abstract class DiffFormatter

backdrop_class_list in core/includes/bootstrap.classes.inc

Lists all the classes used by Backdrop core.

abstract class DiffFormatter {
  /** @var int Number of leading context "lines" to preserve.
   *
   * This should be left at zero for this class, but subclasses
   * may want to set this to other values.
   */
  protected $leadingContextLines = 2;

  /** @var int Number of trailing context "lines" to preserve.
   *
   * This should be left at zero for this class, but subclasses
   * may want to set this to other values.
   */
  protected $trailingContextLines = 2;

  /**
   * Format a diff.
   *
   * @param $diff Diff A Diff object.
   *
   * @return string The formatted output.
   */
  public function format($diff) {
    $xi = $yi = 1;
    $block = FALSE;
    $context = array();

    $nlead = $this->leadingContextLines;
    $ntrail = $this->trailingContextLines;

    $this->startDiff();

    // Initialize $x0 and $y0 to prevent IDEs from getting confused.
    $x0 = $y0 = 0;
    foreach ($diff->edits as $edit) {
      if ($edit->type == 'copy') {
        if (is_array($block)) {
          if (count($edit->orig) <= $nlead + $ntrail) {
            $block[] = $edit;
          }
          else {
            if ($ntrail) {
              $context = array_slice($edit->orig, 0, $ntrail);
              $block[] = new DiffOpCopy($context);
            }
            $this->block($x0, $ntrail + $xi - $x0, 
            $y0, $ntrail + $yi - $y0, 
            $block);
            $block = FALSE;
          }
        }
        $context = $edit->orig;
      }
      else {
        if (!is_array($block)) {
          $context = array_slice($context, count($context) - $nlead);
          $x0 = $xi - count($context);
          $y0 = $yi - count($context);
          $block = array();
          if ($context) {
            $block[] = new DiffOpCopy($context);
          }
        }
        $block[] = $edit;
      }

      if ($edit->orig) {
        $xi += count($edit->orig);
      }
      if ($edit->closing) {
        $yi += count($edit->closing);
      }
    }

    if (is_array($block)) {
      $this->block($x0, $xi - $x0, 
      $y0, $yi - $y0, 
      $block);
    }

    $end = $this->endDiff();

    return $end;
  }

  /**
   * @param int $xbeg
   * @param int $xlen
   * @param int $ybeg
   * @param int $ylen
   * @param $edits
   *
   * @throws Exception
   */
  protected function block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
    $this->startBlock($this->blockHeader($xbeg, $xlen, $ybeg, $ylen));
    foreach ($edits as $edit) {
      if ($edit->type == 'copy') {
        $this->context($edit->orig);
      }
      elseif ($edit->type == 'add') {
        $this->added($edit->closing);
      }
      elseif ($edit->type == 'delete') {
        $this->deleted($edit->orig);
      }
      elseif ($edit->type == 'change') {
        $this->changed($edit->orig, $edit->closing);
      }
      else {
        throw new Exception("Unknown edit type: {$edit->type}");
      }
    }
    $this->endBlock();
  }

  protected function startDiff() {
    ob_start();
  }

  /**
   * @return string
   */
  protected function endDiff() {
    $val = ob_get_contents();
    ob_end_clean();

    return $val;
  }

  /**
   * @param $xbeg
   * @param $xlen
   * @param $ybeg
   * @param $ylen
   *
   * @return string
   */
  protected function blockHeader($xbeg, $xlen, $ybeg, $ylen) {
    if ($xlen > 1) {
      $xbeg .= ',' . ($xbeg + $xlen - 1);
    }
    if ($ylen > 1) {
      $ybeg .= ',' . ($ybeg + $ylen - 1);
    }

    return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
  }

  protected function startBlock($header) {
    echo $header . "\n";
  }

  protected function endBlock() {
  }

  /**
   * @param $lines
   * @param $prefix string
   */
  protected function lines($lines, $prefix = ' ') {
    foreach ($lines as $line) {
      echo "$prefix $line\n";
    }
  }

  /**
   * @param $lines
   */
  protected function context($lines) {
    $this->lines($lines);
  }

  /**
   * @param $lines
   */
  protected function added($lines) {
    $this->lines($lines, '>');
  }

  /**
   * @param $lines
   */
  protected function deleted($lines) {
    $this->lines($lines, '<');
  }

  /**
   * @param $orig
   * @param $closing
   */
  protected function changed($orig, $closing) {
    $this->deleted($orig);
    echo "---\n";
    $this->added($closing);
  }
}