RawCommentList.cpp revision 263508 
1//===--- RawCommentList.cpp - Processing raw comments -----------*- C++ -*-===//
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 "clang/AST/RawCommentList.h"
11#include "clang/AST/ASTContext.h"
12#include "clang/AST/Comment.h"
13#include "clang/AST/CommentBriefParser.h"
14#include "clang/AST/CommentCommandTraits.h"
15#include "clang/AST/CommentLexer.h"
16#include "clang/AST/CommentParser.h"
17#include "clang/AST/CommentSema.h"
18#include "llvm/ADT/STLExtras.h"
19
20using namespace clang;
21
22namespace {
23/// Get comment kind and bool describing if it is a trailing comment.
24std::pair<RawComment::CommentKind, bool> getCommentKind(StringRef Comment,
25                                                        bool ParseAllComments) {
26  const size_t MinCommentLength = ParseAllComments ? 2 : 3;
27  if ((Comment.size() < MinCommentLength) || Comment[0] != '/')
28    return std::make_pair(RawComment::RCK_Invalid, false);
29
30  RawComment::CommentKind K;
31  if (Comment[1] == '/') {
32    if (Comment.size() < 3)
33      return std::make_pair(RawComment::RCK_OrdinaryBCPL, false);
34
35    if (Comment[2] == '/')
36      K = RawComment::RCK_BCPLSlash;
37    else if (Comment[2] == '!')
38      K = RawComment::RCK_BCPLExcl;
39    else
40      return std::make_pair(RawComment::RCK_OrdinaryBCPL, false);
41  } else {
42    assert(Comment.size() >= 4);
43
44    // Comment lexer does not understand escapes in comment markers, so pretend
45    // that this is not a comment.
46    if (Comment[1] != '*' ||
47        Comment[Comment.size() - 2] != '*' ||
48        Comment[Comment.size() - 1] != '/')
49      return std::make_pair(RawComment::RCK_Invalid, false);
50
51    if (Comment[2] == '*')
52      K = RawComment::RCK_JavaDoc;
53    else if (Comment[2] == '!')
54      K = RawComment::RCK_Qt;
55    else
56      return std::make_pair(RawComment::RCK_OrdinaryC, false);
57  }
58  const bool TrailingComment = (Comment.size() > 3) && (Comment[3] == '<');
59  return std::make_pair(K, TrailingComment);
60}
61
62bool mergedCommentIsTrailingComment(StringRef Comment) {
63  return (Comment.size() > 3) && (Comment[3] == '<');
64}
65} // unnamed namespace
66
67RawComment::RawComment(const SourceManager &SourceMgr, SourceRange SR,
68                       bool Merged, bool ParseAllComments) :
69    Range(SR), RawTextValid(false), BriefTextValid(false),
70    IsAttached(false), IsAlmostTrailingComment(false),
71    ParseAllComments(ParseAllComments) {
72  // Extract raw comment text, if possible.
73  if (SR.getBegin() == SR.getEnd() || getRawText(SourceMgr).empty()) {
74    Kind = RCK_Invalid;
75    return;
76  }
77
78  if (!Merged) {
79    // Guess comment kind.
80    std::pair<CommentKind, bool> K = getCommentKind(RawText, ParseAllComments);
81    Kind = K.first;
82    IsTrailingComment = K.second;
83
84    IsAlmostTrailingComment = RawText.startswith("//<") ||
85                                 RawText.startswith("/*<");
86  } else {
87    Kind = RCK_Merged;
88    IsTrailingComment = mergedCommentIsTrailingComment(RawText);
89  }
90}
91
92StringRef RawComment::getRawTextSlow(const SourceManager &SourceMgr) const {
93  FileID BeginFileID;
94  FileID EndFileID;
95  unsigned BeginOffset;
96  unsigned EndOffset;
97
98  llvm::tie(BeginFileID, BeginOffset) =
99      SourceMgr.getDecomposedLoc(Range.getBegin());
100  llvm::tie(EndFileID, EndOffset) =
101      SourceMgr.getDecomposedLoc(Range.getEnd());
102
103  const unsigned Length = EndOffset - BeginOffset;
104  if (Length < 2)
105    return StringRef();
106
107  // The comment can't begin in one file and end in another.
108  assert(BeginFileID == EndFileID);
109
110  bool Invalid = false;
111  const char *BufferStart = SourceMgr.getBufferData(BeginFileID,
112                                                    &Invalid).data();
113  if (Invalid)
114    return StringRef();
115
116  return StringRef(BufferStart + BeginOffset, Length);
117}
118
119const char *RawComment::extractBriefText(const ASTContext &Context) const {
120  // Make sure that RawText is valid.
121  getRawText(Context.getSourceManager());
122
123  // Since we will be copying the resulting text, all allocations made during
124  // parsing are garbage after resulting string is formed.  Thus we can use
125  // a separate allocator for all temporary stuff.
126  llvm::BumpPtrAllocator Allocator;
127
128  comments::Lexer L(Allocator, Context.getDiagnostics(),
129                    Context.getCommentCommandTraits(),
130                    Range.getBegin(),
131                    RawText.begin(), RawText.end());
132  comments::BriefParser P(L, Context.getCommentCommandTraits());
133
134  const std::string Result = P.Parse();
135  const unsigned BriefTextLength = Result.size();
136  char *BriefTextPtr = new (Context) char[BriefTextLength + 1];
137  memcpy(BriefTextPtr, Result.c_str(), BriefTextLength + 1);
138  BriefText = BriefTextPtr;
139  BriefTextValid = true;
140
141  return BriefTextPtr;
142}
143
144comments::FullComment *RawComment::parse(const ASTContext &Context,
145                                         const Preprocessor *PP,
146                                         const Decl *D) const {
147  // Make sure that RawText is valid.
148  getRawText(Context.getSourceManager());
149
150  comments::Lexer L(Context.getAllocator(), Context.getDiagnostics(),
151                    Context.getCommentCommandTraits(),
152                    getSourceRange().getBegin(),
153                    RawText.begin(), RawText.end());
154  comments::Sema S(Context.getAllocator(), Context.getSourceManager(),
155                   Context.getDiagnostics(),
156                   Context.getCommentCommandTraits(),
157                   PP);
158  S.setDecl(D);
159  comments::Parser P(L, S, Context.getAllocator(), Context.getSourceManager(),
160                     Context.getDiagnostics(),
161                     Context.getCommentCommandTraits());
162
163  return P.parseFullComment();
164}
165
166static bool onlyWhitespaceBetween(SourceManager &SM,
167                                  SourceLocation Loc1, SourceLocation Loc2,
168                                  unsigned MaxNewlinesAllowed) {
169  std::pair<FileID, unsigned> Loc1Info = SM.getDecomposedLoc(Loc1);
170  std::pair<FileID, unsigned> Loc2Info = SM.getDecomposedLoc(Loc2);
171
172  // Question does not make sense if locations are in different files.
173  if (Loc1Info.first != Loc2Info.first)
174    return false;
175
176  bool Invalid = false;
177  const char *Buffer = SM.getBufferData(Loc1Info.first, &Invalid).data();
178  if (Invalid)
179    return false;
180
181  unsigned NumNewlines = 0;
182  assert(Loc1Info.second <= Loc2Info.second && "Loc1 after Loc2!");
183  // Look for non-whitespace characters and remember any newlines seen.
184  for (unsigned I = Loc1Info.second; I != Loc2Info.second; ++I) {
185    switch (Buffer[I]) {
186    default:
187      return false;
188    case ' ':
189    case '\t':
190    case '\f':
191    case '\v':
192      break;
193    case '\r':
194    case '\n':
195      ++NumNewlines;
196
197      // Check if we have found more than the maximum allowed number of
198      // newlines.
199      if (NumNewlines > MaxNewlinesAllowed)
200        return false;
201
202      // Collapse \r\n and \n\r into a single newline.
203      if (I + 1 != Loc2Info.second &&
204          (Buffer[I + 1] == '\n' || Buffer[I + 1] == '\r') &&
205          Buffer[I] != Buffer[I + 1])
206        ++I;
207      break;
208    }
209  }
210
211  return true;
212}
213
214void RawCommentList::addComment(const RawComment &RC,
215                                llvm::BumpPtrAllocator &Allocator) {
216  if (RC.isInvalid())
217    return;
218
219  // Check if the comments are not in source order.
220  while (!Comments.empty() &&
221         !SourceMgr.isBeforeInTranslationUnit(Comments.back()->getLocStart(),
222                                              RC.getLocStart())) {
223    // If they are, just pop a few last comments that don't fit.
224    // This happens if an \#include directive contains comments.
225    Comments.pop_back();
226  }
227
228  // Ordinary comments are not interesting for us.
229  if (RC.isOrdinary())
230    return;
231
232  // If this is the first Doxygen comment, save it (because there isn't
233  // anything to merge it with).
234  if (Comments.empty()) {
235    Comments.push_back(new (Allocator) RawComment(RC));
236    return;
237  }
238
239  const RawComment &C1 = *Comments.back();
240  const RawComment &C2 = RC;
241
242  // Merge comments only if there is only whitespace between them.
243  // Can't merge trailing and non-trailing comments.
244  // Merge comments if they are on same or consecutive lines.
245  if (C1.isTrailingComment() == C2.isTrailingComment() &&
246      onlyWhitespaceBetween(SourceMgr, C1.getLocEnd(), C2.getLocStart(),
247                            /*MaxNewlinesAllowed=*/1)) {
248    SourceRange MergedRange(C1.getLocStart(), C2.getLocEnd());
249    *Comments.back() = RawComment(SourceMgr, MergedRange, true,
250                                  RC.isParseAllComments());
251  } else {
252    Comments.push_back(new (Allocator) RawComment(RC));
253  }
254}
255