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<?php
/**
* DOMPDF - PHP5 HTML to PDF renderer
*
* File: $RCSfile: stylesheet.cls.php,v $
* Created on: 2004-06-01
*
* Copyright (c) 2004 - Benj Carson <benjcarson@digitaljunkies.ca>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library in the file LICENSE.LGPL; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307 USA
*
* Alternatively, you may distribute this software under the terms of the
* PHP License, version 3.0 or later. A copy of this license should have
* been distributed with this file in the file LICENSE.PHP . If this is not
* the case, you can obtain a copy at http://www.php.net/license/3_0.txt.
*
* The latest version of DOMPDF might be available at:
* http://www.digitaljunkies.ca/dompdf
*
* @link http://www.digitaljunkies.ca/dompdf
* @copyright 2004 Benj Carson
* @author Benj Carson <benjcarson@digitaljunkies.ca>
* @package dompdf
* @version 0.5.1
*/
/* $Id: stylesheet.cls.php,v 1.16 2006/07/07 21:31:04 benjcarson Exp $ */
/**
* The location of the default built-in CSS file.
* {@link Stylesheet::DEFAULT_STYLESHEET}
*/
define('__DEFAULT_STYLESHEET', DOMPDF_LIB_DIR . DIRECTORY_SEPARATOR . "res" . DIRECTORY_SEPARATOR . "html.css");
/**
* The master stylesheet class
*
* The Stylesheet class is responsible for parsing stylesheets and style
* tags/attributes. It also acts as a registry of the individual Style
* objects generated by the current set of loaded CSS files and style
* elements.
*
* @see Style
* @package dompdf
*/
class Stylesheet {
/**
* the location of the default built-in CSS file.
*
*/
const DEFAULT_STYLESHEET = __DEFAULT_STYLESHEET; // Hack: can't
// concatenate stuff in
// const declarations,
// but I can do this?
// protected members
/**
* array of currently defined styles
* @var array
*/
private $_styles;
/**
* base protocol of the document being parsed
*
* Used to handle relative urls.
*
* @var string
*/
private $_protocol;
/**
* base hostname of the document being parsed
*
* Used to handle relative urls.
* @var string
*/
private $_base_host;
/**
* base path of the document being parsed
*
* Used to handle relative urls.
* @var string
*/
private $_base_path;
/**
* the style defined by @page rules
*
* @var Style
*/
private $_page_style;
/**
* list of loaded files, used to prevent recursion
*
* @var array
*/
private $_loaded_files;
/**
* accepted CSS media types
*/
static $ACCEPTED_MEDIA_TYPES = array("all", "static", "visual",
"bitmap", "paged", "print");
/**
* The class constructor.
*
* The base protocol, host & path are initialized to those of
* the current script.
*/
function __construct() {
$this->_styles = array();
$this->_loaded_files = array();
list($this->_protocol, $this->_base_host, $this->_base_path) = explode_url($_SERVER["SCRIPT_FILENAME"]);
$this->_page_style = null;
}
/**
* Set the base protocol
*
* @param string $proto
*/
function set_protocol($proto) { $this->_protocol = $proto; }
/**
* Set the base host
*
* @param string $host
*/
function set_host($host) { $this->_base_host = $host; }
/**
* Set the base path
*
* @param string $path
*/
function set_base_path($path) { $this->_base_path = $path; }
/**
* Return the base protocol for this stylesheet
*
* @return string
*/
function get_protocol() { return $this->_protocol; }
/**
* Return the base host for this stylesheet
*
* @return string
*/
function get_host() { return $this->_base_host; }
/**
* Return the base path for this stylesheet
*
* @return string
*/
function get_base_path() { return $this->_base_path; }
/**
* add a new Style object to the stylesheet
*
* add_style() adds a new Style object to the current stylesheet, or
* merges a new Style with an existing one.
*
* @param string $key the Style's selector
* @param Style $style the Style to be added
*/
function add_style($key, Style $style) {
if (!is_string($key))
throw new DOMPDF_Exception("CSS rule must be keyed by a string.");
if ( isset($this->_styles[$key]) )
$this->_styles[$key]->merge($style);
else
$this->_styles[$key] = clone $style;
}
/**
* lookup a specifc Style object
*
* lookup() returns the Style specified by $key, or null if the Style is
* not found.
*
* @param string $key the selector of the requested Style
* @return Style
*/
function lookup($key) {
if ( !isset($this->_styles[$key]) )
return null;
return $this->_styles[$key];
}
/**
* create a new Style object associated with this stylesheet
*
* @param Style $parent The style of this style's parent in the DOM tree
* @return Style
*/
function create_style($parent = null) {
return new Style($this, $parent);
}
/**
* load and parse a CSS string
*
* @param string $css
*/
function load_css(&$css) { $this->_parse_css($css); }
/**
* load and parse a CSS file
*
* @param string $file
*/
function load_css_file($file) {
global $_dompdf_warnings;
// Prevent circular references
if ( isset($this->_loaded_files[$file]) )
return;
$this->_loaded_files[$file] = true;
$parsed_url = explode_url($file);
list($this->_protocol, $this->_base_host, $this->_base_path, $filename) = $parsed_url;
if ( !DOMPDF_ENABLE_REMOTE &&
($this->_protocol != "" && $this->_protocol != "file://") ) {
record_warnings(E_USER_WARNING, "Remote CSS file '$file' requested, but DOMPDF_ENABLE_REMOTE is false.", __FILE__, __LINE__);
return;
}
// Fix submitted by Nick Oostveen for aliased directory support:
if ( $this->_protocol == "" )
$file = $this->_base_path . $filename;
else
$file = build_url($this->_protocol, $this->_base_host, $this->_base_path, $filename);
set_error_handler("record_warnings");
$css = file_get_contents($file);
restore_error_handler();
if ( $css == "" ) {
record_warnings(E_USER_WARNING, "Unable to load css file $file", __FILE__, __LINE__);;
return;
}
$this->_parse_css($css);
}
/**
* @link http://www.w3.org/TR/CSS21/cascade.html#specificity}
*
* @param string $selector
* @return int
*/
private function _specificity($selector) {
// http://www.w3.org/TR/CSS21/cascade.html#specificity
$a = ($selector === "!style attribute") ? 1 : 0;
$b = min(mb_substr_count($selector, "#"), 255);
$c = min(mb_substr_count($selector, ".") +
mb_substr_count($selector, ">") +
mb_substr_count($selector, "+"), 255);
$d = min(mb_substr_count($selector, " "), 255);
return ($a << 24) | ($b << 16) | ($c << 8) | ($d);
}
/**
* converts a CSS selector to an XPath query.
*
* @param string $selector
* @return string
*/
private function _css_selector_to_xpath($selector) {
// Collapse white space and strip whitespace around delimiters
// $search = array("/\\s+/", "/\\s+([.>#+:])\\s+/");
// $replace = array(" ", "\\1");
// $selector = preg_replace($search, $replace, trim($selector));
// Initial query (non-absolute)
$query = "//";
// Parse the selector
//$s = preg_split("/([ :>.#+])/", $selector, -1, PREG_SPLIT_DELIM_CAPTURE);
$delimiters = array(" ", ">", ".", "#", "+", ":", "[");
// Add an implicit space at the beginning of the selector if there is no
// delimiter there already.
if ( !in_array($selector{0}, $delimiters) )
$selector = " $selector";
$tok = "";
$len = mb_strlen($selector);
$i = 0;
while ( $i < $len ) {
$s = $selector{$i};
$i++;
// Eat characters up to the next delimiter
$tok = "";
while ($i < $len) {
if ( in_array($selector{$i}, $delimiters) )
break;
$tok .= $selector{$i++};
}
switch ($s) {
case " ":
case ">":
// All elements matching the next token that are direct children of
// the current token
$expr = $s == " " ? "descendant" : "child";
if ( mb_substr($query, -1, 1) != "/" )
$query .= "/";
if ( !$tok )
$tok = "*";
$query .= "$expr::$tok";
$tok = "";
break;
case ".":
case "#":
// All elements matching the current token with a class/id equal to
// the _next_ token.
$attr = $s == "." ? "class" : "id";
// empty class/id == *
if ( mb_substr($query, -1, 1) == "/" )
$query .= "*";
// Match multiple classes: $tok contains the current selected
// class. Search for class attributes with class="$tok",
// class=".* $tok .*" and class=".* $tok"
// This doesn't work because libxml only supports XPath 1.0...
//$query .= "[matches(@$attr,\"^${tok}\$|^${tok}[ ]+|[ ]+${tok}\$|[ ]+${tok}[ ]+\")]";
// Query improvement by Michael Sheakoski <michael@mjsdigital.com>:
$query .= "[contains(concat(' ', @$attr, ' '), concat(' ', '$tok', ' '))]";
$tok = "";
break;
case "+":
// All sibling elements that folow the current token
if ( mb_substr($query, -1, 1) != "/" )
$query .= "/";
$query .= "following-sibling::$tok";
$tok = "";
break;
case ":":
// Pseudo-classes
switch ($tok) {
case "first-child":
break;
case "link":
$query .= "[@href]";
$tok = "";
break;
case "first-line":
break;
case "first-letter":
break;
case "before":
break;
case "after":
break;
}
break;
case "[":
// Attribute selectors. All with an attribute matching the following token(s)
$attr_delimiters = array("=", "]", "~", "|");
$tok_len = mb_strlen($tok);
$j = 0;
$attr = "";
$op = "";
$value = "";
while ( $j < $tok_len ) {
if ( in_array($tok{$j}, $attr_delimiters) )
break;
$attr .= $tok{$j++};
}
switch ( $tok{$j} ) {
case "~":
case "|":
$op .= $tok{$j++};
if ( $tok{$j} != "=" )
throw new DOMPDF_Exception("Invalid CSS selector syntax: invalid attribute selector: $selector");
$op .= $tok{$j};
break;
case "=":
$op = "=";
break;
}
// Read the attribute value, if required
if ( $op != "" ) {
$j++;
while ( $j < $tok_len ) {
if ( $tok{$j} == "]" )
break;
$value .= $tok{$j++};
}
}
if ( $attr == "" )
throw new DOMPDF_Exception("Invalid CSS selector syntax: missing attribute name");
switch ( $op ) {
case "":
$query .= "[@$attr]";
break;
case "=":
$query .= "[@$attr$op\"$value\"]";
break;
case "~=":
// FIXME: this will break if $value contains quoted strings
// (e.g. [type~="a b c" "d e f"])
$values = explode(" ", $value);
$query .= "[";
foreach ( $values as $val )
$query .= "@$attr=\"$val\" or ";
$query = rtrim($query, " or ") . "]";
break;
case "|=":
$values = explode("-", $value);
$query .= "[";
foreach ($values as $val)
$query .= "starts-with(@$attr, \"$val\") or ";
$query = rtrim($query, " or ") . "]";
break;
}
break;
}
}
$i++;
// case ":":
// // Pseudo selectors: ignore for now. Partially handled directly
// // below.
// // Skip until the next special character, leaving the token as-is
// while ( $i < $len ) {
// if ( in_array($selector{$i}, $delimiters) )
// break;
// $i++;
// }
// break;
// default:
// // Add the character to the token
// $tok .= $selector{$i++};
// break;
// }
// }
// Trim the trailing '/' from the query
if ( mb_strlen($query) > 2 )
$query = rtrim($query, "/");
return $query;
}
/**
* applies all current styles to a particular document tree
*
* apply_styles() applies all currently loaded styles to the provided
* {@link Frame_Tree}. Aside from parsing CSS, this is the main purpose
* of this class.
*
* @param Frame_Tree $tree
*/
function apply_styles(Frame_Tree $tree) {
// Use XPath to select nodes. This would be easier if we could attach
// Frame objects directly to DOMNodes using the setUserData() method, but
// we can't do that just yet. Instead, we set a _node attribute_ in
// Frame->set_id() and use that as a handle on the Frame object via
// Frame_Tree::$_registry.
// We create a scratch array of styles indexed by frame id. Once all
// styles have been assigned, we order the cached styles by specificity
// and create a final style object to assign to the frame.
// FIXME: this is not particularly robust...
$styles = array();
$xp = new DOMXPath($tree->get_dom());
// Apply all styles in stylesheet
foreach ($this->_styles as $selector => $style) {
$query = $this->_css_selector_to_xpath($selector);
// pre_var_dump($selector);
// pre_var_dump($query);
// echo ($style);
// Retrieve the nodes
$nodes = $xp->query($query);
foreach ($nodes as $node) {
//echo $node->nodeName . "\n";
// Retrieve the node id
if ( $node->nodeType != 1 ) // Only DOMElements get styles
continue;
$id = $node->getAttribute("frame_id");
// Assign the current style to the scratch array
$spec = $this->_specificity($selector);
$styles[$id][$spec][] = $style;
}
}
// Now create the styles and assign them to the appropriate frames. (We
// iterate over the tree using an implicit Frame_Tree iterator.)
$root_flg = false;
foreach ($tree->get_frames() as $frame) {
// pre_r($frame->get_node()->nodeName . ":");
if ( !$root_flg && $this->_page_style ) {
$style = $this->_page_style;
$root_flg = true;
} else
$style = $this->create_style();
// Find nearest DOMElement parent
$p = $frame;
while ( $p = $p->get_parent() )
if ($p->get_node()->nodeType == 1 )
break;
// Styles can only be applied directly to DOMElements; anonymous
// frames inherit from their parent
if ( $frame->get_node()->nodeType != 1 ) {
if ( $p )
$style->inherit($p->get_style());
$frame->set_style($style);
continue;
}
$id = $frame->get_id();
// Handle HTML 4.0 attributes
Attribute_Translator::translate_attributes($frame);
// Locate any additional style attributes
if ( ($str = $frame->get_node()->getAttribute("style")) !== "" ) {
$spec = $this->_specificity("!style attribute");
$styles[$id][$spec][] = $this->_parse_properties($str);
}
// Grab the applicable styles
if ( isset($styles[$id]) ) {
$applied_styles = $styles[ $frame->get_id() ];
// Sort by specificity
ksort($applied_styles);
// Merge the new styles with the inherited styles
foreach ($applied_styles as $arr) {
foreach ($arr as $s)
$style->merge($s);
}
}
// Inherit parent's styles if required
if ( $p ) {
$style->inherit( $p->get_style() );
}
// pre_r($frame->get_node()->nodeName . ":");
// echo "<pre>";
// echo $style;
// echo "</pre>";
$frame->set_style($style);
}
// We're done! Clean out the registry of all styles since we
// won't be needing this later.
foreach ( array_keys($this->_styles) as $key ) {
unset($this->_styles[$key]);
}
}
/**
* parse a CSS string using a regex parser
*
* Called by {@link Stylesheet::parse_css()}
*
* @param string $str
*/
private function _parse_css($str) {
// Destroy comments
$css = preg_replace("'/\*.*?\*/'si", "", $str);
// FIXME: handle '{' within strings, e.g. [attr="string {}"]
// Something more legible:
$re =
"/\s* # Skip leading whitespace \n".
"( @([^\s]+)\s+([^{;]*) (?:;|({)) )? # Match @rules followed by ';' or '{' \n".
"(?(1) # Only parse sub-sections if we're in an @rule... \n".
" (?(4) # ...and if there was a leading '{' \n".
" \s*( (?:(?>[^{}]+) ({)? # Parse rulesets and individual @page rules \n".
" (?(6) (?>[^}]*) }) \s*)+? \n".
" ) \n".
" }) # Balancing '}' \n".
"| # Branch to match regular rules (not preceeded by '@')\n".
"([^{]*{[^}]*})) # Parse normal rulesets\n".
"/xs";
if ( preg_match_all($re, $css, $matches, PREG_SET_ORDER) === false )
// An error occured
throw new DOMPDF_Exception("Error parsing css file: preg_match_all() failed.");
// After matching, the array indicies are set as follows:
//
// [0] => complete text of match
// [1] => contains '@import ...;' or '@media {' if applicable
// [2] => text following @ for cases where [1] is set
// [3] => media types or full text following '@import ...;'
// [4] => '{', if present
// [5] => rulesets within media rules
// [6] => '{', within media rules
// [7] => individual rules, outside of media rules
//
//pre_r($matches);
foreach ( $matches as $match ) {
$match[2] = trim($match[2]);
if ( $match[2] !== "" ) {
// Handle @rules
switch ($match[2]) {
case "import":
$this->_parse_import($match[3]);
break;
case "media":
if ( in_array(mb_strtolower(trim($match[3])), self::$ACCEPTED_MEDIA_TYPES ) ) {
$this->_parse_sections($match[5]);
}
break;
case "page":
// Store the style for later...
if ( is_null($this->_page_style) )
$this->_page_style = $this->_parse_properties($match[5]);
else
$this->_page_style->merge($this->_parse_properties($match[5]));
break;
default:
// ignore everything else
break;
}
continue;
}
if ( $match[7] !== "" )
$this->_parse_sections($match[7]);
}
}
/**
* parse @import{} sections
*
* @param string $url the url of the imported CSS file
*/
private function _parse_import($url) {
$arr = preg_split("/[\s\n]/", $url);
$url = array_pop($arr);
$accept = false;
if ( count($arr) > 0 ) {
// @import url media_type [media_type...]
foreach ( $arr as $type ) {
if ( in_array($type, self::$ACCEPTED_MEDIA_TYPES) ) {
$accept = true;
break;
}
}
} else
// unconditional import
$accept = true;
if ( $accept ) {
$url = str_replace(array('"',"url", "(", ")"), "", $url);
// Store our current base url properties in case the new url is elsewhere
$protocol = $this->_protocol;
$host = $this->_base_host;
$path = $this->_base_path;
// If the protocol is php, assume that we will import using file://
$url = build_url($protocol == "php://" ? "file://" : $protocol, $host, $path, $url);
$this->load_css_file($url);
// Restore the current base url
$this->_protocol = $protocol;
$this->_base_host = $host;
$this->_base_path = $path;
}
}
/**
* parse regular CSS blocks
*
* _parse_properties() creates a new Style object based on the provided
* CSS rules.
*
* @param string $str CSS rules
* @return Style
*/
private function _parse_properties($str) {
$properties = explode(";", $str);
// Create the style
$style = new Style($this);
foreach ($properties as $prop) {
$prop = trim($prop);
if ($prop == "")
continue;
$i = mb_strpos($prop, ":");
if ( $i === false )
continue;
$prop_name = mb_strtolower(mb_substr($prop, 0, $i));
$value = mb_substr($prop, $i+1);
$style->$prop_name = $value;
}
return $style;
}
/**
* parse selector + rulesets
*
* @param string $str CSS selectors and rulesets
*/
private function _parse_sections($str) {
// Pre-process: collapse all whitespace and strip whitespace around '>',
// '.', ':', '+', '#'
$patterns = array("/[\\s\n]+/", "/\\s+([>.:+#])\\s+/");
$replacements = array(" ", "\\1");
$str = preg_replace($patterns, $replacements, $str);
$sections = explode("}", $str);
foreach ($sections as $sect) {
$i = mb_strpos($sect, "{");
$selectors = explode(",", mb_substr($sect, 0, $i));
$style = $this->_parse_properties(trim(mb_substr($sect, $i+1)));
// Assign it to the selected elements
foreach ($selectors as $selector) {
$selector = trim($selector);
if ($selector == "")
continue;
$this->add_style($selector, $style);
}
}
}
/**
* dumps the entire stylesheet as a string
*
* Generates a string of each selector and associated style in the
* Stylesheet. Useful for debugging.
*
* @return string
*/
function __toString() {
$str = "";
foreach ($this->_styles as $selector => $style)
$str .= "$selector => " . $style->__toString() . "\n";
return $str;
}
}
?>
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