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<?php
/*
* This file is part of PHP CS Fixer.
*
* (c) Fabien Potencier <fabien@symfony.com>
* Dariusz Rumiński <dariusz.ruminski@gmail.com>
*
* This source file is subject to the MIT license that is bundled
* with this source code in the file LICENSE.
*/
namespace Symfony\CS\Fixer\Contrib;
use Symfony\CS\AbstractFixer;
use Symfony\CS\Tokenizer\Tokens;
/**
* @author SpacePossum
*/
final class NoUselessElseFixer extends AbstractFixer
{
/**
* {@inheritdoc}
*/
public function fix(\SplFileInfo $file, $content)
{
$tokens = Tokens::fromCode($content);
foreach ($tokens as $index => $token) {
if (!$token->isGivenKind(T_ELSE)) {
continue;
}
// `else if` vs. `else` and alternative syntax `else:` checks
if ($tokens[$tokens->getNextMeaningfulToken($index)]->equalsAny(array(':', array(T_IF)))) {
continue;
}
// clean up `else` if it is an empty statement
$this->fixEmptyElse($tokens, $index);
if ($token->isEmpty()) {
continue;
}
// clean up `else` if possible
$this->fixElse($tokens, $index);
}
return $tokens->generateCode();
}
/**
* {@inheritdoc}
*/
public function getDescription()
{
return 'There should not be useless else cases.';
}
/**
* {@inheritdoc}
*/
public function getPriority()
{
// should be run before DuplicateSemicolonFixer, WhitespacyLinesFixer, ExtraEmptyLinesFixer and BracesFixer.
return 25;
}
/**
* @param Tokens $tokens
* @param int $index T_ELSE index
*/
private function fixElse(Tokens $tokens, $index)
{
$previousBlockStart = $index;
do {
// Check if all 'if', 'else if ' and 'elseif' blocks above this 'else' always end,
// if so this 'else' is overcomplete.
list($previousBlockStart, $previousBlockEnd) = $this->getPreviousBlock($tokens, $previousBlockStart);
// short 'if' detection
$previous = $previousBlockEnd;
if ($tokens[$previous]->equals('}')) {
$previous = $tokens->getPrevMeaningfulToken($previous);
}
if (
!$tokens[$previous]->equals(';') || // 'if' block doesn't end with semicolon, keep 'else'
$tokens[$tokens->getPrevMeaningfulToken($previous)]->equals('{') // empty 'if' block, keep 'else'
) {
return;
}
$candidateIndex = $tokens->getTokenOfKindSibling(
$previous,
-1,
array(
';',
array(T_CLOSE_TAG),
array(T_BREAK),
array(T_CONTINUE),
array(T_EXIT),
array(T_GOTO),
array(T_RETURN),
array(T_THROW),
)
);
if (
null === $candidateIndex ||
$tokens[$candidateIndex]->equals(';') ||
$tokens[$candidateIndex]->isGivenKind(T_CLOSE_TAG) ||
$this->isInConditional($tokens, $candidateIndex, $previousBlockStart)
) {
return;
}
// implicit continue, i.e. delete candidate
} while (!$tokens[$previousBlockStart]->isGivenKind(T_IF));
// if we made it to here the 'else' can be removed
$this->clearElse($tokens, $index);
}
/**
* Return the first and last token index of the previous block.
*
* [0] First is either T_IF, T_ELSE or T_ELSEIF
* [1] Last is either '}' or ';' / T_CLOSE_TAG for short notation blocks
*
* @param Tokens $tokens
* @param int $index T_IF, T_ELSE, T_ELSEIF
*
* @return int[]
*/
private function getPreviousBlock(Tokens $tokens, $index)
{
$close = $previous = $tokens->getPrevMeaningfulToken($index);
// short 'if' detection
if ($tokens[$close]->equals('}')) {
$previous = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_CURLY_BRACE, $close, false);
}
$open = $tokens->getPrevTokenOfKind($previous, array(array(T_IF), array(T_ELSE), array(T_ELSEIF)));
if ($tokens[$open]->isGivenKind(T_IF)) {
$elseCandidate = $tokens->getPrevMeaningfulToken($open);
if ($tokens[$elseCandidate]->isGivenKind(T_ELSE)) {
$open = $elseCandidate;
}
}
return array($open, $close);
}
/**
* Remove tokens part of an `else` statement if not empty (i.e. no meaningful tokens inside).
*
* @param Tokens $tokens
* @param int $index T_ELSE index
*/
private function fixEmptyElse(Tokens $tokens, $index)
{
$next = $tokens->getNextMeaningfulToken($index);
if ($tokens[$next]->equals('{')) {
$close = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_CURLY_BRACE, $next);
if (1 === $close - $next) { // '{}'
$this->clearElse($tokens, $index);
} elseif ($tokens->getNextMeaningfulToken($next) === $close) { // '{/**/}'
$this->clearElse($tokens, $index);
}
return;
}
// short `else`
$end = $tokens->getNextTokenOfKind($index, array(';', array(T_CLOSE_TAG)));
if ($next === $end) {
$this->clearElse($tokens, $index);
}
}
/**
* @param Tokens $tokens
* @param int $index index of T_ELSE
*/
private function clearElse(Tokens $tokens, $index)
{
$tokens->clearTokenAndMergeSurroundingWhitespace($index);
// clear T_ELSE and the '{' '}' if there are any
$next = $tokens->getNextMeaningfulToken($index);
if (!$tokens[$next]->equals('{')) {
return;
}
$tokens->clearTokenAndMergeSurroundingWhitespace($tokens->findBlockEnd(Tokens::BLOCK_TYPE_CURLY_BRACE, $next));
$tokens->clearTokenAndMergeSurroundingWhitespace($next);
}
/**
* @param Tokens $tokens
* @param int $index Index of the token to check
* @param int $lowerLimitIndex Lower limit index. Since the token to check will always be in a conditional we must stop checking at this index
*
* @return bool
*/
private function isInConditional(Tokens $tokens, $index, $lowerLimitIndex)
{
$candidateIndex = $tokens->getTokenOfKindSibling($index, -1, array(')', ';', ':'));
if ($tokens[$candidateIndex]->equals(':')) {
return true;
}
if (!$tokens[$candidateIndex]->equals(')')) {
return false; // token is ';' or close tag
}
// token is always ')' here.
// If it is part of the condition the token is always in, return false.
// If it is not it is a nested condition so return true
$open = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_PARENTHESIS_BRACE, $candidateIndex, false);
return $tokens->getPrevMeaningfulToken($open) > $lowerLimitIndex;
}
}