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