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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_FORMAT_UNWRAPPED_LINE_PARSER_H
     17 #define LLVM_CLANG_FORMAT_UNWRAPPED_LINE_PARSER_H
     18 
     19 #include "clang/Basic/IdentifierTable.h"
     20 #include "clang/Basic/SourceManager.h"
     21 #include "clang/Format/Format.h"
     22 #include "clang/Lex/Lexer.h"
     23 #include <list>
     24 
     25 namespace clang {
     26 
     27 class DiagnosticsEngine;
     28 
     29 namespace format {
     30 
     31 /// \brief A wrapper around a \c Token storing information about the
     32 /// whitespace characters preceeding it.
     33 struct FormatToken {
     34   FormatToken()
     35       : NewlinesBefore(0), HasUnescapedNewline(false), WhiteSpaceLength(0),
     36         LastNewlineOffset(0), TokenLength(0), IsFirst(false),
     37         MustBreakBefore(false) {}
     38 
     39   /// \brief The \c Token.
     40   Token Tok;
     41 
     42   /// \brief The number of newlines immediately before the \c Token.
     43   ///
     44   /// This can be used to determine what the user wrote in the original code
     45   /// and thereby e.g. leave an empty line between two function definitions.
     46   unsigned NewlinesBefore;
     47 
     48   /// \brief Whether there is at least one unescaped newline before the \c
     49   /// Token.
     50   bool HasUnescapedNewline;
     51 
     52   /// \brief The location of the start of the whitespace immediately preceeding
     53   /// the \c Token.
     54   ///
     55   /// Used together with \c WhiteSpaceLength to create a \c Replacement.
     56   SourceLocation WhiteSpaceStart;
     57 
     58   /// \brief The length in characters of the whitespace immediately preceeding
     59   /// the \c Token.
     60   unsigned WhiteSpaceLength;
     61 
     62   /// \brief The offset just past the last '\n' in this token's leading
     63   /// whitespace (relative to \c WhiteSpaceStart). 0 if there is no '\n'.
     64   unsigned LastNewlineOffset;
     65 
     66   /// \brief The length of the non-whitespace parts of the token. This is
     67   /// necessary because we need to handle escaped newlines that are stored
     68   /// with the token.
     69   unsigned TokenLength;
     70 
     71   /// \brief Indicates that this is the first token.
     72   bool IsFirst;
     73 
     74   /// \brief Whether there must be a line break before this token.
     75   ///
     76   /// This happens for example when a preprocessor directive ended directly
     77   /// before the token.
     78   bool MustBreakBefore;
     79 };
     80 
     81 /// \brief An unwrapped line is a sequence of \c Token, that we would like to
     82 /// put on a single line if there was no column limit.
     83 ///
     84 /// This is used as a main interface between the \c UnwrappedLineParser and the
     85 /// \c UnwrappedLineFormatter. The key property is that changing the formatting
     86 /// within an unwrapped line does not affect any other unwrapped lines.
     87 struct UnwrappedLine {
     88   UnwrappedLine() : Level(0), InPPDirective(false), MustBeDeclaration(false) {
     89   }
     90 
     91   // FIXME: Don't use std::list here.
     92   /// \brief The \c Tokens comprising this \c UnwrappedLine.
     93   std::list<FormatToken> Tokens;
     94 
     95   /// \brief The indent level of the \c UnwrappedLine.
     96   unsigned Level;
     97 
     98   /// \brief Whether this \c UnwrappedLine is part of a preprocessor directive.
     99   bool InPPDirective;
    100 
    101   bool MustBeDeclaration;
    102 };
    103 
    104 class UnwrappedLineConsumer {
    105 public:
    106   virtual ~UnwrappedLineConsumer() {
    107   }
    108   virtual void consumeUnwrappedLine(const UnwrappedLine &Line) = 0;
    109 };
    110 
    111 class FormatTokenSource {
    112 public:
    113   virtual ~FormatTokenSource() {
    114   }
    115   virtual FormatToken getNextToken() = 0;
    116 };
    117 
    118 class UnwrappedLineParser {
    119 public:
    120   UnwrappedLineParser(clang::DiagnosticsEngine &Diag, const FormatStyle &Style,
    121                       FormatTokenSource &Tokens,
    122                       UnwrappedLineConsumer &Callback);
    123 
    124   /// Returns true in case of a structural error.
    125   bool parse();
    126 
    127 private:
    128   bool parseFile();
    129   bool parseLevel(bool HasOpeningBrace);
    130   bool parseBlock(bool MustBeDeclaration, unsigned AddLevels = 1);
    131   void parsePPDirective();
    132   void parsePPDefine();
    133   void parsePPUnknown();
    134   void parseStructuralElement();
    135   void parseBracedList();
    136   void parseReturn();
    137   void parseParens();
    138   void parseIfThenElse();
    139   void parseForOrWhileLoop();
    140   void parseDoWhile();
    141   void parseLabel();
    142   void parseCaseLabel();
    143   void parseSwitch();
    144   void parseNamespace();
    145   void parseAccessSpecifier();
    146   void parseEnum();
    147   void parseRecord();
    148   void parseObjCProtocolList();
    149   void parseObjCUntilAtEnd();
    150   void parseObjCInterfaceOrImplementation();
    151   void parseObjCProtocol();
    152   void addUnwrappedLine();
    153   bool eof() const;
    154   void nextToken();
    155   void readToken();
    156   void flushComments(bool NewlineBeforeNext);
    157   void pushToken(const FormatToken &Tok);
    158 
    159   // FIXME: We are constantly running into bugs where Line.Level is incorrectly
    160   // subtracted from beyond 0. Introduce a method to subtract from Line.Level
    161   // and use that everywhere in the Parser.
    162   OwningPtr<UnwrappedLine> Line;
    163 
    164   // Comments are sorted into unwrapped lines by whether they are in the same
    165   // line as the previous token, or not. If not, they belong to the next token.
    166   // Since the next token might already be in a new unwrapped line, we need to
    167   // store the comments belonging to that token.
    168   SmallVector<FormatToken, 1> CommentsBeforeNextToken;
    169   FormatToken FormatTok;
    170   bool MustBreakBeforeNextToken;
    171 
    172   // The parsed lines. Only added to through \c CurrentLines.
    173   std::vector<UnwrappedLine> Lines;
    174 
    175   // Preprocessor directives are parsed out-of-order from other unwrapped lines.
    176   // Thus, we need to keep a list of preprocessor directives to be reported
    177   // after an unwarpped line that has been started was finished.
    178   std::vector<UnwrappedLine> PreprocessorDirectives;
    179 
    180   // New unwrapped lines are added via CurrentLines.
    181   // Usually points to \c &Lines. While parsing a preprocessor directive when
    182   // there is an unfinished previous unwrapped line, will point to
    183   // \c &PreprocessorDirectives.
    184   std::vector<UnwrappedLine> *CurrentLines;
    185 
    186   // We store for each line whether it must be a declaration depending on
    187   // whether we are in a compound statement or not.
    188   std::vector<bool> DeclarationScopeStack;
    189 
    190   clang::DiagnosticsEngine &Diag;
    191   const FormatStyle &Style;
    192   FormatTokenSource *Tokens;
    193   UnwrappedLineConsumer &Callback;
    194 
    195   friend class ScopedLineState;
    196 };
    197 
    198 } // end namespace format
    199 } // end namespace clang
    200 
    201 #endif // LLVM_CLANG_FORMAT_UNWRAPPED_LINE_PARSER_H
    202