1 //===--- NamespaceCommentCheck.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 
10 #include "NamespaceCommentCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchers.h"
13 #include "clang/Lex/Lexer.h"
14 #include "llvm/ADT/StringExtras.h"
15 
16 using namespace clang::ast_matchers;
17 
18 namespace clang {
19 namespace tidy {
20 namespace readability {
21 
22 NamespaceCommentCheck::NamespaceCommentCheck(StringRef Name,
23                                              ClangTidyContext *Context)
24     : ClangTidyCheck(Name, Context),
25       NamespaceCommentPattern("^/[/*] *(end (of )?)? *(anonymous|unnamed)? *"
26                               "namespace( +([a-zA-Z0-9_]+))?\\.? *(\\*/)?$",
27                               llvm::Regex::IgnoreCase),
28       ShortNamespaceLines(Options.get("ShortNamespaceLines", 1u)),
29       SpacesBeforeComments(Options.get("SpacesBeforeComments", 1u)) {}
30 
31 void NamespaceCommentCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
32   Options.store(Opts, "ShortNamespaceLines", ShortNamespaceLines);
33   Options.store(Opts, "SpacesBeforeComments", SpacesBeforeComments);
34 }
35 
36 void NamespaceCommentCheck::registerMatchers(MatchFinder *Finder) {
37   Finder->addMatcher(namespaceDecl().bind("namespace"), this);
38 }
39 
40 static bool locationsInSameFile(const SourceManager &Sources,
41                                 SourceLocation Loc1, SourceLocation Loc2) {
42   return Loc1.isFileID() && Loc2.isFileID() &&
43          Sources.getFileID(Loc1) == Sources.getFileID(Loc2);
44 }
45 
46 static std::string getNamespaceComment(const NamespaceDecl *ND,
47                                        bool InsertLineBreak) {
48   std::string Fix = "// namespace";
49   if (!ND->isAnonymousNamespace())
50     Fix.append(" ").append(ND->getNameAsString());
51   if (InsertLineBreak)
52     Fix.append("\n");
53   return Fix;
54 }
55 
56 void NamespaceCommentCheck::check(const MatchFinder::MatchResult &Result) {
57   const NamespaceDecl *ND = Result.Nodes.getNodeAs<NamespaceDecl>("namespace");
58   const SourceManager &Sources = *Result.SourceManager;
59 
60   if (!locationsInSameFile(Sources, ND->getLocStart(), ND->getRBraceLoc()))
61     return;
62 
63   // Don't require closing comments for namespaces spanning less than certain
64   // number of lines.
65   unsigned StartLine = Sources.getSpellingLineNumber(ND->getLocStart());
66   unsigned EndLine = Sources.getSpellingLineNumber(ND->getRBraceLoc());
67   if (EndLine - StartLine + 1 <= ShortNamespaceLines)
68     return;
69 
70   // Find next token after the namespace closing brace.
71   SourceLocation AfterRBrace = ND->getRBraceLoc().getLocWithOffset(1);
72   SourceLocation Loc = AfterRBrace;
73   Token Tok;
74   // Skip whitespace until we find the next token.
75   while (Lexer::getRawToken(Loc, Tok, Sources, Result.Context->getLangOpts())) {
76     Loc = Loc.getLocWithOffset(1);
77   }
78   if (!locationsInSameFile(Sources, ND->getRBraceLoc(), Loc))
79     return;
80 
81   bool NextTokenIsOnSameLine = Sources.getSpellingLineNumber(Loc) == EndLine;
82   // If we insert a line comment before the token in the same line, we need
83   // to insert a line break.
84   bool NeedLineBreak = NextTokenIsOnSameLine && Tok.isNot(tok::eof);
85 
86   SourceRange OldCommentRange(AfterRBrace, AfterRBrace);
87   std::string Message = "%0 not terminated with a closing comment";
88 
89   // Try to find existing namespace closing comment on the same line.
90   if (Tok.is(tok::comment) && NextTokenIsOnSameLine) {
91     StringRef Comment(Sources.getCharacterData(Loc), Tok.getLength());
92     SmallVector<StringRef, 7> Groups;
93     if (NamespaceCommentPattern.match(Comment, &Groups)) {
94       StringRef NamespaceNameInComment = Groups.size() > 5 ? Groups[5] : "";
95       StringRef Anonymous = Groups.size() > 3 ? Groups[3] : "";
96 
97       // Check if the namespace in the comment is the same.
98       if ((ND->isAnonymousNamespace() && NamespaceNameInComment.empty()) ||
99           (ND->getNameAsString() == NamespaceNameInComment &&
100            Anonymous.empty())) {
101         // FIXME: Maybe we need a strict mode, where we always fix namespace
102         // comments with different format.
103         return;
104       }
105 
106       // Otherwise we need to fix the comment.
107       NeedLineBreak = Comment.startswith("/*");
108       OldCommentRange =
109           SourceRange(AfterRBrace, Loc.getLocWithOffset(Tok.getLength()));
110       Message =
111           (llvm::Twine(
112                "%0 ends with a comment that refers to a wrong namespace '") +
113            NamespaceNameInComment + "'").str();
114     } else if (Comment.startswith("//")) {
115       // Assume that this is an unrecognized form of a namespace closing line
116       // comment. Replace it.
117       NeedLineBreak = false;
118       OldCommentRange =
119           SourceRange(AfterRBrace, Loc.getLocWithOffset(Tok.getLength()));
120       Message = "%0 ends with an unrecognized comment";
121     }
122     // If it's a block comment, just move it to the next line, as it can be
123     // multi-line or there may be other tokens behind it.
124   }
125 
126   std::string NamespaceName =
127       ND->isAnonymousNamespace()
128           ? "anonymous namespace"
129           : ("namespace '" + ND->getNameAsString() + "'");
130 
131   diag(AfterRBrace, Message)
132       << NamespaceName << FixItHint::CreateReplacement(
133                               CharSourceRange::getCharRange(OldCommentRange),
134                               std::string(SpacesBeforeComments, ' ') +
135                                   getNamespaceComment(ND, NeedLineBreak));
136   diag(ND->getLocation(), "%0 starts here", DiagnosticIDs::Note)
137       << NamespaceName;
138 }
139 
140 } // namespace readability
141 } // namespace tidy
142 } // namespace clang
143