Feature: RedundatCase sniff

Check switch control structure for redundant cases.

src/WebimpressCodingStandard/Sniffs/ControlStructures/RedundantCaseSniff.php

@@ -0,0 +1,241 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WebimpressCodingStandard\Sniffs\ControlStructures;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+use PHP_CodeSniffer\Util\Tokens;
+
+use function array_reverse;
+use function key;
+
+use const T_BREAK;
+use const T_CASE;
+use const T_CLOSE_CURLY_BRACKET;
+use const T_DEFAULT;
+use const T_ENDSWITCH;
+use const T_LNUMBER;
+use const T_OPEN_PARENTHESIS;
+use const T_SEMICOLON;
+use const T_WHITESPACE;
+
+class RedundantCaseSniff implements Sniff
+{
+    /**
+     * @return int[]
+     */
+    public function register() : array
+    {
+        return [
+            T_CASE,
+            T_DEFAULT,
+        ];
+    }
+
+    /**
+     * @param int $stackPtr
+     */
+    public function process(File $phpcsFile, $stackPtr) : int
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        if ($tokens[$stackPtr]['code'] === T_CASE) {
+            $next = $stackPtr;
+
+            do {
+                $last = $tokens[$next]['scope_opener'];
+                $next = $phpcsFile->findNext(Tokens::$emptyTokens + [
+                    T_SEMICOLON => T_SEMICOLON,
+                ], $last + 1, null, true);
+            } while ($tokens[$next]['code'] === T_CASE);
+
+            while ($semicolon = $phpcsFile->findNext(Tokens::$emptyTokens, $last + 1, null, true)) {
+                if ($tokens[$semicolon]['code'] === T_SEMICOLON) {
+                    $last = $semicolon;
+                    continue;
+                }
+
+                break;
+            }
+
+            if ($tokens[$next]['code'] === T_DEFAULT
+                || $tokens[$next]['code'] === T_CLOSE_CURLY_BRACKET
+                || $tokens[$next]['code'] === T_ENDSWITCH
+            ) {
+                $fix = $phpcsFile->addFixableError('Redundant case', $stackPtr, 'RedundantCase');
+
+                if ($fix) {
+                    $this->deleteCase($phpcsFile, $stackPtr, $last);
+                }
+            } elseif ($tokens[$next]['code'] === T_BREAK
+                && $this->hasEmptyDefault($phpcsFile, key(array_reverse($tokens[$stackPtr]['conditions'], true)))
+            ) {
+                $this->onlyBreak($phpcsFile, $stackPtr, $next);
+            }
+
+            return $stackPtr + 1;
+        }
+
+        $next = $stackPtr;
+
+        do {
+            $last = $tokens[$next]['scope_opener'];
+            $next = $phpcsFile->findNext(Tokens::$emptyTokens + [
+                T_SEMICOLON => T_SEMICOLON,
+            ], $last + 1, null, true);
+
+            while ($semicolon = $phpcsFile->findNext(Tokens::$emptyTokens, $last + 1, null, true)) {
+                if ($tokens[$semicolon]['code'] === T_SEMICOLON) {
+                    $last = $semicolon + 1;
+                    continue;
+                }
+
+                break;
+            }
+
+            $isCase = $tokens[$next]['code'] === T_CASE;
+            if ($isCase) {
+                $fix = $phpcsFile->addFixableError('Redundant case', $next, 'RedundantCase');
+
+                if ($fix) {
+                    $phpcsFile->fixer->beginChangeset();
+                    for ($i = $last + 1; $i <= $tokens[$next]['scope_opener']; ++$i) {
+                        $phpcsFile->fixer->replaceToken($i, '');
+                    }
+                    $phpcsFile->fixer->endChangeset();
+                }
+            }
+        } while ($isCase);
+
+        if ($tokens[$next]['code'] === T_CLOSE_CURLY_BRACKET
+            || $tokens[$next]['code'] === T_ENDSWITCH
+        ) {
+            $fix = $phpcsFile->addFixableError('Redundant case', $stackPtr, 'RedundantCase');
+
+            if ($fix) {
+                $this->deleteCase($phpcsFile, $stackPtr, $last);
+            }
+
+            return $next + 1;
+        }
+
+        if ($tokens[$next]['code'] === T_BREAK) {
+            $this->onlyBreak($phpcsFile, $stackPtr, $next);
+
+            return $next + 1;
+        }
+
+        return $stackPtr + 1;
+    }
+
+    private function deleteCase(File $phpcsFile, int $casePtr, int $lastPtr) : void
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        $phpcsFile->fixer->beginChangeset();
+        $i = $casePtr - 1;
+        while ($tokens[$i]['code'] === T_WHITESPACE
+            && $tokens[$i]['line'] === $tokens[$casePtr]['line']
+        ) {
+            $phpcsFile->fixer->replaceToken($i, '');
+            --$i;
+        }
+
+        for ($i = $casePtr; $i <= $lastPtr; ++$i) {
+            $phpcsFile->fixer->replaceToken($i, '');
+        }
+
+        $i = $lastPtr + 1;
+        while ($tokens[$i]['code'] === T_WHITESPACE
+            && $tokens[$i]['line'] === $tokens[$lastPtr]['line']
+        ) {
+            $phpcsFile->fixer->replaceToken($i, '');
+            ++$i;
+        }
+        $closer = $tokens[$casePtr]['scope_closer'];
+        if ($closer > $lastPtr) {
+            $phpcsFile->fixer->replaceToken($closer, $tokens[$closer]['content']);
+        }
+        $phpcsFile->fixer->endChangeset();
+    }
+
+    private function onlyBreak(File $phpcsFile, int $casePtr, int $breakPtr) : void
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        $value = $phpcsFile->findNext(Tokens::$emptyTokens + [
+            T_OPEN_PARENTHESIS => T_OPEN_PARENTHESIS,
+        ], $breakPtr + 1, null, true);
+
+        if ($tokens[$value]['code'] === T_SEMICOLON
+            || ($tokens[$value]['code'] === T_LNUMBER
+                && $tokens[$value]['content'] === '1')
+        ) {
+            $fix = $phpcsFile->addFixableError('Redundant case', $casePtr, 'RedundantCase');
+
+            if ($fix) {
+                $last = $tokens[$breakPtr]['scope_condition'] !== $casePtr
+                    ? $tokens[$casePtr]['scope_opener']
+                    : $phpcsFile->findNext(T_SEMICOLON, $value);
+
+                $this->deleteCase($phpcsFile, $casePtr, $last);
+            }
+        }
+    }
+
+    private function hasEmptyDefault(File $phpcsFile, int $switchPtr) : bool
+    {
+        $tokens = $phpcsFile->getTokens();
+        $from = $tokens[$switchPtr]['scope_opener'];
+        $to = $tokens[$switchPtr]['scope_closer'];
+
+        while ($default = $phpcsFile->findNext(T_DEFAULT, $from, $to)) {
+            $conditions = array_reverse($tokens[$default]['conditions'], true);
+
+            if (key($conditions) !== $switchPtr) {
+                $from = $default + 1;
+                continue;
+            }
+
+            $opener = $tokens[$default]['scope_opener'];
+            $closer = $tokens[$default]['scope_closer'];
+            if ($tokens[$closer]['code'] === T_BREAK) {
+                $value = $phpcsFile->findNext(Tokens::$emptyTokens + [
+                    T_OPEN_PARENTHESIS => T_OPEN_PARENTHESIS,
+                ], $closer + 1, null, true);
+
+                if ($tokens[$value]['code'] !== T_SEMICOLON
+                    && ($tokens[$value]['code'] !== T_LNUMBER
+                        || $tokens[$value]['content'] !== '1')
+                ) {
+                    return false;
+                }
+            } elseif ($tokens[$closer]['code'] !== T_CLOSE_CURLY_BRACKET) {
+                return false;
+            }
+
+            $start = $opener;
+            $end = $closer;
+
+            while ($token = $phpcsFile->findNext(Tokens::$emptyTokens, $start + 1, $end, true)) {
+                if ($tokens[$token]['code'] === T_SEMICOLON) {
+                    $start = $token + 1;
+                    continue;
+                }
+
+                if ($tokens[$token]['code'] === T_CASE) {
+                    $start = $tokens[$token]['scope_opener'] + 1;
+                    continue;
+                }
+
+                return false;
+            }
+
+            return true;
+        }
+
+        return true;
+    }
+}