clang-tools-extra/clang-tidy/objc/NSDateFormatterCheck.cpp

   1 //===--- NSDateFormatterCheck.cpp - clang-tidy ----------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "NSDateFormatterCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12 #include "clang/ASTMatchers/ASTMatchers.h"
  13
  14 using namespace clang::ast_matchers;
  15
  16 namespace clang {
  17 namespace tidy {
  18 namespace objc {
  19
  20 void NSDateFormatterCheck::registerMatchers(MatchFinder *Finder) {
  21   // Adding matchers.
  22
  23   Finder->addMatcher(
  24       objcMessageExpr(hasSelector("setDateFormat:"),
  25                       hasReceiverType(asString("NSDateFormatter *")),
  26                       hasArgument(0, ignoringImpCasts(
  27                                          objcStringLiteral().bind("str_lit")))),
  28       this);
  29 }
  30
  31 static char ValidDatePatternChars[] = {
  32     'G', 'y', 'Y', 'u', 'U', 'r', 'Q', 'q', 'M', 'L', 'I', 'w', 'W', 'd',
  33     'D', 'F', 'g', 'E', 'e', 'c', 'a', 'b', 'B', 'h', 'H', 'K', 'k', 'j',
  34     'J', 'C', 'm', 's', 'S', 'A', 'z', 'Z', 'O', 'v', 'V', 'X', 'x'};
  35
  36 // Checks if the string pattern used as a date format specifier is valid.
  37 // A string pattern is valid if all the letters(a-z, A-Z) in it belong to the
  38 // set of reserved characters. See:
  39 // https://www.unicode.org/reports/tr35/tr35.html#Invalid_Patterns
  40 bool isValidDatePattern(StringRef Pattern) {
  41   return llvm::all_of(Pattern, [](const auto &PatternChar) {
  42     return !isalpha(PatternChar) ||
  43            llvm::is_contained(ValidDatePatternChars, PatternChar);
  44   });
  45 }
  46
  47 // Checks if the string pattern used as a date format specifier contains
  48 // any incorrect pattern and reports it as a warning.
  49 // See: http://www.unicode.org/reports/tr35/tr35-dates.html#Date_Format_Patterns
  50 void NSDateFormatterCheck::check(const MatchFinder::MatchResult &Result) {
  51   // Callback implementation.
  52   const auto *StrExpr = Result.Nodes.getNodeAs<ObjCStringLiteral>("str_lit");
  53   const StringLiteral *SL = cast<ObjCStringLiteral>(StrExpr)->getString();
  54   StringRef SR = SL->getString();
  55
  56   if (!isValidDatePattern(SR)) {
  57     diag(StrExpr->getExprLoc(), "invalid date format specifier");
  58   }
  59
  60   if (SR.contains('y') && SR.contains('w') && !SR.contains('Y')) {
  61     diag(StrExpr->getExprLoc(),
  62          "use of calendar year (y) with week of the year (w); "
  63          "did you mean to use week-year (Y) instead?");
  64   }
  65   if (SR.contains('F')) {
  66     if (!(SR.contains('e') || SR.contains('E'))) {
  67       diag(StrExpr->getExprLoc(),
  68            "day of week in month (F) used without day of the week (e or E); "
  69            "did you forget e (or E) in the format string?");
  70     }
  71     if (!SR.contains('M')) {
  72       diag(StrExpr->getExprLoc(),
  73            "day of week in month (F) used without the month (M); "
  74            "did you forget M in the format string?");
  75     }
  76   }
  77   if (SR.contains('W') && !SR.contains('M')) {
  78     diag(StrExpr->getExprLoc(), "Week of Month (W) used without the month (M); "
  79                                 "did you forget M in the format string?");
  80   }
  81   if (SR.contains('Y') && SR.contains('Q') && !SR.contains('y')) {
  82     diag(StrExpr->getExprLoc(),
  83          "use of week year (Y) with quarter number (Q); "
  84          "did you mean to use calendar year (y) instead?");
  85   }
  86   if (SR.contains('Y') && SR.contains('M') && !SR.contains('y')) {
  87     diag(StrExpr->getExprLoc(),
  88          "use of week year (Y) with month (M); "
  89          "did you mean to use calendar year (y) instead?");
  90   }
  91   if (SR.contains('Y') && SR.contains('D') && !SR.contains('y')) {
  92     diag(StrExpr->getExprLoc(),
  93          "use of week year (Y) with day of the year (D); "
  94          "did you mean to use calendar year (y) instead?");
  95   }
  96   if (SR.contains('Y') && SR.contains('W') && !SR.contains('y')) {
  97     diag(StrExpr->getExprLoc(),
  98          "use of week year (Y) with week of the month (W); "
  99          "did you mean to use calendar year (y) instead?");
 100   }
 101   if (SR.contains('Y') && SR.contains('F') && !SR.contains('y')) {
 102     diag(StrExpr->getExprLoc(),
 103          "use of week year (Y) with day of the week in month (F); "
 104          "did you mean to use calendar year (y) instead?");
 105   }
 106 }
 107
 108 } // namespace objc
 109 } // namespace tidy
 110 } // namespace clang