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//===--- UseStartsEndsWithCheck.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 "UseStartsEndsWithCheck.h"
#include "../utils/OptionsUtils.h"
#include "clang/Lex/Lexer.h"
#include <string>
using namespace clang::ast_matchers;
namespace clang::tidy::modernize {
UseStartsEndsWithCheck::UseStartsEndsWithCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context) {}
void UseStartsEndsWithCheck::registerMatchers(MatchFinder *Finder) {
const auto ZeroLiteral = integerLiteral(equals(0));
const auto HasStartsWithMethodWithName = [](const std::string &Name) {
return hasMethod(
cxxMethodDecl(hasName(Name), isConst(), parameterCountIs(1))
.bind("starts_with_fun"));
};
const auto HasStartsWithMethod =
anyOf(HasStartsWithMethodWithName("starts_with"),
HasStartsWithMethodWithName("startsWith"),
HasStartsWithMethodWithName("startswith"));
const auto ClassWithStartsWithFunction = cxxRecordDecl(anyOf(
HasStartsWithMethod, hasAnyBase(hasType(hasCanonicalType(hasDeclaration(
cxxRecordDecl(HasStartsWithMethod)))))));
const auto FindExpr = cxxMemberCallExpr(
// A method call with no second argument or the second argument is zero...
anyOf(argumentCountIs(1), hasArgument(1, ZeroLiteral)),
// ... named find...
callee(cxxMethodDecl(hasName("find")).bind("find_fun")),
// ... on a class with a starts_with function.
on(hasType(
hasCanonicalType(hasDeclaration(ClassWithStartsWithFunction)))),
// Bind search expression.
hasArgument(0, expr().bind("search_expr")));
const auto RFindExpr = cxxMemberCallExpr(
// A method call with a second argument of zero...
hasArgument(1, ZeroLiteral),
// ... named rfind...
callee(cxxMethodDecl(hasName("rfind")).bind("find_fun")),
// ... on a class with a starts_with function.
on(hasType(
hasCanonicalType(hasDeclaration(ClassWithStartsWithFunction)))),
// Bind search expression.
hasArgument(0, expr().bind("search_expr")));
// Match a string literal and an integer or strlen() call matching the length.
const auto HasStringLiteralAndLengthArgs = [](const auto StringArgIndex,
const auto LengthArgIndex) {
return allOf(
hasArgument(StringArgIndex, stringLiteral().bind("string_literal_arg")),
hasArgument(LengthArgIndex,
anyOf(integerLiteral().bind("integer_literal_size_arg"),
callExpr(callee(functionDecl(parameterCountIs(1),
hasName("strlen"))),
hasArgument(0, stringLiteral().bind(
"strlen_arg"))))));
};
// Match a string variable and a call to length() or size().
const auto HasStringVariableAndSizeCallArgs = [](const auto StringArgIndex,
const auto LengthArgIndex) {
return allOf(
hasArgument(StringArgIndex, declRefExpr(hasDeclaration(
decl().bind("string_var_decl")))),
hasArgument(LengthArgIndex,
cxxMemberCallExpr(
callee(cxxMethodDecl(isConst(), parameterCountIs(0),
hasAnyName("size", "length"))),
on(declRefExpr(
to(decl(equalsBoundNode("string_var_decl"))))))));
};
// Match either one of the two cases above.
const auto HasStringAndLengthArgs =
[HasStringLiteralAndLengthArgs, HasStringVariableAndSizeCallArgs](
const auto StringArgIndex, const auto LengthArgIndex) {
return anyOf(
HasStringLiteralAndLengthArgs(StringArgIndex, LengthArgIndex),
HasStringVariableAndSizeCallArgs(StringArgIndex, LengthArgIndex));
};
const auto CompareExpr = cxxMemberCallExpr(
// A method call with three arguments...
argumentCountIs(3),
// ... where the first argument is zero...
hasArgument(0, ZeroLiteral),
// ... named compare...
callee(cxxMethodDecl(hasName("compare")).bind("find_fun")),
// ... on a class with a starts_with function...
on(hasType(
hasCanonicalType(hasDeclaration(ClassWithStartsWithFunction)))),
// ... where the third argument is some string and the second a length.
HasStringAndLengthArgs(2, 1),
// Bind search expression.
hasArgument(2, expr().bind("search_expr")));
Finder->addMatcher(
// Match [=!]= with a zero on one side and (r?)find|compare on the other.
binaryOperator(
hasAnyOperatorName("==", "!="),
hasOperands(cxxMemberCallExpr(anyOf(FindExpr, RFindExpr, CompareExpr))
.bind("find_expr"),
ZeroLiteral))
.bind("expr"),
this);
}
void UseStartsEndsWithCheck::check(const MatchFinder::MatchResult &Result) {
const auto *ComparisonExpr = Result.Nodes.getNodeAs<BinaryOperator>("expr");
const auto *FindExpr = Result.Nodes.getNodeAs<CXXMemberCallExpr>("find_expr");
const auto *FindFun = Result.Nodes.getNodeAs<CXXMethodDecl>("find_fun");
const auto *SearchExpr = Result.Nodes.getNodeAs<Expr>("search_expr");
const auto *StartsWithFunction =
Result.Nodes.getNodeAs<CXXMethodDecl>("starts_with_fun");
const auto *StringLiteralArg =
Result.Nodes.getNodeAs<StringLiteral>("string_literal_arg");
const auto *IntegerLiteralSizeArg =
Result.Nodes.getNodeAs<IntegerLiteral>("integer_literal_size_arg");
const auto *StrlenArg = Result.Nodes.getNodeAs<StringLiteral>("strlen_arg");
// Filter out compare cases where the length does not match string literal.
if (StringLiteralArg && IntegerLiteralSizeArg &&
StringLiteralArg->getLength() !=
IntegerLiteralSizeArg->getValue().getZExtValue()) {
return;
}
if (StringLiteralArg && StrlenArg &&
StringLiteralArg->getLength() != StrlenArg->getLength()) {
return;
}
if (ComparisonExpr->getBeginLoc().isMacroID()) {
return;
}
const bool Neg = ComparisonExpr->getOpcode() == BO_NE;
auto Diagnostic =
diag(FindExpr->getExprLoc(), "use %0 instead of %1() %select{==|!=}2 0")
<< StartsWithFunction->getName() << FindFun->getName() << Neg;
// Remove possible arguments after search expression and ' [!=]= 0' suffix.
Diagnostic << FixItHint::CreateReplacement(
CharSourceRange::getTokenRange(
Lexer::getLocForEndOfToken(SearchExpr->getEndLoc(), 0,
*Result.SourceManager, getLangOpts()),
ComparisonExpr->getEndLoc()),
")");
// Remove possible '0 [!=]= ' prefix.
Diagnostic << FixItHint::CreateRemoval(CharSourceRange::getCharRange(
ComparisonExpr->getBeginLoc(), FindExpr->getBeginLoc()));
// Replace method name by 'starts_with'.
// Remove possible arguments before search expression.
Diagnostic << FixItHint::CreateReplacement(
CharSourceRange::getCharRange(FindExpr->getExprLoc(),
SearchExpr->getBeginLoc()),
(StartsWithFunction->getName() + "(").str());
// Add possible negation '!'.
if (Neg) {
Diagnostic << FixItHint::CreateInsertion(FindExpr->getBeginLoc(), "!");
}
}
} // namespace clang::tidy::modernize
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