1 //===--- StringFindStrContainsCheck.cc - 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 "StringFindStrContainsCheck.h"
10 
11 #include "../utils/OptionsUtils.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/ASTMatchers/ASTMatchers.h"
14 #include "clang/Frontend/CompilerInstance.h"
15 #include "clang/Tooling/Transformer/RewriteRule.h"
16 #include "clang/Tooling/Transformer/Stencil.h"
17 
18 using namespace clang::ast_matchers;
19 
20 namespace clang {
21 namespace tidy {
22 namespace abseil {
23 
24 using ::clang::transformer::applyFirst;
25 using ::clang::transformer::cat;
26 using ::clang::transformer::change;
27 using ::clang::transformer::makeRule;
28 using ::clang::transformer::node;
29 
30 static const char DefaultStringLikeClasses[] = "::std::basic_string;"
31                                                "::std::basic_string_view;"
32                                                "::absl::string_view";
33 static const char DefaultAbseilStringsMatchHeader[] = "absl/strings/match.h";
34 
35 static llvm::Optional<transformer::RewriteRule>
36 MakeRule(const LangOptions &LangOpts,
37          const ClangTidyCheck::OptionsView &Options) {
38   // Parse options.
39   //
40   // FIXME(tdl-g): These options are being parsed redundantly with the
41   // constructor because TransformerClangTidyCheck forces us to provide MakeRule
42   // before "this" is fully constructed, but StoreOptions requires us to store
43   // the parsed options in "this".  We need to fix TransformerClangTidyCheck and
44   // then we can clean this up.
45   const std::vector<std::string> StringLikeClassNames =
46       utils::options::parseStringList(
47           Options.get("StringLikeClasses", DefaultStringLikeClasses));
48   const std::string AbseilStringsMatchHeader =
49       Options.get("AbseilStringsMatchHeader", DefaultAbseilStringsMatchHeader);
50 
51   auto StringLikeClass = cxxRecordDecl(hasAnyName(SmallVector<StringRef, 4>(
52       StringLikeClassNames.begin(), StringLikeClassNames.end())));
53   auto StringType =
54       hasUnqualifiedDesugaredType(recordType(hasDeclaration(StringLikeClass)));
55   auto CharStarType =
56       hasUnqualifiedDesugaredType(pointerType(pointee(isAnyCharacter())));
57   auto StringNpos = declRefExpr(
58       to(varDecl(hasName("npos"), hasDeclContext(StringLikeClass))));
59   auto StringFind = cxxMemberCallExpr(
60       callee(cxxMethodDecl(
61           hasName("find"),
62           hasParameter(0, parmVarDecl(anyOf(hasType(StringType),
63                                             hasType(CharStarType)))))),
64       on(hasType(StringType)), hasArgument(0, expr().bind("parameter_to_find")),
65       anyOf(hasArgument(1, integerLiteral(equals(0))),
66             hasArgument(1, cxxDefaultArgExpr())),
67       onImplicitObjectArgument(expr().bind("string_being_searched")));
68 
69   tooling::RewriteRule rule = applyFirst(
70       {makeRule(binaryOperator(hasOperatorName("=="),
71                                hasOperands(ignoringParenImpCasts(StringNpos),
72                                            ignoringParenImpCasts(StringFind))),
73                 change(cat("!absl::StrContains(", node("string_being_searched"),
74                            ", ", node("parameter_to_find"), ")")),
75                 cat("use !absl::StrContains instead of find() == npos")),
76        makeRule(binaryOperator(hasOperatorName("!="),
77                                hasOperands(ignoringParenImpCasts(StringNpos),
78                                            ignoringParenImpCasts(StringFind))),
79                 change(cat("absl::StrContains(", node("string_being_searched"),
80                            ", ", node("parameter_to_find"), ")")),
81                 cat("use absl::StrContains instead of find() != npos"))});
82   addInclude(rule, AbseilStringsMatchHeader);
83   return rule;
84 }
85 
86 StringFindStrContainsCheck::StringFindStrContainsCheck(
87     StringRef Name, ClangTidyContext *Context)
88     : TransformerClangTidyCheck(&MakeRule, Name, Context),
89       StringLikeClassesOption(utils::options::parseStringList(
90           Options.get("StringLikeClasses", DefaultStringLikeClasses))),
91       AbseilStringsMatchHeaderOption(Options.get(
92           "AbseilStringsMatchHeader", DefaultAbseilStringsMatchHeader)) {}
93 
94 bool StringFindStrContainsCheck::isLanguageVersionSupported(
95     const LangOptions &LangOpts) const {
96   return LangOpts.CPlusPlus11;
97 }
98 
99 void StringFindStrContainsCheck::storeOptions(
100     ClangTidyOptions::OptionMap &Opts) {
101   TransformerClangTidyCheck::storeOptions(Opts);
102   Options.store(Opts, "StringLikeClasses",
103                 utils::options::serializeStringList(StringLikeClassesOption));
104   Options.store(Opts, "AbseilStringsMatchHeader",
105                 AbseilStringsMatchHeaderOption);
106 }
107 
108 } // namespace abseil
109 } // namespace tidy
110 } // namespace clang
111