xref: /freebsd/contrib/llvm-project/clang/lib/Format/UnwrappedLineParser.h (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
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"
19 #include "clang/Basic/IdentifierTable.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.
47   bool InPPDirective;
48 
49   bool MustBeDeclaration;
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.
55   size_t MatchingOpeningBlockLineIndex = kInvalidIndex;
56 
57   /// If this \c UnwrappedLine opens a block, stores the index of the
58   /// line with the corresponding closing brace.
59   size_t MatchingClosingBlockLineIndex = kInvalidIndex;
60 
61   static const size_t kInvalidIndex = -1;
62 
63   unsigned FirstStartColumn = 0;
64 };
65 
66 class UnwrappedLineConsumer {
67 public:
68   virtual ~UnwrappedLineConsumer() {}
69   virtual void consumeUnwrappedLine(const UnwrappedLine &Line) = 0;
70   virtual void finishRun() = 0;
71 };
72 
73 class FormatTokenSource;
74 
75 class UnwrappedLineParser {
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, bool AddLevel = true,
89                   bool MunchSemi = true);
90   void parseChildBlock();
91   void parsePPDirective();
92   void parsePPDefine();
93   void parsePPIf(bool IfDef);
94   void parsePPElIf();
95   void parsePPElse();
96   void parsePPEndIf();
97   void parsePPUnknown();
98   void readTokenWithJavaScriptASI();
99   void parseStructuralElement();
100   bool tryToParseBracedList();
101   bool parseBracedList(bool ContinueOnSemicolons = false, bool IsEnum = false,
102                        tok::TokenKind ClosingBraceKind = tok::r_brace);
103   void parseParens();
104   void parseSquare(bool LambdaIntroducer = false);
105   void parseIfThenElse();
106   void parseTryCatch();
107   void parseForOrWhileLoop();
108   void parseDoWhile();
109   void parseLabel(bool LeftAlignLabel = false);
110   void parseCaseLabel();
111   void parseSwitch();
112   void parseNamespace();
113   void parseNew();
114   void parseAccessSpecifier();
115   bool parseEnum();
116   void parseJavaEnumBody();
117   // Parses a record (aka class) as a top level element. If ParseAsExpr is true,
118   // parses the record as a child block, i.e. if the class declaration is an
119   // expression.
120   void parseRecord(bool ParseAsExpr = false);
121   void parseObjCMethod();
122   void parseObjCProtocolList();
123   void parseObjCUntilAtEnd();
124   void parseObjCInterfaceOrImplementation();
125   bool parseObjCProtocol();
126   void parseJavaScriptEs6ImportExport();
127   void parseStatementMacro();
128   void parseCSharpAttribute();
129   // Parse a C# generic type constraint: `where T : IComparable<T>`.
130   // See:
131   // https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/where-generic-type-constraint
132   void parseCSharpGenericTypeConstraint();
133   bool tryToParseLambda();
134   bool tryToParseLambdaIntroducer();
135   bool tryToParsePropertyAccessor();
136   void tryToParseJSFunction();
137   bool tryToParseSimpleAttribute();
138   void addUnwrappedLine();
139   bool eof() const;
140   // LevelDifference is the difference of levels after and before the current
141   // token. For example:
142   // - if the token is '{' and opens a block, LevelDifference is 1.
143   // - if the token is '}' and closes a block, LevelDifference is -1.
144   void nextToken(int LevelDifference = 0);
145   void readToken(int LevelDifference = 0);
146 
147   // Decides which comment tokens should be added to the current line and which
148   // should be added as comments before the next token.
149   //
150   // Comments specifies the sequence of comment tokens to analyze. They get
151   // either pushed to the current line or added to the comments before the next
152   // token.
153   //
154   // NextTok specifies the next token. A null pointer NextTok is supported, and
155   // signifies either the absence of a next token, or that the next token
156   // shouldn't be taken into accunt for the analysis.
157   void distributeComments(const SmallVectorImpl<FormatToken *> &Comments,
158                           const FormatToken *NextTok);
159 
160   // Adds the comment preceding the next token to unwrapped lines.
161   void flushComments(bool NewlineBeforeNext);
162   void pushToken(FormatToken *Tok);
163   void calculateBraceTypes(bool ExpectClassBody = false);
164 
165   // Marks a conditional compilation edge (for example, an '#if', '#ifdef',
166   // '#else' or merge conflict marker). If 'Unreachable' is true, assumes
167   // this branch either cannot be taken (for example '#if false'), or should
168   // not be taken in this round.
169   void conditionalCompilationCondition(bool Unreachable);
170   void conditionalCompilationStart(bool Unreachable);
171   void conditionalCompilationAlternative();
172   void conditionalCompilationEnd();
173 
174   bool isOnNewLine(const FormatToken &FormatTok);
175 
176   // Compute hash of the current preprocessor branch.
177   // This is used to identify the different branches, and thus track if block
178   // open and close in the same branch.
179   size_t computePPHash() const;
180 
181   // FIXME: We are constantly running into bugs where Line.Level is incorrectly
182   // subtracted from beyond 0. Introduce a method to subtract from Line.Level
183   // and use that everywhere in the Parser.
184   std::unique_ptr<UnwrappedLine> Line;
185 
186   // Comments are sorted into unwrapped lines by whether they are in the same
187   // line as the previous token, or not. If not, they belong to the next token.
188   // Since the next token might already be in a new unwrapped line, we need to
189   // store the comments belonging to that token.
190   SmallVector<FormatToken *, 1> CommentsBeforeNextToken;
191   FormatToken *FormatTok;
192   bool MustBreakBeforeNextToken;
193 
194   // The parsed lines. Only added to through \c CurrentLines.
195   SmallVector<UnwrappedLine, 8> Lines;
196 
197   // Preprocessor directives are parsed out-of-order from other unwrapped lines.
198   // Thus, we need to keep a list of preprocessor directives to be reported
199   // after an unwrapped line that has been started was finished.
200   SmallVector<UnwrappedLine, 4> PreprocessorDirectives;
201 
202   // New unwrapped lines are added via CurrentLines.
203   // Usually points to \c &Lines. While parsing a preprocessor directive when
204   // there is an unfinished previous unwrapped line, will point to
205   // \c &PreprocessorDirectives.
206   SmallVectorImpl<UnwrappedLine> *CurrentLines;
207 
208   // We store for each line whether it must be a declaration depending on
209   // whether we are in a compound statement or not.
210   std::vector<bool> DeclarationScopeStack;
211 
212   const FormatStyle &Style;
213   const AdditionalKeywords &Keywords;
214 
215   llvm::Regex CommentPragmasRegex;
216 
217   FormatTokenSource *Tokens;
218   UnwrappedLineConsumer &Callback;
219 
220   // FIXME: This is a temporary measure until we have reworked the ownership
221   // of the format tokens. The goal is to have the actual tokens created and
222   // owned outside of and handed into the UnwrappedLineParser.
223   ArrayRef<FormatToken *> AllTokens;
224 
225   // Represents preprocessor branch type, so we can find matching
226   // #if/#else/#endif directives.
227   enum PPBranchKind {
228     PP_Conditional, // Any #if, #ifdef, #ifndef, #elif, block outside #if 0
229     PP_Unreachable  // #if 0 or a conditional preprocessor block inside #if 0
230   };
231 
232   struct PPBranch {
233     PPBranch(PPBranchKind Kind, size_t Line) : Kind(Kind), Line(Line) {}
234     PPBranchKind Kind;
235     size_t Line;
236   };
237 
238   // Keeps a stack of currently active preprocessor branching directives.
239   SmallVector<PPBranch, 16> PPStack;
240 
241   // The \c UnwrappedLineParser re-parses the code for each combination
242   // of preprocessor branches that can be taken.
243   // To that end, we take the same branch (#if, #else, or one of the #elif
244   // branches) for each nesting level of preprocessor branches.
245   // \c PPBranchLevel stores the current nesting level of preprocessor
246   // branches during one pass over the code.
247   int PPBranchLevel;
248 
249   // Contains the current branch (#if, #else or one of the #elif branches)
250   // for each nesting level.
251   SmallVector<int, 8> PPLevelBranchIndex;
252 
253   // Contains the maximum number of branches at each nesting level.
254   SmallVector<int, 8> PPLevelBranchCount;
255 
256   // Contains the number of branches per nesting level we are currently
257   // in while parsing a preprocessor branch sequence.
258   // This is used to update PPLevelBranchCount at the end of a branch
259   // sequence.
260   std::stack<int> PPChainBranchIndex;
261 
262   // Include guard search state. Used to fixup preprocessor indent levels
263   // so that include guards do not participate in indentation.
264   enum IncludeGuardState {
265     IG_Inited,   // Search started, looking for #ifndef.
266     IG_IfNdefed, // #ifndef found, IncludeGuardToken points to condition.
267     IG_Defined,  // Matching #define found, checking other requirements.
268     IG_Found,    // All requirements met, need to fix indents.
269     IG_Rejected, // Search failed or never started.
270   };
271 
272   // Current state of include guard search.
273   IncludeGuardState IncludeGuard;
274 
275   // Points to the #ifndef condition for a potential include guard. Null unless
276   // IncludeGuardState == IG_IfNdefed.
277   FormatToken *IncludeGuardToken;
278 
279   // Contains the first start column where the source begins. This is zero for
280   // normal source code and may be nonzero when formatting a code fragment that
281   // does not start at the beginning of the file.
282   unsigned FirstStartColumn;
283 
284   friend class ScopedLineState;
285   friend class CompoundStatementIndenter;
286 };
287 
288 struct UnwrappedLineNode {
289   UnwrappedLineNode() : Tok(nullptr) {}
290   UnwrappedLineNode(FormatToken *Tok) : Tok(Tok) {}
291 
292   FormatToken *Tok;
293   SmallVector<UnwrappedLine, 0> Children;
294 };
295 
296 inline UnwrappedLine::UnwrappedLine()
297     : Level(0), InPPDirective(false), MustBeDeclaration(false),
298       MatchingOpeningBlockLineIndex(kInvalidIndex) {}
299 
300 } // end namespace format
301 } // end namespace clang
302 
303 #endif
304