Text_Diff_Engine_shell::diff() │ public │ WP 1.0

Returns the array of differences.

{} It's a method of the class: Text_Diff_Engine_shell{}

No Hooks.

Return

Array. all changes made (array with Text_Diff_Op_* objects)

Usage

$Text_Diff_Engine_shell = new Text_Diff_Engine_shell();
$Text_Diff_Engine_shell->diff( $from_lines, $to_lines );

$from_lines(array) (required)

lines of text from old file

$to_lines(array) (required)

lines of text from new file

Code of Text_Diff_Engine_shell::diff() Text Diff Engine shell::diff ^{WP 5.9.3}

function diff($from_lines, $to_lines)
{
    array_walk($from_lines, array('Text_Diff', 'trimNewlines'));
    array_walk($to_lines, array('Text_Diff', 'trimNewlines'));

    $temp_dir = Text_Diff::_getTempDir();

    // Execute gnu diff or similar to get a standard diff file.
    $from_file = tempnam($temp_dir, 'Text_Diff');
    $to_file = tempnam($temp_dir, 'Text_Diff');
    $fp = fopen($from_file, 'w');
    fwrite($fp, implode("\n", $from_lines));
    fclose($fp);
    $fp = fopen($to_file, 'w');
    fwrite($fp, implode("\n", $to_lines));
    fclose($fp);
    $diff = shell_exec($this->_diffCommand . ' ' . $from_file . ' ' . $to_file);
    unlink($from_file);
    unlink($to_file);

    if (is_null($diff)) {
        // No changes were made
        return array(new Text_Diff_Op_copy($from_lines));
    }

    $from_line_no = 1;
    $to_line_no = 1;
    $edits = array();

    // Get changed lines by parsing something like:
    // 0a1,2
    // 1,2c4,6
    // 1,5d6
    preg_match_all('#^(\d+)(?:,(\d+))?([adc])(\d+)(?:,(\d+))?$#m', $diff,
        $matches, PREG_SET_ORDER);

    foreach ($matches as $match) {
        if (!isset($match[5])) {
            // This paren is not set every time (see regex).
            $match[5] = false;
        }

        if ($match[3] == 'a') {
            $from_line_no--;
        }

        if ($match[3] == 'd') {
            $to_line_no--;
        }

        if ($from_line_no < $match[1] || $to_line_no < $match[4]) {
            // copied lines
            assert($match[1] - $from_line_no == $match[4] - $to_line_no);
            array_push($edits,
                new Text_Diff_Op_copy(
                    $this->_getLines($from_lines, $from_line_no, $match[1] - 1),
                    $this->_getLines($to_lines, $to_line_no, $match[4] - 1)));
        }

        switch ($match[3]) {
        case 'd':
            // deleted lines
            array_push($edits,
                new Text_Diff_Op_delete(
                    $this->_getLines($from_lines, $from_line_no, $match[2])));
            $to_line_no++;
            break;

        case 'c':
            // changed lines
            array_push($edits,
                new Text_Diff_Op_change(
                    $this->_getLines($from_lines, $from_line_no, $match[2]),
                    $this->_getLines($to_lines, $to_line_no, $match[5])));
            break;

        case 'a':
            // added lines
            array_push($edits,
                new Text_Diff_Op_add(
                    $this->_getLines($to_lines, $to_line_no, $match[5])));
            $from_line_no++;
            break;
        }
    }

    if (!empty($from_lines)) {
        // Some lines might still be pending. Add them as copied
        array_push($edits,
            new Text_Diff_Op_copy(
                $this->_getLines($from_lines, $from_line_no,
                                 $from_line_no + count($from_lines) - 1),
                $this->_getLines($to_lines, $to_line_no,
                                 $to_line_no + count($to_lines) - 1)));
    }

    return $edits;
}