = array();
}
/**
* Returns the DOMDocument object representing the curent html document
*
* @return DOMDocument
*/
public function get_dom()
{
return $this->_dom;
}
/**
* Returns the root frame of the tree
*
* @return Frame
*/
public function get_root()
{
return $this->_root;
}
/**
* Returns a specific frame given its id
*
* @param string $id
*
* @return Frame|null
*/
public function get_frame($id)
{
return isset($this->_registry[$id]) ? $this->_registry[$id] : null;
}
/**
* Returns a post-order iterator for all frames in the tree
*
* @return FrameTreeList|Frame[]
*/
public function get_frames()
{
return new FrameTreeList($this->_root);
}
/**
* Builds the tree
*/
public function build_tree()
{
$html = $this->_dom->getElementsByTagName("html")->item(0);
if (is_null($html)) {
$html = $this->_dom->firstChild;
}
if (is_null($html)) {
throw new Exception("Requested HTML document contains no data.");
}
$this->fix_tables();
$this->_root = $this->_build_tree_r($html);
}
/**
* Adds missing TBODYs around TR
*/
protected function fix_tables()
{
$xp = new DOMXPath($this->_dom);
// Move table caption before the table
// FIXME find a better way to deal with it...
$captions = $xp->query('//table/caption');
foreach ($captions as $caption) {
$table = $caption->parentNode;
$table->parentNode->insertBefore($caption, $table);
}
$firstRows = $xp->query('//table/tr[1]');
/** @var DOMElement $tableChild */
foreach ($firstRows as $tableChild) {
$tbody = $this->_dom->createElement('tbody');
$tableNode = $tableChild->parentNode;
do {
if ($tableChild->nodeName === 'tr') {
$tmpNode = $tableChild;
$tableChild = $tableChild->nextSibling;
$tableNode->removeChild($tmpNode);
$tbody->appendChild($tmpNode);
} else {
if ($tbody->hasChildNodes() === true) {
$tableNode->insertBefore($tbody, $tableChild);
$tbody = $this->_dom->createElement('tbody');
}
$tableChild = $tableChild->nextSibling;
}
} while ($tableChild);
if ($tbody->hasChildNodes() === true) {
$tableNode->appendChild($tbody);
}
}
}
// FIXME: temporary hack, preferably we will improve rendering of sequential #text nodes
/**
* Remove a child from a node
*
* Remove a child from a node. If the removed node results in two
* adjacent #text nodes then combine them.
*
* @param DOMNode $node the current DOMNode being considered
* @param array $children an array of nodes that are the children of $node
* @param int $index index from the $children array of the node to remove
*/
protected function _remove_node(DOMNode $node, array &$children, $index)
{
$child = $children[$index];
$previousChild = $child->previousSibling;
$nextChild = $child->nextSibling;
$node->removeChild($child);
if (isset($previousChild, $nextChild)) {
if ($previousChild->nodeName === "#text" && $nextChild->nodeName === "#text")
{
$previousChild->nodeValue .= $nextChild->nodeValue;
$this->_remove_node($node, $children, $index+1);
}
}
array_splice($children, $index, 1);
}
/**
* Recursively adds {@link Frame} objects to the tree
*
* Recursively build a tree of Frame objects based on a dom tree.
* No layout information is calculated at this time, although the
* tree may be adjusted (i.e. nodes and frames for generated content
* and images may be created).
*
* @param DOMNode $node the current DOMNode being considered
*
* @return Frame
*/
protected function _build_tree_r(DOMNode $node)
{
$frame = new Frame($node);
$id = $frame->get_id();
$this->_registry[$id] = $frame;
if (!$node->hasChildNodes()) {
return $frame;
}
// Store the children in an array so that the tree can be modified
$children = array();
$length = $node->childNodes->length;
for ($i = 0; $i < $length; $i++) {
$children[] = $node->childNodes->item($i);
}
$index = 0;
// INFO: We don't advance $index if a node is removed to avoid skipping nodes
while ($index < count($children)) {
$child = $children[$index];
$nodeName = strtolower($child->nodeName);
// Skip non-displaying nodes
if (in_array($nodeName, self::$HIDDEN_TAGS)) {
if ($nodeName !== "head" && $nodeName !== "style") {
$this->_remove_node($node, $children, $index);
} else {
$index++;
}
continue;
}
// Skip empty text nodes
if ($nodeName === "#text" && $child->nodeValue === "") {
$this->_remove_node($node, $children, $index);
continue;
}
// Skip empty image nodes
if ($nodeName === "img" && $child->getAttribute("src") === "") {
$this->_remove_node($node, $children, $index);
continue;
}
if (is_object($child)) {
$frame->append_child($this->_build_tree_r($child), false);
}
$index++;
}
return $frame;
}
/**
* @param DOMElement $node
* @param DOMElement $new_node
* @param string $pos
*
* @return mixed
*/
public function insert_node(DOMElement $node, DOMElement $new_node, $pos)
{
if ($pos === "after" || !$node->firstChild) {
$node->appendChild($new_node);
} else {
$node->insertBefore($new_node, $node->firstChild);
}
$this->_build_tree_r($new_node);
$frame_id = $new_node->getAttribute("frame_id");
$frame = $this->get_frame($frame_id);
$parent_id = $node->getAttribute("frame_id");
$parent = $this->get_frame($parent_id);
if ($parent) {
if ($pos === "before") {
$parent->prepend_child($frame, false);
} else {
$parent->append_child($frame, false);
}
}
return $frame_id;
}
}
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