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//===----------------------------------------------------------------------===//
//
// 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 "ContainerContainsCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
using namespace clang::ast_matchers;
namespace clang::tidy::readability {
void ContainerContainsCheck::registerMatchers(MatchFinder *Finder) {
const auto Literal0 = integerLiteral(equals(0));
const auto Literal1 = integerLiteral(equals(1));
const auto ClassWithContains = cxxRecordDecl(
hasMethod(cxxMethodDecl(isConst(), parameterCountIs(1), isPublic(),
unless(isDeleted()), returns(booleanType()),
hasAnyName("contains", "Contains"))
.bind("contains_fun")));
const auto CountCall =
cxxMemberCallExpr(argumentCountIs(1),
callee(cxxMethodDecl(hasAnyName("count", "Count"),
ofClass(ClassWithContains))))
.bind("call");
const auto FindCall =
// Either one argument, or assume the second argument is the position to
// start searching from.
cxxMemberCallExpr(
anyOf(argumentCountIs(1),
allOf(argumentCountIs(2), hasArgument(1, Literal0))),
callee(cxxMethodDecl(hasAnyName("find", "Find"),
ofClass(ClassWithContains))))
.bind("call");
const auto EndCall = cxxMemberCallExpr(
argumentCountIs(0), callee(cxxMethodDecl(hasAnyName("end", "End"),
ofClass(ClassWithContains))));
const auto StringNpos = anyOf(declRefExpr(to(varDecl(hasName("npos")))),
memberExpr(member(hasName("npos"))));
auto AddSimpleMatcher = [&](auto Matcher) {
Finder->addMatcher(
traverse(TK_IgnoreUnlessSpelledInSource, std::move(Matcher)), this);
};
// Find membership tests which use `count()`.
Finder->addMatcher(implicitCastExpr(hasImplicitDestinationType(booleanType()),
hasSourceExpression(CountCall))
.bind("positiveComparison"),
this);
AddSimpleMatcher(
binaryOperation(hasOperatorName("!="), hasOperands(CountCall, Literal0))
.bind("positiveComparison"));
AddSimpleMatcher(
binaryOperation(hasLHS(CountCall), hasOperatorName(">"), hasRHS(Literal0))
.bind("positiveComparison"));
AddSimpleMatcher(
binaryOperation(hasLHS(Literal0), hasOperatorName("<"), hasRHS(CountCall))
.bind("positiveComparison"));
AddSimpleMatcher(binaryOperation(hasLHS(CountCall), hasOperatorName(">="),
hasRHS(Literal1))
.bind("positiveComparison"));
AddSimpleMatcher(binaryOperation(hasLHS(Literal1), hasOperatorName("<="),
hasRHS(CountCall))
.bind("positiveComparison"));
// Find inverted membership tests which use `count()`.
AddSimpleMatcher(
binaryOperation(hasOperatorName("=="), hasOperands(CountCall, Literal0))
.bind("negativeComparison"));
AddSimpleMatcher(binaryOperation(hasLHS(CountCall), hasOperatorName("<="),
hasRHS(Literal0))
.bind("negativeComparison"));
AddSimpleMatcher(binaryOperation(hasLHS(Literal0), hasOperatorName(">="),
hasRHS(CountCall))
.bind("negativeComparison"));
AddSimpleMatcher(
binaryOperation(hasLHS(CountCall), hasOperatorName("<"), hasRHS(Literal1))
.bind("negativeComparison"));
AddSimpleMatcher(
binaryOperation(hasLHS(Literal1), hasOperatorName(">"), hasRHS(CountCall))
.bind("negativeComparison"));
// Find membership tests based on `find() == end()` or `find() == npos`.
AddSimpleMatcher(
binaryOperation(hasOperatorName("!="),
hasOperands(FindCall, anyOf(EndCall, StringNpos)))
.bind("positiveComparison"));
AddSimpleMatcher(
binaryOperation(hasOperatorName("=="),
hasOperands(FindCall, anyOf(EndCall, StringNpos)))
.bind("negativeComparison"));
}
void ContainerContainsCheck::check(const MatchFinder::MatchResult &Result) {
// Extract the information about the match
const auto *Call = Result.Nodes.getNodeAs<CXXMemberCallExpr>("call");
const auto *PositiveComparison =
Result.Nodes.getNodeAs<Expr>("positiveComparison");
const auto *NegativeComparison =
Result.Nodes.getNodeAs<Expr>("negativeComparison");
assert((!PositiveComparison || !NegativeComparison) &&
"only one of PositiveComparison or NegativeComparison should be set");
bool Negated = NegativeComparison != nullptr;
const auto *Comparison = Negated ? NegativeComparison : PositiveComparison;
const StringRef ContainsFunName =
Result.Nodes.getNodeAs<CXXMethodDecl>("contains_fun")->getName();
const Expr *SearchExpr = Call->getArg(0)->IgnoreParenImpCasts();
// Diagnose the issue.
auto Diag = diag(Call->getExprLoc(), "use '%0' to check for membership")
<< ContainsFunName;
// Don't fix it if it's in a macro invocation. Leave fixing it to the user.
SourceLocation FuncCallLoc = Comparison->getEndLoc();
if (!FuncCallLoc.isValid() || FuncCallLoc.isMacroID())
return;
const StringRef SearchExprText = Lexer::getSourceText(
CharSourceRange::getTokenRange(SearchExpr->getSourceRange()),
*Result.SourceManager, Result.Context->getLangOpts());
// Remove everything before the function call.
Diag << FixItHint::CreateRemoval(CharSourceRange::getCharRange(
Comparison->getBeginLoc(), Call->getBeginLoc()));
// Rename the function to `contains`.
Diag << FixItHint::CreateReplacement(Call->getExprLoc(), ContainsFunName);
// Replace arguments and everything after the function call.
Diag << FixItHint::CreateReplacement(
CharSourceRange::getTokenRange(Call->getArg(0)->getBeginLoc(),
Comparison->getEndLoc()),
(SearchExprText + ")").str());
// Add negation if necessary.
if (Negated)
Diag << FixItHint::CreateInsertion(Call->getBeginLoc(), "!");
}
} // namespace clang::tidy::readability
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