178 lines · cpp
1//===----------------------------------------------------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "RawStringLiteralCheck.h"10#include "clang/AST/ASTContext.h"11#include "clang/ASTMatchers/ASTMatchFinder.h"12#include "clang/Basic/LangOptions.h"13#include "clang/Basic/SourceManager.h"14#include "clang/Lex/Lexer.h"15#include "llvm/ADT/StringRef.h"16#include <optional>17 18using namespace clang::ast_matchers;19 20namespace clang::tidy::modernize {21 22static bool containsEscapes(StringRef HayStack, StringRef Escapes) {23 size_t BackSlash = HayStack.find('\\');24 if (BackSlash == StringRef::npos)25 return false;26 27 while (BackSlash != StringRef::npos) {28 if (!Escapes.contains(HayStack[BackSlash + 1]))29 return false;30 BackSlash = HayStack.find('\\', BackSlash + 2);31 }32 33 return true;34}35 36static bool isRawStringLiteral(StringRef Text) {37 // Already a raw string literal if R comes before ".38 const size_t QuotePos = Text.find('"');39 assert(QuotePos != StringRef::npos);40 return (QuotePos > 0) && (Text[QuotePos - 1] == 'R');41}42 43static bool containsEscapedCharacters(const MatchFinder::MatchResult &Result,44 const StringLiteral *Literal,45 const CharsBitSet &DisallowedChars) {46 // FIXME: Handle L"", u8"", u"" and U"" literals.47 if (!Literal->isOrdinary())48 return false;49 50 for (const unsigned char C : Literal->getBytes())51 if (DisallowedChars.test(C))52 return false;53 54 const CharSourceRange CharRange = Lexer::makeFileCharRange(55 CharSourceRange::getTokenRange(Literal->getSourceRange()),56 *Result.SourceManager, Result.Context->getLangOpts());57 const StringRef Text = Lexer::getSourceText(CharRange, *Result.SourceManager,58 Result.Context->getLangOpts());59 if (Text.empty() || isRawStringLiteral(Text))60 return false;61 62 return containsEscapes(Text, R"('\"?x01)");63}64 65static bool containsDelimiter(StringRef Bytes, const std::string &Delimiter) {66 return Bytes.find(Delimiter.empty()67 ? std::string(R"lit()")lit")68 : (")" + Delimiter + R"(")")) != StringRef::npos;69}70 71RawStringLiteralCheck::RawStringLiteralCheck(StringRef Name,72 ClangTidyContext *Context)73 : ClangTidyCheck(Name, Context),74 DelimiterStem(Options.get("DelimiterStem", "lit")),75 ReplaceShorterLiterals(Options.get("ReplaceShorterLiterals", false)) {76 // Non-printing characters are disallowed:77 // \007 = \a bell78 // \010 = \b backspace79 // \011 = \t horizontal tab80 // \012 = \n new line81 // \013 = \v vertical tab82 // \014 = \f form feed83 // \015 = \r carriage return84 // \177 = delete85 for (const unsigned char C : StringRef("\000\001\002\003\004\005\006\a"86 "\b\t\n\v\f\r\016\017"87 "\020\021\022\023\024\025\026\027"88 "\030\031\032\033\034\035\036\037"89 "\177",90 33))91 DisallowedChars.set(C);92 93 // Non-ASCII are disallowed too.94 for (unsigned int C = 0x80U; C <= 0xFFU; ++C)95 DisallowedChars.set(static_cast<unsigned char>(C));96}97 98void RawStringLiteralCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {99 Options.store(Opts, "DelimiterStem", DelimiterStem);100 Options.store(Opts, "ReplaceShorterLiterals", ReplaceShorterLiterals);101}102 103void RawStringLiteralCheck::registerMatchers(MatchFinder *Finder) {104 Finder->addMatcher(105 stringLiteral(unless(hasParent(predefinedExpr()))).bind("lit"), this);106}107 108static std::optional<StringRef>109createUserDefinedSuffix(const StringLiteral *Literal, const SourceManager &SM,110 const LangOptions &LangOpts) {111 const CharSourceRange TokenRange =112 CharSourceRange::getTokenRange(Literal->getSourceRange());113 Token T;114 if (Lexer::getRawToken(Literal->getBeginLoc(), T, SM, LangOpts))115 return std::nullopt;116 const CharSourceRange CharRange =117 Lexer::makeFileCharRange(TokenRange, SM, LangOpts);118 if (T.hasUDSuffix()) {119 const StringRef Text = Lexer::getSourceText(CharRange, SM, LangOpts);120 const size_t UDSuffixPos = Text.find_last_of('"');121 if (UDSuffixPos == StringRef::npos)122 return std::nullopt;123 return Text.slice(UDSuffixPos + 1, Text.size());124 }125 return std::nullopt;126}127 128static std::string createRawStringLiteral(const StringLiteral *Literal,129 const std::string &DelimiterStem,130 const SourceManager &SM,131 const LangOptions &LangOpts) {132 const StringRef Bytes = Literal->getBytes();133 std::string Delimiter;134 for (int I = 0; containsDelimiter(Bytes, Delimiter); ++I) {135 Delimiter = (I == 0) ? DelimiterStem : DelimiterStem + std::to_string(I);136 }137 138 const std::optional<StringRef> UserDefinedSuffix =139 createUserDefinedSuffix(Literal, SM, LangOpts);140 141 if (Delimiter.empty())142 return (R"(R"()" + Bytes + R"lit()")lit" + UserDefinedSuffix.value_or(""))143 .str();144 145 return (R"(R")" + Delimiter + "(" + Bytes + ")" + Delimiter + R"(")" +146 UserDefinedSuffix.value_or(""))147 .str();148}149 150static bool compareStringLength(StringRef Replacement,151 const StringLiteral *Literal,152 const SourceManager &SM,153 const LangOptions &LangOpts) {154 return Replacement.size() <=155 Lexer::MeasureTokenLength(Literal->getBeginLoc(), SM, LangOpts);156}157 158void RawStringLiteralCheck::check(const MatchFinder::MatchResult &Result) {159 const auto *Literal = Result.Nodes.getNodeAs<StringLiteral>("lit");160 if (Literal->getBeginLoc().isMacroID())161 return;162 const SourceManager &SM = *Result.SourceManager;163 const LangOptions &LangOpts = getLangOpts();164 if (containsEscapedCharacters(Result, Literal, DisallowedChars)) {165 const std::string Replacement =166 createRawStringLiteral(Literal, DelimiterStem, SM, LangOpts);167 if (ReplaceShorterLiterals ||168 compareStringLength(Replacement, Literal, SM, LangOpts)) {169 diag(Literal->getBeginLoc(),170 "escaped string literal can be written as a raw string literal")171 << FixItHint::CreateReplacement(Literal->getSourceRange(),172 Replacement);173 }174 }175}176 177} // namespace clang::tidy::modernize178