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wp-includes/class-wp-text-diff-renderer-table.php

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<?php
/**
 * Diff API: WP_Text_Diff_Renderer_Table class
 *
 * @package WordPress
 * @subpackage Diff
 * @since 4.7.0
 */

/**
 * Table renderer to display the diff lines.
 *
 * @since 2.6.0
 * @uses Text_Diff_Renderer Extends
 */
#[AllowDynamicProperties]
class WP_Text_Diff_Renderer_Table extends Text_Diff_Renderer {

    /**
     * @see Text_Diff_Renderer::_leading_context_lines
     * @var int
     * @since 2.6.0
     */
    public $_leading_context_lines = 10000;

    /**
     * @see Text_Diff_Renderer::_trailing_context_lines
     * @var int
     * @since 2.6.0
     */
    public $_trailing_context_lines = 10000;

    /**
     * Title of the item being compared.
     *
     * @since 6.4.0 Declared a previously dynamic property.
     * @var string|null
     */
    public $_title;

    /**
     * Title for the left column.
     *
     * @since 6.4.0 Declared a previously dynamic property.
     * @var string|null
     */
    public $_title_left;

    /**
     * Title for the right column.
     *
     * @since 6.4.0 Declared a previously dynamic property.
     * @var string|null
     */
    public $_title_right;

    /**
     * Threshold for when a diff should be saved or omitted.
     *
     * @var float
     * @since 2.6.0
     */
    protected $_diff_threshold = 0.6;

    /**
     * Inline display helper object name.
     *
     * @var string
     * @since 2.6.0
     */
    protected $inline_diff_renderer = 'WP_Text_Diff_Renderer_inline';

    /**
     * Should we show the split view or not
     *
     * @var string
     * @since 3.6.0
     */
    protected $_show_split_view = true;

    protected $compat_fields = array( '_show_split_view', 'inline_diff_renderer', '_diff_threshold' );

    /**
     * Caches the output of count_chars() in compute_string_distance()
     *
     * @var array
     * @since 5.0.0
     */
    protected $count_cache = array();

    /**
     * Caches the difference calculation in compute_string_distance()
     *
     * @var array
     * @since 5.0.0
     */
    protected $difference_cache = array();

    /**
     * Constructor - Call parent constructor with params array.
     *
     * This will set class properties based on the key value pairs in the array.
     *
     * @since 2.6.0
     *
     * @param array $params
     */
    public function __construct( $params = array() ) {
        parent::__construct( $params );
        if ( isset( $params['show_split_view'] ) ) {
            $this->_show_split_view = $params['show_split_view'];
        }
    }

    /**
     * @ignore
     *
     * @param string $header
     * @return string
     */
    public function _startBlock( $header ) {
        return '';
    }

    /**
     * @ignore
     *
     * @param array  $lines
     * @param string $prefix
     */
    public function _lines( $lines, $prefix = ' ' ) {
    }

    /**
     * @ignore
     *
     * @param string $line HTML-escape the value.
     * @return string
     */
    public function addedLine( $line ) {
        return "<td class='diff-addedline'><span aria-hidden='true' class='dashicons dashicons-plus'></span><span class='screen-reader-text'>" .
            /* translators: Hidden accessibility text. */
            __( 'Added:' ) .
        " </span>{$line}</td>";
    }

    /**
     * @ignore
     *
     * @param string $line HTML-escape the value.
     * @return string
     */
    public function deletedLine( $line ) {
        return "<td class='diff-deletedline'><span aria-hidden='true' class='dashicons dashicons-minus'></span><span class='screen-reader-text'>" .
            /* translators: Hidden accessibility text. */
            __( 'Deleted:' ) .
        " </span>{$line}</td>";
    }

    /**
     * @ignore
     *
     * @param string $line HTML-escape the value.
     * @return string
     */
    public function contextLine( $line ) {
        return "<td class='diff-context'><span class='screen-reader-text'>" .
            /* translators: Hidden accessibility text. */
            __( 'Unchanged:' ) .
        " </span>{$line}</td>";
    }

    /**
     * @ignore
     *
     * @return string
     */
    public function emptyLine() {
        return '<td>&nbsp;</td>';
    }

    /**
     * @ignore
     *
     * @param array $lines
     * @param bool  $encode
     * @return string
     */
    public function _added( $lines, $encode = true ) {
        $r = '';
        foreach ( $lines as $line ) {
            if ( $encode ) {
                $processed_line = htmlspecialchars( $line );

                /**
                 * Contextually filters a diffed line.
                 *
                 * Filters TextDiff processing of diffed line. By default, diffs are processed with
                 * htmlspecialchars. Use this filter to remove or change the processing. Passes a context
                 * indicating if the line is added, deleted or unchanged.
                 *
                 * @since 4.1.0
                 *
                 * @param string $processed_line The processed diffed line.
                 * @param string $line           The unprocessed diffed line.
                 * @param string $context        The line context. Values are 'added', 'deleted' or 'unchanged'.
                 */
                $line = apply_filters( 'process_text_diff_html', $processed_line, $line, 'added' );
            }

            if ( $this->_show_split_view ) {
                $r .= '<tr>' . $this->emptyLine() . $this->addedLine( $line ) . "</tr>\n";
            } else {
                $r .= '<tr>' . $this->addedLine( $line ) . "</tr>\n";
            }
        }
        return $r;
    }

    /**
     * @ignore
     *
     * @param array $lines
     * @param bool  $encode
     * @return string
     */
    public function _deleted( $lines, $encode = true ) {
        $r = '';
        foreach ( $lines as $line ) {
            if ( $encode ) {
                $processed_line = htmlspecialchars( $line );

                /** This filter is documented in wp-includes/wp-diff.php */
                $line = apply_filters( 'process_text_diff_html', $processed_line, $line, 'deleted' );
            }
            if ( $this->_show_split_view ) {
                $r .= '<tr>' . $this->deletedLine( $line ) . $this->emptyLine() . "</tr>\n";
            } else {
                $r .= '<tr>' . $this->deletedLine( $line ) . "</tr>\n";
            }
        }
        return $r;
    }

    /**
     * @ignore
     *
     * @param array $lines
     * @param bool  $encode
     * @return string
     */
    public function _context( $lines, $encode = true ) {
        $r = '';
        foreach ( $lines as $line ) {
            if ( $encode ) {
                $processed_line = htmlspecialchars( $line );

                /** This filter is documented in wp-includes/wp-diff.php */
                $line = apply_filters( 'process_text_diff_html', $processed_line, $line, 'unchanged' );
            }
            if ( $this->_show_split_view ) {
                $r .= '<tr>' . $this->contextLine( $line ) . $this->contextLine( $line ) . "</tr>\n";
            } else {
                $r .= '<tr>' . $this->contextLine( $line ) . "</tr>\n";
            }
        }
        return $r;
    }

    /**
     * Process changed lines to do word-by-word diffs for extra highlighting.
     *
     * (TRAC style) sometimes these lines can actually be deleted or added rows.
     * We do additional processing to figure that out
     *
     * @since 2.6.0
     *
     * @param array $orig
     * @param array $final
     * @return string
     */
    public function _changed( $orig, $final ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.finalFound
        $r = '';

        /*
         * Does the aforementioned additional processing:
         * *_matches tell what rows are "the same" in orig and final. Those pairs will be diffed to get word changes.
         * - match is numeric: an index in other column.
         * - match is 'X': no match. It is a new row.
         * *_rows are column vectors for the orig column and the final column.
         * - row >= 0: an index of the $orig or $final array.
         * - row < 0: a blank row for that column.
         */
        list($orig_matches, $final_matches, $orig_rows, $final_rows) = $this->interleave_changed_lines( $orig, $final );

        // These will hold the word changes as determined by an inline diff.
        $orig_diffs  = array();
        $final_diffs = array();

        // Compute word diffs for each matched pair using the inline diff.
        foreach ( $orig_matches as $o => $f ) {
            if ( is_numeric( $o ) && is_numeric( $f ) ) {
                $text_diff = new Text_Diff( 'auto', array( array( $orig[ $o ] ), array( $final[ $f ] ) ) );
                $renderer  = new $this->inline_diff_renderer();
                $diff      = $renderer->render( $text_diff );

                // If they're too different, don't include any <ins> or <del>'s.
                if ( preg_match_all( '!(<ins>.*?</ins>|<del>.*?</del>)!', $diff, $diff_matches ) ) {
                    // Length of all text between <ins> or <del>.
                    $stripped_matches = strlen( strip_tags( implode( ' ', $diff_matches[0] ) ) );
                    /*
                     * Since we count length of text between <ins> or <del> (instead of picking just one),
                     * we double the length of chars not in those tags.
                     */
                    $stripped_diff = strlen( strip_tags( $diff ) ) * 2 - $stripped_matches;
                    $diff_ratio    = $stripped_matches / $stripped_diff;
                    if ( $diff_ratio > $this->_diff_threshold ) {
                        continue; // Too different. Don't save diffs.
                    }
                }

                // Un-inline the diffs by removing <del> or <ins>.
                $orig_diffs[ $o ]  = preg_replace( '|<ins>.*?</ins>|', '', $diff );
                $final_diffs[ $f ] = preg_replace( '|<del>.*?</del>|', '', $diff );
            }
        }

        foreach ( array_keys( $orig_rows ) as $row ) {
            // Both columns have blanks. Ignore them.
            if ( $orig_rows[ $row ] < 0 && $final_rows[ $row ] < 0 ) {
                continue;
            }

            // If we have a word based diff, use it. Otherwise, use the normal line.
            if ( isset( $orig_diffs[ $orig_rows[ $row ] ] ) ) {
                $orig_line = $orig_diffs[ $orig_rows[ $row ] ];
            } elseif ( isset( $orig[ $orig_rows[ $row ] ] ) ) {
                $orig_line = htmlspecialchars( $orig[ $orig_rows[ $row ] ] );
            } else {
                $orig_line = '';
            }

            if ( isset( $final_diffs[ $final_rows[ $row ] ] ) ) {
                $final_line = $final_diffs[ $final_rows[ $row ] ];
            } elseif ( isset( $final[ $final_rows[ $row ] ] ) ) {
                $final_line = htmlspecialchars( $final[ $final_rows[ $row ] ] );
            } else {
                $final_line = '';
            }

            if ( $orig_rows[ $row ] < 0 ) { // Orig is blank. This is really an added row.
                $r .= $this->_added( array( $final_line ), false );
            } elseif ( $final_rows[ $row ] < 0 ) { // Final is blank. This is really a deleted row.
                $r .= $this->_deleted( array( $orig_line ), false );
            } else { // A true changed row.
                if ( $this->_show_split_view ) {
                    $r .= '<tr>' . $this->deletedLine( $orig_line ) . $this->addedLine( $final_line ) . "</tr>\n";
                } else {
                    $r .= '<tr>' . $this->deletedLine( $orig_line ) . '</tr><tr>' . $this->addedLine( $final_line ) . "</tr>\n";
                }
            }
        }

        return $r;
    }

    /**
     * Takes changed blocks and matches which rows in orig turned into which rows in final.
     *
     * @since 2.6.0
     *
     * @param array $orig  Lines of the original version of the text.
     * @param array $final Lines of the final version of the text.
     * @return array {
     *     Array containing results of comparing the original text to the final text.
     *
     *     @type array $orig_matches  Associative array of original matches. Index == row
     *                                number of `$orig`, value == corresponding row number
     *                                of that same line in `$final` or 'x' if there is no
     *                                corresponding row (indicating it is a deleted line).
     *     @type array $final_matches Associative array of final matches. Index == row
     *                                number of `$final`, value == corresponding row number
     *                                of that same line in `$orig` or 'x' if there is no
     *                                corresponding row (indicating it is a new line).
     *     @type array $orig_rows     Associative array of interleaved rows of `$orig` with
     *                                blanks to keep matches aligned with side-by-side diff
     *                                of `$final`. A value >= 0 corresponds to index of `$orig`.
     *                                Value < 0 indicates a blank row.
     *     @type array $final_rows    Associative array of interleaved rows of `$final` with
     *                                blanks to keep matches aligned with side-by-side diff
     *                                of `$orig`. A value >= 0 corresponds to index of `$final`.
     *                                Value < 0 indicates a blank row.
     * }
     */
    public function interleave_changed_lines( $orig, $final ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.finalFound

        // Contains all pairwise string comparisons. Keys are such that this need only be a one dimensional array.
        $matches = array();
        foreach ( array_keys( $orig ) as $o ) {
            foreach ( array_keys( $final ) as $f ) {
                $matches[ "$o,$f" ] = $this->compute_string_distance( $orig[ $o ], $final[ $f ] );
            }
        }
        asort( $matches ); // Order by string distance.

        $orig_matches  = array();
        $final_matches = array();

        foreach ( $matches as $keys => $difference ) {
            list($o, $f) = explode( ',', $keys );
            $o           = (int) $o;
            $f           = (int) $f;

            // Already have better matches for these guys.
            if ( isset( $orig_matches[ $o ] ) && isset( $final_matches[ $f ] ) ) {
                continue;
            }

            // First match for these guys. Must be best match.
            if ( ! isset( $orig_matches[ $o ] ) && ! isset( $final_matches[ $f ] ) ) {
                $orig_matches[ $o ]  = $f;
                $final_matches[ $f ] = $o;
                continue;
            }

            // Best match of this final is already taken? Must mean this final is a new row.
            if ( isset( $orig_matches[ $o ] ) ) {
                $final_matches[ $f ] = 'x';
            } elseif ( isset( $final_matches[ $f ] ) ) {
                // Best match of this orig is already taken? Must mean this orig is a deleted row.
                $orig_matches[ $o ] = 'x';
            }
        }

        // We read the text in this order.
        ksort( $orig_matches );
        ksort( $final_matches );

        // Stores rows and blanks for each column.
        $orig_rows      = array_keys( $orig_matches );
        $orig_rows_copy = $orig_rows;
        $final_rows     = array_keys( $final_matches );

        /*
         * Interleaves rows with blanks to keep matches aligned.
         * We may end up with some extraneous blank rows, but we'll just ignore them later.
         */
        foreach ( $orig_rows_copy as $orig_row ) {
            $final_pos = array_search( $orig_matches[ $orig_row ], $final_rows, true );
            $orig_pos  = (int) array_search( $orig_row, $orig_rows, true );

            if ( false === $final_pos ) { // This orig is paired with a blank final.
                array_splice( $final_rows, $orig_pos, 0, -1 );
            } elseif ( $final_pos < $orig_pos ) { // This orig's match is up a ways. Pad final with blank rows.
                $diff_array = range( -1, $final_pos - $orig_pos );
                array_splice( $final_rows, $orig_pos, 0, $diff_array );
            } elseif ( $final_pos > $orig_pos ) { // This orig's match is down a ways. Pad orig with blank rows.
                $diff_array = range( -1, $orig_pos - $final_pos );
                array_splice( $orig_rows, $orig_pos, 0, $diff_array );
            }
        }

        // Pad the ends with blank rows if the columns aren't the same length.
        $diff_count = count( $orig_rows ) - count( $final_rows );
        if ( $diff_count < 0 ) {
            while ( $diff_count < 0 ) {
                array_push( $orig_rows, $diff_count++ );
            }
        } elseif ( $diff_count > 0 ) {
            $diff_count = -1 * $diff_count;
            while ( $diff_count < 0 ) {
                array_push( $final_rows, $diff_count++ );
            }
        }

        return array( $orig_matches, $final_matches, $orig_rows, $final_rows );
    }

    /**
     * Computes a number that is intended to reflect the "distance" between two strings.
     *
     * @since 2.6.0
     *
     * @param string $string1
     * @param string $string2
     * @return int
     */
    public function compute_string_distance( $string1, $string2 ) {
        // Use an md5 hash of the strings for a count cache, as it's fast to generate, and collisions aren't a concern.
        $count_key1 = md5( $string1 );
        $count_key2 = md5( $string2 );

        // Cache vectors containing character frequency for all chars in each string.
        if ( ! isset( $this->count_cache[ $count_key1 ] ) ) {
            $this->count_cache[ $count_key1 ] = count_chars( $string1 );
        }
        if ( ! isset( $this->count_cache[ $count_key2 ] ) ) {
            $this->count_cache[ $count_key2 ] = count_chars( $string2 );
        }

        $chars1 = $this->count_cache[ $count_key1 ];
        $chars2 = $this->count_cache[ $count_key2 ];

        $difference_key = md5( implode( ',', $chars1 ) . ':' . implode( ',', $chars2 ) );
        if ( ! isset( $this->difference_cache[ $difference_key ] ) ) {
            // L1-norm of difference vector.
            $this->difference_cache[ $difference_key ] = array_sum( array_map( array( $this, 'difference' ), $chars1, $chars2 ) );
        }

        $difference = $this->difference_cache[ $difference_key ];

        // $string1 has zero length? Odd. Give huge penalty by not dividing.
        if ( ! $string1 ) {
            return $difference;
        }

        // Return distance per character (of string1).
        return $difference / strlen( $string1 );
    }

    /**
     * @ignore
     * @since 2.6.0
     *
     * @param int $a
     * @param int $b
     * @return int
     */
    public function difference( $a, $b ) {
        return abs( $a - $b );
    }

    /**
     * Make private properties readable for backward compatibility.
     *
     * @since 4.0.0
     * @since 6.4.0 Getting a dynamic property is deprecated.
     *
     * @param string $name Property to get.
     * @return mixed A declared property's value, else null.
     */
    public function __get( $name ) {
        if ( in_array( $name, $this->compat_fields, true ) ) {
            return $this->$name;
        }

        wp_trigger_error(
            __METHOD__,
            "The property `{$name}` is not declared. Getting a dynamic property is " .
            'deprecated since version 6.4.0! Instead, declare the property on the class.',
            E_USER_DEPRECATED
        );
        return null;
    }

    /**
     * Make private properties settable for backward compatibility.
     *
     * @since 4.0.0
     * @since 6.4.0 Setting a dynamic property is deprecated.
     *
     * @param string $name  Property to check if set.
     * @param mixed  $value Property value.
     */
    public function __set( $name, $value ) {
        if ( in_array( $name, $this->compat_fields, true ) ) {
            $this->$name = $value;
            return;
        }

        wp_trigger_error(
            __METHOD__,
            "The property `{$name}` is not declared. Setting a dynamic property is " .
            'deprecated since version 6.4.0! Instead, declare the property on the class.',
            E_USER_DEPRECATED
        );
    }

    /**
     * Make private properties checkable for backward compatibility.
     *
     * @since 4.0.0
     * @since 6.4.0 Checking a dynamic property is deprecated.
     *
     * @param string $name Property to check if set.
     * @return bool Whether the property is set.
     */
    public function __isset( $name ) {
        if ( in_array( $name, $this->compat_fields, true ) ) {
            return isset( $this->$name );
        }

        wp_trigger_error(
            __METHOD__,
            "The property `{$name}` is not declared. Checking `isset()` on a dynamic property " .
            'is deprecated since version 6.4.0! Instead, declare the property on the class.',
            E_USER_DEPRECATED
        );
        return false;
    }

    /**
     * Make private properties un-settable for backward compatibility.
     *
     * @since 4.0.0
     * @since 6.4.0 Unsetting a dynamic property is deprecated.
     *
     * @param string $name Property to unset.
     */
    public function __unset( $name ) {
        if ( in_array( $name, $this->compat_fields, true ) ) {
            unset( $this->$name );
            return;
        }

        wp_trigger_error(
            __METHOD__,
            "A property `{$name}` is not declared. Unsetting a dynamic property is " .
            'deprecated since version 6.4.0! Instead, declare the property on the class.',
            E_USER_DEPRECATED
        );
    }
}