1//===-- StringCompareCheck.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 "StringCompareCheck.h"
10#include "../utils/OptionsUtils.h"
11#include "clang/AST/ASTContext.h"
12#include "clang/ASTMatchers/ASTMatchFinder.h"
13#include "clang/ASTMatchers/ASTMatchers.h"
14#include "clang/Tooling/FixIt.h"
15#include "llvm/ADT/StringRef.h"
16
17using namespace clang::ast_matchers;
18namespace optutils = clang::tidy::utils::options;
19
20namespace clang::tidy::readability {
21
22static const StringRef CompareMessage = "do not use 'compare' to test equality "
23 "of strings; use the string equality "
24 "operator instead";
25
26static const StringRef DefaultStringLikeClasses = "::std::basic_string;"
27 "::std::basic_string_view";
28
29StringCompareCheck::StringCompareCheck(StringRef Name,
30 ClangTidyContext *Context)
31 : ClangTidyCheck(Name, Context),
32 StringLikeClasses(optutils::parseStringList(
33 Option: Options.get(LocalName: "StringLikeClasses", Default: DefaultStringLikeClasses))) {}
34
35void StringCompareCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
36 Options.store(Options&: Opts, LocalName: "StringLikeClasses",
37 Value: optutils::serializeStringList(Strings: StringLikeClasses));
38}
39
40void StringCompareCheck::registerMatchers(MatchFinder *Finder) {
41 if (StringLikeClasses.empty()) {
42 return;
43 }
44 const auto StrCompare = cxxMemberCallExpr(
45 callee(InnerMatcher: cxxMethodDecl(hasName(Name: "compare"), ofClass(InnerMatcher: cxxRecordDecl(hasAnyName(
46 StringLikeClasses))))),
47 hasArgument(N: 0, InnerMatcher: expr().bind(ID: "str2")), argumentCountIs(N: 1),
48 callee(InnerMatcher: memberExpr().bind(ID: "str1")));
49
50 // First and second case: cast str.compare(str) to boolean.
51 Finder->addMatcher(
52 NodeMatch: traverse(TK: TK_AsIs,
53 InnerMatcher: implicitCastExpr(hasImplicitDestinationType(InnerMatcher: booleanType()),
54 has(StrCompare))
55 .bind(ID: "match1")),
56 Action: this);
57
58 // Third and fourth case: str.compare(str) == 0 and str.compare(str) != 0.
59 Finder->addMatcher(
60 NodeMatch: binaryOperator(hasAnyOperatorName("==", "!="),
61 hasOperands(Matcher1: StrCompare.bind(ID: "compare"),
62 Matcher2: integerLiteral(equals(Value: 0)).bind(ID: "zero")))
63 .bind(ID: "match2"),
64 Action: this);
65}
66
67void StringCompareCheck::check(const MatchFinder::MatchResult &Result) {
68 if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>(ID: "match1")) {
69 diag(Loc: Matched->getBeginLoc(), Description: CompareMessage);
70 return;
71 }
72
73 if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>(ID: "match2")) {
74 const ASTContext &Ctx = *Result.Context;
75
76 if (const auto *Zero = Result.Nodes.getNodeAs<Stmt>(ID: "zero")) {
77 const auto *Str1 = Result.Nodes.getNodeAs<MemberExpr>(ID: "str1");
78 const auto *Str2 = Result.Nodes.getNodeAs<Stmt>(ID: "str2");
79 const auto *Compare = Result.Nodes.getNodeAs<Stmt>(ID: "compare");
80
81 auto Diag = diag(Loc: Matched->getBeginLoc(), Description: CompareMessage);
82
83 if (Str1->isArrow())
84 Diag << FixItHint::CreateInsertion(InsertionLoc: Str1->getBeginLoc(), Code: "*");
85
86 Diag << tooling::fixit::createReplacement(Destination: *Zero, Source: *Str2, Context: Ctx)
87 << tooling::fixit::createReplacement(Destination: *Compare, Source: *Str1->getBase(),
88 Context: Ctx);
89 }
90 }
91
92 // FIXME: Add fixit to fix the code for case one and two (match1).
93}
94
95} // namespace clang::tidy::readability
96

source code of clang-tools-extra/clang-tidy/readability/StringCompareCheck.cpp