<?php declare(strict_types=1);
/*
* This file is part of sebastian/diff.
*
* (c) Sebastian Bergmann <sebastian@phpunit.de>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace SebastianBergmann\Diff;
use SebastianBergmann\Diff\Output\DiffOutputBuilderInterface;
use SebastianBergmann\Diff\Output\UnifiedDiffOutputBuilder;
/**
* Diff implementation.
*/
final class Differ
{
/**
* @var DiffOutputBuilderInterface
*/
private $outputBuilder;
/**
* @param DiffOutputBuilderInterface $outputBuilder
*
* @throws InvalidArgumentException
*/
public function __construct($outputBuilder = null)
{
if ($outputBuilder instanceof DiffOutputBuilderInterface) {
$this->outputBuilder = $outputBuilder;
} elseif (null === $outputBuilder) {
$this->outputBuilder = new UnifiedDiffOutputBuilder;
} elseif (\is_string($outputBuilder)) {
// PHPUnit 6.1.4, 6.2.0, 6.2.1, 6.2.2, and 6.2.3 support
// @see https://github.com/sebastianbergmann/phpunit/issues/2734#issuecomment-314514056
// @deprecated
$this->outputBuilder = new UnifiedDiffOutputBuilder($outputBuilder);
} else {
throw new InvalidArgumentException(
\sprintf(
'Expected builder to be an instance of DiffOutputBuilderInterface, <null> or a string, got %s.',
\is_object($outputBuilder) ? 'instance of "' . \get_class($outputBuilder) . '"' : \gettype($outputBuilder) . ' "' . $outputBuilder . '"'
)
);
}
}
/**
* Returns the diff between two arrays or strings as string.
*
* @param array|string $from
* @param array|string $to
* @param LongestCommonSubsequenceCalculator|null $lcs
*
* @return string
*/
public function diff($from, $to, LongestCommonSubsequenceCalculator $lcs = null): string
{
$from = $this->validateDiffInput($from);
$to = $this->validateDiffInput($to);
$diff = $this->diffToArray($from, $to, $lcs);
return $this->outputBuilder->getDiff($diff);
}
/**
* Casts variable to string if it is not a string or array.
*
* @param mixed $input
*
* @return string
*/
private function validateDiffInput($input): string
{
if (!\is_array($input) && !\is_string($input)) {
return (string) $input;
}
return $input;
}
/**
* Returns the diff between two arrays or strings as array.
*
* Each array element contains two elements:
* - [0] => mixed $token
* - [1] => 2|1|0
*
* - 2: REMOVED: $token was removed from $from
* - 1: ADDED: $token was added to $from
* - 0: OLD: $token is not changed in $to
*
* @param array|string $from
* @param array|string $to
* @param LongestCommonSubsequenceCalculator $lcs
*
* @return array
*/
public function diffToArray($from, $to, LongestCommonSubsequenceCalculator $lcs = null): array
{
if (\is_string($from)) {
$from = $this->splitStringByLines($from);
} elseif (!\is_array($from)) {
throw new \InvalidArgumentException('"from" must be an array or string.');
}
if (\is_string($to)) {
$to = $this->splitStringByLines($to);
} elseif (!\is_array($to)) {
throw new \InvalidArgumentException('"to" must be an array or string.');
}
list($from, $to, $start, $end) = self::getArrayDiffParted($from, $to);
if ($lcs === null) {
$lcs = $this->selectLcsImplementation($from, $to);
}
$common = $lcs->calculate(\array_values($from), \array_values($to));
$diff = [];
foreach ($start as $token) {
$diff[] = [$token, 0 /* OLD */];
}
\reset($from);
\reset($to);
foreach ($common as $token) {
while (($fromToken = \reset($from)) !== $token) {
$diff[] = [\array_shift($from), 2 /* REMOVED */];
}
while (($toToken = \reset($to)) !== $token) {
$diff[] = [\array_shift($to), 1 /* ADDED */];
}
$diff[] = [$token, 0 /* OLD */];
\array_shift($from);
\array_shift($to);
}
while (($token = \array_shift($from)) !== null) {
$diff[] = [$token, 2 /* REMOVED */];
}
while (($token = \array_shift($to)) !== null) {
$diff[] = [$token, 1 /* ADDED */];
}
foreach ($end as $token) {
$diff[] = [$token, 0 /* OLD */];
}
if ($this->detectUnmatchedLineEndings($diff)) {
\array_unshift($diff, ["#Warning: Strings contain different line endings!\n", 3]);
}
return $diff;
}
/**
* Checks if input is string, if so it will split it line-by-line.
*
* @param string $input
*
* @return array
*/
private function splitStringByLines(string $input): array
{
return \preg_split('/(.*\R)/', $input, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
}
/**
* @param array $from
* @param array $to
*
* @return LongestCommonSubsequenceCalculator
*/
private function selectLcsImplementation(array $from, array $to): LongestCommonSubsequenceCalculator
{
// We do not want to use the time-efficient implementation if its memory
// footprint will probably exceed this value. Note that the footprint
// calculation is only an estimation for the matrix and the LCS method
// will typically allocate a bit more memory than this.
$memoryLimit = 100 * 1024 * 1024;
if ($this->calculateEstimatedFootprint($from, $to) > $memoryLimit) {
return new MemoryEfficientLongestCommonSubsequenceCalculator;
}
return new TimeEfficientLongestCommonSubsequenceCalculator;
}
/**
* Calculates the estimated memory footprint for the DP-based method.
*
* @param array $from
* @param array $to
*
* @return int|float
*/
private function calculateEstimatedFootprint(array $from, array $to)
{
$itemSize = PHP_INT_SIZE === 4 ? 76 : 144;
return $itemSize * \min(\count($from), \count($to)) ** 2;
}
/**
* Returns true if line ends don't match in a diff.
*
* @param array $diff
*
* @return bool
*/
private function detectUnmatchedLineEndings(array $diff): bool
{
$newLineBreaks = ['' => true];
$oldLineBreaks = ['' => true];
foreach ($diff as $entry) {
if (0 === $entry[1]) { /* OLD */
$ln = $this->getLinebreak($entry[0]);
$oldLineBreaks[$ln] = true;
$newLineBreaks[$ln] = true;
} elseif (1 === $entry[1]) { /* ADDED */
$newLineBreaks[$this->getLinebreak($entry[0])] = true;
} elseif (2 === $entry[1]) { /* REMOVED */
$oldLineBreaks[$this->getLinebreak($entry[0])] = true;
}
}
// if either input or output is a single line without breaks than no warning should be raised
if (['' => true] === $newLineBreaks || ['' => true] === $oldLineBreaks) {
return false;
}
// two way compare
foreach ($newLineBreaks as $break => $set) {
if (!isset($oldLineBreaks[$break])) {
return true;
}
}
foreach ($oldLineBreaks as $break => $set) {
if (!isset($newLineBreaks[$break])) {
return true;
}
}
return false;
}
private function getLinebreak($line): string
{
if (!\is_string($line)) {
return '';
}
$lc = \substr($line, -1);
if ("\r" === $lc) {
return "\r";
}
if ("\n" !== $lc) {
return '';
}
if ("\r\n" === \substr($line, -2)) {
return "\r\n";
}
return "\n";
}
private static function getArrayDiffParted(array &$from, array &$to): array
{
$start = [];
$end = [];
\reset($to);
foreach ($from as $k => $v) {
$toK = \key($to);
if ($toK === $k && $v === $to[$k]) {
$start[$k] = $v;
unset($from[$k], $to[$k]);
} else {
break;
}
}
\end($from);
\end($to);
do {
$fromK = \key($from);
$toK = \key($to);
if (null === $fromK || null === $toK || \current($from) !== \current($to)) {
break;
}
\prev($from);
\prev($to);
$end = [$fromK => $from[$fromK]] + $end;
unset($from[$fromK], $to[$toK]);
} while (true);
return [$from, $to, $start, $end];
}
}