<?php declare(strict_types=1);
/*
* This file is part of sebastian/diff.
*
* (c) Sebastian Bergmann <[email protected]>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace SebastianBergmann\Diff\Output;
use function array_splice;
use function count;
use function fclose;
use function fopen;
use function fwrite;
use function max;
use function min;
use function stream_get_contents;
use function strlen;
use function substr;
use SebastianBergmann\Diff\Differ;
/**
* Builds a diff string representation in unified diff format in chunks.
*/
final class UnifiedDiffOutputBuilder extends AbstractChunkOutputBuilder
{
/**
* @var bool
*/
private $collapseRanges = true;
/**
* @var int >= 0
*/
private $commonLineThreshold = 6;
/**
* @var int >= 0
*/
private $contextLines = 3;
/**
* @var string
*/
private $header;
/**
* @var bool
*/
private $addLineNumbers;
public function __construct(string $header = "--- Original\n+++ New\n", bool $addLineNumbers = false)
{
$this->header = $header;
$this->addLineNumbers = $addLineNumbers;
}
public function getDiff(array $diff): string
{
$buffer = fopen('php://memory', 'r+b');
if ('' !== $this->header) {
fwrite($buffer, $this->header);
if ("\n" !== substr($this->header, -1, 1)) {
fwrite($buffer, "\n");
}
}
if (0 !== count($diff)) {
$this->writeDiffHunks($buffer, $diff);
}
$diff = stream_get_contents($buffer, -1, 0);
fclose($buffer);
// If the diff is non-empty and last char is not a linebreak: add it.
// This might happen when both the `from` and `to` do not have a trailing linebreak
$last = substr($diff, -1);
return 0 !== strlen($diff) && "\n" !== $last && "\r" !== $last
? $diff . "\n"
: $diff;
}
private function writeDiffHunks($output, array $diff): void
{
// detect "No newline at end of file" and insert into `$diff` if needed
$upperLimit = count($diff);
if (0 === $diff[$upperLimit - 1][1]) {
$lc = substr($diff[$upperLimit - 1][0], -1);
if ("\n" !== $lc) {
array_splice($diff, $upperLimit, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
}
} else {
// search back for the last `+` and `-` line,
// check if has trailing linebreak, else add under it warning under it
$toFind = [1 => true, 2 => true];
for ($i = $upperLimit - 1; $i >= 0; --$i) {
if (isset($toFind[$diff[$i][1]])) {
unset($toFind[$diff[$i][1]]);
$lc = substr($diff[$i][0], -1);
if ("\n" !== $lc) {
array_splice($diff, $i + 1, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
}
if (!count($toFind)) {
break;
}
}
}
}
// write hunks to output buffer
$cutOff = max($this->commonLineThreshold, $this->contextLines);
$hunkCapture = false;
$sameCount = $toRange = $fromRange = 0;
$toStart = $fromStart = 1;
$i = 0;
/** @var int $i */
foreach ($diff as $i => $entry) {
if (0 === $entry[1]) { // same
if (false === $hunkCapture) {
++$fromStart;
++$toStart;
continue;
}
++$sameCount;
++$toRange;
++$fromRange;
if ($sameCount === $cutOff) {
$contextStartOffset = ($hunkCapture - $this->contextLines) < 0
? $hunkCapture
: $this->contextLines;
// note: $contextEndOffset = $this->contextLines;
//
// because we never go beyond the end of the diff.
// with the cutoff/contextlines here the follow is never true;
//
// if ($i - $cutOff + $this->contextLines + 1 > \count($diff)) {
// $contextEndOffset = count($diff) - 1;
// }
//
// ; that would be true for a trailing incomplete hunk case which is dealt with after this loop
$this->writeHunk(
$diff,
$hunkCapture - $contextStartOffset,
$i - $cutOff + $this->contextLines + 1,
$fromStart - $contextStartOffset,
$fromRange - $cutOff + $contextStartOffset + $this->contextLines,
$toStart - $contextStartOffset,
$toRange - $cutOff + $contextStartOffset + $this->contextLines,
$output
);
$fromStart += $fromRange;
$toStart += $toRange;
$hunkCapture = false;
$sameCount = $toRange = $fromRange = 0;
}
continue;
}
$sameCount = 0;
if ($entry[1] === Differ::NO_LINE_END_EOF_WARNING) {
continue;
}
if (false === $hunkCapture) {
$hunkCapture = $i;
}
if (Differ::ADDED === $entry[1]) {
++$toRange;
}
if (Differ::REMOVED === $entry[1]) {
++$fromRange;
}
}
if (false === $hunkCapture) {
return;
}
// we end here when cutoff (commonLineThreshold) was not reached, but we where capturing a hunk,
// do not render hunk till end automatically because the number of context lines might be less than the commonLineThreshold
$contextStartOffset = $hunkCapture - $this->contextLines < 0
? $hunkCapture
: $this->contextLines;
// prevent trying to write out more common lines than there are in the diff _and_
// do not write more than configured through the context lines
$contextEndOffset = min($sameCount, $this->contextLines);
$fromRange -= $sameCount;
$toRange -= $sameCount;
$this->writeHunk(
$diff,
$hunkCapture - $contextStartOffset,
$i - $sameCount + $contextEndOffset + 1,
$fromStart - $contextStartOffset,
$fromRange + $contextStartOffset + $contextEndOffset,
$toStart - $contextStartOffset,
$toRange + $contextStartOffset + $contextEndOffset,
$output
);
}
private function writeHunk(
array $diff,
int $diffStartIndex,
int $diffEndIndex,
int $fromStart,
int $fromRange,
int $toStart,
int $toRange,
$output
): void {
if ($this->addLineNumbers) {
fwrite($output, '@@ -' . $fromStart);
if (!$this->collapseRanges || 1 !== $fromRange) {
fwrite($output, ',' . $fromRange);
}
fwrite($output, ' +' . $toStart);
if (!$this->collapseRanges || 1 !== $toRange) {
fwrite($output, ',' . $toRange);
}
fwrite($output, " @@\n");
} else {
fwrite($output, "@@ @@\n");
}
for ($i = $diffStartIndex; $i < $diffEndIndex; ++$i) {
if ($diff[$i][1] === Differ::ADDED) {
fwrite($output, '+' . $diff[$i][0]);
} elseif ($diff[$i][1] === Differ::REMOVED) {
fwrite($output, '-' . $diff[$i][0]);
} elseif ($diff[$i][1] === Differ::OLD) {
fwrite($output, ' ' . $diff[$i][0]);
} elseif ($diff[$i][1] === Differ::NO_LINE_END_EOF_WARNING) {
fwrite($output, "\n"); // $diff[$i][0]
} else { /* Not changed (old) Differ::OLD or Warning Differ::DIFF_LINE_END_WARNING */
fwrite($output, ' ' . $diff[$i][0]);
}
}
}
}