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 += encoding::columnWidthWithTabs(
  86         Text.substr(MaxSplitBytes, BytesInChar), ContentStartColumn + NumChars,
  87         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 BreakableStringLiteralUsingOperators::BreakableStringLiteralUsingOperators(
 296     const FormatToken &Tok, QuoteStyleType QuoteStyle, bool UnindentPlus,
 297     unsigned StartColumn, unsigned UnbreakableTailLength, bool InPPDirective,
 298     encoding::Encoding Encoding, const FormatStyle &Style)
 299     : BreakableStringLiteral(
 300           Tok, StartColumn, /*Prefix=*/QuoteStyle == SingleQuotes ? "'"
 301                             : QuoteStyle == AtDoubleQuotes        ? "@\""
 302                                                                   : "\"",
 303           /*Postfix=*/QuoteStyle == SingleQuotes ? "'" : "\"",
 304           UnbreakableTailLength, InPPDirective, Encoding, Style),
 305       BracesNeeded(Tok.isNot(TT_StringInConcatenation)),
 306       QuoteStyle(QuoteStyle) {
 307   // Find the replacement text for inserting braces and quotes and line breaks.
 308   // We don't create an allocated string concatenated from parts here because it
 309   // has to outlive the BreakableStringliteral object.  The brace replacements
 310   // include a quote so that WhitespaceManager can tell it apart from whitespace
 311   // replacements between the string and surrounding tokens.
 312
 313   // The option is not implemented in JavaScript.
 314   bool SignOnNewLine =
 315       !Style.isJavaScript() &&
 316       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None;
 317
 318   if (Style.isVerilog()) {
 319     // In Verilog, all strings are quoted by double quotes, joined by commas,
 320     // and wrapped in braces.  The comma is always before the newline.
 321     assert(QuoteStyle == DoubleQuotes);
 322     LeftBraceQuote = Style.Cpp11BracedListStyle ? "{\"" : "{ \"";
 323     RightBraceQuote = Style.Cpp11BracedListStyle ? "\"}" : "\" }";
 324     Postfix = "\",";
 325     Prefix = "\"";
 326   } else {
 327     // The plus sign may be on either line.  And also C# and JavaScript have
 328     // several quoting styles.
 329     if (QuoteStyle == SingleQuotes) {
 330       LeftBraceQuote = Style.SpacesInParensOptions.Other ? "( '" : "('";
 331       RightBraceQuote = Style.SpacesInParensOptions.Other ? "' )" : "')";
 332       Postfix = SignOnNewLine ? "'" : "' +";
 333       Prefix = SignOnNewLine ? "+ '" : "'";
 334     } else {
 335       if (QuoteStyle == AtDoubleQuotes) {
 336         LeftBraceQuote = Style.SpacesInParensOptions.Other ? "( @" : "(@";
 337         Prefix = SignOnNewLine ? "+ @\"" : "@\"";
 338       } else {
 339         LeftBraceQuote = Style.SpacesInParensOptions.Other ? "( \"" : "(\"";
 340         Prefix = SignOnNewLine ? "+ \"" : "\"";
 341       }
 342       RightBraceQuote = Style.SpacesInParensOptions.Other ? "\" )" : "\")";
 343       Postfix = SignOnNewLine ? "\"" : "\" +";
 344     }
 345   }
 346
 347   // Following lines are indented by the width of the brace and space if any.
 348   ContinuationIndent = BracesNeeded ? LeftBraceQuote.size() - 1 : 0;
 349   // The plus sign may need to be unindented depending on the style.
 350   // FIXME: Add support for DontAlign.
 351   if (!Style.isVerilog() && SignOnNewLine && !BracesNeeded && UnindentPlus &&
 352       Style.AlignOperands == FormatStyle::OAS_AlignAfterOperator) {
 353     ContinuationIndent -= 2;
 354   }
 355 }
 356
 357 unsigned BreakableStringLiteralUsingOperators::getRemainingLength(
 358     unsigned LineIndex, unsigned Offset, unsigned StartColumn) const {
 359   return UnbreakableTailLength + (BracesNeeded ? RightBraceQuote.size() : 1) +
 360          encoding::columnWidthWithTabs(Line.substr(Offset), StartColumn,
 361                                        Style.TabWidth, Encoding);
 362 }
 363
 364 unsigned
 365 BreakableStringLiteralUsingOperators::getContentStartColumn(unsigned LineIndex,
 366                                                             bool Break) const {
 367   return std::max(
 368       0,
 369       static_cast<int>(StartColumn) +
 370           (Break ? ContinuationIndent + static_cast<int>(Prefix.size())
 371                  : (BracesNeeded ? static_cast<int>(LeftBraceQuote.size()) - 1
 372                                  : 0) +
 373                        (QuoteStyle == AtDoubleQuotes ? 2 : 1)));
 374 }
 375
 376 void BreakableStringLiteralUsingOperators::insertBreak(
 377     unsigned LineIndex, unsigned TailOffset, Split Split,
 378     unsigned ContentIndent, WhitespaceManager &Whitespaces) const {
 379   Whitespaces.replaceWhitespaceInToken(
 380       Tok, /*Offset=*/(QuoteStyle == AtDoubleQuotes ? 2 : 1) + TailOffset +
 381                Split.first,
 382       /*ReplaceChars=*/Split.second, /*PreviousPostfix=*/Postfix,
 383       /*CurrentPrefix=*/Prefix, InPPDirective, /*NewLines=*/1,
 384       /*Spaces=*/
 385       std::max(0, static_cast<int>(StartColumn) + ContinuationIndent));
 386 }
 387
 388 void BreakableStringLiteralUsingOperators::updateAfterBroken(
 389     WhitespaceManager &Whitespaces) const {
 390   // Add the braces required for breaking the token if they are needed.
 391   if (!BracesNeeded)
 392     return;
 393
 394   // To add a brace or parenthesis, we replace the quote (or the at sign) with a
 395   // brace and another quote.  This is because the rest of the program requires
 396   // one replacement for each source range.  If we replace the empty strings
 397   // around the string, it may conflict with whitespace replacements between the
 398   // string and adjacent tokens.
 399   Whitespaces.replaceWhitespaceInToken(
 400       Tok, /*Offset=*/0, /*ReplaceChars=*/1, /*PreviousPostfix=*/"",
 401       /*CurrentPrefix=*/LeftBraceQuote, InPPDirective, /*NewLines=*/0,
 402       /*Spaces=*/0);
 403   Whitespaces.replaceWhitespaceInToken(
 404       Tok, /*Offset=*/Tok.TokenText.size() - 1, /*ReplaceChars=*/1,
 405       /*PreviousPostfix=*/RightBraceQuote,
 406       /*CurrentPrefix=*/"", InPPDirective, /*NewLines=*/0, /*Spaces=*/0);
 407 }
 408
 409 BreakableComment::BreakableComment(const FormatToken &Token,
 410                                    unsigned StartColumn, bool InPPDirective,
 411                                    encoding::Encoding Encoding,
 412                                    const FormatStyle &Style)
 413     : BreakableToken(Token, InPPDirective, Encoding, Style),
 414       StartColumn(StartColumn) {}
 415
 416 unsigned BreakableComment::getLineCount() const { return Lines.size(); }
 417
 418 BreakableToken::Split
 419 BreakableComment::getSplit(unsigned LineIndex, unsigned TailOffset,
 420                            unsigned ColumnLimit, unsigned ContentStartColumn,
 421                            const llvm::Regex &CommentPragmasRegex) const {
 422   // Don't break lines matching the comment pragmas regex.
 423   if (CommentPragmasRegex.match(Content[LineIndex]))
 424     return Split(StringRef::npos, 0);
 425   return getCommentSplit(Content[LineIndex].substr(TailOffset),
 426                          ContentStartColumn, ColumnLimit, Style.TabWidth,
 427                          Encoding, Style);
 428 }
 429
 430 void BreakableComment::compressWhitespace(
 431     unsigned LineIndex, unsigned TailOffset, Split Split,
 432     WhitespaceManager &Whitespaces) const {
 433   StringRef Text = Content[LineIndex].substr(TailOffset);
 434   // Text is relative to the content line, but Whitespaces operates relative to
 435   // the start of the corresponding token, so compute the start of the Split
 436   // that needs to be compressed into a single space relative to the start of
 437   // its token.
 438   unsigned BreakOffsetInToken =
 439       Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
 440   unsigned CharsToRemove = Split.second;
 441   Whitespaces.replaceWhitespaceInToken(
 442       tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "", "",
 443       /*InPPDirective=*/false, /*Newlines=*/0, /*Spaces=*/1);
 444 }
 445
 446 const FormatToken &BreakableComment::tokenAt(unsigned LineIndex) const {
 447   return Tokens[LineIndex] ? *Tokens[LineIndex] : Tok;
 448 }
 449
 450 static bool mayReflowContent(StringRef Content) {
 451   Content = Content.trim(Blanks);
 452   // Lines starting with '@' commonly have special meaning.
 453   // Lines starting with '-', '-#', '+' or '*' are bulleted/numbered lists.
 454   bool hasSpecialMeaningPrefix = false;
 455   for (StringRef Prefix :
 456        {"@", "TODO", "FIXME", "XXX", "-# ", "- ", "+ ", "* "}) {
 457     if (Content.startswith(Prefix)) {
 458       hasSpecialMeaningPrefix = true;
 459       break;
 460     }
 461   }
 462
 463   // Numbered lists may also start with a number followed by '.'
 464   // To avoid issues if a line starts with a number which is actually the end
 465   // of a previous line, we only consider numbers with up to 2 digits.
 466   static const auto kNumberedListRegexp = llvm::Regex("^[1-9][0-9]?\\. ");
 467   hasSpecialMeaningPrefix =
 468       hasSpecialMeaningPrefix || kNumberedListRegexp.match(Content);
 469
 470   // Simple heuristic for what to reflow: content should contain at least two
 471   // characters and either the first or second character must be
 472   // non-punctuation.
 473   return Content.size() >= 2 && !hasSpecialMeaningPrefix &&
 474          !Content.endswith("\\") &&
 475          // Note that this is UTF-8 safe, since if isPunctuation(Content[0]) is
 476          // true, then the first code point must be 1 byte long.
 477          (!isPunctuation(Content[0]) || !isPunctuation(Content[1]));
 478 }
 479
 480 BreakableBlockComment::BreakableBlockComment(
 481     const FormatToken &Token, unsigned StartColumn,
 482     unsigned OriginalStartColumn, bool FirstInLine, bool InPPDirective,
 483     encoding::Encoding Encoding, const FormatStyle &Style, bool UseCRLF)
 484     : BreakableComment(Token, StartColumn, InPPDirective, Encoding, Style),
 485       DelimitersOnNewline(false),
 486       UnbreakableTailLength(Token.UnbreakableTailLength) {
 487   assert(Tok.is(TT_BlockComment) &&
 488          "block comment section must start with a block comment");
 489
 490   StringRef TokenText(Tok.TokenText);
 491   assert(TokenText.startswith("/*") && TokenText.endswith("*/"));
 492   TokenText.substr(2, TokenText.size() - 4)
 493       .split(Lines, UseCRLF ? "\r\n" : "\n");
 494
 495   int IndentDelta = StartColumn - OriginalStartColumn;
 496   Content.resize(Lines.size());
 497   Content[0] = Lines[0];
 498   ContentColumn.resize(Lines.size());
 499   // Account for the initial '/*'.
 500   ContentColumn[0] = StartColumn + 2;
 501   Tokens.resize(Lines.size());
 502   for (size_t i = 1; i < Lines.size(); ++i)
 503     adjustWhitespace(i, IndentDelta);
 504
 505   // Align decorations with the column of the star on the first line,
 506   // that is one column after the start "/*".
 507   DecorationColumn = StartColumn + 1;
 508
 509   // Account for comment decoration patterns like this:
 510   //
 511   // /*
 512   // ** blah blah blah
 513   // */
 514   if (Lines.size() >= 2 && Content[1].startswith("**") &&
 515       static_cast<unsigned>(ContentColumn[1]) == StartColumn) {
 516     DecorationColumn = StartColumn;
 517   }
 518
 519   Decoration = "* ";
 520   if (Lines.size() == 1 && !FirstInLine) {
 521     // Comments for which FirstInLine is false can start on arbitrary column,
 522     // and available horizontal space can be too small to align consecutive
 523     // lines with the first one.
 524     // FIXME: We could, probably, align them to current indentation level, but
 525     // now we just wrap them without stars.
 526     Decoration = "";
 527   }
 528   for (size_t i = 1, e = Content.size(); i < e && !Decoration.empty(); ++i) {
 529     const StringRef &Text = Content[i];
 530     if (i + 1 == e) {
 531       // If the last line is empty, the closing "*/" will have a star.
 532       if (Text.empty())
 533         break;
 534     } else if (!Text.empty() && Decoration.startswith(Text)) {
 535       continue;
 536     }
 537     while (!Text.startswith(Decoration))
 538       Decoration = Decoration.drop_back(1);
 539   }
 540
 541   LastLineNeedsDecoration = true;
 542   IndentAtLineBreak = ContentColumn[0] + 1;
 543   for (size_t i = 1, e = Lines.size(); i < e; ++i) {
 544     if (Content[i].empty()) {
 545       if (i + 1 == e) {
 546         // Empty last line means that we already have a star as a part of the
 547         // trailing */. We also need to preserve whitespace, so that */ is
 548         // correctly indented.
 549         LastLineNeedsDecoration = false;
 550         // Align the star in the last '*/' with the stars on the previous lines.
 551         if (e >= 2 && !Decoration.empty())
 552           ContentColumn[i] = DecorationColumn;
 553       } else if (Decoration.empty()) {
 554         // For all other lines, set the start column to 0 if they're empty, so
 555         // we do not insert trailing whitespace anywhere.
 556         ContentColumn[i] = 0;
 557       }
 558       continue;
 559     }
 560
 561     // The first line already excludes the star.
 562     // The last line excludes the star if LastLineNeedsDecoration is false.
 563     // For all other lines, adjust the line to exclude the star and
 564     // (optionally) the first whitespace.
 565     unsigned DecorationSize = Decoration.startswith(Content[i])
 566                                   ? Content[i].size()
 567                                   : Decoration.size();
 568     if (DecorationSize)
 569       ContentColumn[i] = DecorationColumn + DecorationSize;
 570     Content[i] = Content[i].substr(DecorationSize);
 571     if (!Decoration.startswith(Content[i])) {
 572       IndentAtLineBreak =
 573           std::min<int>(IndentAtLineBreak, std::max(0, ContentColumn[i]));
 574     }
 575   }
 576   IndentAtLineBreak = std::max<unsigned>(IndentAtLineBreak, Decoration.size());
 577
 578   // Detect a multiline jsdoc comment and set DelimitersOnNewline in that case.
 579   if (Style.isJavaScript() || Style.Language == FormatStyle::LK_Java) {
 580     if ((Lines[0] == "*" || Lines[0].startswith("* ")) && Lines.size() > 1) {
 581       // This is a multiline jsdoc comment.
 582       DelimitersOnNewline = true;
 583     } else if (Lines[0].startswith("* ") && Lines.size() == 1) {
 584       // Detect a long single-line comment, like:
 585       // /** long long long */
 586       // Below, '2' is the width of '*/'.
 587       unsigned EndColumn =
 588           ContentColumn[0] +
 589           encoding::columnWidthWithTabs(Lines[0], ContentColumn[0],
 590                                         Style.TabWidth, Encoding) +
 591           2;
 592       DelimitersOnNewline = EndColumn > Style.ColumnLimit;
 593     }
 594   }
 595
 596   LLVM_DEBUG({
 597     llvm::dbgs() << "IndentAtLineBreak " << IndentAtLineBreak << "\n";
 598     llvm::dbgs() << "DelimitersOnNewline " << DelimitersOnNewline << "\n";
 599     for (size_t i = 0; i < Lines.size(); ++i) {
 600       llvm::dbgs() << i << " |" << Content[i] << "| "
 601                    << "CC=" << ContentColumn[i] << "| "
 602                    << "IN=" << (Content[i].data() - Lines[i].data()) << "\n";
 603     }
 604   });
 605 }
 606
 607 BreakableToken::Split BreakableBlockComment::getSplit(
 608     unsigned LineIndex, unsigned TailOffset, unsigned ColumnLimit,
 609     unsigned ContentStartColumn, const llvm::Regex &CommentPragmasRegex) const {
 610   // Don't break lines matching the comment pragmas regex.
 611   if (CommentPragmasRegex.match(Content[LineIndex]))
 612     return Split(StringRef::npos, 0);
 613   return getCommentSplit(Content[LineIndex].substr(TailOffset),
 614                          ContentStartColumn, ColumnLimit, Style.TabWidth,
 615                          Encoding, Style, Decoration.endswith("*"));
 616 }
 617
 618 void BreakableBlockComment::adjustWhitespace(unsigned LineIndex,
 619                                              int IndentDelta) {
 620   // When in a preprocessor directive, the trailing backslash in a block comment
 621   // is not needed, but can serve a purpose of uniformity with necessary escaped
 622   // newlines outside the comment. In this case we remove it here before
 623   // trimming the trailing whitespace. The backslash will be re-added later when
 624   // inserting a line break.
 625   size_t EndOfPreviousLine = Lines[LineIndex - 1].size();
 626   if (InPPDirective && Lines[LineIndex - 1].endswith("\\"))
 627     --EndOfPreviousLine;
 628
 629   // Calculate the end of the non-whitespace text in the previous line.
 630   EndOfPreviousLine =
 631       Lines[LineIndex - 1].find_last_not_of(Blanks, EndOfPreviousLine);
 632   if (EndOfPreviousLine == StringRef::npos)
 633     EndOfPreviousLine = 0;
 634   else
 635     ++EndOfPreviousLine;
 636   // Calculate the start of the non-whitespace text in the current line.
 637   size_t StartOfLine = Lines[LineIndex].find_first_not_of(Blanks);
 638   if (StartOfLine == StringRef::npos)
 639     StartOfLine = Lines[LineIndex].size();
 640
 641   StringRef Whitespace = Lines[LineIndex].substr(0, StartOfLine);
 642   // Adjust Lines to only contain relevant text.
 643   size_t PreviousContentOffset =
 644       Content[LineIndex - 1].data() - Lines[LineIndex - 1].data();
 645   Content[LineIndex - 1] = Lines[LineIndex - 1].substr(
 646       PreviousContentOffset, EndOfPreviousLine - PreviousContentOffset);
 647   Content[LineIndex] = Lines[LineIndex].substr(StartOfLine);
 648
 649   // Adjust the start column uniformly across all lines.
 650   ContentColumn[LineIndex] =
 651       encoding::columnWidthWithTabs(Whitespace, 0, Style.TabWidth, Encoding) +
 652       IndentDelta;
 653 }
 654
 655 unsigned BreakableBlockComment::getRangeLength(unsigned LineIndex,
 656                                                unsigned Offset,
 657                                                StringRef::size_type Length,
 658                                                unsigned StartColumn) const {
 659   return encoding::columnWidthWithTabs(
 660       Content[LineIndex].substr(Offset, Length), StartColumn, Style.TabWidth,
 661       Encoding);
 662 }
 663
 664 unsigned BreakableBlockComment::getRemainingLength(unsigned LineIndex,
 665                                                    unsigned Offset,
 666                                                    unsigned StartColumn) const {
 667   unsigned LineLength =
 668       UnbreakableTailLength +
 669       getRangeLength(LineIndex, Offset, StringRef::npos, StartColumn);
 670   if (LineIndex + 1 == Lines.size()) {
 671     LineLength += 2;
 672     // We never need a decoration when breaking just the trailing "*/" postfix.
 673     bool HasRemainingText = Offset < Content[LineIndex].size();
 674     if (!HasRemainingText) {
 675       bool HasDecoration = Lines[LineIndex].ltrim().startswith(Decoration);
 676       if (HasDecoration)
 677         LineLength -= Decoration.size();
 678     }
 679   }
 680   return LineLength;
 681 }
 682
 683 unsigned BreakableBlockComment::getContentStartColumn(unsigned LineIndex,
 684                                                       bool Break) const {
 685   if (Break)
 686     return IndentAtLineBreak;
 687   return std::max(0, ContentColumn[LineIndex]);
 688 }
 689
 690 const llvm::StringSet<>
 691     BreakableBlockComment::ContentIndentingJavadocAnnotations = {
 692         "@param", "@return",     "@returns", "@throws",  "@type", "@template",
 693         "@see",   "@deprecated", "@define",  "@exports", "@mods", "@private",
 694 };
 695
 696 unsigned BreakableBlockComment::getContentIndent(unsigned LineIndex) const {
 697   if (Style.Language != FormatStyle::LK_Java && !Style.isJavaScript())
 698     return 0;
 699   // The content at LineIndex 0 of a comment like:
 700   // /** line 0 */
 701   // is "* line 0", so we need to skip over the decoration in that case.
 702   StringRef ContentWithNoDecoration = Content[LineIndex];
 703   if (LineIndex == 0 && ContentWithNoDecoration.startswith("*"))
 704     ContentWithNoDecoration = ContentWithNoDecoration.substr(1).ltrim(Blanks);
 705   StringRef FirstWord = ContentWithNoDecoration.substr(
 706       0, ContentWithNoDecoration.find_first_of(Blanks));
 707   if (ContentIndentingJavadocAnnotations.contains(FirstWord))
 708     return Style.ContinuationIndentWidth;
 709   return 0;
 710 }
 711
 712 void BreakableBlockComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
 713                                         Split Split, unsigned ContentIndent,
 714                                         WhitespaceManager &Whitespaces) const {
 715   StringRef Text = Content[LineIndex].substr(TailOffset);
 716   StringRef Prefix = Decoration;
 717   // We need this to account for the case when we have a decoration "* " for all
 718   // the lines except for the last one, where the star in "*/" acts as a
 719   // decoration.
 720   unsigned LocalIndentAtLineBreak = IndentAtLineBreak;
 721   if (LineIndex + 1 == Lines.size() &&
 722       Text.size() == Split.first + Split.second) {
 723     // For the last line we need to break before "*/", but not to add "* ".
 724     Prefix = "";
 725     if (LocalIndentAtLineBreak >= 2)
 726       LocalIndentAtLineBreak -= 2;
 727   }
 728   // The split offset is from the beginning of the line. Convert it to an offset
 729   // from the beginning of the token text.
 730   unsigned BreakOffsetInToken =
 731       Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
 732   unsigned CharsToRemove = Split.second;
 733   assert(LocalIndentAtLineBreak >= Prefix.size());
 734   std::string PrefixWithTrailingIndent = std::string(Prefix);
 735   PrefixWithTrailingIndent.append(ContentIndent, ' ');
 736   Whitespaces.replaceWhitespaceInToken(
 737       tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "",
 738       PrefixWithTrailingIndent, InPPDirective, /*Newlines=*/1,
 739       /*Spaces=*/LocalIndentAtLineBreak + ContentIndent -
 740           PrefixWithTrailingIndent.size());
 741 }
 742
 743 BreakableToken::Split BreakableBlockComment::getReflowSplit(
 744     unsigned LineIndex, const llvm::Regex &CommentPragmasRegex) const {
 745   if (!mayReflow(LineIndex, CommentPragmasRegex))
 746     return Split(StringRef::npos, 0);
 747
 748   // If we're reflowing into a line with content indent, only reflow the next
 749   // line if its starting whitespace matches the content indent.
 750   size_t Trimmed = Content[LineIndex].find_first_not_of(Blanks);
 751   if (LineIndex) {
 752     unsigned PreviousContentIndent = getContentIndent(LineIndex - 1);
 753     if (PreviousContentIndent && Trimmed != StringRef::npos &&
 754         Trimmed != PreviousContentIndent) {
 755       return Split(StringRef::npos, 0);
 756     }
 757   }
 758
 759   return Split(0, Trimmed != StringRef::npos ? Trimmed : 0);
 760 }
 761
 762 bool BreakableBlockComment::introducesBreakBeforeToken() const {
 763   // A break is introduced when we want delimiters on newline.
 764   return DelimitersOnNewline &&
 765          Lines[0].substr(1).find_first_not_of(Blanks) != StringRef::npos;
 766 }
 767
 768 void BreakableBlockComment::reflow(unsigned LineIndex,
 769                                    WhitespaceManager &Whitespaces) const {
 770   StringRef TrimmedContent = Content[LineIndex].ltrim(Blanks);
 771   // Here we need to reflow.
 772   assert(Tokens[LineIndex - 1] == Tokens[LineIndex] &&
 773          "Reflowing whitespace within a token");
 774   // This is the offset of the end of the last line relative to the start of
 775   // the token text in the token.
 776   unsigned WhitespaceOffsetInToken = Content[LineIndex - 1].data() +
 777                                      Content[LineIndex - 1].size() -
 778                                      tokenAt(LineIndex).TokenText.data();
 779   unsigned WhitespaceLength = TrimmedContent.data() -
 780                               tokenAt(LineIndex).TokenText.data() -
 781                               WhitespaceOffsetInToken;
 782   Whitespaces.replaceWhitespaceInToken(
 783       tokenAt(LineIndex), WhitespaceOffsetInToken,
 784       /*ReplaceChars=*/WhitespaceLength, /*PreviousPostfix=*/"",
 785       /*CurrentPrefix=*/ReflowPrefix, InPPDirective, /*Newlines=*/0,
 786       /*Spaces=*/0);
 787 }
 788
 789 void BreakableBlockComment::adaptStartOfLine(
 790     unsigned LineIndex, WhitespaceManager &Whitespaces) const {
 791   if (LineIndex == 0) {
 792     if (DelimitersOnNewline) {
 793       // Since we're breaking at index 1 below, the break position and the
 794       // break length are the same.
 795       // Note: this works because getCommentSplit is careful never to split at
 796       // the beginning of a line.
 797       size_t BreakLength = Lines[0].substr(1).find_first_not_of(Blanks);
 798       if (BreakLength != StringRef::npos) {
 799         insertBreak(LineIndex, 0, Split(1, BreakLength), /*ContentIndent=*/0,
 800                     Whitespaces);
 801       }
 802     }
 803     return;
 804   }
 805   // Here no reflow with the previous line will happen.
 806   // Fix the decoration of the line at LineIndex.
 807   StringRef Prefix = Decoration;
 808   if (Content[LineIndex].empty()) {
 809     if (LineIndex + 1 == Lines.size()) {
 810       if (!LastLineNeedsDecoration) {
 811         // If the last line was empty, we don't need a prefix, as the */ will
 812         // line up with the decoration (if it exists).
 813         Prefix = "";
 814       }
 815     } else if (!Decoration.empty()) {
 816       // For other empty lines, if we do have a decoration, adapt it to not
 817       // contain a trailing whitespace.
 818       Prefix = Prefix.substr(0, 1);
 819     }
 820   } else if (ContentColumn[LineIndex] == 1) {
 821     // This line starts immediately after the decorating *.
 822     Prefix = Prefix.substr(0, 1);
 823   }
 824   // This is the offset of the end of the last line relative to the start of the
 825   // token text in the token.
 826   unsigned WhitespaceOffsetInToken = Content[LineIndex - 1].data() +
 827                                      Content[LineIndex - 1].size() -
 828                                      tokenAt(LineIndex).TokenText.data();
 829   unsigned WhitespaceLength = Content[LineIndex].data() -
 830                               tokenAt(LineIndex).TokenText.data() -
 831                               WhitespaceOffsetInToken;
 832   Whitespaces.replaceWhitespaceInToken(
 833       tokenAt(LineIndex), WhitespaceOffsetInToken, WhitespaceLength, "", Prefix,
 834       InPPDirective, /*Newlines=*/1, ContentColumn[LineIndex] - Prefix.size());
 835 }
 836
 837 BreakableToken::Split
 838 BreakableBlockComment::getSplitAfterLastLine(unsigned TailOffset) const {
 839   if (DelimitersOnNewline) {
 840     // Replace the trailing whitespace of the last line with a newline.
 841     // In case the last line is empty, the ending '*/' is already on its own
 842     // line.
 843     StringRef Line = Content.back().substr(TailOffset);
 844     StringRef TrimmedLine = Line.rtrim(Blanks);
 845     if (!TrimmedLine.empty())
 846       return Split(TrimmedLine.size(), Line.size() - TrimmedLine.size());
 847   }
 848   return Split(StringRef::npos, 0);
 849 }
 850
 851 bool BreakableBlockComment::mayReflow(
 852     unsigned LineIndex, const llvm::Regex &CommentPragmasRegex) const {
 853   // Content[LineIndex] may exclude the indent after the '*' decoration. In that
 854   // case, we compute the start of the comment pragma manually.
 855   StringRef IndentContent = Content[LineIndex];
 856   if (Lines[LineIndex].ltrim(Blanks).startswith("*"))
 857     IndentContent = Lines[LineIndex].ltrim(Blanks).substr(1);
 858   return LineIndex > 0 && !CommentPragmasRegex.match(IndentContent) &&
 859          mayReflowContent(Content[LineIndex]) && !Tok.Finalized &&
 860          !switchesFormatting(tokenAt(LineIndex));
 861 }
 862
 863 BreakableLineCommentSection::BreakableLineCommentSection(
 864     const FormatToken &Token, unsigned StartColumn, bool InPPDirective,
 865     encoding::Encoding Encoding, const FormatStyle &Style)
 866     : BreakableComment(Token, StartColumn, InPPDirective, Encoding, Style) {
 867   assert(Tok.is(TT_LineComment) &&
 868          "line comment section must start with a line comment");
 869   FormatToken *LineTok = nullptr;
 870   const int Minimum = Style.SpacesInLineCommentPrefix.Minimum;
 871   // How many spaces we changed in the first line of the section, this will be
 872   // applied in all following lines
 873   int FirstLineSpaceChange = 0;
 874   for (const FormatToken *CurrentTok = &Tok;
 875        CurrentTok && CurrentTok->is(TT_LineComment);
 876        CurrentTok = CurrentTok->Next) {
 877     LastLineTok = LineTok;
 878     StringRef TokenText(CurrentTok->TokenText);
 879     assert((TokenText.startswith("//") || TokenText.startswith("#")) &&
 880            "unsupported line comment prefix, '//' and '#' are supported");
 881     size_t FirstLineIndex = Lines.size();
 882     TokenText.split(Lines, "\n");
 883     Content.resize(Lines.size());
 884     ContentColumn.resize(Lines.size());
 885     PrefixSpaceChange.resize(Lines.size());
 886     Tokens.resize(Lines.size());
 887     Prefix.resize(Lines.size());
 888     OriginalPrefix.resize(Lines.size());
 889     for (size_t i = FirstLineIndex, e = Lines.size(); i < e; ++i) {
 890       Lines[i] = Lines[i].ltrim(Blanks);
 891       StringRef IndentPrefix = getLineCommentIndentPrefix(Lines[i], Style);
 892       OriginalPrefix[i] = IndentPrefix;
 893       const int SpacesInPrefix = llvm::count(IndentPrefix, ' ');
 894
 895       // This lambda also considers multibyte character that is not handled in
 896       // functions like isPunctuation provided by CharInfo.
 897       const auto NoSpaceBeforeFirstCommentChar = [&]() {
 898         assert(Lines[i].size() > IndentPrefix.size());
 899         const char FirstCommentChar = Lines[i][IndentPrefix.size()];
 900         const unsigned FirstCharByteSize =
 901             encoding::getCodePointNumBytes(FirstCommentChar, Encoding);
 902         if (encoding::columnWidth(
 903                 Lines[i].substr(IndentPrefix.size(), FirstCharByteSize),
 904                 Encoding) != 1) {
 905           return false;
 906         }
 907         // In C-like comments, add a space before #. For example this is useful
 908         // to preserve the relative indentation when commenting out code with
 909         // #includes.
 910         //
 911         // In languages using # as the comment leader such as proto, don't
 912         // add a space to support patterns like:
 913         // #########
 914         // # section
 915         // #########
 916         if (FirstCommentChar == '#' && !TokenText.startswith("#"))
 917           return false;
 918         return FirstCommentChar == '\\' || isPunctuation(FirstCommentChar) ||
 919                isHorizontalWhitespace(FirstCommentChar);
 920       };
 921
 922       // On the first line of the comment section we calculate how many spaces
 923       // are to be added or removed, all lines after that just get only the
 924       // change and we will not look at the maximum anymore. Additionally to the
 925       // actual first line, we calculate that when the non space Prefix changes,
 926       // e.g. from "///" to "//".
 927       if (i == 0 || OriginalPrefix[i].rtrim(Blanks) !=
 928                         OriginalPrefix[i - 1].rtrim(Blanks)) {
 929         if (SpacesInPrefix < Minimum && Lines[i].size() > IndentPrefix.size() &&
 930             !NoSpaceBeforeFirstCommentChar()) {
 931           FirstLineSpaceChange = Minimum - SpacesInPrefix;
 932         } else if (static_cast<unsigned>(SpacesInPrefix) >
 933                    Style.SpacesInLineCommentPrefix.Maximum) {
 934           FirstLineSpaceChange =
 935               Style.SpacesInLineCommentPrefix.Maximum - SpacesInPrefix;
 936         } else {
 937           FirstLineSpaceChange = 0;
 938         }
 939       }
 940
 941       if (Lines[i].size() != IndentPrefix.size()) {
 942         PrefixSpaceChange[i] = FirstLineSpaceChange;
 943
 944         if (SpacesInPrefix + PrefixSpaceChange[i] < Minimum) {
 945           PrefixSpaceChange[i] +=
 946               Minimum - (SpacesInPrefix + PrefixSpaceChange[i]);
 947         }
 948
 949         assert(Lines[i].size() > IndentPrefix.size());
 950         const auto FirstNonSpace = Lines[i][IndentPrefix.size()];
 951         const bool IsFormatComment = LineTok && switchesFormatting(*LineTok);
 952         const bool LineRequiresLeadingSpace =
 953             !NoSpaceBeforeFirstCommentChar() ||
 954             (FirstNonSpace == '}' && FirstLineSpaceChange != 0);
 955         const bool AllowsSpaceChange =
 956             !IsFormatComment &&
 957             (SpacesInPrefix != 0 || LineRequiresLeadingSpace);
 958
 959         if (PrefixSpaceChange[i] > 0 && AllowsSpaceChange) {
 960           Prefix[i] = IndentPrefix.str();
 961           Prefix[i].append(PrefixSpaceChange[i], ' ');
 962         } else if (PrefixSpaceChange[i] < 0 && AllowsSpaceChange) {
 963           Prefix[i] = IndentPrefix
 964                           .drop_back(std::min<std::size_t>(
 965                               -PrefixSpaceChange[i], SpacesInPrefix))
 966                           .str();
 967         } else {
 968           Prefix[i] = IndentPrefix.str();
 969         }
 970       } else {
 971         // If the IndentPrefix is the whole line, there is no content and we
 972         // drop just all space
 973         Prefix[i] = IndentPrefix.drop_back(SpacesInPrefix).str();
 974       }
 975
 976       Tokens[i] = LineTok;
 977       Content[i] = Lines[i].substr(IndentPrefix.size());
 978       ContentColumn[i] =
 979           StartColumn + encoding::columnWidthWithTabs(Prefix[i], StartColumn,
 980                                                       Style.TabWidth, Encoding);
 981
 982       // Calculate the end of the non-whitespace text in this line.
 983       size_t EndOfLine = Content[i].find_last_not_of(Blanks);
 984       if (EndOfLine == StringRef::npos)
 985         EndOfLine = Content[i].size();
 986       else
 987         ++EndOfLine;
 988       Content[i] = Content[i].substr(0, EndOfLine);
 989     }
 990     LineTok = CurrentTok->Next;
 991     if (CurrentTok->Next && !CurrentTok->Next->ContinuesLineCommentSection) {
 992       // A line comment section needs to broken by a line comment that is
 993       // preceded by at least two newlines. Note that we put this break here
 994       // instead of breaking at a previous stage during parsing, since that
 995       // would split the contents of the enum into two unwrapped lines in this
 996       // example, which is undesirable:
 997       // enum A {
 998       //   a, // comment about a
 999       //
1000       //   // comment about b
1001       //   b
1002       // };
1003       //
1004       // FIXME: Consider putting separate line comment sections as children to
1005       // the unwrapped line instead.
1006       break;
1007     }
1008   }
1009 }
1010
1011 unsigned
1012 BreakableLineCommentSection::getRangeLength(unsigned LineIndex, unsigned Offset,
1013                                             StringRef::size_type Length,
1014                                             unsigned StartColumn) const {
1015   return encoding::columnWidthWithTabs(
1016       Content[LineIndex].substr(Offset, Length), StartColumn, Style.TabWidth,
1017       Encoding);
1018 }
1019
1020 unsigned
1021 BreakableLineCommentSection::getContentStartColumn(unsigned LineIndex,
1022                                                    bool /*Break*/) const {
1023   return ContentColumn[LineIndex];
1024 }
1025
1026 void BreakableLineCommentSection::insertBreak(
1027     unsigned LineIndex, unsigned TailOffset, Split Split,
1028     unsigned ContentIndent, WhitespaceManager &Whitespaces) const {
1029   StringRef Text = Content[LineIndex].substr(TailOffset);
1030   // Compute the offset of the split relative to the beginning of the token
1031   // text.
1032   unsigned BreakOffsetInToken =
1033       Text.data() - tokenAt(LineIndex).TokenText.data() + Split.first;
1034   unsigned CharsToRemove = Split.second;
1035   Whitespaces.replaceWhitespaceInToken(
1036       tokenAt(LineIndex), BreakOffsetInToken, CharsToRemove, "",
1037       Prefix[LineIndex], InPPDirective, /*Newlines=*/1,
1038       /*Spaces=*/ContentColumn[LineIndex] - Prefix[LineIndex].size());
1039 }
1040
1041 BreakableComment::Split BreakableLineCommentSection::getReflowSplit(
1042     unsigned LineIndex, const llvm::Regex &CommentPragmasRegex) const {
1043   if (!mayReflow(LineIndex, CommentPragmasRegex))
1044     return Split(StringRef::npos, 0);
1045
1046   size_t Trimmed = Content[LineIndex].find_first_not_of(Blanks);
1047
1048   // In a line comment section each line is a separate token; thus, after a
1049   // split we replace all whitespace before the current line comment token
1050   // (which does not need to be included in the split), plus the start of the
1051   // line up to where the content starts.
1052   return Split(0, Trimmed != StringRef::npos ? Trimmed : 0);
1053 }
1054
1055 void BreakableLineCommentSection::reflow(unsigned LineIndex,
1056                                          WhitespaceManager &Whitespaces) const {
1057   if (LineIndex > 0 && Tokens[LineIndex] != Tokens[LineIndex - 1]) {
1058     // Reflow happens between tokens. Replace the whitespace between the
1059     // tokens by the empty string.
1060     Whitespaces.replaceWhitespace(
1061         *Tokens[LineIndex], /*Newlines=*/0, /*Spaces=*/0,
1062         /*StartOfTokenColumn=*/StartColumn, /*IsAligned=*/true,
1063         /*InPPDirective=*/false);
1064   } else if (LineIndex > 0) {
1065     // In case we're reflowing after the '\' in:
1066     //
1067     //   // line comment \
1068     //   // line 2
1069     //
1070     // the reflow happens inside the single comment token (it is a single line
1071     // comment with an unescaped newline).
1072     // Replace the whitespace between the '\' and '//' with the empty string.
1073     //
1074     // Offset points to after the '\' relative to start of the token.
1075     unsigned Offset = Lines[LineIndex - 1].data() +
1076                       Lines[LineIndex - 1].size() -
1077                       tokenAt(LineIndex - 1).TokenText.data();
1078     // WhitespaceLength is the number of chars between the '\' and the '//' on
1079     // the next line.
1080     unsigned WhitespaceLength =
1081         Lines[LineIndex].data() - tokenAt(LineIndex).TokenText.data() - Offset;
1082     Whitespaces.replaceWhitespaceInToken(*Tokens[LineIndex], Offset,
1083                                          /*ReplaceChars=*/WhitespaceLength,
1084                                          /*PreviousPostfix=*/"",
1085                                          /*CurrentPrefix=*/"",
1086                                          /*InPPDirective=*/false,
1087                                          /*Newlines=*/0,
1088                                          /*Spaces=*/0);
1089   }
1090   // Replace the indent and prefix of the token with the reflow prefix.
1091   unsigned Offset =
1092       Lines[LineIndex].data() - tokenAt(LineIndex).TokenText.data();
1093   unsigned WhitespaceLength =
1094       Content[LineIndex].data() - Lines[LineIndex].data();
1095   Whitespaces.replaceWhitespaceInToken(*Tokens[LineIndex], Offset,
1096                                        /*ReplaceChars=*/WhitespaceLength,
1097                                        /*PreviousPostfix=*/"",
1098                                        /*CurrentPrefix=*/ReflowPrefix,
1099                                        /*InPPDirective=*/false,
1100                                        /*Newlines=*/0,
1101                                        /*Spaces=*/0);
1102 }
1103
1104 void BreakableLineCommentSection::adaptStartOfLine(
1105     unsigned LineIndex, WhitespaceManager &Whitespaces) const {
1106   // If this is the first line of a token, we need to inform Whitespace Manager
1107   // about it: either adapt the whitespace range preceding it, or mark it as an
1108   // untouchable token.
1109   // This happens for instance here:
1110   // // line 1 \
1111   // // line 2
1112   if (LineIndex > 0 && Tokens[LineIndex] != Tokens[LineIndex - 1]) {
1113     // This is the first line for the current token, but no reflow with the
1114     // previous token is necessary. However, we still may need to adjust the
1115     // start column. Note that ContentColumn[LineIndex] is the expected
1116     // content column after a possible update to the prefix, hence the prefix
1117     // length change is included.
1118     unsigned LineColumn =
1119         ContentColumn[LineIndex] -
1120         (Content[LineIndex].data() - Lines[LineIndex].data()) +
1121         (OriginalPrefix[LineIndex].size() - Prefix[LineIndex].size());
1122
1123     // We always want to create a replacement instead of adding an untouchable
1124     // token, even if LineColumn is the same as the original column of the
1125     // token. This is because WhitespaceManager doesn't align trailing
1126     // comments if they are untouchable.
1127     Whitespaces.replaceWhitespace(*Tokens[LineIndex],
1128                                   /*Newlines=*/1,
1129                                   /*Spaces=*/LineColumn,
1130                                   /*StartOfTokenColumn=*/LineColumn,
1131                                   /*IsAligned=*/true,
1132                                   /*InPPDirective=*/false);
1133   }
1134   if (OriginalPrefix[LineIndex] != Prefix[LineIndex]) {
1135     // Adjust the prefix if necessary.
1136     const auto SpacesToRemove = -std::min(PrefixSpaceChange[LineIndex], 0);
1137     const auto SpacesToAdd = std::max(PrefixSpaceChange[LineIndex], 0);
1138     Whitespaces.replaceWhitespaceInToken(
1139         tokenAt(LineIndex), OriginalPrefix[LineIndex].size() - SpacesToRemove,
1140         /*ReplaceChars=*/SpacesToRemove, "", "", /*InPPDirective=*/false,
1141         /*Newlines=*/0, /*Spaces=*/SpacesToAdd);
1142   }
1143 }
1144
1145 void BreakableLineCommentSection::updateNextToken(LineState &State) const {
1146   if (LastLineTok)
1147     State.NextToken = LastLineTok->Next;
1148 }
1149
1150 bool BreakableLineCommentSection::mayReflow(
1151     unsigned LineIndex, const llvm::Regex &CommentPragmasRegex) const {
1152   // Line comments have the indent as part of the prefix, so we need to
1153   // recompute the start of the line.
1154   StringRef IndentContent = Content[LineIndex];
1155   if (Lines[LineIndex].startswith("//"))
1156     IndentContent = Lines[LineIndex].substr(2);
1157   // FIXME: Decide whether we want to reflow non-regular indents:
1158   // Currently, we only reflow when the OriginalPrefix[LineIndex] matches the
1159   // OriginalPrefix[LineIndex-1]. That means we don't reflow
1160   // // text that protrudes
1161   // //    into text with different indent
1162   // We do reflow in that case in block comments.
1163   return LineIndex > 0 && !CommentPragmasRegex.match(IndentContent) &&
1164          mayReflowContent(Content[LineIndex]) && !Tok.Finalized &&
1165          !switchesFormatting(tokenAt(LineIndex)) &&
1166          OriginalPrefix[LineIndex] == OriginalPrefix[LineIndex - 1];
1167 }
1168
1169 } // namespace format
1170 } // namespace clang