1 //===--- UnwrappedLineFormatter.cpp - Format C++ code ---------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "UnwrappedLineFormatter.h" 11 #include "WhitespaceManager.h" 12 #include "llvm/Support/Debug.h" 13 14 #define DEBUG_TYPE "format-formatter" 15 16 namespace clang { 17 namespace format { 18 19 namespace { 20 21 bool startsExternCBlock(const AnnotatedLine &Line) { 22 const FormatToken *Next = Line.First->getNextNonComment(); 23 const FormatToken *NextNext = Next ? Next->getNextNonComment() : nullptr; 24 return Line.startsWith(tok::kw_extern) && Next && Next->isStringLiteral() && 25 NextNext && NextNext->is(tok::l_brace); 26 } 27 28 /// \brief Tracks the indent level of \c AnnotatedLines across levels. 29 /// 30 /// \c nextLine must be called for each \c AnnotatedLine, after which \c 31 /// getIndent() will return the indent for the last line \c nextLine was called 32 /// with. 33 /// If the line is not formatted (and thus the indent does not change), calling 34 /// \c adjustToUnmodifiedLine after the call to \c nextLine will cause 35 /// subsequent lines on the same level to be indented at the same level as the 36 /// given line. 37 class LevelIndentTracker { 38 public: 39 LevelIndentTracker(const FormatStyle &Style, 40 const AdditionalKeywords &Keywords, unsigned StartLevel, 41 int AdditionalIndent) 42 : Style(Style), Keywords(Keywords), AdditionalIndent(AdditionalIndent) { 43 for (unsigned i = 0; i != StartLevel; ++i) 44 IndentForLevel.push_back(Style.IndentWidth * i + AdditionalIndent); 45 } 46 47 /// \brief Returns the indent for the current line. 48 unsigned getIndent() const { return Indent; } 49 50 /// \brief Update the indent state given that \p Line is going to be formatted 51 /// next. 52 void nextLine(const AnnotatedLine &Line) { 53 Offset = getIndentOffset(*Line.First); 54 // Update the indent level cache size so that we can rely on it 55 // having the right size in adjustToUnmodifiedline. 56 while (IndentForLevel.size() <= Line.Level) 57 IndentForLevel.push_back(-1); 58 if (Line.InPPDirective) { 59 Indent = Line.Level * Style.IndentWidth + AdditionalIndent; 60 } else { 61 IndentForLevel.resize(Line.Level + 1); 62 Indent = getIndent(IndentForLevel, Line.Level); 63 } 64 if (static_cast<int>(Indent) + Offset >= 0) 65 Indent += Offset; 66 } 67 68 /// \brief Update the level indent to adapt to the given \p Line. 69 /// 70 /// When a line is not formatted, we move the subsequent lines on the same 71 /// level to the same indent. 72 /// Note that \c nextLine must have been called before this method. 73 void adjustToUnmodifiedLine(const AnnotatedLine &Line) { 74 unsigned LevelIndent = Line.First->OriginalColumn; 75 if (static_cast<int>(LevelIndent) - Offset >= 0) 76 LevelIndent -= Offset; 77 if ((!Line.First->is(tok::comment) || IndentForLevel[Line.Level] == -1) && 78 !Line.InPPDirective) 79 IndentForLevel[Line.Level] = LevelIndent; 80 } 81 82 private: 83 /// \brief Get the offset of the line relatively to the level. 84 /// 85 /// For example, 'public:' labels in classes are offset by 1 or 2 86 /// characters to the left from their level. 87 int getIndentOffset(const FormatToken &RootToken) { 88 if (Style.Language == FormatStyle::LK_Java || 89 Style.Language == FormatStyle::LK_JavaScript) 90 return 0; 91 if (RootToken.isAccessSpecifier(false) || 92 RootToken.isObjCAccessSpecifier() || 93 (RootToken.isOneOf(Keywords.kw_signals, Keywords.kw_qsignals) && 94 RootToken.Next && RootToken.Next->is(tok::colon))) 95 return Style.AccessModifierOffset; 96 return 0; 97 } 98 99 /// \brief Get the indent of \p Level from \p IndentForLevel. 100 /// 101 /// \p IndentForLevel must contain the indent for the level \c l 102 /// at \p IndentForLevel[l], or a value < 0 if the indent for 103 /// that level is unknown. 104 unsigned getIndent(ArrayRef<int> IndentForLevel, unsigned Level) { 105 if (IndentForLevel[Level] != -1) 106 return IndentForLevel[Level]; 107 if (Level == 0) 108 return 0; 109 return getIndent(IndentForLevel, Level - 1) + Style.IndentWidth; 110 } 111 112 const FormatStyle &Style; 113 const AdditionalKeywords &Keywords; 114 const unsigned AdditionalIndent; 115 116 /// \brief The indent in characters for each level. 117 std::vector<int> IndentForLevel; 118 119 /// \brief Offset of the current line relative to the indent level. 120 /// 121 /// For example, the 'public' keywords is often indented with a negative 122 /// offset. 123 int Offset = 0; 124 125 /// \brief The current line's indent. 126 unsigned Indent = 0; 127 }; 128 129 class LineJoiner { 130 public: 131 LineJoiner(const FormatStyle &Style, const AdditionalKeywords &Keywords, 132 const SmallVectorImpl<AnnotatedLine *> &Lines) 133 : Style(Style), Keywords(Keywords), End(Lines.end()), 134 Next(Lines.begin()) {} 135 136 /// \brief Returns the next line, merging multiple lines into one if possible. 137 const AnnotatedLine *getNextMergedLine(bool DryRun, 138 LevelIndentTracker &IndentTracker) { 139 if (Next == End) 140 return nullptr; 141 const AnnotatedLine *Current = *Next; 142 IndentTracker.nextLine(*Current); 143 unsigned MergedLines = 144 tryFitMultipleLinesInOne(IndentTracker.getIndent(), Next, End); 145 if (MergedLines > 0 && Style.ColumnLimit == 0) 146 // Disallow line merging if there is a break at the start of one of the 147 // input lines. 148 for (unsigned i = 0; i < MergedLines; ++i) 149 if (Next[i + 1]->First->NewlinesBefore > 0) 150 MergedLines = 0; 151 if (!DryRun) 152 for (unsigned i = 0; i < MergedLines; ++i) 153 join(*Next[i], *Next[i + 1]); 154 Next = Next + MergedLines + 1; 155 return Current; 156 } 157 158 private: 159 /// \brief Calculates how many lines can be merged into 1 starting at \p I. 160 unsigned 161 tryFitMultipleLinesInOne(unsigned Indent, 162 SmallVectorImpl<AnnotatedLine *>::const_iterator I, 163 SmallVectorImpl<AnnotatedLine *>::const_iterator E) { 164 // Can't join the last line with anything. 165 if (I + 1 == E) 166 return 0; 167 // We can never merge stuff if there are trailing line comments. 168 const AnnotatedLine *TheLine = *I; 169 if (TheLine->Last->is(TT_LineComment)) 170 return 0; 171 if (I[1]->Type == LT_Invalid || I[1]->First->MustBreakBefore) 172 return 0; 173 if (TheLine->InPPDirective && 174 (!I[1]->InPPDirective || I[1]->First->HasUnescapedNewline)) 175 return 0; 176 177 if (Style.ColumnLimit > 0 && Indent > Style.ColumnLimit) 178 return 0; 179 180 unsigned Limit = 181 Style.ColumnLimit == 0 ? UINT_MAX : Style.ColumnLimit - Indent; 182 // If we already exceed the column limit, we set 'Limit' to 0. The different 183 // tryMerge..() functions can then decide whether to still do merging. 184 Limit = TheLine->Last->TotalLength > Limit 185 ? 0 186 : Limit - TheLine->Last->TotalLength; 187 188 // FIXME: TheLine->Level != 0 might or might not be the right check to do. 189 // If necessary, change to something smarter. 190 bool MergeShortFunctions = 191 Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_All || 192 (Style.AllowShortFunctionsOnASingleLine >= FormatStyle::SFS_Empty && 193 I[1]->First->is(tok::r_brace)) || 194 (Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_Inline && 195 TheLine->Level != 0); 196 197 if (TheLine->Last->is(TT_FunctionLBrace) && 198 TheLine->First != TheLine->Last) { 199 return MergeShortFunctions ? tryMergeSimpleBlock(I, E, Limit) : 0; 200 } 201 if (TheLine->Last->is(tok::l_brace)) { 202 return !Style.BraceWrapping.AfterFunction 203 ? tryMergeSimpleBlock(I, E, Limit) 204 : 0; 205 } 206 if (I[1]->First->is(TT_FunctionLBrace) && 207 Style.BraceWrapping.AfterFunction) { 208 if (I[1]->Last->is(TT_LineComment)) 209 return 0; 210 211 // Check for Limit <= 2 to account for the " {". 212 if (Limit <= 2 || (Style.ColumnLimit == 0 && containsMustBreak(TheLine))) 213 return 0; 214 Limit -= 2; 215 216 unsigned MergedLines = 0; 217 if (MergeShortFunctions) { 218 MergedLines = tryMergeSimpleBlock(I + 1, E, Limit); 219 // If we managed to merge the block, count the function header, which is 220 // on a separate line. 221 if (MergedLines > 0) 222 ++MergedLines; 223 } 224 return MergedLines; 225 } 226 if (TheLine->First->is(tok::kw_if)) { 227 return Style.AllowShortIfStatementsOnASingleLine 228 ? tryMergeSimpleControlStatement(I, E, Limit) 229 : 0; 230 } 231 if (TheLine->First->isOneOf(tok::kw_for, tok::kw_while)) { 232 return Style.AllowShortLoopsOnASingleLine 233 ? tryMergeSimpleControlStatement(I, E, Limit) 234 : 0; 235 } 236 if (TheLine->First->isOneOf(tok::kw_case, tok::kw_default)) { 237 return Style.AllowShortCaseLabelsOnASingleLine 238 ? tryMergeShortCaseLabels(I, E, Limit) 239 : 0; 240 } 241 if (TheLine->InPPDirective && 242 (TheLine->First->HasUnescapedNewline || TheLine->First->IsFirst)) { 243 return tryMergeSimplePPDirective(I, E, Limit); 244 } 245 return 0; 246 } 247 248 unsigned 249 tryMergeSimplePPDirective(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 250 SmallVectorImpl<AnnotatedLine *>::const_iterator E, 251 unsigned Limit) { 252 if (Limit == 0) 253 return 0; 254 if (I + 2 != E && I[2]->InPPDirective && !I[2]->First->HasUnescapedNewline) 255 return 0; 256 if (1 + I[1]->Last->TotalLength > Limit) 257 return 0; 258 return 1; 259 } 260 261 unsigned tryMergeSimpleControlStatement( 262 SmallVectorImpl<AnnotatedLine *>::const_iterator I, 263 SmallVectorImpl<AnnotatedLine *>::const_iterator E, unsigned Limit) { 264 if (Limit == 0) 265 return 0; 266 if (Style.BraceWrapping.AfterControlStatement && 267 (I[1]->First->is(tok::l_brace) && !Style.AllowShortBlocksOnASingleLine)) 268 return 0; 269 if (I[1]->InPPDirective != (*I)->InPPDirective || 270 (I[1]->InPPDirective && I[1]->First->HasUnescapedNewline)) 271 return 0; 272 Limit = limitConsideringMacros(I + 1, E, Limit); 273 AnnotatedLine &Line = **I; 274 if (Line.Last->isNot(tok::r_paren)) 275 return 0; 276 if (1 + I[1]->Last->TotalLength > Limit) 277 return 0; 278 if (I[1]->First->isOneOf(tok::semi, tok::kw_if, tok::kw_for, tok::kw_while, 279 TT_LineComment)) 280 return 0; 281 // Only inline simple if's (no nested if or else). 282 if (I + 2 != E && Line.startsWith(tok::kw_if) && 283 I[2]->First->is(tok::kw_else)) 284 return 0; 285 return 1; 286 } 287 288 unsigned 289 tryMergeShortCaseLabels(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 290 SmallVectorImpl<AnnotatedLine *>::const_iterator E, 291 unsigned Limit) { 292 if (Limit == 0 || I + 1 == E || 293 I[1]->First->isOneOf(tok::kw_case, tok::kw_default)) 294 return 0; 295 unsigned NumStmts = 0; 296 unsigned Length = 0; 297 bool InPPDirective = I[0]->InPPDirective; 298 for (; NumStmts < 3; ++NumStmts) { 299 if (I + 1 + NumStmts == E) 300 break; 301 const AnnotatedLine *Line = I[1 + NumStmts]; 302 if (Line->InPPDirective != InPPDirective) 303 break; 304 if (Line->First->isOneOf(tok::kw_case, tok::kw_default, tok::r_brace)) 305 break; 306 if (Line->First->isOneOf(tok::kw_if, tok::kw_for, tok::kw_switch, 307 tok::kw_while, tok::comment) || 308 Line->Last->is(tok::comment)) 309 return 0; 310 Length += I[1 + NumStmts]->Last->TotalLength + 1; // 1 for the space. 311 } 312 if (NumStmts == 0 || NumStmts == 3 || Length > Limit) 313 return 0; 314 return NumStmts; 315 } 316 317 unsigned 318 tryMergeSimpleBlock(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 319 SmallVectorImpl<AnnotatedLine *>::const_iterator E, 320 unsigned Limit) { 321 AnnotatedLine &Line = **I; 322 323 // Don't merge ObjC @ keywords and methods. 324 // FIXME: If an option to allow short exception handling clauses on a single 325 // line is added, change this to not return for @try and friends. 326 if (Style.Language != FormatStyle::LK_Java && 327 Line.First->isOneOf(tok::at, tok::minus, tok::plus)) 328 return 0; 329 330 // Check that the current line allows merging. This depends on whether we 331 // are in a control flow statements as well as several style flags. 332 if (Line.First->isOneOf(tok::kw_else, tok::kw_case) || 333 (Line.First->Next && Line.First->Next->is(tok::kw_else))) 334 return 0; 335 if (Line.First->isOneOf(tok::kw_if, tok::kw_while, tok::kw_do, tok::kw_try, 336 tok::kw___try, tok::kw_catch, tok::kw___finally, 337 tok::kw_for, tok::r_brace, Keywords.kw___except)) { 338 if (!Style.AllowShortBlocksOnASingleLine) 339 return 0; 340 if (!Style.AllowShortIfStatementsOnASingleLine && 341 Line.startsWith(tok::kw_if)) 342 return 0; 343 if (!Style.AllowShortLoopsOnASingleLine && 344 Line.First->isOneOf(tok::kw_while, tok::kw_do, tok::kw_for)) 345 return 0; 346 // FIXME: Consider an option to allow short exception handling clauses on 347 // a single line. 348 // FIXME: This isn't covered by tests. 349 // FIXME: For catch, __except, __finally the first token on the line 350 // is '}', so this isn't correct here. 351 if (Line.First->isOneOf(tok::kw_try, tok::kw___try, tok::kw_catch, 352 Keywords.kw___except, tok::kw___finally)) 353 return 0; 354 } 355 356 FormatToken *Tok = I[1]->First; 357 if (Tok->is(tok::r_brace) && !Tok->MustBreakBefore && 358 (Tok->getNextNonComment() == nullptr || 359 Tok->getNextNonComment()->is(tok::semi))) { 360 // We merge empty blocks even if the line exceeds the column limit. 361 Tok->SpacesRequiredBefore = 0; 362 Tok->CanBreakBefore = true; 363 return 1; 364 } else if (Limit != 0 && !Line.startsWith(tok::kw_namespace) && 365 !startsExternCBlock(Line)) { 366 // We don't merge short records. 367 if (Line.First->isOneOf(tok::kw_class, tok::kw_union, tok::kw_struct, 368 Keywords.kw_interface)) 369 return 0; 370 371 // Check that we still have three lines and they fit into the limit. 372 if (I + 2 == E || I[2]->Type == LT_Invalid) 373 return 0; 374 Limit = limitConsideringMacros(I + 2, E, Limit); 375 376 if (!nextTwoLinesFitInto(I, Limit)) 377 return 0; 378 379 // Second, check that the next line does not contain any braces - if it 380 // does, readability declines when putting it into a single line. 381 if (I[1]->Last->is(TT_LineComment)) 382 return 0; 383 do { 384 if (Tok->is(tok::l_brace) && Tok->BlockKind != BK_BracedInit) 385 return 0; 386 Tok = Tok->Next; 387 } while (Tok); 388 389 // Last, check that the third line starts with a closing brace. 390 Tok = I[2]->First; 391 if (Tok->isNot(tok::r_brace)) 392 return 0; 393 394 // Don't merge "if (a) { .. } else {". 395 if (Tok->Next && Tok->Next->is(tok::kw_else)) 396 return 0; 397 398 return 2; 399 } 400 return 0; 401 } 402 403 /// Returns the modified column limit for \p I if it is inside a macro and 404 /// needs a trailing '\'. 405 unsigned 406 limitConsideringMacros(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 407 SmallVectorImpl<AnnotatedLine *>::const_iterator E, 408 unsigned Limit) { 409 if (I[0]->InPPDirective && I + 1 != E && 410 !I[1]->First->HasUnescapedNewline && !I[1]->First->is(tok::eof)) { 411 return Limit < 2 ? 0 : Limit - 2; 412 } 413 return Limit; 414 } 415 416 bool nextTwoLinesFitInto(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 417 unsigned Limit) { 418 if (I[1]->First->MustBreakBefore || I[2]->First->MustBreakBefore) 419 return false; 420 return 1 + I[1]->Last->TotalLength + 1 + I[2]->Last->TotalLength <= Limit; 421 } 422 423 bool containsMustBreak(const AnnotatedLine *Line) { 424 for (const FormatToken *Tok = Line->First; Tok; Tok = Tok->Next) { 425 if (Tok->MustBreakBefore) 426 return true; 427 } 428 return false; 429 } 430 431 void join(AnnotatedLine &A, const AnnotatedLine &B) { 432 assert(!A.Last->Next); 433 assert(!B.First->Previous); 434 if (B.Affected) 435 A.Affected = true; 436 A.Last->Next = B.First; 437 B.First->Previous = A.Last; 438 B.First->CanBreakBefore = true; 439 unsigned LengthA = A.Last->TotalLength + B.First->SpacesRequiredBefore; 440 for (FormatToken *Tok = B.First; Tok; Tok = Tok->Next) { 441 Tok->TotalLength += LengthA; 442 A.Last = Tok; 443 } 444 } 445 446 const FormatStyle &Style; 447 const AdditionalKeywords &Keywords; 448 const SmallVectorImpl<AnnotatedLine *>::const_iterator End; 449 450 SmallVectorImpl<AnnotatedLine *>::const_iterator Next; 451 }; 452 453 static void markFinalized(FormatToken *Tok) { 454 for (; Tok; Tok = Tok->Next) { 455 Tok->Finalized = true; 456 for (AnnotatedLine *Child : Tok->Children) 457 markFinalized(Child->First); 458 } 459 } 460 461 #ifndef NDEBUG 462 static void printLineState(const LineState &State) { 463 llvm::dbgs() << "State: "; 464 for (const ParenState &P : State.Stack) { 465 llvm::dbgs() << P.Indent << "|" << P.LastSpace << "|" << P.NestedBlockIndent 466 << " "; 467 } 468 llvm::dbgs() << State.NextToken->TokenText << "\n"; 469 } 470 #endif 471 472 /// \brief Base class for classes that format one \c AnnotatedLine. 473 class LineFormatter { 474 public: 475 LineFormatter(ContinuationIndenter *Indenter, WhitespaceManager *Whitespaces, 476 const FormatStyle &Style, 477 UnwrappedLineFormatter *BlockFormatter) 478 : Indenter(Indenter), Whitespaces(Whitespaces), Style(Style), 479 BlockFormatter(BlockFormatter) {} 480 virtual ~LineFormatter() {} 481 482 /// \brief Formats an \c AnnotatedLine and returns the penalty. 483 /// 484 /// If \p DryRun is \c false, directly applies the changes. 485 virtual unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent, 486 bool DryRun) = 0; 487 488 protected: 489 /// \brief If the \p State's next token is an r_brace closing a nested block, 490 /// format the nested block before it. 491 /// 492 /// Returns \c true if all children could be placed successfully and adapts 493 /// \p Penalty as well as \p State. If \p DryRun is false, also directly 494 /// creates changes using \c Whitespaces. 495 /// 496 /// The crucial idea here is that children always get formatted upon 497 /// encountering the closing brace right after the nested block. Now, if we 498 /// are currently trying to keep the "}" on the same line (i.e. \p NewLine is 499 /// \c false), the entire block has to be kept on the same line (which is only 500 /// possible if it fits on the line, only contains a single statement, etc. 501 /// 502 /// If \p NewLine is true, we format the nested block on separate lines, i.e. 503 /// break after the "{", format all lines with correct indentation and the put 504 /// the closing "}" on yet another new line. 505 /// 506 /// This enables us to keep the simple structure of the 507 /// \c UnwrappedLineFormatter, where we only have two options for each token: 508 /// break or don't break. 509 bool formatChildren(LineState &State, bool NewLine, bool DryRun, 510 unsigned &Penalty) { 511 const FormatToken *LBrace = State.NextToken->getPreviousNonComment(); 512 FormatToken &Previous = *State.NextToken->Previous; 513 if (!LBrace || LBrace->isNot(tok::l_brace) || 514 LBrace->BlockKind != BK_Block || Previous.Children.size() == 0) 515 // The previous token does not open a block. Nothing to do. We don't 516 // assert so that we can simply call this function for all tokens. 517 return true; 518 519 if (NewLine) { 520 int AdditionalIndent = State.Stack.back().Indent - 521 Previous.Children[0]->Level * Style.IndentWidth; 522 523 Penalty += 524 BlockFormatter->format(Previous.Children, DryRun, AdditionalIndent, 525 /*FixBadIndentation=*/true); 526 return true; 527 } 528 529 if (Previous.Children[0]->First->MustBreakBefore) 530 return false; 531 532 // Cannot merge multiple statements into a single line. 533 if (Previous.Children.size() > 1) 534 return false; 535 536 // Cannot merge into one line if this line ends on a comment. 537 if (Previous.is(tok::comment)) 538 return false; 539 540 // We can't put the closing "}" on a line with a trailing comment. 541 if (Previous.Children[0]->Last->isTrailingComment()) 542 return false; 543 544 // If the child line exceeds the column limit, we wouldn't want to merge it. 545 // We add +2 for the trailing " }". 546 if (Style.ColumnLimit > 0 && 547 Previous.Children[0]->Last->TotalLength + State.Column + 2 > 548 Style.ColumnLimit) 549 return false; 550 551 if (!DryRun) { 552 Whitespaces->replaceWhitespace( 553 *Previous.Children[0]->First, 554 /*Newlines=*/0, /*IndentLevel=*/0, /*Spaces=*/1, 555 /*StartOfTokenColumn=*/State.Column, State.Line->InPPDirective); 556 } 557 Penalty += formatLine(*Previous.Children[0], State.Column + 1, DryRun); 558 559 State.Column += 1 + Previous.Children[0]->Last->TotalLength; 560 return true; 561 } 562 563 ContinuationIndenter *Indenter; 564 565 private: 566 WhitespaceManager *Whitespaces; 567 const FormatStyle &Style; 568 UnwrappedLineFormatter *BlockFormatter; 569 }; 570 571 /// \brief Formatter that keeps the existing line breaks. 572 class NoColumnLimitLineFormatter : public LineFormatter { 573 public: 574 NoColumnLimitLineFormatter(ContinuationIndenter *Indenter, 575 WhitespaceManager *Whitespaces, 576 const FormatStyle &Style, 577 UnwrappedLineFormatter *BlockFormatter) 578 : LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {} 579 580 /// \brief Formats the line, simply keeping all of the input's line breaking 581 /// decisions. 582 unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent, 583 bool DryRun) override { 584 assert(!DryRun); 585 LineState State = 586 Indenter->getInitialState(FirstIndent, &Line, /*DryRun=*/false); 587 while (State.NextToken) { 588 bool Newline = 589 Indenter->mustBreak(State) || 590 (Indenter->canBreak(State) && State.NextToken->NewlinesBefore > 0); 591 unsigned Penalty = 0; 592 formatChildren(State, Newline, /*DryRun=*/false, Penalty); 593 Indenter->addTokenToState(State, Newline, /*DryRun=*/false); 594 } 595 return 0; 596 } 597 }; 598 599 /// \brief Formatter that puts all tokens into a single line without breaks. 600 class NoLineBreakFormatter : public LineFormatter { 601 public: 602 NoLineBreakFormatter(ContinuationIndenter *Indenter, 603 WhitespaceManager *Whitespaces, const FormatStyle &Style, 604 UnwrappedLineFormatter *BlockFormatter) 605 : LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {} 606 607 /// \brief Puts all tokens into a single line. 608 unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent, 609 bool DryRun) override { 610 unsigned Penalty = 0; 611 LineState State = Indenter->getInitialState(FirstIndent, &Line, DryRun); 612 while (State.NextToken) { 613 formatChildren(State, /*Newline=*/false, DryRun, Penalty); 614 Indenter->addTokenToState(State, /*Newline=*/false, DryRun); 615 } 616 return Penalty; 617 } 618 }; 619 620 /// \brief Finds the best way to break lines. 621 class OptimizingLineFormatter : public LineFormatter { 622 public: 623 OptimizingLineFormatter(ContinuationIndenter *Indenter, 624 WhitespaceManager *Whitespaces, 625 const FormatStyle &Style, 626 UnwrappedLineFormatter *BlockFormatter) 627 : LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {} 628 629 /// \brief Formats the line by finding the best line breaks with line lengths 630 /// below the column limit. 631 unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent, 632 bool DryRun) override { 633 LineState State = Indenter->getInitialState(FirstIndent, &Line, DryRun); 634 635 // If the ObjC method declaration does not fit on a line, we should format 636 // it with one arg per line. 637 if (State.Line->Type == LT_ObjCMethodDecl) 638 State.Stack.back().BreakBeforeParameter = true; 639 640 // Find best solution in solution space. 641 return analyzeSolutionSpace(State, DryRun); 642 } 643 644 private: 645 struct CompareLineStatePointers { 646 bool operator()(LineState *obj1, LineState *obj2) const { 647 return *obj1 < *obj2; 648 } 649 }; 650 651 /// \brief A pair of <penalty, count> that is used to prioritize the BFS on. 652 /// 653 /// In case of equal penalties, we want to prefer states that were inserted 654 /// first. During state generation we make sure that we insert states first 655 /// that break the line as late as possible. 656 typedef std::pair<unsigned, unsigned> OrderedPenalty; 657 658 /// \brief An edge in the solution space from \c Previous->State to \c State, 659 /// inserting a newline dependent on the \c NewLine. 660 struct StateNode { 661 StateNode(const LineState &State, bool NewLine, StateNode *Previous) 662 : State(State), NewLine(NewLine), Previous(Previous) {} 663 LineState State; 664 bool NewLine; 665 StateNode *Previous; 666 }; 667 668 /// \brief An item in the prioritized BFS search queue. The \c StateNode's 669 /// \c State has the given \c OrderedPenalty. 670 typedef std::pair<OrderedPenalty, StateNode *> QueueItem; 671 672 /// \brief The BFS queue type. 673 typedef std::priority_queue<QueueItem, std::vector<QueueItem>, 674 std::greater<QueueItem>> QueueType; 675 676 /// \brief Analyze the entire solution space starting from \p InitialState. 677 /// 678 /// This implements a variant of Dijkstra's algorithm on the graph that spans 679 /// the solution space (\c LineStates are the nodes). The algorithm tries to 680 /// find the shortest path (the one with lowest penalty) from \p InitialState 681 /// to a state where all tokens are placed. Returns the penalty. 682 /// 683 /// If \p DryRun is \c false, directly applies the changes. 684 unsigned analyzeSolutionSpace(LineState &InitialState, bool DryRun) { 685 std::set<LineState *, CompareLineStatePointers> Seen; 686 687 // Increasing count of \c StateNode items we have created. This is used to 688 // create a deterministic order independent of the container. 689 unsigned Count = 0; 690 QueueType Queue; 691 692 // Insert start element into queue. 693 StateNode *Node = 694 new (Allocator.Allocate()) StateNode(InitialState, false, nullptr); 695 Queue.push(QueueItem(OrderedPenalty(0, Count), Node)); 696 ++Count; 697 698 unsigned Penalty = 0; 699 700 // While not empty, take first element and follow edges. 701 while (!Queue.empty()) { 702 Penalty = Queue.top().first.first; 703 StateNode *Node = Queue.top().second; 704 if (!Node->State.NextToken) { 705 DEBUG(llvm::dbgs() << "\n---\nPenalty for line: " << Penalty << "\n"); 706 break; 707 } 708 Queue.pop(); 709 710 // Cut off the analysis of certain solutions if the analysis gets too 711 // complex. See description of IgnoreStackForComparison. 712 if (Count > 50000) 713 Node->State.IgnoreStackForComparison = true; 714 715 if (!Seen.insert(&Node->State).second) 716 // State already examined with lower penalty. 717 continue; 718 719 FormatDecision LastFormat = Node->State.NextToken->Decision; 720 if (LastFormat == FD_Unformatted || LastFormat == FD_Continue) 721 addNextStateToQueue(Penalty, Node, /*NewLine=*/false, &Count, &Queue); 722 if (LastFormat == FD_Unformatted || LastFormat == FD_Break) 723 addNextStateToQueue(Penalty, Node, /*NewLine=*/true, &Count, &Queue); 724 } 725 726 if (Queue.empty()) { 727 // We were unable to find a solution, do nothing. 728 // FIXME: Add diagnostic? 729 DEBUG(llvm::dbgs() << "Could not find a solution.\n"); 730 return 0; 731 } 732 733 // Reconstruct the solution. 734 if (!DryRun) 735 reconstructPath(InitialState, Queue.top().second); 736 737 DEBUG(llvm::dbgs() << "Total number of analyzed states: " << Count << "\n"); 738 DEBUG(llvm::dbgs() << "---\n"); 739 740 return Penalty; 741 } 742 743 /// \brief Add the following state to the analysis queue \c Queue. 744 /// 745 /// Assume the current state is \p PreviousNode and has been reached with a 746 /// penalty of \p Penalty. Insert a line break if \p NewLine is \c true. 747 void addNextStateToQueue(unsigned Penalty, StateNode *PreviousNode, 748 bool NewLine, unsigned *Count, QueueType *Queue) { 749 if (NewLine && !Indenter->canBreak(PreviousNode->State)) 750 return; 751 if (!NewLine && Indenter->mustBreak(PreviousNode->State)) 752 return; 753 754 StateNode *Node = new (Allocator.Allocate()) 755 StateNode(PreviousNode->State, NewLine, PreviousNode); 756 if (!formatChildren(Node->State, NewLine, /*DryRun=*/true, Penalty)) 757 return; 758 759 Penalty += Indenter->addTokenToState(Node->State, NewLine, true); 760 761 Queue->push(QueueItem(OrderedPenalty(Penalty, *Count), Node)); 762 ++(*Count); 763 } 764 765 /// \brief Applies the best formatting by reconstructing the path in the 766 /// solution space that leads to \c Best. 767 void reconstructPath(LineState &State, StateNode *Best) { 768 std::deque<StateNode *> Path; 769 // We do not need a break before the initial token. 770 while (Best->Previous) { 771 Path.push_front(Best); 772 Best = Best->Previous; 773 } 774 for (std::deque<StateNode *>::iterator I = Path.begin(), E = Path.end(); 775 I != E; ++I) { 776 unsigned Penalty = 0; 777 formatChildren(State, (*I)->NewLine, /*DryRun=*/false, Penalty); 778 Penalty += Indenter->addTokenToState(State, (*I)->NewLine, false); 779 780 DEBUG({ 781 printLineState((*I)->Previous->State); 782 if ((*I)->NewLine) { 783 llvm::dbgs() << "Penalty for placing " 784 << (*I)->Previous->State.NextToken->Tok.getName() << ": " 785 << Penalty << "\n"; 786 } 787 }); 788 } 789 } 790 791 llvm::SpecificBumpPtrAllocator<StateNode> Allocator; 792 }; 793 794 } // anonymous namespace 795 796 unsigned 797 UnwrappedLineFormatter::format(const SmallVectorImpl<AnnotatedLine *> &Lines, 798 bool DryRun, int AdditionalIndent, 799 bool FixBadIndentation) { 800 LineJoiner Joiner(Style, Keywords, Lines); 801 802 // Try to look up already computed penalty in DryRun-mode. 803 std::pair<const SmallVectorImpl<AnnotatedLine *> *, unsigned> CacheKey( 804 &Lines, AdditionalIndent); 805 auto CacheIt = PenaltyCache.find(CacheKey); 806 if (DryRun && CacheIt != PenaltyCache.end()) 807 return CacheIt->second; 808 809 assert(!Lines.empty()); 810 unsigned Penalty = 0; 811 LevelIndentTracker IndentTracker(Style, Keywords, Lines[0]->Level, 812 AdditionalIndent); 813 const AnnotatedLine *PreviousLine = nullptr; 814 const AnnotatedLine *NextLine = nullptr; 815 816 // The minimum level of consecutive lines that have been formatted. 817 unsigned RangeMinLevel = UINT_MAX; 818 819 for (const AnnotatedLine *Line = 820 Joiner.getNextMergedLine(DryRun, IndentTracker); 821 Line; Line = NextLine) { 822 const AnnotatedLine &TheLine = *Line; 823 unsigned Indent = IndentTracker.getIndent(); 824 825 // We continue formatting unchanged lines to adjust their indent, e.g. if a 826 // scope was added. However, we need to carefully stop doing this when we 827 // exit the scope of affected lines to prevent indenting a the entire 828 // remaining file if it currently missing a closing brace. 829 bool ContinueFormatting = 830 TheLine.Level > RangeMinLevel || 831 (TheLine.Level == RangeMinLevel && !TheLine.startsWith(tok::r_brace)); 832 833 bool FixIndentation = (FixBadIndentation || ContinueFormatting) && 834 Indent != TheLine.First->OriginalColumn; 835 bool ShouldFormat = TheLine.Affected || FixIndentation; 836 // We cannot format this line; if the reason is that the line had a 837 // parsing error, remember that. 838 if (ShouldFormat && TheLine.Type == LT_Invalid && IncompleteFormat) 839 *IncompleteFormat = true; 840 841 if (ShouldFormat && TheLine.Type != LT_Invalid) { 842 if (!DryRun) 843 formatFirstToken(*TheLine.First, PreviousLine, TheLine.Level, Indent, 844 TheLine.InPPDirective); 845 846 NextLine = Joiner.getNextMergedLine(DryRun, IndentTracker); 847 unsigned ColumnLimit = getColumnLimit(TheLine.InPPDirective, NextLine); 848 bool FitsIntoOneLine = 849 TheLine.Last->TotalLength + Indent <= ColumnLimit || 850 (TheLine.Type == LT_ImportStatement && 851 (Style.Language != FormatStyle::LK_JavaScript || 852 !Style.JavaScriptWrapImports)); 853 854 if (Style.ColumnLimit == 0) 855 NoColumnLimitLineFormatter(Indenter, Whitespaces, Style, this) 856 .formatLine(TheLine, Indent, DryRun); 857 else if (FitsIntoOneLine) 858 Penalty += NoLineBreakFormatter(Indenter, Whitespaces, Style, this) 859 .formatLine(TheLine, Indent, DryRun); 860 else 861 Penalty += OptimizingLineFormatter(Indenter, Whitespaces, Style, this) 862 .formatLine(TheLine, Indent, DryRun); 863 RangeMinLevel = std::min(RangeMinLevel, TheLine.Level); 864 } else { 865 // If no token in the current line is affected, we still need to format 866 // affected children. 867 if (TheLine.ChildrenAffected) 868 for (const FormatToken *Tok = TheLine.First; Tok; Tok = Tok->Next) 869 if (!Tok->Children.empty()) 870 format(Tok->Children, DryRun); 871 872 // Adapt following lines on the current indent level to the same level 873 // unless the current \c AnnotatedLine is not at the beginning of a line. 874 bool StartsNewLine = 875 TheLine.First->NewlinesBefore > 0 || TheLine.First->IsFirst; 876 if (StartsNewLine) 877 IndentTracker.adjustToUnmodifiedLine(TheLine); 878 if (!DryRun) { 879 bool ReformatLeadingWhitespace = 880 StartsNewLine && ((PreviousLine && PreviousLine->Affected) || 881 TheLine.LeadingEmptyLinesAffected); 882 // Format the first token. 883 if (ReformatLeadingWhitespace) 884 formatFirstToken(*TheLine.First, PreviousLine, TheLine.Level, 885 TheLine.First->OriginalColumn, 886 TheLine.InPPDirective); 887 else 888 Whitespaces->addUntouchableToken(*TheLine.First, 889 TheLine.InPPDirective); 890 891 // Notify the WhitespaceManager about the unchanged whitespace. 892 for (FormatToken *Tok = TheLine.First->Next; Tok; Tok = Tok->Next) 893 Whitespaces->addUntouchableToken(*Tok, TheLine.InPPDirective); 894 } 895 NextLine = Joiner.getNextMergedLine(DryRun, IndentTracker); 896 RangeMinLevel = UINT_MAX; 897 } 898 if (!DryRun) 899 markFinalized(TheLine.First); 900 PreviousLine = &TheLine; 901 } 902 PenaltyCache[CacheKey] = Penalty; 903 return Penalty; 904 } 905 906 void UnwrappedLineFormatter::formatFirstToken(FormatToken &RootToken, 907 const AnnotatedLine *PreviousLine, 908 unsigned IndentLevel, 909 unsigned Indent, 910 bool InPPDirective) { 911 if (RootToken.is(tok::eof)) { 912 unsigned Newlines = std::min(RootToken.NewlinesBefore, 1u); 913 Whitespaces->replaceWhitespace(RootToken, Newlines, /*IndentLevel=*/0, 914 /*Spaces=*/0, /*TargetColumn=*/0); 915 return; 916 } 917 unsigned Newlines = 918 std::min(RootToken.NewlinesBefore, Style.MaxEmptyLinesToKeep + 1); 919 // Remove empty lines before "}" where applicable. 920 if (RootToken.is(tok::r_brace) && 921 (!RootToken.Next || 922 (RootToken.Next->is(tok::semi) && !RootToken.Next->Next))) 923 Newlines = std::min(Newlines, 1u); 924 if (Newlines == 0 && !RootToken.IsFirst) 925 Newlines = 1; 926 if (RootToken.IsFirst && !RootToken.HasUnescapedNewline) 927 Newlines = 0; 928 929 // Remove empty lines after "{". 930 if (!Style.KeepEmptyLinesAtTheStartOfBlocks && PreviousLine && 931 PreviousLine->Last->is(tok::l_brace) && 932 PreviousLine->First->isNot(tok::kw_namespace) && 933 !startsExternCBlock(*PreviousLine)) 934 Newlines = 1; 935 936 // Insert extra new line before access specifiers. 937 if (PreviousLine && PreviousLine->Last->isOneOf(tok::semi, tok::r_brace) && 938 RootToken.isAccessSpecifier() && RootToken.NewlinesBefore == 1) 939 ++Newlines; 940 941 // Remove empty lines after access specifiers. 942 if (PreviousLine && PreviousLine->First->isAccessSpecifier() && 943 (!PreviousLine->InPPDirective || !RootToken.HasUnescapedNewline)) 944 Newlines = std::min(1u, Newlines); 945 946 Whitespaces->replaceWhitespace(RootToken, Newlines, IndentLevel, Indent, 947 Indent, InPPDirective && 948 !RootToken.HasUnescapedNewline); 949 } 950 951 unsigned 952 UnwrappedLineFormatter::getColumnLimit(bool InPPDirective, 953 const AnnotatedLine *NextLine) const { 954 // In preprocessor directives reserve two chars for trailing " \" if the 955 // next line continues the preprocessor directive. 956 bool ContinuesPPDirective = 957 InPPDirective && 958 // If there is no next line, this is likely a child line and the parent 959 // continues the preprocessor directive. 960 (!NextLine || 961 (NextLine->InPPDirective && 962 // If there is an unescaped newline between this line and the next, the 963 // next line starts a new preprocessor directive. 964 !NextLine->First->HasUnescapedNewline)); 965 return Style.ColumnLimit - (ContinuesPPDirective ? 2 : 0); 966 } 967 968 } // namespace format 969 } // namespace clang 970