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| //===-- StringCompareCheck.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 "StringCompareCheck.h"
#include "../utils/FixItHintUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Tooling/FixIt.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace readability {
static const StringRef CompareMessage = "do not use 'compare' to test equality "
"of strings; use the string equality "
"operator instead";
void StringCompareCheck::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus)
return;
const auto StrCompare = cxxMemberCallExpr(
callee(cxxMethodDecl(hasName("compare"),
ofClass(classTemplateSpecializationDecl(
hasName("::std::basic_string"))))),
hasArgument(0, expr().bind("str2")), argumentCountIs(1),
callee(memberExpr().bind("str1")));
// First and second case: cast str.compare(str) to boolean.
Finder->addMatcher(implicitCastExpr(hasImplicitDestinationType(booleanType()),
has(StrCompare))
.bind("match1"),
this);
// Third and fourth case: str.compare(str) == 0 and str.compare(str) != 0.
Finder->addMatcher(
binaryOperator(anyOf(hasOperatorName("=="), hasOperatorName("!=")),
hasEitherOperand(StrCompare.bind("compare")),
hasEitherOperand(integerLiteral(equals(0)).bind("zero")))
.bind("match2"),
this);
}
void StringCompareCheck::check(const MatchFinder::MatchResult &Result) {
if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>("match1")) {
diag(Matched->getBeginLoc(), CompareMessage);
return;
}
if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>("match2")) {
const ASTContext &Ctx = *Result.Context;
if (const auto *Zero = Result.Nodes.getNodeAs<Stmt>("zero")) {
const auto *Str1 = Result.Nodes.getNodeAs<MemberExpr>("str1");
const auto *Str2 = Result.Nodes.getNodeAs<Stmt>("str2");
const auto *Compare = Result.Nodes.getNodeAs<Stmt>("compare");
auto Diag = diag(Matched->getBeginLoc(), CompareMessage);
if (Str1->isArrow())
Diag << FixItHint::CreateInsertion(Str1->getBeginLoc(), "*");
Diag << tooling::fixit::createReplacement(*Zero, *Str2, Ctx)
<< tooling::fixit::createReplacement(*Compare, *Str1->getBase(),
Ctx);
}
}
// FIXME: Add fixit to fix the code for case one and two (match1).
}
} // namespace readability
} // namespace tidy
} // namespace clang
|