clang/lib/Format/BreakableToken.cpp

   1 //===--- BreakableToken.cpp - Format C++ code -----------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 ///
   9 /// \file
  10 /// Contains implementation of BreakableToken class and classes derived
  11 /// from it.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "BreakableToken.h"
  16 #include "ContinuationIndenter.h"
  17 #include "clang/Basic/CharInfo.h"
  18 #include "clang/Format/Format.h"
  19 #include "llvm/ADT/STLExtras.h"
  20 #include "llvm/Support/Debug.h"
  21 #include <algorithm>
  22
  23 #define DEBUG_TYPE "format-token-breaker"
  24
  25 namespace clang {
  26 namespace format {
  27
  28 static constexpr StringRef Blanks = " \t\v\f\r";
  29 static bool IsBlank(char C) {
  30   switch (C) {
  31   case ' ':
  32   case '\t':
  33   case '\v':
  34   case '\f':
  35   case '\r':
  36     return true;
  37   default:
  38     return false;
  39   }
  40 }
  41
  42 static StringRef getLineCommentIndentPrefix(StringRef Comment,
  43                                             const FormatStyle &Style) {
  44   static constexpr StringRef KnownCStylePrefixes[] = {"///<", "//!<", "///",
  45                                                       "//!",  "//:",  "//"};
  46   static constexpr StringRef KnownTextProtoPrefixes[] = {"####", "###", "##",
  47                                                          "//", "#"};
  48   ArrayRef<StringRef> KnownPrefixes(KnownCStylePrefixes);
  49   if (Style.Language == FormatStyle::LK_TextProto)
  50     KnownPrefixes = KnownTextProtoPrefixes;
  51
  52   assert(
  53       llvm::is_sorted(KnownPrefixes, [](StringRef Lhs, StringRef Rhs) noexcept {
  54         return Lhs.size() > Rhs.size();
  55       }));
  56
  57   for (StringRef KnownPrefix : KnownPrefixes) {
  58     if (Comment.startswith(KnownPrefix)) {
  59       const auto PrefixLength =
  60           Comment.find_first_not_of(' ', KnownPrefix.size());
  61       return Comment.substr(0, PrefixLength);
  62     }
  63   }
  64   return {};
  65 }
  66
  67 static BreakableToken::Split
  68 getCommentSplit(StringRef Text, unsigned ContentStartColumn,
  69                 unsigned ColumnLimit, unsigned TabWidth,
  70                 encoding::Encoding Encoding, const FormatStyle &Style,
  71                 bool DecorationEndsWithStar = false) {
  72   LLVM_DEBUG(llvm::dbgs() << "Comment split: \"" << Text
  73                           << "\", Column limit: " << ColumnLimit
  74                           << ", Content start: " << ContentStartColumn << "\n");
  75   if (ColumnLimit <= ContentStartColumn + 1)
  76     return BreakableToken::Split(StringRef::npos, 0);
  77
  78   unsigned MaxSplit = ColumnLimit - ContentStartColumn + 1;
  79   unsigned MaxSplitBytes = 0;
  80
  81   for (unsigned NumChars = 0;
  82        NumChars < MaxSplit && MaxSplitBytes < Text.size();) {
  83     unsigned BytesInChar =
  84         encoding::getCodePointNumBytes(Text[MaxSplitBytes], Encoding);
  85     NumChars +=
  86         encoding::columnWidthWithTabs(Text.substr(MaxSplitBytes, BytesInChar),
  87                                       ContentStartColumn, TabWidth, Encoding);
  88     MaxSplitBytes += BytesInChar;
  89   }
  90
  91   // In JavaScript, some @tags can be followed by {, and machinery that parses
  92   // these comments will fail to understand the comment if followed by a line
  93   // break. So avoid ever breaking before a {.
  94   if (Style.isJavaScript()) {
  95     StringRef::size_type SpaceOffset =
  96         Text.find_first_of(Blanks, MaxSplitBytes);
  97     if (SpaceOffset != StringRef::npos && SpaceOffset + 1 < Text.size() &&
  98         Text[SpaceOffset + 1] == '{') {
  99       MaxSplitBytes = SpaceOffset + 1;
 100     }
 101   }
 102
 103   StringRef::size_type SpaceOffset = Text.find_last_of(Blanks, MaxSplitBytes);
 104
 105   static const auto kNumberedListRegexp = llvm::Regex("^[1-9][0-9]?\\.");
 106   // Some spaces are unacceptable to break on, rewind past them.
 107   while (SpaceOffset != StringRef::npos) {
 108     // If a line-comment ends with `\`, the next line continues the comment,
 109     // whether or not it starts with `//`. This is confusing and triggers
 110     // -Wcomment.
 111     // Avoid introducing multiline comments by not allowing a break right
 112     // after '\'.
 113     if (Style.isCpp()) {
 114       StringRef::size_type LastNonBlank =
 115           Text.find_last_not_of(Blanks, SpaceOffset);
 116       if (LastNonBlank != StringRef::npos && Text[LastNonBlank] == '\\') {
 117         SpaceOffset = Text.find_last_of(Blanks, LastNonBlank);
 118         continue;
 119       }
 120     }
 121
 122     // Do not split before a number followed by a dot: this would be interpreted
 123     // as a numbered list, which would prevent re-flowing in subsequent passes.
 124     if (kNumberedListRegexp.match(Text.substr(SpaceOffset).ltrim(Blanks))) {
 125       SpaceOffset = Text.find_last_of(Blanks, SpaceOffset);
 126       continue;
 127     }
 128
 129     // Avoid ever breaking before a @tag or a { in JavaScript.
 130     if (Style.isJavaScript() && SpaceOffset + 1 < Text.size() &&
 131         (Text[SpaceOffset + 1] == '{' || Text[SpaceOffset + 1] == '@')) {
 132       SpaceOffset = Text.find_last_of(Blanks, SpaceOffset);
 133       continue;
 134     }
 135
 136     break;
 137   }
 138
 139   if (SpaceOffset == StringRef::npos ||
 140       // Don't break at leading whitespace.
 141       Text.find_last_not_of(Blanks, SpaceOffset) == StringRef::npos) {
 142     // Make sure that we don't break at leading whitespace that
 143     // reaches past MaxSplit.
 144     StringRef::size_type FirstNonWhitespace = Text.find_first_not_of(Blanks);
 145     if (FirstNonWhitespace == StringRef::npos) {
 146       // If the comment is only whitespace, we cannot split.
 147       return BreakableToken::Split(StringRef::npos, 0);
 148     }
 149     SpaceOffset = Text.find_first_of(
 150         Blanks, std::max<unsigned>(MaxSplitBytes, FirstNonWhitespace));
 151   }
 152   if (SpaceOffset != StringRef::npos && SpaceOffset != 0) {
 153     // adaptStartOfLine will break after lines starting with /** if the comment
 154     // is broken anywhere. Avoid emitting this break twice here.
 155     // Example: in /** longtextcomesherethatbreaks */ (with ColumnLimit 20) will
 156     // insert a break after /**, so this code must not insert the same break.
 157     if (SpaceOffset == 1 && Text[SpaceOffset - 1] == '*')
 158       return BreakableToken::Split(StringRef::npos, 0);
 159     StringRef BeforeCut = Text.substr(0, SpaceOffset).rtrim(Blanks);
 160     StringRef AfterCut = Text.substr(SpaceOffset);
 161     // Don't trim the leading blanks if it would create a */ after the break.
 162     if (!DecorationEndsWithStar || AfterCut.size() <= 1 || AfterCut[1] != '/')
 163       AfterCut = AfterCut.ltrim(Blanks);
 164     return BreakableToken::Split(BeforeCut.size(),
 165                                  AfterCut.begin() - BeforeCut.end());
 166   }
 167   return BreakableToken::Split(StringRef::npos, 0);
 168 }
 169
 170 static BreakableToken::Split
 171 getStringSplit(StringRef Text, unsigned UsedColumns, unsigned ColumnLimit,
 172                unsigned TabWidth, encoding::Encoding Encoding) {
 173   // FIXME: Reduce unit test case.
 174   if (Text.empty())
 175     return BreakableToken::Split(StringRef::npos, 0);
 176   if (ColumnLimit <= UsedColumns)
 177     return BreakableToken::Split(StringRef::npos, 0);
 178   unsigned MaxSplit = ColumnLimit - UsedColumns;
 179   StringRef::size_type SpaceOffset = 0;
 180   StringRef::size_type SlashOffset = 0;
 181   StringRef::size_type WordStartOffset = 0;
 182   StringRef::size_type SplitPoint = 0;
 183   for (unsigned Chars = 0;;) {
 184     unsigned Advance;
 185     if (Text[0] == '\\') {
 186       Advance = encoding::getEscapeSequenceLength(Text);
 187       Chars += Advance;
 188     } else {
 189       Advance = encoding::getCodePointNumBytes(Text[0], Encoding);
 190       Chars += encoding::columnWidthWithTabs(
 191           Text.substr(0, Advance), UsedColumns + Chars, TabWidth, Encoding);
 192     }
 193
 194     if (Chars > MaxSplit || Text.size() <= Advance)
 195       break;
 196
 197     if (IsBlank(Text[0]))
 198       SpaceOffset = SplitPoint;
 199     if (Text[0] == '/')
 200       SlashOffset = SplitPoint;
 201     if (Advance == 1 && !isAlphanumeric(Text[0]))
 202       WordStartOffset = SplitPoint;
 203
 204     SplitPoint += Advance;
 205     Text = Text.substr(Advance);
 206   }
 207
 208   if (SpaceOffset != 0)
 209     return BreakableToken::Split(SpaceOffset + 1, 0);
 210   if (SlashOffset != 0)
 211     return BreakableToken::Split(SlashOffset + 1, 0);
 212   if (WordStartOffset != 0)
 213     return BreakableToken::Split(WordStartOffset + 1, 0);
 214   if (SplitPoint != 0)
 215     return BreakableToken::Split(SplitPoint, 0);
 216   return BreakableToken::Split(StringRef::npos, 0);
 217 }
 218
 219 bool switchesFormatting(const FormatToken &Token) {
 220   assert((Token.is(TT_BlockComment) || Token.is(TT_LineComment)) &&
 221          "formatting regions are switched by comment tokens");
 222   StringRef Content = Token.TokenText.substr(2).ltrim();
 223   return Content.startswith("clang-format on") ||
 224          Content.startswith("clang-format off");
 225 }
 226
 227 unsigned
 228 BreakableToken::getLengthAfterCompression(unsigned RemainingTokenColumns,
 229                                           Split Split) const {
 230   // Example: consider the content
 231   // lala  lala
 232   // - RemainingTokenColumns is the original number of columns, 10;
 233   // - Split is (4, 2), denoting the two spaces between the two words;
 234   //
 235   // We compute the number of columns when the split is compressed into a single
 236   // space, like:
 237   // lala lala
 238   //
 239   // FIXME: Correctly measure the length of whitespace in Split.second so it
 240   // works with tabs.
 241   return RemainingTokenColumns + 1 - Split.second;
 242 }
 243
 244 unsigned BreakableStringLiteral::getLineCount() const { return 1; }
 245
 246 unsigned BreakableStringLiteral::getRangeLength(unsigned LineIndex,
 247                                                 unsigned Offset,
 248                                                 StringRef::size_type Length,
 249                                                 unsigned StartColumn) const {
 250   llvm_unreachable("Getting the length of a part of the string literal "
 251                    "indicates that the code tries to reflow it.");
 252 }
 253
 254 unsigned
 255 BreakableStringLiteral::getRemainingLength(unsigned LineIndex, unsigned Offset,
 256                                            unsigned StartColumn) const {
 257   return UnbreakableTailLength + Postfix.size() +
 258          encoding::columnWidthWithTabs(Line.substr(Offset), StartColumn,
 259                                        Style.TabWidth, Encoding);
 260 }
 261
 262 unsigned BreakableStringLiteral::getContentStartColumn(unsigned LineIndex,
 263                                                        bool Break) const {
 264   return StartColumn + Prefix.size();
 265 }
 266
 267 BreakableStringLiteral::BreakableStringLiteral(
 268     const FormatToken &Tok, unsigned StartColumn, StringRef Prefix,
 269     StringRef Postfix, unsigned UnbreakableTailLength, bool InPPDirective,
 270     encoding::Encoding Encoding, const FormatStyle &Style)
 271     : BreakableToken(Tok, InPPDirective, Encoding, Style),
 272       StartColumn(StartColumn), Prefix(Prefix), Postfix(Postfix),
 273       UnbreakableTailLength(UnbreakableTailLength) {
 274   assert(Tok.TokenText.startswith(Prefix) && Tok.TokenText.endswith(Postfix));
 275   Line = Tok.TokenText.substr(
 276       Prefix.size(), Tok.TokenText.size() - Prefix.size() - Postfix.size());
 277 }
 278
 279 BreakableToken::Split BreakableStringLiteral::getSplit(
 280     unsigned LineIndex, unsigned TailOffset, unsigned ColumnLimit,
 281     unsigned ContentStartColumn, const llvm::Regex &CommentPragmasRegex) const {
 282   return getStringSplit(Line.substr(TailOffset), ContentStartColumn,
 283                         ColumnLimit - Postfix.size(), Style.TabWidth, Encoding);
 284 }
 285
 286 void BreakableStringLiteral::insertBreak(unsigned LineIndex,
 287                                          unsigned TailOffset, Split Split,
 288                                          unsigned ContentIndent,
 289                                          WhitespaceManager &Whitespaces) const {
 290   Whitespaces.replaceWhitespaceInToken(
 291       Tok, Prefix.size() + TailOffset + Split.first, Split.second, Postfix,
 292       Prefix, InPPDirective, 1, StartColumn);
 293 }
 294
 295 BreakableComment::BreakableComment(const FormatToken &Token,
 296                                    unsigned StartColumn, bool InPPDirective,
 297                                    encoding::Encoding Encoding,
 298                                    const FormatStyle &Style)
 299     : BreakableToken(Token, InPPDirective, Encoding, Style),
 300       StartColumn(StartColumn) {}
 301
 302 unsigned BreakableComment::getLineCount() const { return Lines.size(); }
 303
 304 BreakableToken::Split
 305 BreakableComment::getSplit(unsigned LineIndex, unsigned TailOffset,
 306                            unsigned ColumnLimit, unsigned ContentStartColumn,
 307                            const llvm::Regex &CommentPragmasRegex) const {
 308   // Don't break lines matching the comment pragmas regex.
 309   if (CommentPragmasRegex.match(Content[LineIndex]))
 310     return Split(StringRef::npos, 0);
 311   return getCommentSplit(Content[LineIndex].substr(TailOffset),
 312                          ContentStartColumn, ColumnLimit, Style.TabWidth,
 313                          Encoding, Style);
 314 }
 315
 316 void BreakableComment::compressWhitespace(
 317     unsigned LineIndex, unsigned TailOffset, Split Split,
 318     WhitespaceManager &Whitespaces) const {
 319   StringRef Text = Content[LineIndex].substr(TailOffset);
 320   // Text is relative to the content line, but Whitespaces operates relative to
 321   // the start of the corresponding token, so compute the start of the Split
 322   // that needs to be compressed into a single space relative to the start of
 323   // its token.
 324   unsigned BreakOffsetInToken =
 325       Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
 326   unsigned CharsToRemove = Split.second;
 327   Whitespaces.replaceWhitespaceInToken(
 328       tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "", "",
 329       /*InPPDirective=*/false, /*Newlines=*/0, /*Spaces=*/1);
 330 }
 331
 332 const FormatToken &BreakableComment::tokenAt(unsigned LineIndex) const {
 333   return Tokens[LineIndex] ? *Tokens[LineIndex] : Tok;
 334 }
 335
 336 static bool mayReflowContent(StringRef Content) {
 337   Content = Content.trim(Blanks);
 338   // Lines starting with '@' commonly have special meaning.
 339   // Lines starting with '-', '-#', '+' or '*' are bulleted/numbered lists.
 340   bool hasSpecialMeaningPrefix = false;
 341   for (StringRef Prefix :
 342        {"@", "TODO", "FIXME", "XXX", "-# ", "- ", "+ ", "* "}) {
 343     if (Content.startswith(Prefix)) {
 344       hasSpecialMeaningPrefix = true;
 345       break;
 346     }
 347   }
 348
 349   // Numbered lists may also start with a number followed by '.'
 350   // To avoid issues if a line starts with a number which is actually the end
 351   // of a previous line, we only consider numbers with up to 2 digits.
 352   static const auto kNumberedListRegexp = llvm::Regex("^[1-9][0-9]?\\. ");
 353   hasSpecialMeaningPrefix =
 354       hasSpecialMeaningPrefix || kNumberedListRegexp.match(Content);
 355
 356   // Simple heuristic for what to reflow: content should contain at least two
 357   // characters and either the first or second character must be
 358   // non-punctuation.
 359   return Content.size() >= 2 && !hasSpecialMeaningPrefix &&
 360          !Content.endswith("\\") &&
 361          // Note that this is UTF-8 safe, since if isPunctuation(Content[0]) is
 362          // true, then the first code point must be 1 byte long.
 363          (!isPunctuation(Content[0]) || !isPunctuation(Content[1]));
 364 }
 365
 366 BreakableBlockComment::BreakableBlockComment(
 367     const FormatToken &Token, unsigned StartColumn,
 368     unsigned OriginalStartColumn, bool FirstInLine, bool InPPDirective,
 369     encoding::Encoding Encoding, const FormatStyle &Style, bool UseCRLF)
 370     : BreakableComment(Token, StartColumn, InPPDirective, Encoding, Style),
 371       DelimitersOnNewline(false),
 372       UnbreakableTailLength(Token.UnbreakableTailLength) {
 373   assert(Tok.is(TT_BlockComment) &&
 374          "block comment section must start with a block comment");
 375
 376   StringRef TokenText(Tok.TokenText);
 377   assert(TokenText.startswith("/*") && TokenText.endswith("*/"));
 378   TokenText.substr(2, TokenText.size() - 4)
 379       .split(Lines, UseCRLF ? "\r\n" : "\n");
 380
 381   int IndentDelta = StartColumn - OriginalStartColumn;
 382   Content.resize(Lines.size());
 383   Content[0] = Lines[0];
 384   ContentColumn.resize(Lines.size());
 385   // Account for the initial '/*'.
 386   ContentColumn[0] = StartColumn + 2;
 387   Tokens.resize(Lines.size());
 388   for (size_t i = 1; i < Lines.size(); ++i)
 389     adjustWhitespace(i, IndentDelta);
 390
 391   // Align decorations with the column of the star on the first line,
 392   // that is one column after the start "/*".
 393   DecorationColumn = StartColumn + 1;
 394
 395   // Account for comment decoration patterns like this:
 396   //
 397   // /*
 398   // ** blah blah blah
 399   // */
 400   if (Lines.size() >= 2 && Content[1].startswith("**") &&
 401       static_cast<unsigned>(ContentColumn[1]) == StartColumn) {
 402     DecorationColumn = StartColumn;
 403   }
 404
 405   Decoration = "* ";
 406   if (Lines.size() == 1 && !FirstInLine) {
 407     // Comments for which FirstInLine is false can start on arbitrary column,
 408     // and available horizontal space can be too small to align consecutive
 409     // lines with the first one.
 410     // FIXME: We could, probably, align them to current indentation level, but
 411     // now we just wrap them without stars.
 412     Decoration = "";
 413   }
 414   for (size_t i = 1, e = Content.size(); i < e && !Decoration.empty(); ++i) {
 415     const StringRef &Text = Content[i];
 416     if (i + 1 == e) {
 417       // If the last line is empty, the closing "*/" will have a star.
 418       if (Text.empty())
 419         break;
 420     } else if (!Text.empty() && Decoration.startswith(Text)) {
 421       continue;
 422     }
 423     while (!Text.startswith(Decoration))
 424       Decoration = Decoration.drop_back(1);
 425   }
 426
 427   LastLineNeedsDecoration = true;
 428   IndentAtLineBreak = ContentColumn[0] + 1;
 429   for (size_t i = 1, e = Lines.size(); i < e; ++i) {
 430     if (Content[i].empty()) {
 431       if (i + 1 == e) {
 432         // Empty last line means that we already have a star as a part of the
 433         // trailing */. We also need to preserve whitespace, so that */ is
 434         // correctly indented.
 435         LastLineNeedsDecoration = false;
 436         // Align the star in the last '*/' with the stars on the previous lines.
 437         if (e >= 2 && !Decoration.empty())
 438           ContentColumn[i] = DecorationColumn;
 439       } else if (Decoration.empty()) {
 440         // For all other lines, set the start column to 0 if they're empty, so
 441         // we do not insert trailing whitespace anywhere.
 442         ContentColumn[i] = 0;
 443       }
 444       continue;
 445     }
 446
 447     // The first line already excludes the star.
 448     // The last line excludes the star if LastLineNeedsDecoration is false.
 449     // For all other lines, adjust the line to exclude the star and
 450     // (optionally) the first whitespace.
 451     unsigned DecorationSize = Decoration.startswith(Content[i])
 452                                   ? Content[i].size()
 453                                   : Decoration.size();
 454     if (DecorationSize)
 455       ContentColumn[i] = DecorationColumn + DecorationSize;
 456     Content[i] = Content[i].substr(DecorationSize);
 457     if (!Decoration.startswith(Content[i])) {
 458       IndentAtLineBreak =
 459           std::min<int>(IndentAtLineBreak, std::max(0, ContentColumn[i]));
 460     }
 461   }
 462   IndentAtLineBreak = std::max<unsigned>(IndentAtLineBreak, Decoration.size());
 463
 464   // Detect a multiline jsdoc comment and set DelimitersOnNewline in that case.
 465   if (Style.isJavaScript() || Style.Language == FormatStyle::LK_Java) {
 466     if ((Lines[0] == "*" || Lines[0].startswith("* ")) && Lines.size() > 1) {
 467       // This is a multiline jsdoc comment.
 468       DelimitersOnNewline = true;
 469     } else if (Lines[0].startswith("* ") && Lines.size() == 1) {
 470       // Detect a long single-line comment, like:
 471       // /** long long long */
 472       // Below, '2' is the width of '*/'.
 473       unsigned EndColumn =
 474           ContentColumn[0] +
 475           encoding::columnWidthWithTabs(Lines[0], ContentColumn[0],
 476                                         Style.TabWidth, Encoding) +
 477           2;
 478       DelimitersOnNewline = EndColumn > Style.ColumnLimit;
 479     }
 480   }
 481
 482   LLVM_DEBUG({
 483     llvm::dbgs() << "IndentAtLineBreak " << IndentAtLineBreak << "\n";
 484     llvm::dbgs() << "DelimitersOnNewline " << DelimitersOnNewline << "\n";
 485     for (size_t i = 0; i < Lines.size(); ++i) {
 486       llvm::dbgs() << i << " |" << Content[i] << "| "
 487                    << "CC=" << ContentColumn[i] << "| "
 488                    << "IN=" << (Content[i].data() - Lines[i].data()) << "\n";
 489     }
 490   });
 491 }
 492
 493 BreakableToken::Split BreakableBlockComment::getSplit(
 494     unsigned LineIndex, unsigned TailOffset, unsigned ColumnLimit,
 495     unsigned ContentStartColumn, const llvm::Regex &CommentPragmasRegex) const {
 496   // Don't break lines matching the comment pragmas regex.
 497   if (CommentPragmasRegex.match(Content[LineIndex]))
 498     return Split(StringRef::npos, 0);
 499   return getCommentSplit(Content[LineIndex].substr(TailOffset),
 500                          ContentStartColumn, ColumnLimit, Style.TabWidth,
 501                          Encoding, Style, Decoration.endswith("*"));
 502 }
 503
 504 void BreakableBlockComment::adjustWhitespace(unsigned LineIndex,
 505                                              int IndentDelta) {
 506   // When in a preprocessor directive, the trailing backslash in a block comment
 507   // is not needed, but can serve a purpose of uniformity with necessary escaped
 508   // newlines outside the comment. In this case we remove it here before
 509   // trimming the trailing whitespace. The backslash will be re-added later when
 510   // inserting a line break.
 511   size_t EndOfPreviousLine = Lines[LineIndex - 1].size();
 512   if (InPPDirective && Lines[LineIndex - 1].endswith("\\"))
 513     --EndOfPreviousLine;
 514
 515   // Calculate the end of the non-whitespace text in the previous line.
 516   EndOfPreviousLine =
 517       Lines[LineIndex - 1].find_last_not_of(Blanks, EndOfPreviousLine);
 518   if (EndOfPreviousLine == StringRef::npos)
 519     EndOfPreviousLine = 0;
 520   else
 521     ++EndOfPreviousLine;
 522   // Calculate the start of the non-whitespace text in the current line.
 523   size_t StartOfLine = Lines[LineIndex].find_first_not_of(Blanks);
 524   if (StartOfLine == StringRef::npos)
 525     StartOfLine = Lines[LineIndex].size();
 526
 527   StringRef Whitespace = Lines[LineIndex].substr(0, StartOfLine);
 528   // Adjust Lines to only contain relevant text.
 529   size_t PreviousContentOffset =
 530       Content[LineIndex - 1].data() - Lines[LineIndex - 1].data();
 531   Content[LineIndex - 1] = Lines[LineIndex - 1].substr(
 532       PreviousContentOffset, EndOfPreviousLine - PreviousContentOffset);
 533   Content[LineIndex] = Lines[LineIndex].substr(StartOfLine);
 534
 535   // Adjust the start column uniformly across all lines.
 536   ContentColumn[LineIndex] =
 537       encoding::columnWidthWithTabs(Whitespace, 0, Style.TabWidth, Encoding) +
 538       IndentDelta;
 539 }
 540
 541 unsigned BreakableBlockComment::getRangeLength(unsigned LineIndex,
 542                                                unsigned Offset,
 543                                                StringRef::size_type Length,
 544                                                unsigned StartColumn) const {
 545   return encoding::columnWidthWithTabs(
 546       Content[LineIndex].substr(Offset, Length), StartColumn, Style.TabWidth,
 547       Encoding);
 548 }
 549
 550 unsigned BreakableBlockComment::getRemainingLength(unsigned LineIndex,
 551                                                    unsigned Offset,
 552                                                    unsigned StartColumn) const {
 553   unsigned LineLength =
 554       UnbreakableTailLength +
 555       getRangeLength(LineIndex, Offset, StringRef::npos, StartColumn);
 556   if (LineIndex + 1 == Lines.size()) {
 557     LineLength += 2;
 558     // We never need a decoration when breaking just the trailing "*/" postfix.
 559     bool HasRemainingText = Offset < Content[LineIndex].size();
 560     if (!HasRemainingText) {
 561       bool HasDecoration = Lines[LineIndex].ltrim().startswith(Decoration);
 562       if (HasDecoration)
 563         LineLength -= Decoration.size();
 564     }
 565   }
 566   return LineLength;
 567 }
 568
 569 unsigned BreakableBlockComment::getContentStartColumn(unsigned LineIndex,
 570                                                       bool Break) const {
 571   if (Break)
 572     return IndentAtLineBreak;
 573   return std::max(0, ContentColumn[LineIndex]);
 574 }
 575
 576 const llvm::StringSet<>
 577     BreakableBlockComment::ContentIndentingJavadocAnnotations = {
 578         "@param", "@return",     "@returns", "@throws",  "@type", "@template",
 579         "@see",   "@deprecated", "@define",  "@exports", "@mods", "@private",
 580 };
 581
 582 unsigned BreakableBlockComment::getContentIndent(unsigned LineIndex) const {
 583   if (Style.Language != FormatStyle::LK_Java && !Style.isJavaScript())
 584     return 0;
 585   // The content at LineIndex 0 of a comment like:
 586   // /** line 0 */
 587   // is "* line 0", so we need to skip over the decoration in that case.
 588   StringRef ContentWithNoDecoration = Content[LineIndex];
 589   if (LineIndex == 0 && ContentWithNoDecoration.startswith("*"))
 590     ContentWithNoDecoration = ContentWithNoDecoration.substr(1).ltrim(Blanks);
 591   StringRef FirstWord = ContentWithNoDecoration.substr(
 592       0, ContentWithNoDecoration.find_first_of(Blanks));
 593   if (ContentIndentingJavadocAnnotations.contains(FirstWord))
 594     return Style.ContinuationIndentWidth;
 595   return 0;
 596 }
 597
 598 void BreakableBlockComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
 599                                         Split Split, unsigned ContentIndent,
 600                                         WhitespaceManager &Whitespaces) const {
 601   StringRef Text = Content[LineIndex].substr(TailOffset);
 602   StringRef Prefix = Decoration;
 603   // We need this to account for the case when we have a decoration "* " for all
 604   // the lines except for the last one, where the star in "*/" acts as a
 605   // decoration.
 606   unsigned LocalIndentAtLineBreak = IndentAtLineBreak;
 607   if (LineIndex + 1 == Lines.size() &&
 608       Text.size() == Split.first + Split.second) {
 609     // For the last line we need to break before "*/", but not to add "* ".
 610     Prefix = "";
 611     if (LocalIndentAtLineBreak >= 2)
 612       LocalIndentAtLineBreak -= 2;
 613   }
 614   // The split offset is from the beginning of the line. Convert it to an offset
 615   // from the beginning of the token text.
 616   unsigned BreakOffsetInToken =
 617       Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
 618   unsigned CharsToRemove = Split.second;
 619   assert(LocalIndentAtLineBreak >= Prefix.size());
 620   std::string PrefixWithTrailingIndent = std::string(Prefix);
 621   PrefixWithTrailingIndent.append(ContentIndent, ' ');
 622   Whitespaces.replaceWhitespaceInToken(
 623       tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "",
 624       PrefixWithTrailingIndent, InPPDirective, /*Newlines=*/1,
 625       /*Spaces=*/LocalIndentAtLineBreak + ContentIndent -
 626           PrefixWithTrailingIndent.size());
 627 }
 628
 629 BreakableToken::Split BreakableBlockComment::getReflowSplit(
 630     unsigned LineIndex, const llvm::Regex &CommentPragmasRegex) const {
 631   if (!mayReflow(LineIndex, CommentPragmasRegex))
 632     return Split(StringRef::npos, 0);
 633
 634   // If we're reflowing into a line with content indent, only reflow the next
 635   // line if its starting whitespace matches the content indent.
 636   size_t Trimmed = Content[LineIndex].find_first_not_of(Blanks);
 637   if (LineIndex) {
 638     unsigned PreviousContentIndent = getContentIndent(LineIndex - 1);
 639     if (PreviousContentIndent && Trimmed != StringRef::npos &&
 640         Trimmed != PreviousContentIndent) {
 641       return Split(StringRef::npos, 0);
 642     }
 643   }
 644
 645   return Split(0, Trimmed != StringRef::npos ? Trimmed : 0);
 646 }
 647
 648 bool BreakableBlockComment::introducesBreakBeforeToken() const {
 649   // A break is introduced when we want delimiters on newline.
 650   return DelimitersOnNewline &&
 651          Lines[0].substr(1).find_first_not_of(Blanks) != StringRef::npos;
 652 }
 653
 654 void BreakableBlockComment::reflow(unsigned LineIndex,
 655                                    WhitespaceManager &Whitespaces) const {
 656   StringRef TrimmedContent = Content[LineIndex].ltrim(Blanks);
 657   // Here we need to reflow.
 658   assert(Tokens[LineIndex - 1] == Tokens[LineIndex] &&
 659          "Reflowing whitespace within a token");
 660   // This is the offset of the end of the last line relative to the start of
 661   // the token text in the token.
 662   unsigned WhitespaceOffsetInToken = Content[LineIndex - 1].data() +
 663                                      Content[LineIndex - 1].size() -
 664                                      tokenAt(LineIndex).TokenText.data();
 665   unsigned WhitespaceLength = TrimmedContent.data() -
 666                               tokenAt(LineIndex).TokenText.data() -
 667                               WhitespaceOffsetInToken;
 668   Whitespaces.replaceWhitespaceInToken(
 669       tokenAt(LineIndex), WhitespaceOffsetInToken,
 670       /*ReplaceChars=*/WhitespaceLength, /*PreviousPostfix=*/"",
 671       /*CurrentPrefix=*/ReflowPrefix, InPPDirective, /*Newlines=*/0,
 672       /*Spaces=*/0);
 673 }
 674
 675 void BreakableBlockComment::adaptStartOfLine(
 676     unsigned LineIndex, WhitespaceManager &Whitespaces) const {
 677   if (LineIndex == 0) {
 678     if (DelimitersOnNewline) {
 679       // Since we're breaking at index 1 below, the break position and the
 680       // break length are the same.
 681       // Note: this works because getCommentSplit is careful never to split at
 682       // the beginning of a line.
 683       size_t BreakLength = Lines[0].substr(1).find_first_not_of(Blanks);
 684       if (BreakLength != StringRef::npos) {
 685         insertBreak(LineIndex, 0, Split(1, BreakLength), /*ContentIndent=*/0,
 686                     Whitespaces);
 687       }
 688     }
 689     return;
 690   }
 691   // Here no reflow with the previous line will happen.
 692   // Fix the decoration of the line at LineIndex.
 693   StringRef Prefix = Decoration;
 694   if (Content[LineIndex].empty()) {
 695     if (LineIndex + 1 == Lines.size()) {
 696       if (!LastLineNeedsDecoration) {
 697         // If the last line was empty, we don't need a prefix, as the */ will
 698         // line up with the decoration (if it exists).
 699         Prefix = "";
 700       }
 701     } else if (!Decoration.empty()) {
 702       // For other empty lines, if we do have a decoration, adapt it to not
 703       // contain a trailing whitespace.
 704       Prefix = Prefix.substr(0, 1);
 705     }
 706   } else if (ContentColumn[LineIndex] == 1) {
 707     // This line starts immediately after the decorating *.
 708     Prefix = Prefix.substr(0, 1);
 709   }
 710   // This is the offset of the end of the last line relative to the start of the
 711   // token text in the token.
 712   unsigned WhitespaceOffsetInToken = Content[LineIndex - 1].data() +
 713                                      Content[LineIndex - 1].size() -
 714                                      tokenAt(LineIndex).TokenText.data();
 715   unsigned WhitespaceLength = Content[LineIndex].data() -
 716                               tokenAt(LineIndex).TokenText.data() -
 717                               WhitespaceOffsetInToken;
 718   Whitespaces.replaceWhitespaceInToken(
 719       tokenAt(LineIndex), WhitespaceOffsetInToken, WhitespaceLength, "", Prefix,
 720       InPPDirective, /*Newlines=*/1, ContentColumn[LineIndex] - Prefix.size());
 721 }
 722
 723 BreakableToken::Split
 724 BreakableBlockComment::getSplitAfterLastLine(unsigned TailOffset) const {
 725   if (DelimitersOnNewline) {
 726     // Replace the trailing whitespace of the last line with a newline.
 727     // In case the last line is empty, the ending '*/' is already on its own
 728     // line.
 729     StringRef Line = Content.back().substr(TailOffset);
 730     StringRef TrimmedLine = Line.rtrim(Blanks);
 731     if (!TrimmedLine.empty())
 732       return Split(TrimmedLine.size(), Line.size() - TrimmedLine.size());
 733   }
 734   return Split(StringRef::npos, 0);
 735 }
 736
 737 bool BreakableBlockComment::mayReflow(
 738     unsigned LineIndex, const llvm::Regex &CommentPragmasRegex) const {
 739   // Content[LineIndex] may exclude the indent after the '*' decoration. In that
 740   // case, we compute the start of the comment pragma manually.
 741   StringRef IndentContent = Content[LineIndex];
 742   if (Lines[LineIndex].ltrim(Blanks).startswith("*"))
 743     IndentContent = Lines[LineIndex].ltrim(Blanks).substr(1);
 744   return LineIndex > 0 && !CommentPragmasRegex.match(IndentContent) &&
 745          mayReflowContent(Content[LineIndex]) && !Tok.Finalized &&
 746          !switchesFormatting(tokenAt(LineIndex));
 747 }
 748
 749 BreakableLineCommentSection::BreakableLineCommentSection(
 750     const FormatToken &Token, unsigned StartColumn, bool InPPDirective,
 751     encoding::Encoding Encoding, const FormatStyle &Style)
 752     : BreakableComment(Token, StartColumn, InPPDirective, Encoding, Style) {
 753   assert(Tok.is(TT_LineComment) &&
 754          "line comment section must start with a line comment");
 755   FormatToken *LineTok = nullptr;
 756   const int Minimum = Style.SpacesInLineCommentPrefix.Minimum;
 757   // How many spaces we changed in the first line of the section, this will be
 758   // applied in all following lines
 759   int FirstLineSpaceChange = 0;
 760   for (const FormatToken *CurrentTok = &Tok;
 761        CurrentTok && CurrentTok->is(TT_LineComment);
 762        CurrentTok = CurrentTok->Next) {
 763     LastLineTok = LineTok;
 764     StringRef TokenText(CurrentTok->TokenText);
 765     assert((TokenText.startswith("//") || TokenText.startswith("#")) &&
 766            "unsupported line comment prefix, '//' and '#' are supported");
 767     size_t FirstLineIndex = Lines.size();
 768     TokenText.split(Lines, "\n");
 769     Content.resize(Lines.size());
 770     ContentColumn.resize(Lines.size());
 771     PrefixSpaceChange.resize(Lines.size());
 772     Tokens.resize(Lines.size());
 773     Prefix.resize(Lines.size());
 774     OriginalPrefix.resize(Lines.size());
 775     for (size_t i = FirstLineIndex, e = Lines.size(); i < e; ++i) {
 776       Lines[i] = Lines[i].ltrim(Blanks);
 777       StringRef IndentPrefix = getLineCommentIndentPrefix(Lines[i], Style);
 778       OriginalPrefix[i] = IndentPrefix;
 779       const int SpacesInPrefix = llvm::count(IndentPrefix, ' ');
 780
 781       // This lambda also considers multibyte character that is not handled in
 782       // functions like isPunctuation provided by CharInfo.
 783       const auto NoSpaceBeforeFirstCommentChar = [&]() {
 784         assert(Lines[i].size() > IndentPrefix.size());
 785         const char FirstCommentChar = Lines[i][IndentPrefix.size()];
 786         const unsigned FirstCharByteSize =
 787             encoding::getCodePointNumBytes(FirstCommentChar, Encoding);
 788         if (encoding::columnWidth(
 789                 Lines[i].substr(IndentPrefix.size(), FirstCharByteSize),
 790                 Encoding) != 1) {
 791           return false;
 792         }
 793         // In C-like comments, add a space before #. For example this is useful
 794         // to preserve the relative indentation when commenting out code with
 795         // #includes.
 796         //
 797         // In languages using # as the comment leader such as proto, don't
 798         // add a space to support patterns like:
 799         // #########
 800         // # section
 801         // #########
 802         if (FirstCommentChar == '#' && !TokenText.startswith("#"))
 803           return false;
 804         return FirstCommentChar == '\\' || isPunctuation(FirstCommentChar) ||
 805                isHorizontalWhitespace(FirstCommentChar);
 806       };
 807
 808       // On the first line of the comment section we calculate how many spaces
 809       // are to be added or removed, all lines after that just get only the
 810       // change and we will not look at the maximum anymore. Additionally to the
 811       // actual first line, we calculate that when the non space Prefix changes,
 812       // e.g. from "///" to "//".
 813       if (i == 0 || OriginalPrefix[i].rtrim(Blanks) !=
 814                         OriginalPrefix[i - 1].rtrim(Blanks)) {
 815         if (SpacesInPrefix < Minimum && Lines[i].size() > IndentPrefix.size() &&
 816             !NoSpaceBeforeFirstCommentChar()) {
 817           FirstLineSpaceChange = Minimum - SpacesInPrefix;
 818         } else if (static_cast<unsigned>(SpacesInPrefix) >
 819                    Style.SpacesInLineCommentPrefix.Maximum) {
 820           FirstLineSpaceChange =
 821               Style.SpacesInLineCommentPrefix.Maximum - SpacesInPrefix;
 822         } else {
 823           FirstLineSpaceChange = 0;
 824         }
 825       }
 826
 827       if (Lines[i].size() != IndentPrefix.size()) {
 828         PrefixSpaceChange[i] = FirstLineSpaceChange;
 829
 830         if (SpacesInPrefix + PrefixSpaceChange[i] < Minimum) {
 831           PrefixSpaceChange[i] +=
 832               Minimum - (SpacesInPrefix + PrefixSpaceChange[i]);
 833         }
 834
 835         assert(Lines[i].size() > IndentPrefix.size());
 836         const auto FirstNonSpace = Lines[i][IndentPrefix.size()];
 837         const bool IsFormatComment = LineTok && switchesFormatting(*LineTok);
 838         const bool LineRequiresLeadingSpace =
 839             !NoSpaceBeforeFirstCommentChar() ||
 840             (FirstNonSpace == '}' && FirstLineSpaceChange != 0);
 841         const bool AllowsSpaceChange =
 842             !IsFormatComment &&
 843             (SpacesInPrefix != 0 || LineRequiresLeadingSpace);
 844
 845         if (PrefixSpaceChange[i] > 0 && AllowsSpaceChange) {
 846           Prefix[i] = IndentPrefix.str();
 847           Prefix[i].append(PrefixSpaceChange[i], ' ');
 848         } else if (PrefixSpaceChange[i] < 0 && AllowsSpaceChange) {
 849           Prefix[i] = IndentPrefix
 850                           .drop_back(std::min<std::size_t>(
 851                               -PrefixSpaceChange[i], SpacesInPrefix))
 852                           .str();
 853         } else {
 854           Prefix[i] = IndentPrefix.str();
 855         }
 856       } else {
 857         // If the IndentPrefix is the whole line, there is no content and we
 858         // drop just all space
 859         Prefix[i] = IndentPrefix.drop_back(SpacesInPrefix).str();
 860       }
 861
 862       Tokens[i] = LineTok;
 863       Content[i] = Lines[i].substr(IndentPrefix.size());
 864       ContentColumn[i] =
 865           StartColumn + encoding::columnWidthWithTabs(Prefix[i], StartColumn,
 866                                                       Style.TabWidth, Encoding);
 867
 868       // Calculate the end of the non-whitespace text in this line.
 869       size_t EndOfLine = Content[i].find_last_not_of(Blanks);
 870       if (EndOfLine == StringRef::npos)
 871         EndOfLine = Content[i].size();
 872       else
 873         ++EndOfLine;
 874       Content[i] = Content[i].substr(0, EndOfLine);
 875     }
 876     LineTok = CurrentTok->Next;
 877     if (CurrentTok->Next && !CurrentTok->Next->ContinuesLineCommentSection) {
 878       // A line comment section needs to broken by a line comment that is
 879       // preceded by at least two newlines. Note that we put this break here
 880       // instead of breaking at a previous stage during parsing, since that
 881       // would split the contents of the enum into two unwrapped lines in this
 882       // example, which is undesirable:
 883       // enum A {
 884       //   a, // comment about a
 885       //
 886       //   // comment about b
 887       //   b
 888       // };
 889       //
 890       // FIXME: Consider putting separate line comment sections as children to
 891       // the unwrapped line instead.
 892       break;
 893     }
 894   }
 895 }
 896
 897 unsigned
 898 BreakableLineCommentSection::getRangeLength(unsigned LineIndex, unsigned Offset,
 899                                             StringRef::size_type Length,
 900                                             unsigned StartColumn) const {
 901   return encoding::columnWidthWithTabs(
 902       Content[LineIndex].substr(Offset, Length), StartColumn, Style.TabWidth,
 903       Encoding);
 904 }
 905
 906 unsigned
 907 BreakableLineCommentSection::getContentStartColumn(unsigned LineIndex,
 908                                                    bool /*Break*/) const {
 909   return ContentColumn[LineIndex];
 910 }
 911
 912 void BreakableLineCommentSection::insertBreak(
 913     unsigned LineIndex, unsigned TailOffset, Split Split,
 914     unsigned ContentIndent, WhitespaceManager &Whitespaces) const {
 915   StringRef Text = Content[LineIndex].substr(TailOffset);
 916   // Compute the offset of the split relative to the beginning of the token
 917   // text.
 918   unsigned BreakOffsetInToken =
 919       Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
 920   unsigned CharsToRemove = Split.second;
 921   Whitespaces.replaceWhitespaceInToken(
 922       tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "",
 923       Prefix[LineIndex], InPPDirective, /*Newlines=*/1,
 924       /*Spaces=*/ContentColumn[LineIndex] - Prefix[LineIndex].size());
 925 }
 926
 927 BreakableComment::Split BreakableLineCommentSection::getReflowSplit(
 928     unsigned LineIndex, const llvm::Regex &CommentPragmasRegex) const {
 929   if (!mayReflow(LineIndex, CommentPragmasRegex))
 930     return Split(StringRef::npos, 0);
 931
 932   size_t Trimmed = Content[LineIndex].find_first_not_of(Blanks);
 933
 934   // In a line comment section each line is a separate token; thus, after a
 935   // split we replace all whitespace before the current line comment token
 936   // (which does not need to be included in the split), plus the start of the
 937   // line up to where the content starts.
 938   return Split(0, Trimmed != StringRef::npos ? Trimmed : 0);
 939 }
 940
 941 void BreakableLineCommentSection::reflow(unsigned LineIndex,
 942                                          WhitespaceManager &Whitespaces) const {
 943   if (LineIndex > 0 && Tokens[LineIndex] != Tokens[LineIndex - 1]) {
 944     // Reflow happens between tokens. Replace the whitespace between the
 945     // tokens by the empty string.
 946     Whitespaces.replaceWhitespace(
 947         *Tokens[LineIndex], /*Newlines=*/0, /*Spaces=*/0,
 948         /*StartOfTokenColumn=*/StartColumn, /*IsAligned=*/true,
 949         /*InPPDirective=*/false);
 950   } else if (LineIndex > 0) {
 951     // In case we're reflowing after the '\' in:
 952     //
 953     //   // line comment \
 954     //   // line 2
 955     //
 956     // the reflow happens inside the single comment token (it is a single line
 957     // comment with an unescaped newline).
 958     // Replace the whitespace between the '\' and '//' with the empty string.
 959     //
 960     // Offset points to after the '\' relative to start of the token.
 961     unsigned Offset = Lines[LineIndex - 1].data() +
 962                       Lines[LineIndex - 1].size() -
 963                       tokenAt(LineIndex - 1).TokenText.data();
 964     // WhitespaceLength is the number of chars between the '\' and the '//' on
 965     // the next line.
 966     unsigned WhitespaceLength =
 967         Lines[LineIndex].data() - tokenAt(LineIndex).TokenText.data() - Offset;
 968     Whitespaces.replaceWhitespaceInToken(*Tokens[LineIndex], Offset,
 969                                          /*ReplaceChars=*/WhitespaceLength,
 970                                          /*PreviousPostfix=*/"",
 971                                          /*CurrentPrefix=*/"",
 972                                          /*InPPDirective=*/false,
 973                                          /*Newlines=*/0,
 974                                          /*Spaces=*/0);
 975   }
 976   // Replace the indent and prefix of the token with the reflow prefix.
 977   unsigned Offset =
 978       Lines[LineIndex].data() - tokenAt(LineIndex).TokenText.data();
 979   unsigned WhitespaceLength =
 980       Content[LineIndex].data() - Lines[LineIndex].data();
 981   Whitespaces.replaceWhitespaceInToken(*Tokens[LineIndex], Offset,
 982                                        /*ReplaceChars=*/WhitespaceLength,
 983                                        /*PreviousPostfix=*/"",
 984                                        /*CurrentPrefix=*/ReflowPrefix,
 985                                        /*InPPDirective=*/false,
 986                                        /*Newlines=*/0,
 987                                        /*Spaces=*/0);
 988 }
 989
 990 void BreakableLineCommentSection::adaptStartOfLine(
 991     unsigned LineIndex, WhitespaceManager &Whitespaces) const {
 992   // If this is the first line of a token, we need to inform Whitespace Manager
 993   // about it: either adapt the whitespace range preceding it, or mark it as an
 994   // untouchable token.
 995   // This happens for instance here:
 996   // // line 1 \
 997   // // line 2
 998   if (LineIndex > 0 && Tokens[LineIndex] != Tokens[LineIndex - 1]) {
 999     // This is the first line for the current token, but no reflow with the
1000     // previous token is necessary. However, we still may need to adjust the
1001     // start column. Note that ContentColumn[LineIndex] is the expected
1002     // content column after a possible update to the prefix, hence the prefix
1003     // length change is included.
1004     unsigned LineColumn =
1005         ContentColumn[LineIndex] -
1006         (Content[LineIndex].data() - Lines[LineIndex].data()) +
1007         (OriginalPrefix[LineIndex].size() - Prefix[LineIndex].size());
1008
1009     // We always want to create a replacement instead of adding an untouchable
1010     // token, even if LineColumn is the same as the original column of the
1011     // token. This is because WhitespaceManager doesn't align trailing
1012     // comments if they are untouchable.
1013     Whitespaces.replaceWhitespace(*Tokens[LineIndex],
1014                                   /*Newlines=*/1,
1015                                   /*Spaces=*/LineColumn,
1016                                   /*StartOfTokenColumn=*/LineColumn,
1017                                   /*IsAligned=*/true,
1018                                   /*InPPDirective=*/false);
1019   }
1020   if (OriginalPrefix[LineIndex] != Prefix[LineIndex]) {
1021     // Adjust the prefix if necessary.
1022     const auto SpacesToRemove = -std::min(PrefixSpaceChange[LineIndex], 0);
1023     const auto SpacesToAdd = std::max(PrefixSpaceChange[LineIndex], 0);
1024     Whitespaces.replaceWhitespaceInToken(
1025         tokenAt(LineIndex), OriginalPrefix[LineIndex].size() - SpacesToRemove,
1026         /*ReplaceChars=*/SpacesToRemove, "", "", /*InPPDirective=*/false,
1027         /*Newlines=*/0, /*Spaces=*/SpacesToAdd);
1028   }
1029 }
1030
1031 void BreakableLineCommentSection::updateNextToken(LineState &State) const {
1032   if (LastLineTok)
1033     State.NextToken = LastLineTok->Next;
1034 }
1035
1036 bool BreakableLineCommentSection::mayReflow(
1037     unsigned LineIndex, const llvm::Regex &CommentPragmasRegex) const {
1038   // Line comments have the indent as part of the prefix, so we need to
1039   // recompute the start of the line.
1040   StringRef IndentContent = Content[LineIndex];
1041   if (Lines[LineIndex].startswith("//"))
1042     IndentContent = Lines[LineIndex].substr(2);
1043   // FIXME: Decide whether we want to reflow non-regular indents:
1044   // Currently, we only reflow when the OriginalPrefix[LineIndex] matches the
1045   // OriginalPrefix[LineIndex-1]. That means we don't reflow
1046   // // text that protrudes
1047   // //    into text with different indent
1048   // We do reflow in that case in block comments.
1049   return LineIndex > 0 && !CommentPragmasRegex.match(IndentContent) &&
1050          mayReflowContent(Content[LineIndex]) && !Tok.Finalized &&
1051          !switchesFormatting(tokenAt(LineIndex)) &&
1052          OriginalPrefix[LineIndex] == OriginalPrefix[LineIndex - 1];
1053 }
1054
1055 } // namespace format
1056 } // namespace clang