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1 //===--- UnwrappedLineParser.h - Format C++ code ----------------*- C++ -*-===//
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 /// \file
11 /// \brief This file contains the declaration of the UnwrappedLineParser,
12 /// which turns a stream of tokens into UnwrappedLines.
13 ///
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEPARSER_H
17 #define LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEPARSER_H
18 
19 #include "FormatToken.h"
20 #include "clang/Basic/IdentifierTable.h"
21 #include "clang/Format/Format.h"
22 #include <list>
23 #include <stack>
24 
25 namespace clang {
26 namespace format {
27 
28 struct UnwrappedLineNode;
29 
30 /// \brief 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   /// \brief The \c Tokens comprising this \c UnwrappedLine.
41   std::list<UnwrappedLineNode> Tokens;
42 
43   /// \brief The indent level of the \c UnwrappedLine.
44   unsigned Level;
45 
46   /// \brief Whether this \c UnwrappedLine is part of a preprocessor directive.
47   bool InPPDirective;
48 
49   bool MustBeDeclaration;
50 };
51 
52 class UnwrappedLineConsumer {
53 public:
~UnwrappedLineConsumer()54   virtual ~UnwrappedLineConsumer() {}
55   virtual void consumeUnwrappedLine(const UnwrappedLine &Line) = 0;
56   virtual void finishRun() = 0;
57 };
58 
59 class FormatTokenSource;
60 
61 class UnwrappedLineParser {
62 public:
63   UnwrappedLineParser(const FormatStyle &Style,
64                       const AdditionalKeywords &Keywords,
65                       ArrayRef<FormatToken *> Tokens,
66                       UnwrappedLineConsumer &Callback);
67 
68   void parse();
69 
70 private:
71   void reset();
72   void parseFile();
73   void parseLevel(bool HasOpeningBrace);
74   void parseBlock(bool MustBeDeclaration, bool AddLevel = true,
75                   bool MunchSemi = true);
76   void parseChildBlock();
77   void parsePPDirective();
78   void parsePPDefine();
79   void parsePPIf(bool IfDef);
80   void parsePPElIf();
81   void parsePPElse();
82   void parsePPEndIf();
83   void parsePPUnknown();
84   void readTokenWithJavaScriptASI();
85   void parseStructuralElement();
86   bool tryToParseBracedList();
87   bool parseBracedList(bool ContinueOnSemicolons = false);
88   void parseParens();
89   void parseSquare();
90   void parseIfThenElse();
91   void parseTryCatch();
92   void parseForOrWhileLoop();
93   void parseDoWhile();
94   void parseLabel();
95   void parseCaseLabel();
96   void parseSwitch();
97   void parseNamespace();
98   void parseNew();
99   void parseAccessSpecifier();
100   bool parseEnum();
101   void parseJavaEnumBody();
102   void parseRecord();
103   void parseObjCProtocolList();
104   void parseObjCUntilAtEnd();
105   void parseObjCInterfaceOrImplementation();
106   void parseObjCProtocol();
107   void parseJavaScriptEs6ImportExport();
108   bool tryToParseLambda();
109   bool tryToParseLambdaIntroducer();
110   void tryToParseJSFunction();
111   void addUnwrappedLine();
112   bool eof() const;
113   void nextToken();
114   const FormatToken *getPreviousToken();
115   void readToken();
116   void flushComments(bool NewlineBeforeNext);
117   void pushToken(FormatToken *Tok);
118   void calculateBraceTypes(bool ExpectClassBody = false);
119 
120   // Marks a conditional compilation edge (for example, an '#if', '#ifdef',
121   // '#else' or merge conflict marker). If 'Unreachable' is true, assumes
122   // this branch either cannot be taken (for example '#if false'), or should
123   // not be taken in this round.
124   void conditionalCompilationCondition(bool Unreachable);
125   void conditionalCompilationStart(bool Unreachable);
126   void conditionalCompilationAlternative();
127   void conditionalCompilationEnd();
128 
129   bool isOnNewLine(const FormatToken &FormatTok);
130 
131   // FIXME: We are constantly running into bugs where Line.Level is incorrectly
132   // subtracted from beyond 0. Introduce a method to subtract from Line.Level
133   // and use that everywhere in the Parser.
134   std::unique_ptr<UnwrappedLine> Line;
135 
136   // Comments are sorted into unwrapped lines by whether they are in the same
137   // line as the previous token, or not. If not, they belong to the next token.
138   // Since the next token might already be in a new unwrapped line, we need to
139   // store the comments belonging to that token.
140   SmallVector<FormatToken *, 1> CommentsBeforeNextToken;
141   FormatToken *FormatTok;
142   bool MustBreakBeforeNextToken;
143 
144   // The parsed lines. Only added to through \c CurrentLines.
145   SmallVector<UnwrappedLine, 8> Lines;
146 
147   // Preprocessor directives are parsed out-of-order from other unwrapped lines.
148   // Thus, we need to keep a list of preprocessor directives to be reported
149   // after an unwarpped line that has been started was finished.
150   SmallVector<UnwrappedLine, 4> PreprocessorDirectives;
151 
152   // New unwrapped lines are added via CurrentLines.
153   // Usually points to \c &Lines. While parsing a preprocessor directive when
154   // there is an unfinished previous unwrapped line, will point to
155   // \c &PreprocessorDirectives.
156   SmallVectorImpl<UnwrappedLine> *CurrentLines;
157 
158   // We store for each line whether it must be a declaration depending on
159   // whether we are in a compound statement or not.
160   std::vector<bool> DeclarationScopeStack;
161 
162   const FormatStyle &Style;
163   const AdditionalKeywords &Keywords;
164 
165   FormatTokenSource *Tokens;
166   UnwrappedLineConsumer &Callback;
167 
168   // FIXME: This is a temporary measure until we have reworked the ownership
169   // of the format tokens. The goal is to have the actual tokens created and
170   // owned outside of and handed into the UnwrappedLineParser.
171   ArrayRef<FormatToken *> AllTokens;
172 
173   // Represents preprocessor branch type, so we can find matching
174   // #if/#else/#endif directives.
175   enum PPBranchKind {
176     PP_Conditional, // Any #if, #ifdef, #ifndef, #elif, block outside #if 0
177     PP_Unreachable  // #if 0 or a conditional preprocessor block inside #if 0
178   };
179 
180   // Keeps a stack of currently active preprocessor branching directives.
181   SmallVector<PPBranchKind, 16> PPStack;
182 
183   // The \c UnwrappedLineParser re-parses the code for each combination
184   // of preprocessor branches that can be taken.
185   // To that end, we take the same branch (#if, #else, or one of the #elif
186   // branches) for each nesting level of preprocessor branches.
187   // \c PPBranchLevel stores the current nesting level of preprocessor
188   // branches during one pass over the code.
189   int PPBranchLevel;
190 
191   // Contains the current branch (#if, #else or one of the #elif branches)
192   // for each nesting level.
193   SmallVector<int, 8> PPLevelBranchIndex;
194 
195   // Contains the maximum number of branches at each nesting level.
196   SmallVector<int, 8> PPLevelBranchCount;
197 
198   // Contains the number of branches per nesting level we are currently
199   // in while parsing a preprocessor branch sequence.
200   // This is used to update PPLevelBranchCount at the end of a branch
201   // sequence.
202   std::stack<int> PPChainBranchIndex;
203 
204   friend class ScopedLineState;
205   friend class CompoundStatementIndenter;
206 };
207 
208 struct UnwrappedLineNode {
UnwrappedLineNodeUnwrappedLineNode209   UnwrappedLineNode() : Tok(nullptr) {}
UnwrappedLineNodeUnwrappedLineNode210   UnwrappedLineNode(FormatToken *Tok) : Tok(Tok) {}
211 
212   FormatToken *Tok;
213   SmallVector<UnwrappedLine, 0> Children;
214 };
215 
UnwrappedLine()216 inline UnwrappedLine::UnwrappedLine()
217     : Level(0), InPPDirective(false), MustBeDeclaration(false) {}
218 
219 } // end namespace format
220 } // end namespace clang
221 
222 #endif
223