PHP_Typography\Fixes\Node_Fixes\Dewidow_Fix

Complexity

Total Complexity

17

Size/Duplication

Total Lines	150
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	4

Test Coverage

Coverage

100%

Importance

Changes

0

5 Methods

Rating	Name	Duplication	Size	Complexity
B	apply()	0	12	5
A	strip_breaking_characters()	0	3	1
C	dewidow()	0	31	7
A	is_narrow_space()	0	3	3
A	make_space_nonbreaking()	0	15	1

<?php
/**
 *  This file is part of PHP-Typography.
 *
 *  Copyright 2014-2017 Peter Putzer.
 *  Copyright 2009-2011 KINGdesk, LLC.
 *
 *  This program is free software; you can redistribute it and/or modify modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 *  ***
 *
 *  @package mundschenk-at/php-typography
 *  @license http://www.gnu.org/licenses/gpl-2.0.html
 */

namespace PHP_Typography\Fixes\Node_Fixes;

use PHP_Typography\DOM;
use PHP_Typography\RE;
use PHP_Typography\Settings;
use PHP_Typography\Strings;
use PHP_Typography\U;

/**
 * Prevents widows (if enabled).
 *
 * @author Peter Putzer <github@mundschenk.at>
 *
 * @since 5.0.0
 */
class Dewidow_Fix extends Abstract_Node_Fix {
	const SPACE_BETWEEN = '[\s]+'; // \s includes all special spaces (but not ZWSP) with the u flag.
	const WIDOW         = '[\w\p{M}\-' . U::ZERO_WIDTH_SPACE . U::SOFT_HYPHEN . ']+?'; // \w includes all alphanumeric Unicode characters but not composed characters.

	// Mandatory UTF-8 modifer.
	const REGEX_START = '/
		(?:
			\A
			|
			(?:
				(?<space_before>            # subpattern 1: space before (note: ZWSP is not a space)
					[\s' . U::ZERO_WIDTH_SPACE . U::SOFT_HYPHEN . ']+
				)
				(?<neighbor>                # subpattern 2: neighbors widow (short as possible)
					[^\s' . U::ZERO_WIDTH_SPACE . U::SOFT_HYPHEN . ']+?
				)
			)
		)
		(?<space_between>                   # subpattern 3: space between
			' . self::SPACE_BETWEEN . '
		)
		(?<widow>                           # subpattern 4: widow
			' . self::WIDOW . '
			(?:
				' . self::SPACE_BETWEEN . self::WIDOW . '
			){0,'; // The maximum number of repetitions is missing.

	const REGEX_END =
		'})
		(?<trailing>                       # subpattern 5: any trailing punctuation or spaces
			[^\w\p{M}]*
		)
		\Z
	/Sxu';

	const MASKED_NARROW_SPACE = '__NO_BREAK_NARROW_SPACE__';

	/**
	 * Apply the fix to a given textnode.
	 *
	 * @param \DOMText $textnode Required.
	 * @param Settings $settings Required.
	 * @param bool     $is_title Optional. Default false.
	 */
	public function apply( \DOMText $textnode, Settings $settings, $is_title = false ) {
		// Intervening inline tags may interfere with widow identification, but that is a sacrifice of using the parser.
		// Intervening tags will only interfere if they separate the widow from previous or preceding whitespace.
		if ( empty( $settings['dewidow'] ) || empty( $settings['dewidowMaxPull'] ) || empty( $settings['dewidowMaxLength'] ) ) {
			return;
		}

		if ( '' === DOM::get_next_chr( $textnode ) ) {
			// We have the last type "text" child of a block level element.
			$textnode->data = $this->dewidow( $textnode->data, Strings::functions( $textnode->data ), $settings['dewidowMaxPull'], $settings['dewidowMaxLength'], $settings['dewidowWordNumber'], $settings->no_break_narrow_space() );
		}
	}

	/**
	 * Dewidow a given text fragment.
	 *
	 * @param  string $text         The text fragment to dewidow.
	 * @param  array  $func         An array of string functions.
	 * @param  int    $max_pull     Maximum number of characters pulled from previous line.
	 * @param  int    $max_length   Maximum widow length.
	 * @param  int    $word_number  Maximum number of words allowed in widow.
	 * @param  string $narrow_space The narrow no-break space character.
	 *
	 * @return string
	 */
	protected function dewidow( $text, array $func, $max_pull, $max_length, $word_number, $narrow_space ) {
		if ( $word_number < 1 ) {
			return $text; // We are done.
		}

		// Do what we have to do.
		return preg_replace_callback( self::REGEX_START . ( $word_number - 1 ) . self::REGEX_END, function( array $widow ) use ( $func, $max_pull, $max_length, $word_number, $narrow_space ) {

			// If we are here, we know that widows are being protected in some fashion
			// with that, we will assert that widows should never be hyphenated or wrapped
			// as such, we will strip soft hyphens and zero-width-spaces.
			$widow['widow']    = self::strip_breaking_characters( $widow['widow'] );
			$widow['trailing'] = self::strip_breaking_characters( self::make_space_nonbreaking( $widow['trailing'], $narrow_space, $func['u'] ) );

			if (
				// Eject if widows neighbor is proceeded by a no break space (the pulled text would be too long).
				'' === $widow['space_before'] || false !== \strpos( $widow['space_before'], U::NO_BREAK_SPACE ) ||

				// Eject if widows neighbor length exceeds the max allowed or widow length exceeds max allowed.
				$func['strlen']( $widow['neighbor'] ) > $max_pull || $func['strlen']( $widow['widow'] ) > $max_length ||

				// Never replace thin and hair spaces with &nbsp;.
				self::is_narrow_space( $widow['space_between'] )
			) {
				return $widow['space_before'] . $widow['neighbor'] . $this->dewidow( $widow['space_between'] . $widow['widow'] . $widow['trailing'], $func, $max_pull, $max_length, $word_number - 1, $narrow_space );
			}

			// Let's protect some widows!
			return $widow['space_before'] . $widow['neighbor'] . U::NO_BREAK_SPACE . self::make_space_nonbreaking( $widow['widow'], $narrow_space, $func['u'] ) . $widow['trailing'];
		}, $text );
	}

	/**
	 * Strip zero-width space and soft hyphens from the given string.
	 *
	 * @param  string $string Required.
	 *
	 * @return string
	 */
	protected static function strip_breaking_characters( $string ) {
		return str_replace( [ U::ZERO_WIDTH_SPACE, U::SOFT_HYPHEN ], '', $string );
	}

	/**
	 * Is the given string one of the narrow space characters?
	 *
	 * @since 6.0.0
	 *
	 * @param  string $string The whitespace to test.
	 *
	 * @return bool
	 */
	protected static function is_narrow_space( $string ) {
		return U::THIN_SPACE === $string || U::HAIR_SPACE === $string || U::NO_BREAK_NARROW_SPACE === $string;
	}

	/**
	 * Strip zero-width space and soft hyphens from the given string.
	 *
	 * @param  string $string       Required.
	 * @param  string $narrow_space The narrow no-break space character.
	 * @param  string $u            Either 'u' or the empty string.
	 *
	 * @return string
	 */
	protected static function make_space_nonbreaking( $string, $narrow_space, $u ) {
		return preg_replace(
			[
				'/\s*' . U::THIN_SPACE . '\s*/u',
				'/\s*' . U::NO_BREAK_NARROW_SPACE . '\s*/u',
				"/\\s+/$u",
				'/' . self::MASKED_NARROW_SPACE . "/$u",
			], [
				self::MASKED_NARROW_SPACE,
				self::MASKED_NARROW_SPACE,
				U::NO_BREAK_SPACE,
				$narrow_space,
			], $string
		);
	}
}