Add new check in google module for Objective-C code to ensure global variables follow the naming convention of Google Objective-C Style Guide
Summary:
This is a new checker for objc files in clang-tidy.
The new check finds global variable declarations in Objective-C files that are not follow the pattern of variable names in Google's Objective-C Style Guide.
All the global variables should follow the pattern of "g[A-Z].*" (variables) or "k[A-Z].*" (constants). The check will suggest a variable name that follows the pattern
if it can be inferred from the original name.
Patch by Yan Zhang!
Reviewers: benhamilton, hokein, alexfh
Reviewed By: hokein
Subscribers: Eugene.Zelenko, mgorny
Differential Revision: https://reviews.llvm.org/D39391
llvm-svn: 317552
diff --git a/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.cpp b/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.cpp
new file mode 100644
index 0000000..a278be1
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/google/GlobalVariableDeclarationCheck.cpp
@@ -0,0 +1,90 @@
+//===--- GlobalVariableDeclarationCheck.cpp - clang-tidy-------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GlobalVariableDeclarationCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringRef.h"
+
+#include <string>
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace google {
+namespace objc {
+
+namespace {
+
+FixItHint generateFixItHint(const VarDecl *Decl, bool IsConst) {
+ char FC = Decl->getName()[0];
+ if (!llvm::isAlpha(FC) || Decl->getName().size() == 1) {
+ // No fix available if first character is not alphabetical character, or it
+ // is a single-character variable, since it is difficult to determine the
+ // proper fix in this case. Users should create a proper variable name by
+ // their own.
+ return FixItHint();
+ }
+ char SC = Decl->getName()[1];
+ if ((FC == 'k' || FC == 'g') && !llvm::isAlpha(SC)) {
+ // No fix available if the prefix is correct but the second character is not
+ // alphabetical, since it is difficult to determine the proper fix in this
+ // case.
+ return FixItHint();
+ }
+ auto NewName = (IsConst ? "k" : "g") +
+ llvm::StringRef(std::string(1, FC)).upper() +
+ Decl->getName().substr(1).str();
+ return FixItHint::CreateReplacement(
+ CharSourceRange::getTokenRange(SourceRange(Decl->getLocation())),
+ llvm::StringRef(NewName));
+}
+} // namespace
+
+void GlobalVariableDeclarationCheck::registerMatchers(MatchFinder *Finder) {
+ // The relevant Style Guide rule only applies to Objective-C.
+ if (!getLangOpts().ObjC1 && !getLangOpts().ObjC2) {
+ return;
+ }
+ // need to add two matchers since we need to bind different ids to distinguish
+ // constants and variables. Since bind() can only be called on node matchers,
+ // we cannot make it in one matcher.
+ Finder->addMatcher(
+ varDecl(hasGlobalStorage(), unless(hasType(isConstQualified())),
+ unless(matchesName("::g[A-Z]")))
+ .bind("global_var"),
+ this);
+ Finder->addMatcher(varDecl(hasGlobalStorage(), hasType(isConstQualified()),
+ unless(matchesName("::k[A-Z]")))
+ .bind("global_const"),
+ this);
+}
+
+void GlobalVariableDeclarationCheck::check(
+ const MatchFinder::MatchResult &Result) {
+ if (const auto *Decl = Result.Nodes.getNodeAs<VarDecl>("global_var")) {
+ diag(Decl->getLocation(),
+ "non-const global variable '%0' must have a name which starts with "
+ "'g[A-Z]'")
+ << Decl->getName() << generateFixItHint(Decl, false);
+ }
+ if (const auto *Decl = Result.Nodes.getNodeAs<VarDecl>("global_const")) {
+ diag(Decl->getLocation(),
+ "const global variable '%0' must have a name which starts with "
+ "'k[A-Z]'")
+ << Decl->getName() << generateFixItHint(Decl, true);
+ }
+}
+
+} // namespace objc
+} // namespace google
+} // namespace tidy
+} // namespace clang