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//===--- StringFindStartswithCheck.cc - clang-tidy---------------*- C++ -*-===//
//
// 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 "StringFindStartswithCheck.h"
#include "../utils/OptionsUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/Preprocessor.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace abseil {
StringFindStartswithCheck::StringFindStartswithCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
StringLikeClasses(utils::options::parseStringList(
Options.get("StringLikeClasses", "::std::basic_string"))),
IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
utils::IncludeSorter::IS_LLVM)),
AbseilStringsMatchHeader(
Options.get("AbseilStringsMatchHeader", "absl/strings/match.h")) {}
void StringFindStartswithCheck::registerMatchers(MatchFinder *Finder) {
auto ZeroLiteral = integerLiteral(equals(0));
auto StringClassMatcher = cxxRecordDecl(hasAnyName(SmallVector<StringRef, 4>(
StringLikeClasses.begin(), StringLikeClasses.end())));
auto StringType = hasUnqualifiedDesugaredType(
recordType(hasDeclaration(StringClassMatcher)));
auto StringFind = cxxMemberCallExpr(
// .find()-call on a string...
callee(cxxMethodDecl(hasName("find")).bind("findfun")),
on(hasType(StringType)),
// ... with some search expression ...
hasArgument(0, expr().bind("needle")),
// ... and either "0" as second argument or the default argument (also 0).
anyOf(hasArgument(1, ZeroLiteral), hasArgument(1, cxxDefaultArgExpr())));
Finder->addMatcher(
// Match [=!]= with a zero on one side and a string.find on the other.
binaryOperator(
hasAnyOperatorName("==", "!="),
hasOperands(ignoringParenImpCasts(ZeroLiteral),
ignoringParenImpCasts(StringFind.bind("findexpr"))))
.bind("expr"),
this);
auto StringRFind = cxxMemberCallExpr(
// .rfind()-call on a string...
callee(cxxMethodDecl(hasName("rfind")).bind("findfun")),
on(hasType(StringType)),
// ... with some search expression ...
hasArgument(0, expr().bind("needle")),
// ... and "0" as second argument.
hasArgument(1, ZeroLiteral));
Finder->addMatcher(
// Match [=!]= with either a zero or npos on one side and a string.rfind
// on the other.
binaryOperator(
hasAnyOperatorName("==", "!="),
hasOperands(ignoringParenImpCasts(ZeroLiteral),
ignoringParenImpCasts(StringRFind.bind("findexpr"))))
.bind("expr"),
this);
}
void StringFindStartswithCheck::check(const MatchFinder::MatchResult &Result) {
const ASTContext &Context = *Result.Context;
const SourceManager &Source = Context.getSourceManager();
// Extract matching (sub)expressions
const auto *ComparisonExpr = Result.Nodes.getNodeAs<BinaryOperator>("expr");
assert(ComparisonExpr != nullptr);
const auto *Needle = Result.Nodes.getNodeAs<Expr>("needle");
assert(Needle != nullptr);
const Expr *Haystack = Result.Nodes.getNodeAs<CXXMemberCallExpr>("findexpr")
->getImplicitObjectArgument();
assert(Haystack != nullptr);
const CXXMethodDecl *FindFun =
Result.Nodes.getNodeAs<CXXMethodDecl>("findfun");
assert(FindFun != nullptr);
bool Rev = FindFun->getName().contains("rfind");
if (ComparisonExpr->getBeginLoc().isMacroID())
return;
// Get the source code blocks (as characters) for both the string object
// and the search expression
const StringRef NeedleExprCode = Lexer::getSourceText(
CharSourceRange::getTokenRange(Needle->getSourceRange()), Source,
Context.getLangOpts());
const StringRef HaystackExprCode = Lexer::getSourceText(
CharSourceRange::getTokenRange(Haystack->getSourceRange()), Source,
Context.getLangOpts());
// Create the StartsWith string, negating if comparison was "!=".
bool Neg = ComparisonExpr->getOpcode() == BO_NE;
// Create the warning message and a FixIt hint replacing the original expr.
auto Diagnostic =
diag(ComparisonExpr->getBeginLoc(),
"use %select{absl::StartsWith|!absl::StartsWith}0 "
"instead of %select{find()|rfind()}1 %select{==|!=}0 0")
<< Neg << Rev;
Diagnostic << FixItHint::CreateReplacement(
ComparisonExpr->getSourceRange(),
((Neg ? "!absl::StartsWith(" : "absl::StartsWith(") + HaystackExprCode +
", " + NeedleExprCode + ")")
.str());
// Create a preprocessor #include FixIt hint (createIncludeInsertion checks
// whether this already exists).
Diagnostic << IncludeInserter.createIncludeInsertion(
Source.getFileID(ComparisonExpr->getBeginLoc()),
AbseilStringsMatchHeader);
}
void StringFindStartswithCheck::registerPPCallbacks(
const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
IncludeInserter.registerPreprocessor(PP);
}
void StringFindStartswithCheck::storeOptions(
ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "StringLikeClasses",
utils::options::serializeStringList(StringLikeClasses));
Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
Options.store(Opts, "AbseilStringsMatchHeader", AbseilStringsMatchHeader);
}
} // namespace abseil
} // namespace tidy
} // namespace clang
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