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<?php
namespace Masterminds\HTML5\Parser;
use Masterminds\HTML5\Elements;
use Masterminds\HTML5\InstructionProcessor;
/**
* Create an HTML5 DOM tree from events.
*
* This attempts to create a DOM from events emitted by a parser. This
* attempts (but does not guarantee) to up-convert older HTML documents
* to HTML5. It does this by applying HTML5's rules, but it will not
* change the architecture of the document itself.
*
* Many of the error correction and quirks features suggested in the specification
* are implemented herein; however, not all of them are. Since we do not
* assume a graphical user agent, no presentation-specific logic is conducted
* during tree building.
*
* FIXME: The present tree builder does not exactly follow the state machine rules
* for insert modes as outlined in the HTML5 spec. The processor needs to be
* re-written to accomodate this. See, for example, the Go language HTML5
* parser.
*/
class DOMTreeBuilder implements EventHandler
{
/**
* Defined in http://www.w3.org/TR/html51/infrastructure.html#html-namespace-0.
*/
const NAMESPACE_HTML = 'http://www.w3.org/1999/xhtml';
const NAMESPACE_MATHML = 'http://www.w3.org/1998/Math/MathML';
const NAMESPACE_SVG = 'http://www.w3.org/2000/svg';
const NAMESPACE_XLINK = 'http://www.w3.org/1999/xlink';
const NAMESPACE_XML = 'http://www.w3.org/XML/1998/namespace';
const NAMESPACE_XMLNS = 'http://www.w3.org/2000/xmlns/';
const OPT_DISABLE_HTML_NS = 'disable_html_ns';
const OPT_TARGET_DOC = 'target_document';
const OPT_IMPLICIT_NS = 'implicit_namespaces';
/**
* Holds the HTML5 element names that causes a namespace switch.
*
* @var array
*/
protected $nsRoots = array(
'html' => self::NAMESPACE_HTML,
'svg' => self::NAMESPACE_SVG,
'math' => self::NAMESPACE_MATHML,
);
/**
* Holds the always available namespaces (which does not require the XMLNS declaration).
*
* @var array
*/
protected $implicitNamespaces = array(
'xml' => self::NAMESPACE_XML,
'xmlns' => self::NAMESPACE_XMLNS,
'xlink' => self::NAMESPACE_XLINK,
);
/**
* Holds a stack of currently active namespaces.
*
* @var array
*/
protected $nsStack = array();
/**
* Holds the number of namespaces declared by a node.
*
* @var array
*/
protected $pushes = array();
/**
* Defined in 8.2.5.
*/
const IM_INITIAL = 0;
const IM_BEFORE_HTML = 1;
const IM_BEFORE_HEAD = 2;
const IM_IN_HEAD = 3;
const IM_IN_HEAD_NOSCRIPT = 4;
const IM_AFTER_HEAD = 5;
const IM_IN_BODY = 6;
const IM_TEXT = 7;
const IM_IN_TABLE = 8;
const IM_IN_TABLE_TEXT = 9;
const IM_IN_CAPTION = 10;
const IM_IN_COLUMN_GROUP = 11;
const IM_IN_TABLE_BODY = 12;
const IM_IN_ROW = 13;
const IM_IN_CELL = 14;
const IM_IN_SELECT = 15;
const IM_IN_SELECT_IN_TABLE = 16;
const IM_AFTER_BODY = 17;
const IM_IN_FRAMESET = 18;
const IM_AFTER_FRAMESET = 19;
const IM_AFTER_AFTER_BODY = 20;
const IM_AFTER_AFTER_FRAMESET = 21;
const IM_IN_SVG = 22;
const IM_IN_MATHML = 23;
protected $options = array();
protected $stack = array();
protected $current; // Pointer in the tag hierarchy.
protected $rules;
protected $doc;
protected $frag;
protected $processor;
protected $insertMode = 0;
/**
* Track if we are in an element that allows only inline child nodes.
*
* @var string|null
*/
protected $onlyInline;
/**
* Quirks mode is enabled by default.
* Any document that is missing the DT will be considered to be in quirks mode.
*/
protected $quirks = true;
protected $errors = array();
public function __construct($isFragment = false, array $options = array())
{
$this->options = $options;
if (isset($options[self::OPT_TARGET_DOC])) {
$this->doc = $options[self::OPT_TARGET_DOC];
} else {
$impl = new \DOMImplementation();
// XXX:
// Create the doctype. For now, we are always creating HTML5
// documents, and attempting to up-convert any older DTDs to HTML5.
$dt = $impl->createDocumentType('html');
// $this->doc = \DOMImplementation::createDocument(NULL, 'html', $dt);
$this->doc = $impl->createDocument(null, '', $dt);
$this->doc->encoding = !empty($options['encoding']) ? $options['encoding'] : 'UTF-8';
}
$this->errors = array();
$this->current = $this->doc; // ->documentElement;
// Create a rules engine for tags.
$this->rules = new TreeBuildingRules();
$implicitNS = array();
if (isset($this->options[self::OPT_IMPLICIT_NS])) {
$implicitNS = $this->options[self::OPT_IMPLICIT_NS];
} elseif (isset($this->options['implicitNamespaces'])) {
$implicitNS = $this->options['implicitNamespaces'];
}
// Fill $nsStack with the defalut HTML5 namespaces, plus the "implicitNamespaces" array taken form $options
array_unshift($this->nsStack, $implicitNS + array('' => self::NAMESPACE_HTML) + $this->implicitNamespaces);
if ($isFragment) {
$this->insertMode = static::IM_IN_BODY;
$this->frag = $this->doc->createDocumentFragment();
$this->current = $this->frag;
}
}
/**
* Get the document.
*/
public function document()
{
return $this->doc;
}
/**
* Get the DOM fragment for the body.
*
* This returns a DOMNodeList because a fragment may have zero or more
* DOMNodes at its root.
*
* @see http://www.w3.org/TR/2012/CR-html5-20121217/syntax.html#concept-frag-parse-context
*
* @return \DOMDocumentFragment
*/
public function fragment()
{
return $this->frag;
}
/**
* Provide an instruction processor.
*
* This is used for handling Processor Instructions as they are
* inserted. If omitted, PI's are inserted directly into the DOM tree.
*
* @param InstructionProcessor $proc
*/
public function setInstructionProcessor(InstructionProcessor $proc)
{
$this->processor = $proc;
}
public function doctype($name, $idType = 0, $id = null, $quirks = false)
{
// This is used solely for setting quirks mode. Currently we don't
// try to preserve the inbound DT. We convert it to HTML5.
$this->quirks = $quirks;
if ($this->insertMode > static::IM_INITIAL) {
$this->parseError('Illegal placement of DOCTYPE tag. Ignoring: ' . $name);
return;
}
$this->insertMode = static::IM_BEFORE_HTML;
}
/**
* Process the start tag.
*
* @todo - XMLNS namespace handling (we need to parse, even if it's not valid)
* - XLink, MathML and SVG namespace handling
* - Omission rules: 8.1.2.4 Optional tags
*
* @param string $name
* @param array $attributes
* @param bool $selfClosing
*
* @return int
*/
public function startTag($name, $attributes = array(), $selfClosing = false)
{
$lname = $this->normalizeTagName($name);
// Make sure we have an html element.
if (!$this->doc->documentElement && 'html' !== $name && !$this->frag) {
$this->startTag('html');
}
// Set quirks mode if we're at IM_INITIAL with no doctype.
if ($this->insertMode === static::IM_INITIAL) {
$this->quirks = true;
$this->parseError('No DOCTYPE specified.');
}
// SPECIAL TAG HANDLING:
// Spec says do this, and "don't ask."
// find the spec where this is defined... looks problematic
if ('image' === $name && !($this->insertMode === static::IM_IN_SVG || $this->insertMode === static::IM_IN_MATHML)) {
$name = 'img';
}
// Autoclose p tags where appropriate.
if ($this->insertMode >= static::IM_IN_BODY && Elements::isA($name, Elements::AUTOCLOSE_P)) {
$this->autoclose('p');
}
// Set insert mode:
switch ($name) {
case 'html':
$this->insertMode = static::IM_BEFORE_HEAD;
break;
case 'head':
if ($this->insertMode > static::IM_BEFORE_HEAD) {
$this->parseError('Unexpected head tag outside of head context.');
} else {
$this->insertMode = static::IM_IN_HEAD;
}
break;
case 'body':
$this->insertMode = static::IM_IN_BODY;
break;
case 'svg':
$this->insertMode = static::IM_IN_SVG;
break;
case 'math':
$this->insertMode = static::IM_IN_MATHML;
break;
case 'noscript':
if ($this->insertMode === static::IM_IN_HEAD) {
$this->insertMode = static::IM_IN_HEAD_NOSCRIPT;
}
break;
}
// Special case handling for SVG.
if ($this->insertMode === static::IM_IN_SVG) {
$lname = Elements::normalizeSvgElement($lname);
}
$pushes = 0;
// when we found a tag thats appears inside $nsRoots, we have to switch the defalut namespace
if (isset($this->nsRoots[$lname]) && $this->nsStack[0][''] !== $this->nsRoots[$lname]) {
array_unshift($this->nsStack, array(
'' => $this->nsRoots[$lname],
) + $this->nsStack[0]);
++$pushes;
}
$needsWorkaround = false;
if (isset($this->options['xmlNamespaces']) && $this->options['xmlNamespaces']) {
// when xmlNamespaces is true a and we found a 'xmlns' or 'xmlns:*' attribute, we should add a new item to the $nsStack
foreach ($attributes as $aName => $aVal) {
if ('xmlns' === $aName) {
$needsWorkaround = $aVal;
array_unshift($this->nsStack, array(
'' => $aVal,
) + $this->nsStack[0]);
++$pushes;
} elseif ('xmlns' === (($pos = strpos($aName, ':')) ? substr($aName, 0, $pos) : '')) {
array_unshift($this->nsStack, array(
substr($aName, $pos + 1) => $aVal,
) + $this->nsStack[0]);
++$pushes;
}
}
}
if ($this->onlyInline && Elements::isA($lname, Elements::BLOCK_TAG)) {
$this->autoclose($this->onlyInline);
$this->onlyInline = null;
}
// some elements as table related tags might have optional end tags that force us to auto close multiple tags
// https://www.w3.org/TR/html401/struct/tables.html
if ($this->current instanceof \DOMElement && isset(Elements::$optionalEndElementsParentsToClose[$lname])) {
foreach (Elements::$optionalEndElementsParentsToClose[$lname] as $parentElName) {
if ($this->current instanceof \DOMElement && $this->current->tagName === $parentElName) {
$this->autoclose($parentElName);
}
}
}
try {
$prefix = ($pos = strpos($lname, ':')) ? substr($lname, 0, $pos) : '';
if (false !== $needsWorkaround) {
$xml = "<$lname xmlns=\"$needsWorkaround\" " . (strlen($prefix) && isset($this->nsStack[0][$prefix]) ? ("xmlns:$prefix=\"" . $this->nsStack[0][$prefix] . '"') : '') . '/>';
$frag = new \DOMDocument('1.0', 'UTF-8');
$frag->loadXML($xml);
$ele = $this->doc->importNode($frag->documentElement, true);
} else {
if (!isset($this->nsStack[0][$prefix]) || ('' === $prefix && isset($this->options[self::OPT_DISABLE_HTML_NS]) && $this->options[self::OPT_DISABLE_HTML_NS])) {
$ele = $this->doc->createElement($lname);
} else {
$ele = $this->doc->createElementNS($this->nsStack[0][$prefix], $lname);
}
}
} catch (\DOMException $e) {
$this->parseError("Illegal tag name: <$lname>. Replaced with <invalid>.");
$ele = $this->doc->createElement('invalid');
}
if (Elements::isA($lname, Elements::BLOCK_ONLY_INLINE)) {
$this->onlyInline = $lname;
}
// When we add some namespacess, we have to track them. Later, when "endElement" is invoked, we have to remove them.
// When we are on a void tag, we do not need to care about namesapce nesting.
if ($pushes > 0 && !Elements::isA($name, Elements::VOID_TAG)) {
// PHP tends to free the memory used by DOM,
// to avoid spl_object_hash collisions whe have to avoid garbage collection of $ele storing it into $pushes
// see https://bugs.php.net/bug.php?id=67459
$this->pushes[spl_object_hash($ele)] = array($pushes, $ele);
}
foreach ($attributes as $aName => $aVal) {
// xmlns attributes can't be set
if ('xmlns' === $aName) {
continue;
}
if ($this->insertMode === static::IM_IN_SVG) {
$aName = Elements::normalizeSvgAttribute($aName);
} elseif ($this->insertMode === static::IM_IN_MATHML) {
$aName = Elements::normalizeMathMlAttribute($aName);
}
$aVal = (string) $aVal;
try {
$prefix = ($pos = strpos($aName, ':')) ? substr($aName, 0, $pos) : false;
if ('xmlns' === $prefix) {
$ele->setAttributeNS(self::NAMESPACE_XMLNS, $aName, $aVal);
} elseif (false !== $prefix && isset($this->nsStack[0][$prefix])) {
$ele->setAttributeNS($this->nsStack[0][$prefix], $aName, $aVal);
} else {
$ele->setAttribute($aName, $aVal);
}
} catch (\DOMException $e) {
$this->parseError("Illegal attribute name for tag $name. Ignoring: $aName");
continue;
}
// This is necessary on a non-DTD schema, like HTML5.
if ('id' === $aName) {
$ele->setIdAttribute('id', true);
}
}
if ($this->frag !== $this->current && $this->rules->hasRules($name)) {
// Some elements have special processing rules. Handle those separately.
$this->current = $this->rules->evaluate($ele, $this->current);
} else {
// Otherwise, it's a standard element.
$this->current->appendChild($ele);
if (!Elements::isA($name, Elements::VOID_TAG)) {
$this->current = $ele;
}
// Self-closing tags should only be respected on foreign elements
// (and are implied on void elements)
// See: https://www.w3.org/TR/html5/syntax.html#start-tags
if (Elements::isHtml5Element($name)) {
$selfClosing = false;
}
}
// This is sort of a last-ditch attempt to correct for cases where no head/body
// elements are provided.
if ($this->insertMode <= static::IM_BEFORE_HEAD && 'head' !== $name && 'html' !== $name) {
$this->insertMode = static::IM_IN_BODY;
}
// When we are on a void tag, we do not need to care about namesapce nesting,
// but we have to remove the namespaces pushed to $nsStack.
if ($pushes > 0 && Elements::isA($name, Elements::VOID_TAG)) {
// remove the namespaced definded by current node
for ($i = 0; $i < $pushes; ++$i) {
array_shift($this->nsStack);
}
}
if ($selfClosing) {
$this->endTag($name);
}
// Return the element mask, which the tokenizer can then use to set
// various processing rules.
return Elements::element($name);
}
public function endTag($name)
{
$lname = $this->normalizeTagName($name);
// Special case within 12.2.6.4.7: An end tag whose tag name is "br" should be treated as an opening tag
if ('br' === $name) {
$this->parseError('Closing tag encountered for void element br.');
$this->startTag('br');
}
// Ignore closing tags for other unary elements.
elseif (Elements::isA($name, Elements::VOID_TAG)) {
return;
}
if ($this->insertMode <= static::IM_BEFORE_HTML) {
// 8.2.5.4.2
if (in_array($name, array(
'html',
'br',
'head',
'title',
))) {
$this->startTag('html');
$this->endTag($name);
$this->insertMode = static::IM_BEFORE_HEAD;
return;
}
// Ignore the tag.
$this->parseError('Illegal closing tag at global scope.');
return;
}
// Special case handling for SVG.
if ($this->insertMode === static::IM_IN_SVG) {
$lname = Elements::normalizeSvgElement($lname);
}
$cid = spl_object_hash($this->current);
// XXX: HTML has no parent. What do we do, though,
// if this element appears in the wrong place?
if ('html' === $lname) {
return;
}
// remove the namespaced definded by current node
if (isset($this->pushes[$cid])) {
for ($i = 0; $i < $this->pushes[$cid][0]; ++$i) {
array_shift($this->nsStack);
}
unset($this->pushes[$cid]);
}
if (!$this->autoclose($lname)) {
$this->parseError('Could not find closing tag for ' . $lname);
}
switch ($lname) {
case 'head':
$this->insertMode = static::IM_AFTER_HEAD;
break;
case 'body':
$this->insertMode = static::IM_AFTER_BODY;
break;
case 'svg':
case 'mathml':
$this->insertMode = static::IM_IN_BODY;
break;
}
}
public function comment($cdata)
{
// TODO: Need to handle case where comment appears outside of the HTML tag.
$node = $this->doc->createComment($cdata);
$this->current->appendChild($node);
}
public function text($data)
{
// XXX: Hmmm.... should we really be this strict?
if ($this->insertMode < static::IM_IN_HEAD) {
// Per '8.2.5.4.3 The "before head" insertion mode' the characters
// " \t\n\r\f" should be ignored but no mention of a parse error. This is
// practical as most documents contain these characters. Other text is not
// expected here so recording a parse error is necessary.
$dataTmp = trim($data, " \t\n\r\f");
if (!empty($dataTmp)) {
// fprintf(STDOUT, "Unexpected insert mode: %d", $this->insertMode);
$this->parseError('Unexpected text. Ignoring: ' . $dataTmp);
}
return;
}
// fprintf(STDOUT, "Appending text %s.", $data);
$node = $this->doc->createTextNode($data);
$this->current->appendChild($node);
}
public function eof()
{
// If the $current isn't the $root, do we need to do anything?
}
public function parseError($msg, $line = 0, $col = 0)
{
$this->errors[] = sprintf('Line %d, Col %d: %s', $line, $col, $msg);
}
public function getErrors()
{
return $this->errors;
}
public function cdata($data)
{
$node = $this->doc->createCDATASection($data);
$this->current->appendChild($node);
}
public function processingInstruction($name, $data = null)
{
// XXX: Ignore initial XML declaration, per the spec.
if ($this->insertMode === static::IM_INITIAL && 'xml' === strtolower($name)) {
return;
}
// Important: The processor may modify the current DOM tree however it sees fit.
if ($this->processor instanceof InstructionProcessor) {
$res = $this->processor->process($this->current, $name, $data);
if (!empty($res)) {
$this->current = $res;
}
return;
}
// Otherwise, this is just a dumb PI element.
$node = $this->doc->createProcessingInstruction($name, $data);
$this->current->appendChild($node);
}
// ==========================================================================
// UTILITIES
// ==========================================================================
/**
* Apply normalization rules to a tag name.
* See sections 2.9 and 8.1.2.
*
* @param string $tagName
*
* @return string The normalized tag name.
*/
protected function normalizeTagName($tagName)
{
/*
* Section 2.9 suggests that we should not do this. if (strpos($name, ':') !== false) { // We know from the grammar that there must be at least one other // char besides :, since : is not a legal tag start. $parts = explode(':', $name); return array_pop($parts); }
*/
return $tagName;
}
protected function quirksTreeResolver($name)
{
throw new \Exception('Not implemented.');
}
/**
* Automatically climb the tree and close the closest node with the matching $tag.
*
* @param string $tagName
*
* @return bool
*/
protected function autoclose($tagName)
{
$working = $this->current;
do {
if (XML_ELEMENT_NODE !== $working->nodeType) {
return false;
}
if ($working->tagName === $tagName) {
$this->current = $working->parentNode;
return true;
}
} while ($working = $working->parentNode);
return false;
}
/**
* Checks if the given tagname is an ancestor of the present candidate.
*
* If $this->current or anything above $this->current matches the given tag
* name, this returns true.
*
* @param string $tagName
*
* @return bool
*/
protected function isAncestor($tagName)
{
$candidate = $this->current;
while (XML_ELEMENT_NODE === $candidate->nodeType) {
if ($candidate->tagName === $tagName) {
return true;
}
$candidate = $candidate->parentNode;
}
return false;
}
/**
* Returns true if the immediate parent element is of the given tagname.
*
* @param string $tagName
*
* @return bool
*/
protected function isParent($tagName)
{
return $this->current->tagName === $tagName;
}
}
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