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//===--- RawStringLiteralCheck.cpp - clang-tidy----------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "RawStringLiteralCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/StringRef.h"
#include <optional>
using namespace clang::ast_matchers;
namespace clang::tidy::modernize {
namespace {
bool containsEscapes(StringRef HayStack, StringRef Escapes) {
size_t BackSlash = HayStack.find('\\');
if (BackSlash == StringRef::npos)
return false;
while (BackSlash != StringRef::npos) {
if (!Escapes.contains(HayStack[BackSlash + 1]))
return false;
BackSlash = HayStack.find('\\', BackSlash + 2);
}
return true;
}
bool isRawStringLiteral(StringRef Text) {
// Already a raw string literal if R comes before ".
const size_t QuotePos = Text.find('"');
assert(QuotePos != StringRef::npos);
return (QuotePos > 0) && (Text[QuotePos - 1] == 'R');
}
bool containsEscapedCharacters(const MatchFinder::MatchResult &Result,
const StringLiteral *Literal,
const CharsBitSet &DisallowedChars) {
// FIXME: Handle L"", u8"", u"" and U"" literals.
if (!Literal->isOrdinary())
return false;
for (const unsigned char C : Literal->getBytes())
if (DisallowedChars.test(C))
return false;
CharSourceRange CharRange = Lexer::makeFileCharRange(
CharSourceRange::getTokenRange(Literal->getSourceRange()),
*Result.SourceManager, Result.Context->getLangOpts());
StringRef Text = Lexer::getSourceText(CharRange, *Result.SourceManager,
Result.Context->getLangOpts());
if (Text.empty() || isRawStringLiteral(Text))
return false;
return containsEscapes(Text, R"('\"?x01)");
}
bool containsDelimiter(StringRef Bytes, const std::string &Delimiter) {
return Bytes.find(Delimiter.empty()
? std::string(R"lit()")lit")
: (")" + Delimiter + R"(")")) != StringRef::npos;
}
} // namespace
RawStringLiteralCheck::RawStringLiteralCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
DelimiterStem(Options.get("DelimiterStem", "lit")),
ReplaceShorterLiterals(Options.get("ReplaceShorterLiterals", false)) {
// Non-printing characters are disallowed:
// \007 = \a bell
// \010 = \b backspace
// \011 = \t horizontal tab
// \012 = \n new line
// \013 = \v vertical tab
// \014 = \f form feed
// \015 = \r carriage return
// \177 = delete
for (const unsigned char C : StringRef("\000\001\002\003\004\005\006\a"
"\b\t\n\v\f\r\016\017"
"\020\021\022\023\024\025\026\027"
"\030\031\032\033\034\035\036\037"
"\177",
33))
DisallowedChars.set(C);
// Non-ASCII are disallowed too.
for (unsigned int C = 0x80U; C <= 0xFFU; ++C)
DisallowedChars.set(static_cast<unsigned char>(C));
}
void RawStringLiteralCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "DelimiterStem", DelimiterStem);
Options.store(Opts, "ReplaceShorterLiterals", ReplaceShorterLiterals);
}
void RawStringLiteralCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
stringLiteral(unless(hasParent(predefinedExpr()))).bind("lit"), this);
}
static std::optional<StringRef>
createUserDefinedSuffix(const StringLiteral *Literal, const SourceManager &SM,
const LangOptions &LangOpts) {
const CharSourceRange TokenRange =
CharSourceRange::getTokenRange(Literal->getSourceRange());
Token T;
if (Lexer::getRawToken(Literal->getBeginLoc(), T, SM, LangOpts))
return std::nullopt;
const CharSourceRange CharRange =
Lexer::makeFileCharRange(TokenRange, SM, LangOpts);
if (T.hasUDSuffix()) {
StringRef Text = Lexer::getSourceText(CharRange, SM, LangOpts);
const size_t UDSuffixPos = Text.find_last_of('"');
if (UDSuffixPos == StringRef::npos)
return std::nullopt;
return Text.slice(UDSuffixPos + 1, Text.size());
}
return std::nullopt;
}
static std::string createRawStringLiteral(const StringLiteral *Literal,
const std::string &DelimiterStem,
const SourceManager &SM,
const LangOptions &LangOpts) {
const StringRef Bytes = Literal->getBytes();
std::string Delimiter;
for (int I = 0; containsDelimiter(Bytes, Delimiter); ++I) {
Delimiter = (I == 0) ? DelimiterStem : DelimiterStem + std::to_string(I);
}
std::optional<StringRef> UserDefinedSuffix =
createUserDefinedSuffix(Literal, SM, LangOpts);
if (Delimiter.empty())
return (R"(R"()" + Bytes + R"lit()")lit" + UserDefinedSuffix.value_or(""))
.str();
return (R"(R")" + Delimiter + "(" + Bytes + ")" + Delimiter + R"(")" +
UserDefinedSuffix.value_or(""))
.str();
}
static bool compareStringLength(StringRef Replacement,
const StringLiteral *Literal,
const SourceManager &SM,
const LangOptions &LangOpts) {
return Replacement.size() <=
Lexer::MeasureTokenLength(Literal->getBeginLoc(), SM, LangOpts);
}
void RawStringLiteralCheck::check(const MatchFinder::MatchResult &Result) {
const auto *Literal = Result.Nodes.getNodeAs<StringLiteral>("lit");
if (Literal->getBeginLoc().isMacroID())
return;
const SourceManager &SM = *Result.SourceManager;
const LangOptions &LangOpts = getLangOpts();
if (containsEscapedCharacters(Result, Literal, DisallowedChars)) {
const std::string Replacement =
createRawStringLiteral(Literal, DelimiterStem, SM, LangOpts);
if (ReplaceShorterLiterals ||
compareStringLength(Replacement, Literal, SM, LangOpts)) {
diag(Literal->getBeginLoc(),
"escaped string literal can be written as a raw string literal")
<< FixItHint::CreateReplacement(Literal->getSourceRange(),
Replacement);
}
}
}
} // namespace clang::tidy::modernize
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