clang-tools  6.0.0
GlobalVariableDeclarationCheck.cpp
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1 //===--- GlobalVariableDeclarationCheck.cpp - clang-tidy-------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "llvm/ADT/StringExtras.h"
14 #include "llvm/ADT/StringRef.h"
15 
16 #include <string>
17 
18 using namespace clang::ast_matchers;
19 
20 namespace clang {
21 namespace tidy {
22 namespace google {
23 namespace objc {
24 
25 namespace {
26 
27 FixItHint generateFixItHint(const VarDecl *Decl, bool IsConst) {
28  char FC = Decl->getName()[0];
29  if (!llvm::isAlpha(FC) || Decl->getName().size() == 1) {
30  // No fix available if first character is not alphabetical character, or it
31  // is a single-character variable, since it is difficult to determine the
32  // proper fix in this case. Users should create a proper variable name by
33  // their own.
34  return FixItHint();
35  }
36  char SC = Decl->getName()[1];
37  if ((FC == 'k' || FC == 'g') && !llvm::isAlpha(SC)) {
38  // No fix available if the prefix is correct but the second character is not
39  // alphabetical, since it is difficult to determine the proper fix in this
40  // case.
41  return FixItHint();
42  }
43  auto NewName = (IsConst ? "k" : "g") +
44  llvm::StringRef(std::string(1, FC)).upper() +
45  Decl->getName().substr(1).str();
46  return FixItHint::CreateReplacement(
47  CharSourceRange::getTokenRange(SourceRange(Decl->getLocation())),
48  llvm::StringRef(NewName));
49 }
50 } // namespace
51 
52 void GlobalVariableDeclarationCheck::registerMatchers(MatchFinder *Finder) {
53  // The relevant Style Guide rule only applies to Objective-C.
54  if (!getLangOpts().ObjC1 && !getLangOpts().ObjC2) {
55  return;
56  }
57  // need to add two matchers since we need to bind different ids to distinguish
58  // constants and variables. Since bind() can only be called on node matchers,
59  // we cannot make it in one matcher.
60  Finder->addMatcher(
61  varDecl(hasGlobalStorage(), unless(hasType(isConstQualified())),
62  unless(matchesName("::g[A-Z]")))
63  .bind("global_var"),
64  this);
65  Finder->addMatcher(varDecl(hasGlobalStorage(), hasType(isConstQualified()),
66  unless(matchesName("::k[A-Z]")))
67  .bind("global_const"),
68  this);
69 }
70 
71 void GlobalVariableDeclarationCheck::check(
72  const MatchFinder::MatchResult &Result) {
73  if (const auto *Decl = Result.Nodes.getNodeAs<VarDecl>("global_var")) {
74  diag(Decl->getLocation(),
75  "non-const global variable '%0' must have a name which starts with "
76  "'g[A-Z]'")
77  << Decl->getName() << generateFixItHint(Decl, false);
78  }
79  if (const auto *Decl = Result.Nodes.getNodeAs<VarDecl>("global_const")) {
80  diag(Decl->getLocation(),
81  "const global variable '%0' must have a name which starts with "
82  "'k[A-Z]'")
83  << Decl->getName() << generateFixItHint(Decl, true);
84  }
85 }
86 
87 } // namespace objc
88 } // namespace google
89 } // namespace tidy
90 } // namespace clang