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UnwrappedLineParser.h
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1 //===--- UnwrappedLineParser.h - Format C++ code ----------------*- C++ -*-===//
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 /// This file contains the declaration of the UnwrappedLineParser,
11 /// which turns a stream of tokens into UnwrappedLines.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEPARSER_H
16 #define LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEPARSER_H
17 
18 #include "FormatToken.h"
20 #include "clang/Format/Format.h"
21 #include "llvm/Support/Regex.h"
22 #include <list>
23 #include <stack>
24 
25 namespace clang {
26 namespace format {
27 
28 struct UnwrappedLineNode;
29 
30 /// An unwrapped line is a sequence of \c Token, that we would like to
31 /// put on a single line if there was no column limit.
32 ///
33 /// This is used as a main interface between the \c UnwrappedLineParser and the
34 /// \c UnwrappedLineFormatter. The key property is that changing the formatting
35 /// within an unwrapped line does not affect any other unwrapped lines.
36 struct UnwrappedLine {
37  UnwrappedLine();
38 
39  // FIXME: Don't use std::list here.
40  /// The \c Tokens comprising this \c UnwrappedLine.
41  std::list<UnwrappedLineNode> Tokens;
42 
43  /// The indent level of the \c UnwrappedLine.
44  unsigned Level;
45 
46  /// Whether this \c UnwrappedLine is part of a preprocessor directive.
48 
50 
51  /// If this \c UnwrappedLine closes a block in a sequence of lines,
52  /// \c MatchingOpeningBlockLineIndex stores the index of the corresponding
53  /// opening line. Otherwise, \c MatchingOpeningBlockLineIndex must be
54  /// \c kInvalidIndex.
56 
57  /// If this \c UnwrappedLine opens a block, stores the index of the
58  /// line with the corresponding closing brace.
60 
61  static const size_t kInvalidIndex = -1;
62 
63  unsigned FirstStartColumn = 0;
64 };
65 
67 public:
69  virtual void consumeUnwrappedLine(const UnwrappedLine &Line) = 0;
70  virtual void finishRun() = 0;
71 };
72 
73 class FormatTokenSource;
74 
76 public:
77  UnwrappedLineParser(const FormatStyle &Style,
78  const AdditionalKeywords &Keywords,
79  unsigned FirstStartColumn, ArrayRef<FormatToken *> Tokens,
80  UnwrappedLineConsumer &Callback);
81 
82  void parse();
83 
84 private:
85  void reset();
86  void parseFile();
87  void parseLevel(bool HasOpeningBrace);
88  void parseBlock(bool MustBeDeclaration, unsigned AddLevels = 1u,
89  bool MunchSemi = true,
90  bool UnindentWhitesmithsBraces = false);
91  void parseChildBlock();
92  void parsePPDirective();
93  void parsePPDefine();
94  void parsePPIf(bool IfDef);
95  void parsePPElIf();
96  void parsePPElse();
97  void parsePPEndIf();
98  void parsePPUnknown();
99  void readTokenWithJavaScriptASI();
100  void parseStructuralElement();
101  bool tryToParseBracedList();
102  bool parseBracedList(bool ContinueOnSemicolons = false, bool IsEnum = false,
103  tok::TokenKind ClosingBraceKind = tok::r_brace);
104  void parseParens();
105  void parseSquare(bool LambdaIntroducer = false);
106  void parseIfThenElse();
107  void parseTryCatch();
108  void parseForOrWhileLoop();
109  void parseDoWhile();
110  void parseLabel(bool LeftAlignLabel = false);
111  void parseCaseLabel();
112  void parseSwitch();
113  void parseNamespace();
114  void parseNew();
115  void parseAccessSpecifier();
116  bool parseEnum();
117  void parseConcept();
118  void parseRequires();
119  void parseRequiresExpression(unsigned int OriginalLevel);
120  void parseConstraintExpression(unsigned int OriginalLevel);
121  void parseJavaEnumBody();
122  // Parses a record (aka class) as a top level element. If ParseAsExpr is true,
123  // parses the record as a child block, i.e. if the class declaration is an
124  // expression.
125  void parseRecord(bool ParseAsExpr = false);
126  void parseObjCLightweightGenerics();
127  void parseObjCMethod();
128  void parseObjCProtocolList();
129  void parseObjCUntilAtEnd();
130  void parseObjCInterfaceOrImplementation();
131  bool parseObjCProtocol();
132  void parseJavaScriptEs6ImportExport();
133  void parseStatementMacro();
134  void parseCSharpAttribute();
135  // Parse a C# generic type constraint: `where T : IComparable<T>`.
136  // See:
137  // https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/where-generic-type-constraint
138  void parseCSharpGenericTypeConstraint();
139  bool tryToParseLambda();
140  bool tryToParseLambdaIntroducer();
141  bool tryToParsePropertyAccessor();
142  void tryToParseJSFunction();
143  bool tryToParseSimpleAttribute();
144 
145  // Used by addUnwrappedLine to denote whether to keep or remove a level
146  // when resetting the line state.
147  enum class LineLevel { Remove, Keep };
148 
149  void addUnwrappedLine(LineLevel AdjustLevel = LineLevel::Remove);
150  bool eof() const;
151  // LevelDifference is the difference of levels after and before the current
152  // token. For example:
153  // - if the token is '{' and opens a block, LevelDifference is 1.
154  // - if the token is '}' and closes a block, LevelDifference is -1.
155  void nextToken(int LevelDifference = 0);
156  void readToken(int LevelDifference = 0);
157 
158  // Decides which comment tokens should be added to the current line and which
159  // should be added as comments before the next token.
160  //
161  // Comments specifies the sequence of comment tokens to analyze. They get
162  // either pushed to the current line or added to the comments before the next
163  // token.
164  //
165  // NextTok specifies the next token. A null pointer NextTok is supported, and
166  // signifies either the absence of a next token, or that the next token
167  // shouldn't be taken into accunt for the analysis.
168  void distributeComments(const SmallVectorImpl<FormatToken *> &Comments,
169  const FormatToken *NextTok);
170 
171  // Adds the comment preceding the next token to unwrapped lines.
172  void flushComments(bool NewlineBeforeNext);
173  void pushToken(FormatToken *Tok);
174  void calculateBraceTypes(bool ExpectClassBody = false);
175 
176  // Marks a conditional compilation edge (for example, an '#if', '#ifdef',
177  // '#else' or merge conflict marker). If 'Unreachable' is true, assumes
178  // this branch either cannot be taken (for example '#if false'), or should
179  // not be taken in this round.
180  void conditionalCompilationCondition(bool Unreachable);
181  void conditionalCompilationStart(bool Unreachable);
182  void conditionalCompilationAlternative();
183  void conditionalCompilationEnd();
184 
185  bool isOnNewLine(const FormatToken &FormatTok);
186 
187  // Compute hash of the current preprocessor branch.
188  // This is used to identify the different branches, and thus track if block
189  // open and close in the same branch.
190  size_t computePPHash() const;
191 
192  // FIXME: We are constantly running into bugs where Line.Level is incorrectly
193  // subtracted from beyond 0. Introduce a method to subtract from Line.Level
194  // and use that everywhere in the Parser.
195  std::unique_ptr<UnwrappedLine> Line;
196 
197  // Comments are sorted into unwrapped lines by whether they are in the same
198  // line as the previous token, or not. If not, they belong to the next token.
199  // Since the next token might already be in a new unwrapped line, we need to
200  // store the comments belonging to that token.
201  SmallVector<FormatToken *, 1> CommentsBeforeNextToken;
202  FormatToken *FormatTok;
203  bool MustBreakBeforeNextToken;
204 
205  // The parsed lines. Only added to through \c CurrentLines.
207 
208  // Preprocessor directives are parsed out-of-order from other unwrapped lines.
209  // Thus, we need to keep a list of preprocessor directives to be reported
210  // after an unwrapped line that has been started was finished.
211  SmallVector<UnwrappedLine, 4> PreprocessorDirectives;
212 
213  // New unwrapped lines are added via CurrentLines.
214  // Usually points to \c &Lines. While parsing a preprocessor directive when
215  // there is an unfinished previous unwrapped line, will point to
216  // \c &PreprocessorDirectives.
217  SmallVectorImpl<UnwrappedLine> *CurrentLines;
218 
219  // We store for each line whether it must be a declaration depending on
220  // whether we are in a compound statement or not.
221  std::vector<bool> DeclarationScopeStack;
222 
223  const FormatStyle &Style;
224  const AdditionalKeywords &Keywords;
225 
226  llvm::Regex CommentPragmasRegex;
227 
228  FormatTokenSource *Tokens;
229  UnwrappedLineConsumer &Callback;
230 
231  // FIXME: This is a temporary measure until we have reworked the ownership
232  // of the format tokens. The goal is to have the actual tokens created and
233  // owned outside of and handed into the UnwrappedLineParser.
234  ArrayRef<FormatToken *> AllTokens;
235 
236  // Represents preprocessor branch type, so we can find matching
237  // #if/#else/#endif directives.
238  enum PPBranchKind {
239  PP_Conditional, // Any #if, #ifdef, #ifndef, #elif, block outside #if 0
240  PP_Unreachable // #if 0 or a conditional preprocessor block inside #if 0
241  };
242 
243  struct PPBranch {
244  PPBranch(PPBranchKind Kind, size_t Line) : Kind(Kind), Line(Line) {}
245  PPBranchKind Kind;
246  size_t Line;
247  };
248 
249  // Keeps a stack of currently active preprocessor branching directives.
251 
252  // The \c UnwrappedLineParser re-parses the code for each combination
253  // of preprocessor branches that can be taken.
254  // To that end, we take the same branch (#if, #else, or one of the #elif
255  // branches) for each nesting level of preprocessor branches.
256  // \c PPBranchLevel stores the current nesting level of preprocessor
257  // branches during one pass over the code.
258  int PPBranchLevel;
259 
260  // Contains the current branch (#if, #else or one of the #elif branches)
261  // for each nesting level.
262  SmallVector<int, 8> PPLevelBranchIndex;
263 
264  // Contains the maximum number of branches at each nesting level.
265  SmallVector<int, 8> PPLevelBranchCount;
266 
267  // Contains the number of branches per nesting level we are currently
268  // in while parsing a preprocessor branch sequence.
269  // This is used to update PPLevelBranchCount at the end of a branch
270  // sequence.
271  std::stack<int> PPChainBranchIndex;
272 
273  // Include guard search state. Used to fixup preprocessor indent levels
274  // so that include guards do not participate in indentation.
275  enum IncludeGuardState {
276  IG_Inited, // Search started, looking for #ifndef.
277  IG_IfNdefed, // #ifndef found, IncludeGuardToken points to condition.
278  IG_Defined, // Matching #define found, checking other requirements.
279  IG_Found, // All requirements met, need to fix indents.
280  IG_Rejected, // Search failed or never started.
281  };
282 
283  // Current state of include guard search.
284  IncludeGuardState IncludeGuard;
285 
286  // Points to the #ifndef condition for a potential include guard. Null unless
287  // IncludeGuardState == IG_IfNdefed.
288  FormatToken *IncludeGuardToken;
289 
290  // Contains the first start column where the source begins. This is zero for
291  // normal source code and may be nonzero when formatting a code fragment that
292  // does not start at the beginning of the file.
293  unsigned FirstStartColumn;
294 
295  friend class ScopedLineState;
297 };
298 
300  UnwrappedLineNode() : Tok(nullptr) {}
302 
305 };
306 
308  : Level(0), InPPDirective(false), MustBeDeclaration(false),
309  MatchingOpeningBlockLineIndex(kInvalidIndex) {}
310 
311 } // end namespace format
312 } // end namespace clang
313 
314 #endif
clang::format::CompoundStatementIndenter
Definition: UnwrappedLineParser.cpp:172
clang::format::ScopedLineState
Definition: UnwrappedLineParser.cpp:139
clang::format::UnwrappedLineNode::Children
SmallVector< UnwrappedLine, 0 > Children
Definition: UnwrappedLineParser.h:304
clang::LambdaIntroducer
Represents a complete lambda introducer.
Definition: DeclSpec.h:2665
llvm::SmallVector
Definition: LLVM.h:38
clang::format::UnwrappedLineParser::parse
void parse()
Definition: UnwrappedLineParser.cpp:256
clang::format::UnwrappedLineConsumer::~UnwrappedLineConsumer
virtual ~UnwrappedLineConsumer()
Definition: UnwrappedLineParser.h:68
clang::format::UnwrappedLine::kInvalidIndex
static const size_t kInvalidIndex
Definition: UnwrappedLineParser.h:61
clang::format::FormatStyle
The FormatStyle is used to configure the formatting to follow specific guidelines.
Definition: Format.h:55
clang::format::FormatToken
A wrapper around a Token storing information about the whitespace characters preceding it.
Definition: FormatToken.h:211
clang::format::AdditionalKeywords
Encapsulates keywords that are context sensitive or for languages not properly supported by Clang's l...
Definition: FormatToken.h:833
clang::format::UnwrappedLine
An unwrapped line is a sequence of Token, that we would like to put on a single line if there was no ...
Definition: UnwrappedLineParser.h:36
Format.h
clang::format::UnwrappedLineParser
Definition: UnwrappedLineParser.h:75
clang::format::UnwrappedLineConsumer
Definition: UnwrappedLineParser.h:66
clang::format::UnwrappedLine::InPPDirective
bool InPPDirective
Whether this UnwrappedLine is part of a preprocessor directive.
Definition: UnwrappedLineParser.h:47
clang::format::UnwrappedLineNode::Tok
FormatToken * Tok
Definition: UnwrappedLineParser.h:303
IdentifierTable.h
Line
const AnnotatedLine * Line
Definition: UsingDeclarationsSorter.cpp:68
clang::format::UnwrappedLine::MustBeDeclaration
bool MustBeDeclaration
Definition: UnwrappedLineParser.h:49
clang::format::UnwrappedLine::MatchingClosingBlockLineIndex
size_t MatchingClosingBlockLineIndex
If this UnwrappedLine opens a block, stores the index of the line with the corresponding closing brac...
Definition: UnwrappedLineParser.h:59
clang::tok::TokenKind
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:25
false
#define false
Definition: stdbool.h:17
clang::format::UnwrappedLineNode::UnwrappedLineNode
UnwrappedLineNode(FormatToken *Tok)
Definition: UnwrappedLineParser.h:301
llvm::ArrayRef
Definition: LLVM.h:34
clang::format::UnwrappedLine::UnwrappedLine
UnwrappedLine()
Definition: UnwrappedLineParser.h:307
clang::ObjCPropertyAttribute::Kind
Kind
Definition: DeclObjCCommon.h:22
clang::format::UnwrappedLineConsumer::consumeUnwrappedLine
virtual void consumeUnwrappedLine(const UnwrappedLine &Line)=0
clang::format::UnwrappedLineNode
Definition: UnwrappedLineParser.h:299
clang
Dataflow Directional Tag Classes.
Definition: CalledOnceCheck.h:17
clang::format::UnwrappedLineConsumer::finishRun
virtual void finishRun()=0
clang::prec::Level
Level
Definition: OperatorPrecedence.h:26
clang::format::UnwrappedLineNode::UnwrappedLineNode
UnwrappedLineNode()
Definition: UnwrappedLineParser.h:300
FormatToken.h
clang::format::UnwrappedLine::Level
unsigned Level
The indent level of the UnwrappedLine.
Definition: UnwrappedLineParser.h:44
llvm::SmallVectorImpl
Definition: LLVM.h:39
clang::format::UnwrappedLine::MatchingOpeningBlockLineIndex
size_t MatchingOpeningBlockLineIndex
If this UnwrappedLine closes a block in a sequence of lines, MatchingOpeningBlockLineIndex stores the...
Definition: UnwrappedLineParser.h:55
clang::format::UnwrappedLine::Tokens
std::list< UnwrappedLineNode > Tokens
The Tokens comprising this UnwrappedLine.
Definition: UnwrappedLineParser.h:41
clang::format::UnwrappedLine::FirstStartColumn
unsigned FirstStartColumn
Definition: UnwrappedLineParser.h:63
clang::format::UnwrappedLineParser::UnwrappedLineParser
UnwrappedLineParser(const FormatStyle &Style, const AdditionalKeywords &Keywords, unsigned FirstStartColumn, ArrayRef< FormatToken * > Tokens, UnwrappedLineConsumer &Callback)
Definition: UnwrappedLineParser.cpp:225
clang::format::FormatTokenSource
Definition: UnwrappedLineParser.cpp:28