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//===--- FunctionNamingCheck.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 "FunctionNamingCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "llvm/Support/Regex.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace google {
namespace objc {
namespace {
std::string validFunctionNameRegex(bool RequirePrefix) {
// Allow the following name patterns for all functions:
// • ABFoo (prefix + UpperCamelCase)
// • ABURL (prefix + capitalized acronym/initialism)
//
// If no prefix is required, additionally allow the following name patterns:
// • Foo (UpperCamelCase)
// • URL (capitalized acronym/initialism)
//
// The function name following the prefix can contain standard and
// non-standard capitalized character sequences including acronyms,
// initialisms, and prefixes of symbols (e.g., UIColorFromNSString). For this
// reason, the regex only verifies that the function name after the prefix
// begins with a capital letter followed by an arbitrary sequence of
// alphanumeric characters.
//
// If a prefix is required, the regex checks for a capital letter followed by
// another capital letter or number that is part of the prefix and another
// capital letter or number that begins the name following the prefix.
std::string FunctionNameMatcher =
std::string(RequirePrefix ? "[A-Z][A-Z0-9]+" : "") + "[A-Z][a-zA-Z0-9]*";
return std::string("::(") + FunctionNameMatcher + ")$";
}
/// For now we will only fix functions of static storage class with names like
/// 'functionName' or 'function_name' and convert them to 'FunctionName'. For
/// other cases the user must determine an appropriate name on their own.
FixItHint generateFixItHint(const FunctionDecl *Decl) {
// A fixit can be generated for functions of static storage class but
// otherwise the check cannot determine the appropriate function name prefix
// to use.
if (Decl->getStorageClass() != SC_Static)
return FixItHint();
StringRef Name = Decl->getName();
std::string NewName = Decl->getName().str();
size_t Index = 0;
bool AtWordBoundary = true;
while (Index < NewName.size()) {
char Ch = NewName[Index];
if (isalnum(Ch)) {
// Capitalize the first letter after every word boundary.
if (AtWordBoundary) {
NewName[Index] = toupper(NewName[Index]);
AtWordBoundary = false;
}
// Advance the index after every alphanumeric character.
Index++;
} else {
// Strip out any characters other than alphanumeric characters.
NewName.erase(Index, 1);
AtWordBoundary = true;
}
}
// Generate a fixit hint if the new name is different.
if (NewName != Name)
return FixItHint::CreateReplacement(
CharSourceRange::getTokenRange(SourceRange(Decl->getLocation())),
llvm::StringRef(NewName));
return FixItHint();
}
} // namespace
void FunctionNamingCheck::registerMatchers(MatchFinder *Finder) {
// Enforce Objective-C function naming conventions on all functions except:
// • Functions defined in system headers.
// • C++ member functions.
// • Namespaced functions.
// • Implicitly defined functions.
// • The main function.
Finder->addMatcher(
functionDecl(
unless(anyOf(isExpansionInSystemHeader(), cxxMethodDecl(),
hasAncestor(namespaceDecl()), isMain(), isImplicit(),
matchesName(validFunctionNameRegex(true)),
allOf(isStaticStorageClass(),
matchesName(validFunctionNameRegex(false))))))
.bind("function"),
this);
}
void FunctionNamingCheck::check(const MatchFinder::MatchResult &Result) {
const auto *MatchedDecl = Result.Nodes.getNodeAs<FunctionDecl>("function");
bool IsGlobal = MatchedDecl->getStorageClass() != SC_Static;
diag(MatchedDecl->getLocation(),
"%select{static function|function in global namespace}1 named %0 must "
"%select{be in|have an appropriate prefix followed by}1 Pascal case as "
"required by Google Objective-C style guide")
<< MatchedDecl << IsGlobal << generateFixItHint(MatchedDecl);
}
} // namespace objc
} // namespace google
} // namespace tidy
} // namespace clang