UnwrappedLineFormatter.cpp revision 321369
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#include <queue> 14 15#define DEBUG_TYPE "format-formatter" 16 17namespace clang { 18namespace format { 19 20namespace { 21 22bool startsExternCBlock(const AnnotatedLine &Line) { 23 const FormatToken *Next = Line.First->getNextNonComment(); 24 const FormatToken *NextNext = Next ? Next->getNextNonComment() : nullptr; 25 return Line.startsWith(tok::kw_extern) && Next && Next->isStringLiteral() && 26 NextNext && NextNext->is(tok::l_brace); 27} 28 29/// \brief Tracks the indent level of \c AnnotatedLines across levels. 30/// 31/// \c nextLine must be called for each \c AnnotatedLine, after which \c 32/// getIndent() will return the indent for the last line \c nextLine was called 33/// with. 34/// If the line is not formatted (and thus the indent does not change), calling 35/// \c adjustToUnmodifiedLine after the call to \c nextLine will cause 36/// subsequent lines on the same level to be indented at the same level as the 37/// given line. 38class LevelIndentTracker { 39public: 40 LevelIndentTracker(const FormatStyle &Style, 41 const AdditionalKeywords &Keywords, unsigned StartLevel, 42 int AdditionalIndent) 43 : Style(Style), Keywords(Keywords), AdditionalIndent(AdditionalIndent) { 44 for (unsigned i = 0; i != StartLevel; ++i) 45 IndentForLevel.push_back(Style.IndentWidth * i + AdditionalIndent); 46 } 47 48 /// \brief Returns the indent for the current line. 49 unsigned getIndent() const { return Indent; } 50 51 /// \brief Update the indent state given that \p Line is going to be formatted 52 /// next. 53 void nextLine(const AnnotatedLine &Line) { 54 Offset = getIndentOffset(*Line.First); 55 // Update the indent level cache size so that we can rely on it 56 // having the right size in adjustToUnmodifiedline. 57 while (IndentForLevel.size() <= Line.Level) 58 IndentForLevel.push_back(-1); 59 if (Line.InPPDirective) { 60 Indent = Line.Level * Style.IndentWidth + AdditionalIndent; 61 } else { 62 IndentForLevel.resize(Line.Level + 1); 63 Indent = getIndent(IndentForLevel, Line.Level); 64 } 65 if (static_cast<int>(Indent) + Offset >= 0) 66 Indent += Offset; 67 } 68 69 /// \brief Update the indent state given that \p Line indent should be 70 /// skipped. 71 void skipLine(const AnnotatedLine &Line) { 72 while (IndentForLevel.size() <= Line.Level) 73 IndentForLevel.push_back(Indent); 74 } 75 76 /// \brief Update the level indent to adapt to the given \p Line. 77 /// 78 /// When a line is not formatted, we move the subsequent lines on the same 79 /// level to the same indent. 80 /// Note that \c nextLine must have been called before this method. 81 void adjustToUnmodifiedLine(const AnnotatedLine &Line) { 82 unsigned LevelIndent = Line.First->OriginalColumn; 83 if (static_cast<int>(LevelIndent) - Offset >= 0) 84 LevelIndent -= Offset; 85 if ((!Line.First->is(tok::comment) || IndentForLevel[Line.Level] == -1) && 86 !Line.InPPDirective) 87 IndentForLevel[Line.Level] = LevelIndent; 88 } 89 90private: 91 /// \brief Get the offset of the line relatively to the level. 92 /// 93 /// For example, 'public:' labels in classes are offset by 1 or 2 94 /// characters to the left from their level. 95 int getIndentOffset(const FormatToken &RootToken) { 96 if (Style.Language == FormatStyle::LK_Java || 97 Style.Language == FormatStyle::LK_JavaScript) 98 return 0; 99 if (RootToken.isAccessSpecifier(false) || 100 RootToken.isObjCAccessSpecifier() || 101 (RootToken.isOneOf(Keywords.kw_signals, Keywords.kw_qsignals) && 102 RootToken.Next && RootToken.Next->is(tok::colon))) 103 return Style.AccessModifierOffset; 104 return 0; 105 } 106 107 /// \brief Get the indent of \p Level from \p IndentForLevel. 108 /// 109 /// \p IndentForLevel must contain the indent for the level \c l 110 /// at \p IndentForLevel[l], or a value < 0 if the indent for 111 /// that level is unknown. 112 unsigned getIndent(ArrayRef<int> IndentForLevel, unsigned Level) { 113 if (IndentForLevel[Level] != -1) 114 return IndentForLevel[Level]; 115 if (Level == 0) 116 return 0; 117 return getIndent(IndentForLevel, Level - 1) + Style.IndentWidth; 118 } 119 120 const FormatStyle &Style; 121 const AdditionalKeywords &Keywords; 122 const unsigned AdditionalIndent; 123 124 /// \brief The indent in characters for each level. 125 std::vector<int> IndentForLevel; 126 127 /// \brief Offset of the current line relative to the indent level. 128 /// 129 /// For example, the 'public' keywords is often indented with a negative 130 /// offset. 131 int Offset = 0; 132 133 /// \brief The current line's indent. 134 unsigned Indent = 0; 135}; 136 137bool isNamespaceDeclaration(const AnnotatedLine *Line) { 138 const FormatToken *NamespaceTok = Line->First; 139 return NamespaceTok && NamespaceTok->getNamespaceToken(); 140} 141 142bool isEndOfNamespace(const AnnotatedLine *Line, 143 const SmallVectorImpl<AnnotatedLine *> &AnnotatedLines) { 144 if (!Line->startsWith(tok::r_brace)) 145 return false; 146 size_t StartLineIndex = Line->MatchingOpeningBlockLineIndex; 147 if (StartLineIndex == UnwrappedLine::kInvalidIndex) 148 return false; 149 assert(StartLineIndex < AnnotatedLines.size()); 150 return isNamespaceDeclaration(AnnotatedLines[StartLineIndex]); 151} 152 153class LineJoiner { 154public: 155 LineJoiner(const FormatStyle &Style, const AdditionalKeywords &Keywords, 156 const SmallVectorImpl<AnnotatedLine *> &Lines) 157 : Style(Style), Keywords(Keywords), End(Lines.end()), Next(Lines.begin()), 158 AnnotatedLines(Lines) {} 159 160 /// \brief Returns the next line, merging multiple lines into one if possible. 161 const AnnotatedLine *getNextMergedLine(bool DryRun, 162 LevelIndentTracker &IndentTracker) { 163 if (Next == End) 164 return nullptr; 165 const AnnotatedLine *Current = *Next; 166 IndentTracker.nextLine(*Current); 167 unsigned MergedLines = 168 tryFitMultipleLinesInOne(IndentTracker, Next, End); 169 if (MergedLines > 0 && Style.ColumnLimit == 0) 170 // Disallow line merging if there is a break at the start of one of the 171 // input lines. 172 for (unsigned i = 0; i < MergedLines; ++i) 173 if (Next[i + 1]->First->NewlinesBefore > 0) 174 MergedLines = 0; 175 if (!DryRun) 176 for (unsigned i = 0; i < MergedLines; ++i) 177 join(*Next[0], *Next[i + 1]); 178 Next = Next + MergedLines + 1; 179 return Current; 180 } 181 182private: 183 /// \brief Calculates how many lines can be merged into 1 starting at \p I. 184 unsigned 185 tryFitMultipleLinesInOne(LevelIndentTracker &IndentTracker, 186 SmallVectorImpl<AnnotatedLine *>::const_iterator I, 187 SmallVectorImpl<AnnotatedLine *>::const_iterator E) { 188 const unsigned Indent = IndentTracker.getIndent(); 189 190 // Can't join the last line with anything. 191 if (I + 1 == E) 192 return 0; 193 // We can never merge stuff if there are trailing line comments. 194 const AnnotatedLine *TheLine = *I; 195 if (TheLine->Last->is(TT_LineComment)) 196 return 0; 197 if (I[1]->Type == LT_Invalid || I[1]->First->MustBreakBefore) 198 return 0; 199 if (TheLine->InPPDirective && 200 (!I[1]->InPPDirective || I[1]->First->HasUnescapedNewline)) 201 return 0; 202 203 if (Style.ColumnLimit > 0 && Indent > Style.ColumnLimit) 204 return 0; 205 206 unsigned Limit = 207 Style.ColumnLimit == 0 ? UINT_MAX : Style.ColumnLimit - Indent; 208 // If we already exceed the column limit, we set 'Limit' to 0. The different 209 // tryMerge..() functions can then decide whether to still do merging. 210 Limit = TheLine->Last->TotalLength > Limit 211 ? 0 212 : Limit - TheLine->Last->TotalLength; 213 214 if (TheLine->Last->is(TT_FunctionLBrace) && 215 TheLine->First == TheLine->Last && 216 !Style.BraceWrapping.SplitEmptyFunction && 217 I[1]->First->is(tok::r_brace)) 218 return tryMergeSimpleBlock(I, E, Limit); 219 220 // Handle empty record blocks where the brace has already been wrapped 221 if (TheLine->Last->is(tok::l_brace) && TheLine->First == TheLine->Last && 222 I != AnnotatedLines.begin()) { 223 bool EmptyBlock = I[1]->First->is(tok::r_brace); 224 225 const FormatToken *Tok = I[-1]->First; 226 if (Tok && Tok->is(tok::comment)) 227 Tok = Tok->getNextNonComment(); 228 229 if (Tok && Tok->getNamespaceToken()) 230 return !Style.BraceWrapping.SplitEmptyNamespace && EmptyBlock 231 ? tryMergeSimpleBlock(I, E, Limit) : 0; 232 233 if (Tok && Tok->is(tok::kw_typedef)) 234 Tok = Tok->getNextNonComment(); 235 if (Tok && Tok->isOneOf(tok::kw_class, tok::kw_struct, tok::kw_union, 236 Keywords.kw_interface)) 237 return !Style.BraceWrapping.SplitEmptyRecord && EmptyBlock 238 ? tryMergeSimpleBlock(I, E, Limit) : 0; 239 } 240 241 // FIXME: TheLine->Level != 0 might or might not be the right check to do. 242 // If necessary, change to something smarter. 243 bool MergeShortFunctions = 244 Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_All || 245 (Style.AllowShortFunctionsOnASingleLine >= FormatStyle::SFS_Empty && 246 I[1]->First->is(tok::r_brace)) || 247 (Style.AllowShortFunctionsOnASingleLine & FormatStyle::SFS_InlineOnly && 248 TheLine->Level != 0); 249 250 if (Style.CompactNamespaces) { 251 if (isNamespaceDeclaration(TheLine)) { 252 int i = 0; 253 unsigned closingLine = TheLine->MatchingOpeningBlockLineIndex - 1; 254 for (; I + 1 + i != E && isNamespaceDeclaration(I[i + 1]) && 255 closingLine == I[i + 1]->MatchingOpeningBlockLineIndex && 256 I[i + 1]->Last->TotalLength < Limit; 257 i++, closingLine--) { 258 // No extra indent for compacted namespaces 259 IndentTracker.skipLine(*I[i + 1]); 260 261 Limit -= I[i + 1]->Last->TotalLength; 262 } 263 return i; 264 } 265 266 if (isEndOfNamespace(TheLine, AnnotatedLines)) { 267 int i = 0; 268 unsigned openingLine = TheLine->MatchingOpeningBlockLineIndex - 1; 269 for (; I + 1 + i != E && isEndOfNamespace(I[i + 1], AnnotatedLines) && 270 openingLine == I[i + 1]->MatchingOpeningBlockLineIndex; 271 i++, openingLine--) { 272 // No space between consecutive braces 273 I[i + 1]->First->SpacesRequiredBefore = !I[i]->Last->is(tok::r_brace); 274 275 // Indent like the outer-most namespace 276 IndentTracker.nextLine(*I[i + 1]); 277 } 278 return i; 279 } 280 } 281 282 if (TheLine->Last->is(TT_FunctionLBrace) && 283 TheLine->First != TheLine->Last) { 284 return MergeShortFunctions ? tryMergeSimpleBlock(I, E, Limit) : 0; 285 } 286 if (TheLine->Last->is(tok::l_brace)) { 287 return !Style.BraceWrapping.AfterFunction 288 ? tryMergeSimpleBlock(I, E, Limit) 289 : 0; 290 } 291 if (I[1]->First->is(TT_FunctionLBrace) && 292 Style.BraceWrapping.AfterFunction) { 293 if (I[1]->Last->is(TT_LineComment)) 294 return 0; 295 296 // Check for Limit <= 2 to account for the " {". 297 if (Limit <= 2 || (Style.ColumnLimit == 0 && containsMustBreak(TheLine))) 298 return 0; 299 Limit -= 2; 300 301 unsigned MergedLines = 0; 302 if (MergeShortFunctions || 303 (Style.AllowShortFunctionsOnASingleLine >= FormatStyle::SFS_Empty && 304 I[1]->First == I[1]->Last && I + 2 != E && 305 I[2]->First->is(tok::r_brace))) { 306 MergedLines = tryMergeSimpleBlock(I + 1, E, Limit); 307 // If we managed to merge the block, count the function header, which is 308 // on a separate line. 309 if (MergedLines > 0) 310 ++MergedLines; 311 } 312 return MergedLines; 313 } 314 if (TheLine->First->is(tok::kw_if)) { 315 return Style.AllowShortIfStatementsOnASingleLine 316 ? tryMergeSimpleControlStatement(I, E, Limit) 317 : 0; 318 } 319 if (TheLine->First->isOneOf(tok::kw_for, tok::kw_while)) { 320 return Style.AllowShortLoopsOnASingleLine 321 ? tryMergeSimpleControlStatement(I, E, Limit) 322 : 0; 323 } 324 if (TheLine->First->isOneOf(tok::kw_case, tok::kw_default)) { 325 return Style.AllowShortCaseLabelsOnASingleLine 326 ? tryMergeShortCaseLabels(I, E, Limit) 327 : 0; 328 } 329 if (TheLine->InPPDirective && 330 (TheLine->First->HasUnescapedNewline || TheLine->First->IsFirst)) { 331 return tryMergeSimplePPDirective(I, E, Limit); 332 } 333 return 0; 334 } 335 336 unsigned 337 tryMergeSimplePPDirective(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 338 SmallVectorImpl<AnnotatedLine *>::const_iterator E, 339 unsigned Limit) { 340 if (Limit == 0) 341 return 0; 342 if (I + 2 != E && I[2]->InPPDirective && !I[2]->First->HasUnescapedNewline) 343 return 0; 344 if (1 + I[1]->Last->TotalLength > Limit) 345 return 0; 346 return 1; 347 } 348 349 unsigned tryMergeSimpleControlStatement( 350 SmallVectorImpl<AnnotatedLine *>::const_iterator I, 351 SmallVectorImpl<AnnotatedLine *>::const_iterator E, unsigned Limit) { 352 if (Limit == 0) 353 return 0; 354 if (Style.BraceWrapping.AfterControlStatement && 355 (I[1]->First->is(tok::l_brace) && !Style.AllowShortBlocksOnASingleLine)) 356 return 0; 357 if (I[1]->InPPDirective != (*I)->InPPDirective || 358 (I[1]->InPPDirective && I[1]->First->HasUnescapedNewline)) 359 return 0; 360 Limit = limitConsideringMacros(I + 1, E, Limit); 361 AnnotatedLine &Line = **I; 362 if (Line.Last->isNot(tok::r_paren)) 363 return 0; 364 if (1 + I[1]->Last->TotalLength > Limit) 365 return 0; 366 if (I[1]->First->isOneOf(tok::semi, tok::kw_if, tok::kw_for, tok::kw_while, 367 TT_LineComment)) 368 return 0; 369 // Only inline simple if's (no nested if or else). 370 if (I + 2 != E && Line.startsWith(tok::kw_if) && 371 I[2]->First->is(tok::kw_else)) 372 return 0; 373 return 1; 374 } 375 376 unsigned 377 tryMergeShortCaseLabels(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 378 SmallVectorImpl<AnnotatedLine *>::const_iterator E, 379 unsigned Limit) { 380 if (Limit == 0 || I + 1 == E || 381 I[1]->First->isOneOf(tok::kw_case, tok::kw_default)) 382 return 0; 383 unsigned NumStmts = 0; 384 unsigned Length = 0; 385 bool InPPDirective = I[0]->InPPDirective; 386 for (; NumStmts < 3; ++NumStmts) { 387 if (I + 1 + NumStmts == E) 388 break; 389 const AnnotatedLine *Line = I[1 + NumStmts]; 390 if (Line->InPPDirective != InPPDirective) 391 break; 392 if (Line->First->isOneOf(tok::kw_case, tok::kw_default, tok::r_brace)) 393 break; 394 if (Line->First->isOneOf(tok::kw_if, tok::kw_for, tok::kw_switch, 395 tok::kw_while, tok::comment) || 396 Line->Last->is(tok::comment)) 397 return 0; 398 Length += I[1 + NumStmts]->Last->TotalLength + 1; // 1 for the space. 399 } 400 if (NumStmts == 0 || NumStmts == 3 || Length > Limit) 401 return 0; 402 return NumStmts; 403 } 404 405 unsigned 406 tryMergeSimpleBlock(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 407 SmallVectorImpl<AnnotatedLine *>::const_iterator E, 408 unsigned Limit) { 409 AnnotatedLine &Line = **I; 410 411 // Don't merge ObjC @ keywords and methods. 412 // FIXME: If an option to allow short exception handling clauses on a single 413 // line is added, change this to not return for @try and friends. 414 if (Style.Language != FormatStyle::LK_Java && 415 Line.First->isOneOf(tok::at, tok::minus, tok::plus)) 416 return 0; 417 418 // Check that the current line allows merging. This depends on whether we 419 // are in a control flow statements as well as several style flags. 420 if (Line.First->isOneOf(tok::kw_else, tok::kw_case) || 421 (Line.First->Next && Line.First->Next->is(tok::kw_else))) 422 return 0; 423 if (Line.First->isOneOf(tok::kw_if, tok::kw_while, tok::kw_do, tok::kw_try, 424 tok::kw___try, tok::kw_catch, tok::kw___finally, 425 tok::kw_for, tok::r_brace, Keywords.kw___except)) { 426 if (!Style.AllowShortBlocksOnASingleLine) 427 return 0; 428 if (!Style.AllowShortIfStatementsOnASingleLine && 429 Line.startsWith(tok::kw_if)) 430 return 0; 431 if (!Style.AllowShortLoopsOnASingleLine && 432 Line.First->isOneOf(tok::kw_while, tok::kw_do, tok::kw_for)) 433 return 0; 434 // FIXME: Consider an option to allow short exception handling clauses on 435 // a single line. 436 // FIXME: This isn't covered by tests. 437 // FIXME: For catch, __except, __finally the first token on the line 438 // is '}', so this isn't correct here. 439 if (Line.First->isOneOf(tok::kw_try, tok::kw___try, tok::kw_catch, 440 Keywords.kw___except, tok::kw___finally)) 441 return 0; 442 } 443 444 FormatToken *Tok = I[1]->First; 445 if (Tok->is(tok::r_brace) && !Tok->MustBreakBefore && 446 (Tok->getNextNonComment() == nullptr || 447 Tok->getNextNonComment()->is(tok::semi))) { 448 // We merge empty blocks even if the line exceeds the column limit. 449 Tok->SpacesRequiredBefore = 0; 450 Tok->CanBreakBefore = true; 451 return 1; 452 } else if (Limit != 0 && !Line.startsWith(tok::kw_namespace) && 453 !startsExternCBlock(Line)) { 454 // We don't merge short records. 455 FormatToken *RecordTok = 456 Line.First->is(tok::kw_typedef) ? Line.First->Next : Line.First; 457 if (RecordTok && 458 RecordTok->isOneOf(tok::kw_class, tok::kw_union, tok::kw_struct, 459 Keywords.kw_interface)) 460 return 0; 461 462 // Check that we still have three lines and they fit into the limit. 463 if (I + 2 == E || I[2]->Type == LT_Invalid) 464 return 0; 465 Limit = limitConsideringMacros(I + 2, E, Limit); 466 467 if (!nextTwoLinesFitInto(I, Limit)) 468 return 0; 469 470 // Second, check that the next line does not contain any braces - if it 471 // does, readability declines when putting it into a single line. 472 if (I[1]->Last->is(TT_LineComment)) 473 return 0; 474 do { 475 if (Tok->is(tok::l_brace) && Tok->BlockKind != BK_BracedInit) 476 return 0; 477 Tok = Tok->Next; 478 } while (Tok); 479 480 // Last, check that the third line starts with a closing brace. 481 Tok = I[2]->First; 482 if (Tok->isNot(tok::r_brace)) 483 return 0; 484 485 // Don't merge "if (a) { .. } else {". 486 if (Tok->Next && Tok->Next->is(tok::kw_else)) 487 return 0; 488 489 return 2; 490 } 491 return 0; 492 } 493 494 /// Returns the modified column limit for \p I if it is inside a macro and 495 /// needs a trailing '\'. 496 unsigned 497 limitConsideringMacros(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 498 SmallVectorImpl<AnnotatedLine *>::const_iterator E, 499 unsigned Limit) { 500 if (I[0]->InPPDirective && I + 1 != E && 501 !I[1]->First->HasUnescapedNewline && !I[1]->First->is(tok::eof)) { 502 return Limit < 2 ? 0 : Limit - 2; 503 } 504 return Limit; 505 } 506 507 bool nextTwoLinesFitInto(SmallVectorImpl<AnnotatedLine *>::const_iterator I, 508 unsigned Limit) { 509 if (I[1]->First->MustBreakBefore || I[2]->First->MustBreakBefore) 510 return false; 511 return 1 + I[1]->Last->TotalLength + 1 + I[2]->Last->TotalLength <= Limit; 512 } 513 514 bool containsMustBreak(const AnnotatedLine *Line) { 515 for (const FormatToken *Tok = Line->First; Tok; Tok = Tok->Next) { 516 if (Tok->MustBreakBefore) 517 return true; 518 } 519 return false; 520 } 521 522 void join(AnnotatedLine &A, const AnnotatedLine &B) { 523 assert(!A.Last->Next); 524 assert(!B.First->Previous); 525 if (B.Affected) 526 A.Affected = true; 527 A.Last->Next = B.First; 528 B.First->Previous = A.Last; 529 B.First->CanBreakBefore = true; 530 unsigned LengthA = A.Last->TotalLength + B.First->SpacesRequiredBefore; 531 for (FormatToken *Tok = B.First; Tok; Tok = Tok->Next) { 532 Tok->TotalLength += LengthA; 533 A.Last = Tok; 534 } 535 } 536 537 const FormatStyle &Style; 538 const AdditionalKeywords &Keywords; 539 const SmallVectorImpl<AnnotatedLine *>::const_iterator End; 540 541 SmallVectorImpl<AnnotatedLine *>::const_iterator Next; 542 const SmallVectorImpl<AnnotatedLine *> &AnnotatedLines; 543}; 544 545static void markFinalized(FormatToken *Tok) { 546 for (; Tok; Tok = Tok->Next) { 547 Tok->Finalized = true; 548 for (AnnotatedLine *Child : Tok->Children) 549 markFinalized(Child->First); 550 } 551} 552 553#ifndef NDEBUG 554static void printLineState(const LineState &State) { 555 llvm::dbgs() << "State: "; 556 for (const ParenState &P : State.Stack) { 557 llvm::dbgs() << P.Indent << "|" << P.LastSpace << "|" << P.NestedBlockIndent 558 << " "; 559 } 560 llvm::dbgs() << State.NextToken->TokenText << "\n"; 561} 562#endif 563 564/// \brief Base class for classes that format one \c AnnotatedLine. 565class LineFormatter { 566public: 567 LineFormatter(ContinuationIndenter *Indenter, WhitespaceManager *Whitespaces, 568 const FormatStyle &Style, 569 UnwrappedLineFormatter *BlockFormatter) 570 : Indenter(Indenter), Whitespaces(Whitespaces), Style(Style), 571 BlockFormatter(BlockFormatter) {} 572 virtual ~LineFormatter() {} 573 574 /// \brief Formats an \c AnnotatedLine and returns the penalty. 575 /// 576 /// If \p DryRun is \c false, directly applies the changes. 577 virtual unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent, 578 bool DryRun) = 0; 579 580protected: 581 /// \brief If the \p State's next token is an r_brace closing a nested block, 582 /// format the nested block before it. 583 /// 584 /// Returns \c true if all children could be placed successfully and adapts 585 /// \p Penalty as well as \p State. If \p DryRun is false, also directly 586 /// creates changes using \c Whitespaces. 587 /// 588 /// The crucial idea here is that children always get formatted upon 589 /// encountering the closing brace right after the nested block. Now, if we 590 /// are currently trying to keep the "}" on the same line (i.e. \p NewLine is 591 /// \c false), the entire block has to be kept on the same line (which is only 592 /// possible if it fits on the line, only contains a single statement, etc. 593 /// 594 /// If \p NewLine is true, we format the nested block on separate lines, i.e. 595 /// break after the "{", format all lines with correct indentation and the put 596 /// the closing "}" on yet another new line. 597 /// 598 /// This enables us to keep the simple structure of the 599 /// \c UnwrappedLineFormatter, where we only have two options for each token: 600 /// break or don't break. 601 bool formatChildren(LineState &State, bool NewLine, bool DryRun, 602 unsigned &Penalty) { 603 const FormatToken *LBrace = State.NextToken->getPreviousNonComment(); 604 FormatToken &Previous = *State.NextToken->Previous; 605 if (!LBrace || LBrace->isNot(tok::l_brace) || 606 LBrace->BlockKind != BK_Block || Previous.Children.size() == 0) 607 // The previous token does not open a block. Nothing to do. We don't 608 // assert so that we can simply call this function for all tokens. 609 return true; 610 611 if (NewLine) { 612 int AdditionalIndent = State.Stack.back().Indent - 613 Previous.Children[0]->Level * Style.IndentWidth; 614 615 Penalty += 616 BlockFormatter->format(Previous.Children, DryRun, AdditionalIndent, 617 /*FixBadIndentation=*/true); 618 return true; 619 } 620 621 if (Previous.Children[0]->First->MustBreakBefore) 622 return false; 623 624 // Cannot merge into one line if this line ends on a comment. 625 if (Previous.is(tok::comment)) 626 return false; 627 628 // Cannot merge multiple statements into a single line. 629 if (Previous.Children.size() > 1) 630 return false; 631 632 const AnnotatedLine *Child = Previous.Children[0]; 633 // We can't put the closing "}" on a line with a trailing comment. 634 if (Child->Last->isTrailingComment()) 635 return false; 636 637 // If the child line exceeds the column limit, we wouldn't want to merge it. 638 // We add +2 for the trailing " }". 639 if (Style.ColumnLimit > 0 && 640 Child->Last->TotalLength + State.Column + 2 > Style.ColumnLimit) 641 return false; 642 643 if (!DryRun) { 644 Whitespaces->replaceWhitespace( 645 *Child->First, /*Newlines=*/0, /*Spaces=*/1, 646 /*StartOfTokenColumn=*/State.Column, State.Line->InPPDirective); 647 } 648 Penalty += formatLine(*Child, State.Column + 1, DryRun); 649 650 State.Column += 1 + Child->Last->TotalLength; 651 return true; 652 } 653 654 ContinuationIndenter *Indenter; 655 656private: 657 WhitespaceManager *Whitespaces; 658 const FormatStyle &Style; 659 UnwrappedLineFormatter *BlockFormatter; 660}; 661 662/// \brief Formatter that keeps the existing line breaks. 663class NoColumnLimitLineFormatter : public LineFormatter { 664public: 665 NoColumnLimitLineFormatter(ContinuationIndenter *Indenter, 666 WhitespaceManager *Whitespaces, 667 const FormatStyle &Style, 668 UnwrappedLineFormatter *BlockFormatter) 669 : LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {} 670 671 /// \brief Formats the line, simply keeping all of the input's line breaking 672 /// decisions. 673 unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent, 674 bool DryRun) override { 675 assert(!DryRun); 676 LineState State = 677 Indenter->getInitialState(FirstIndent, &Line, /*DryRun=*/false); 678 while (State.NextToken) { 679 bool Newline = 680 Indenter->mustBreak(State) || 681 (Indenter->canBreak(State) && State.NextToken->NewlinesBefore > 0); 682 unsigned Penalty = 0; 683 formatChildren(State, Newline, /*DryRun=*/false, Penalty); 684 Indenter->addTokenToState(State, Newline, /*DryRun=*/false); 685 } 686 return 0; 687 } 688}; 689 690/// \brief Formatter that puts all tokens into a single line without breaks. 691class NoLineBreakFormatter : public LineFormatter { 692public: 693 NoLineBreakFormatter(ContinuationIndenter *Indenter, 694 WhitespaceManager *Whitespaces, const FormatStyle &Style, 695 UnwrappedLineFormatter *BlockFormatter) 696 : LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {} 697 698 /// \brief Puts all tokens into a single line. 699 unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent, 700 bool DryRun) override { 701 unsigned Penalty = 0; 702 LineState State = Indenter->getInitialState(FirstIndent, &Line, DryRun); 703 while (State.NextToken) { 704 formatChildren(State, /*Newline=*/false, DryRun, Penalty); 705 Indenter->addTokenToState( 706 State, /*Newline=*/State.NextToken->MustBreakBefore, DryRun); 707 } 708 return Penalty; 709 } 710}; 711 712/// \brief Finds the best way to break lines. 713class OptimizingLineFormatter : public LineFormatter { 714public: 715 OptimizingLineFormatter(ContinuationIndenter *Indenter, 716 WhitespaceManager *Whitespaces, 717 const FormatStyle &Style, 718 UnwrappedLineFormatter *BlockFormatter) 719 : LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {} 720 721 /// \brief Formats the line by finding the best line breaks with line lengths 722 /// below the column limit. 723 unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent, 724 bool DryRun) override { 725 LineState State = Indenter->getInitialState(FirstIndent, &Line, DryRun); 726 727 // If the ObjC method declaration does not fit on a line, we should format 728 // it with one arg per line. 729 if (State.Line->Type == LT_ObjCMethodDecl) 730 State.Stack.back().BreakBeforeParameter = true; 731 732 // Find best solution in solution space. 733 return analyzeSolutionSpace(State, DryRun); 734 } 735 736private: 737 struct CompareLineStatePointers { 738 bool operator()(LineState *obj1, LineState *obj2) const { 739 return *obj1 < *obj2; 740 } 741 }; 742 743 /// \brief A pair of <penalty, count> that is used to prioritize the BFS on. 744 /// 745 /// In case of equal penalties, we want to prefer states that were inserted 746 /// first. During state generation we make sure that we insert states first 747 /// that break the line as late as possible. 748 typedef std::pair<unsigned, unsigned> OrderedPenalty; 749 750 /// \brief An edge in the solution space from \c Previous->State to \c State, 751 /// inserting a newline dependent on the \c NewLine. 752 struct StateNode { 753 StateNode(const LineState &State, bool NewLine, StateNode *Previous) 754 : State(State), NewLine(NewLine), Previous(Previous) {} 755 LineState State; 756 bool NewLine; 757 StateNode *Previous; 758 }; 759 760 /// \brief An item in the prioritized BFS search queue. The \c StateNode's 761 /// \c State has the given \c OrderedPenalty. 762 typedef std::pair<OrderedPenalty, StateNode *> QueueItem; 763 764 /// \brief The BFS queue type. 765 typedef std::priority_queue<QueueItem, std::vector<QueueItem>, 766 std::greater<QueueItem>> QueueType; 767 768 /// \brief Analyze the entire solution space starting from \p InitialState. 769 /// 770 /// This implements a variant of Dijkstra's algorithm on the graph that spans 771 /// the solution space (\c LineStates are the nodes). The algorithm tries to 772 /// find the shortest path (the one with lowest penalty) from \p InitialState 773 /// to a state where all tokens are placed. Returns the penalty. 774 /// 775 /// If \p DryRun is \c false, directly applies the changes. 776 unsigned analyzeSolutionSpace(LineState &InitialState, bool DryRun) { 777 std::set<LineState *, CompareLineStatePointers> Seen; 778 779 // Increasing count of \c StateNode items we have created. This is used to 780 // create a deterministic order independent of the container. 781 unsigned Count = 0; 782 QueueType Queue; 783 784 // Insert start element into queue. 785 StateNode *Node = 786 new (Allocator.Allocate()) StateNode(InitialState, false, nullptr); 787 Queue.push(QueueItem(OrderedPenalty(0, Count), Node)); 788 ++Count; 789 790 unsigned Penalty = 0; 791 792 // While not empty, take first element and follow edges. 793 while (!Queue.empty()) { 794 Penalty = Queue.top().first.first; 795 StateNode *Node = Queue.top().second; 796 if (!Node->State.NextToken) { 797 DEBUG(llvm::dbgs() << "\n---\nPenalty for line: " << Penalty << "\n"); 798 break; 799 } 800 Queue.pop(); 801 802 // Cut off the analysis of certain solutions if the analysis gets too 803 // complex. See description of IgnoreStackForComparison. 804 if (Count > 50000) 805 Node->State.IgnoreStackForComparison = true; 806 807 if (!Seen.insert(&Node->State).second) 808 // State already examined with lower penalty. 809 continue; 810 811 FormatDecision LastFormat = Node->State.NextToken->Decision; 812 if (LastFormat == FD_Unformatted || LastFormat == FD_Continue) 813 addNextStateToQueue(Penalty, Node, /*NewLine=*/false, &Count, &Queue); 814 if (LastFormat == FD_Unformatted || LastFormat == FD_Break) 815 addNextStateToQueue(Penalty, Node, /*NewLine=*/true, &Count, &Queue); 816 } 817 818 if (Queue.empty()) { 819 // We were unable to find a solution, do nothing. 820 // FIXME: Add diagnostic? 821 DEBUG(llvm::dbgs() << "Could not find a solution.\n"); 822 return 0; 823 } 824 825 // Reconstruct the solution. 826 if (!DryRun) 827 reconstructPath(InitialState, Queue.top().second); 828 829 DEBUG(llvm::dbgs() << "Total number of analyzed states: " << Count << "\n"); 830 DEBUG(llvm::dbgs() << "---\n"); 831 832 return Penalty; 833 } 834 835 /// \brief Add the following state to the analysis queue \c Queue. 836 /// 837 /// Assume the current state is \p PreviousNode and has been reached with a 838 /// penalty of \p Penalty. Insert a line break if \p NewLine is \c true. 839 void addNextStateToQueue(unsigned Penalty, StateNode *PreviousNode, 840 bool NewLine, unsigned *Count, QueueType *Queue) { 841 if (NewLine && !Indenter->canBreak(PreviousNode->State)) 842 return; 843 if (!NewLine && Indenter->mustBreak(PreviousNode->State)) 844 return; 845 846 StateNode *Node = new (Allocator.Allocate()) 847 StateNode(PreviousNode->State, NewLine, PreviousNode); 848 if (!formatChildren(Node->State, NewLine, /*DryRun=*/true, Penalty)) 849 return; 850 851 Penalty += Indenter->addTokenToState(Node->State, NewLine, true); 852 853 Queue->push(QueueItem(OrderedPenalty(Penalty, *Count), Node)); 854 ++(*Count); 855 } 856 857 /// \brief Applies the best formatting by reconstructing the path in the 858 /// solution space that leads to \c Best. 859 void reconstructPath(LineState &State, StateNode *Best) { 860 std::deque<StateNode *> Path; 861 // We do not need a break before the initial token. 862 while (Best->Previous) { 863 Path.push_front(Best); 864 Best = Best->Previous; 865 } 866 for (std::deque<StateNode *>::iterator I = Path.begin(), E = Path.end(); 867 I != E; ++I) { 868 unsigned Penalty = 0; 869 formatChildren(State, (*I)->NewLine, /*DryRun=*/false, Penalty); 870 Penalty += Indenter->addTokenToState(State, (*I)->NewLine, false); 871 872 DEBUG({ 873 printLineState((*I)->Previous->State); 874 if ((*I)->NewLine) { 875 llvm::dbgs() << "Penalty for placing " 876 << (*I)->Previous->State.NextToken->Tok.getName() << ": " 877 << Penalty << "\n"; 878 } 879 }); 880 } 881 } 882 883 llvm::SpecificBumpPtrAllocator<StateNode> Allocator; 884}; 885 886} // anonymous namespace 887 888unsigned 889UnwrappedLineFormatter::format(const SmallVectorImpl<AnnotatedLine *> &Lines, 890 bool DryRun, int AdditionalIndent, 891 bool FixBadIndentation) { 892 LineJoiner Joiner(Style, Keywords, Lines); 893 894 // Try to look up already computed penalty in DryRun-mode. 895 std::pair<const SmallVectorImpl<AnnotatedLine *> *, unsigned> CacheKey( 896 &Lines, AdditionalIndent); 897 auto CacheIt = PenaltyCache.find(CacheKey); 898 if (DryRun && CacheIt != PenaltyCache.end()) 899 return CacheIt->second; 900 901 assert(!Lines.empty()); 902 unsigned Penalty = 0; 903 LevelIndentTracker IndentTracker(Style, Keywords, Lines[0]->Level, 904 AdditionalIndent); 905 const AnnotatedLine *PreviousLine = nullptr; 906 const AnnotatedLine *NextLine = nullptr; 907 908 // The minimum level of consecutive lines that have been formatted. 909 unsigned RangeMinLevel = UINT_MAX; 910 911 for (const AnnotatedLine *Line = 912 Joiner.getNextMergedLine(DryRun, IndentTracker); 913 Line; Line = NextLine) { 914 const AnnotatedLine &TheLine = *Line; 915 unsigned Indent = IndentTracker.getIndent(); 916 917 // We continue formatting unchanged lines to adjust their indent, e.g. if a 918 // scope was added. However, we need to carefully stop doing this when we 919 // exit the scope of affected lines to prevent indenting a the entire 920 // remaining file if it currently missing a closing brace. 921 bool ContinueFormatting = 922 TheLine.Level > RangeMinLevel || 923 (TheLine.Level == RangeMinLevel && !TheLine.startsWith(tok::r_brace)); 924 925 bool FixIndentation = (FixBadIndentation || ContinueFormatting) && 926 Indent != TheLine.First->OriginalColumn; 927 bool ShouldFormat = TheLine.Affected || FixIndentation; 928 // We cannot format this line; if the reason is that the line had a 929 // parsing error, remember that. 930 if (ShouldFormat && TheLine.Type == LT_Invalid && Status) { 931 Status->FormatComplete = false; 932 Status->Line = 933 SourceMgr.getSpellingLineNumber(TheLine.First->Tok.getLocation()); 934 } 935 936 if (ShouldFormat && TheLine.Type != LT_Invalid) { 937 if (!DryRun) 938 formatFirstToken(TheLine, PreviousLine, Indent); 939 940 NextLine = Joiner.getNextMergedLine(DryRun, IndentTracker); 941 unsigned ColumnLimit = getColumnLimit(TheLine.InPPDirective, NextLine); 942 bool FitsIntoOneLine = 943 TheLine.Last->TotalLength + Indent <= ColumnLimit || 944 (TheLine.Type == LT_ImportStatement && 945 (Style.Language != FormatStyle::LK_JavaScript || 946 !Style.JavaScriptWrapImports)); 947 948 if (Style.ColumnLimit == 0) 949 NoColumnLimitLineFormatter(Indenter, Whitespaces, Style, this) 950 .formatLine(TheLine, Indent, DryRun); 951 else if (FitsIntoOneLine) 952 Penalty += NoLineBreakFormatter(Indenter, Whitespaces, Style, this) 953 .formatLine(TheLine, Indent, DryRun); 954 else 955 Penalty += OptimizingLineFormatter(Indenter, Whitespaces, Style, this) 956 .formatLine(TheLine, Indent, DryRun); 957 RangeMinLevel = std::min(RangeMinLevel, TheLine.Level); 958 } else { 959 // If no token in the current line is affected, we still need to format 960 // affected children. 961 if (TheLine.ChildrenAffected) 962 for (const FormatToken *Tok = TheLine.First; Tok; Tok = Tok->Next) 963 if (!Tok->Children.empty()) 964 format(Tok->Children, DryRun); 965 966 // Adapt following lines on the current indent level to the same level 967 // unless the current \c AnnotatedLine is not at the beginning of a line. 968 bool StartsNewLine = 969 TheLine.First->NewlinesBefore > 0 || TheLine.First->IsFirst; 970 if (StartsNewLine) 971 IndentTracker.adjustToUnmodifiedLine(TheLine); 972 if (!DryRun) { 973 bool ReformatLeadingWhitespace = 974 StartsNewLine && ((PreviousLine && PreviousLine->Affected) || 975 TheLine.LeadingEmptyLinesAffected); 976 // Format the first token. 977 if (ReformatLeadingWhitespace) 978 formatFirstToken(TheLine, PreviousLine, 979 TheLine.First->OriginalColumn); 980 else 981 Whitespaces->addUntouchableToken(*TheLine.First, 982 TheLine.InPPDirective); 983 984 // Notify the WhitespaceManager about the unchanged whitespace. 985 for (FormatToken *Tok = TheLine.First->Next; Tok; Tok = Tok->Next) 986 Whitespaces->addUntouchableToken(*Tok, TheLine.InPPDirective); 987 } 988 NextLine = Joiner.getNextMergedLine(DryRun, IndentTracker); 989 RangeMinLevel = UINT_MAX; 990 } 991 if (!DryRun) 992 markFinalized(TheLine.First); 993 PreviousLine = &TheLine; 994 } 995 PenaltyCache[CacheKey] = Penalty; 996 return Penalty; 997} 998 999void UnwrappedLineFormatter::formatFirstToken(const AnnotatedLine &Line, 1000 const AnnotatedLine *PreviousLine, 1001 unsigned Indent) { 1002 FormatToken& RootToken = *Line.First; 1003 if (RootToken.is(tok::eof)) { 1004 unsigned Newlines = std::min(RootToken.NewlinesBefore, 1u); 1005 Whitespaces->replaceWhitespace(RootToken, Newlines, /*Spaces=*/0, 1006 /*StartOfTokenColumn=*/0); 1007 return; 1008 } 1009 unsigned Newlines = 1010 std::min(RootToken.NewlinesBefore, Style.MaxEmptyLinesToKeep + 1); 1011 // Remove empty lines before "}" where applicable. 1012 if (RootToken.is(tok::r_brace) && 1013 (!RootToken.Next || 1014 (RootToken.Next->is(tok::semi) && !RootToken.Next->Next))) 1015 Newlines = std::min(Newlines, 1u); 1016 if (Newlines == 0 && !RootToken.IsFirst) 1017 Newlines = 1; 1018 if (RootToken.IsFirst && !RootToken.HasUnescapedNewline) 1019 Newlines = 0; 1020 1021 // Remove empty lines after "{". 1022 if (!Style.KeepEmptyLinesAtTheStartOfBlocks && PreviousLine && 1023 PreviousLine->Last->is(tok::l_brace) && 1024 PreviousLine->First->isNot(tok::kw_namespace) && 1025 !startsExternCBlock(*PreviousLine)) 1026 Newlines = 1; 1027 1028 // Insert extra new line before access specifiers. 1029 if (PreviousLine && PreviousLine->Last->isOneOf(tok::semi, tok::r_brace) && 1030 RootToken.isAccessSpecifier() && RootToken.NewlinesBefore == 1) 1031 ++Newlines; 1032 1033 // Remove empty lines after access specifiers. 1034 if (PreviousLine && PreviousLine->First->isAccessSpecifier() && 1035 (!PreviousLine->InPPDirective || !RootToken.HasUnescapedNewline)) 1036 Newlines = std::min(1u, Newlines); 1037 1038 Whitespaces->replaceWhitespace(RootToken, Newlines, Indent, Indent, 1039 Line.InPPDirective && 1040 !RootToken.HasUnescapedNewline); 1041} 1042 1043unsigned 1044UnwrappedLineFormatter::getColumnLimit(bool InPPDirective, 1045 const AnnotatedLine *NextLine) const { 1046 // In preprocessor directives reserve two chars for trailing " \" if the 1047 // next line continues the preprocessor directive. 1048 bool ContinuesPPDirective = 1049 InPPDirective && 1050 // If there is no next line, this is likely a child line and the parent 1051 // continues the preprocessor directive. 1052 (!NextLine || 1053 (NextLine->InPPDirective && 1054 // If there is an unescaped newline between this line and the next, the 1055 // next line starts a new preprocessor directive. 1056 !NextLine->First->HasUnescapedNewline)); 1057 return Style.ColumnLimit - (ContinuesPPDirective ? 2 : 0); 1058} 1059 1060} // namespace format 1061} // namespace clang 1062