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      1 //===--- FormatToken.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 FormatToken, a wrapper
     12 /// around Token with additional information related to formatting.
     13 ///
     14 //===----------------------------------------------------------------------===//
     15 
     16 #ifndef LLVM_CLANG_FORMAT_FORMAT_TOKEN_H
     17 #define LLVM_CLANG_FORMAT_FORMAT_TOKEN_H
     18 
     19 #include "clang/Basic/OperatorPrecedence.h"
     20 #include "clang/Lex/Lexer.h"
     21 
     22 namespace clang {
     23 namespace format {
     24 
     25 enum TokenType {
     26   TT_BinaryOperator,
     27   TT_BlockComment,
     28   TT_CastRParen,
     29   TT_ConditionalExpr,
     30   TT_CtorInitializerColon,
     31   TT_CtorInitializerComma,
     32   TT_DesignatedInitializerPeriod,
     33   TT_ImplicitStringLiteral,
     34   TT_InlineASMColon,
     35   TT_InheritanceColon,
     36   TT_FunctionTypeLParen,
     37   TT_LineComment,
     38   TT_ObjCArrayLiteral,
     39   TT_ObjCBlockLParen,
     40   TT_ObjCDecl,
     41   TT_ObjCDictLiteral,
     42   TT_ObjCForIn,
     43   TT_ObjCMethodExpr,
     44   TT_ObjCMethodSpecifier,
     45   TT_ObjCProperty,
     46   TT_ObjCSelectorName,
     47   TT_OverloadedOperator,
     48   TT_OverloadedOperatorLParen,
     49   TT_PointerOrReference,
     50   TT_PureVirtualSpecifier,
     51   TT_RangeBasedForLoopColon,
     52   TT_StartOfName,
     53   TT_TemplateCloser,
     54   TT_TemplateOpener,
     55   TT_TrailingReturnArrow,
     56   TT_TrailingUnaryOperator,
     57   TT_UnaryOperator,
     58   TT_Unknown
     59 };
     60 
     61 // Represents what type of block a set of braces open.
     62 enum BraceBlockKind {
     63   BK_Unknown,
     64   BK_Block,
     65   BK_BracedInit
     66 };
     67 
     68 // The packing kind of a function's parameters.
     69 enum ParameterPackingKind {
     70   PPK_BinPacked,
     71   PPK_OnePerLine,
     72   PPK_Inconclusive
     73 };
     74 
     75 /// \brief A wrapper around a \c Token storing information about the
     76 /// whitespace characters preceeding it.
     77 struct FormatToken {
     78   FormatToken()
     79       : NewlinesBefore(0), HasUnescapedNewline(false), LastNewlineOffset(0),
     80         CodePointCount(0), IsFirst(false), MustBreakBefore(false),
     81         IsUnterminatedLiteral(false), BlockKind(BK_Unknown), Type(TT_Unknown),
     82         SpacesRequiredBefore(0), CanBreakBefore(false),
     83         ClosesTemplateDeclaration(false), ParameterCount(0),
     84         PackingKind(PPK_Inconclusive), TotalLength(0), UnbreakableTailLength(0),
     85         BindingStrength(0), SplitPenalty(0), LongestObjCSelectorName(0),
     86         FakeRParens(0), LastInChainOfCalls(false),
     87         PartOfMultiVariableDeclStmt(false), MatchingParen(NULL), Previous(NULL),
     88         Next(NULL) {}
     89 
     90   /// \brief The \c Token.
     91   Token Tok;
     92 
     93   /// \brief The number of newlines immediately before the \c Token.
     94   ///
     95   /// This can be used to determine what the user wrote in the original code
     96   /// and thereby e.g. leave an empty line between two function definitions.
     97   unsigned NewlinesBefore;
     98 
     99   /// \brief Whether there is at least one unescaped newline before the \c
    100   /// Token.
    101   bool HasUnescapedNewline;
    102 
    103   /// \brief The range of the whitespace immediately preceeding the \c Token.
    104   SourceRange WhitespaceRange;
    105 
    106   /// \brief The offset just past the last '\n' in this token's leading
    107   /// whitespace (relative to \c WhiteSpaceStart). 0 if there is no '\n'.
    108   unsigned LastNewlineOffset;
    109 
    110   /// \brief The length of the non-whitespace parts of the token in CodePoints.
    111   /// We need this to correctly measure number of columns a token spans.
    112   unsigned CodePointCount;
    113 
    114   /// \brief Indicates that this is the first token.
    115   bool IsFirst;
    116 
    117   /// \brief Whether there must be a line break before this token.
    118   ///
    119   /// This happens for example when a preprocessor directive ended directly
    120   /// before the token.
    121   bool MustBreakBefore;
    122 
    123   /// \brief Returns actual token start location without leading escaped
    124   /// newlines and whitespace.
    125   ///
    126   /// This can be different to Tok.getLocation(), which includes leading escaped
    127   /// newlines.
    128   SourceLocation getStartOfNonWhitespace() const {
    129     return WhitespaceRange.getEnd();
    130   }
    131 
    132   /// \brief The raw text of the token.
    133   ///
    134   /// Contains the raw token text without leading whitespace and without leading
    135   /// escaped newlines.
    136   StringRef TokenText;
    137 
    138   /// \brief Set to \c true if this token is an unterminated literal.
    139   bool IsUnterminatedLiteral;
    140 
    141   /// \brief Contains the kind of block if this token is a brace.
    142   BraceBlockKind BlockKind;
    143 
    144   TokenType Type;
    145 
    146   unsigned SpacesRequiredBefore;
    147   bool CanBreakBefore;
    148 
    149   bool ClosesTemplateDeclaration;
    150 
    151   /// \brief Number of parameters, if this is "(", "[" or "<".
    152   ///
    153   /// This is initialized to 1 as we don't need to distinguish functions with
    154   /// 0 parameters from functions with 1 parameter. Thus, we can simply count
    155   /// the number of commas.
    156   unsigned ParameterCount;
    157 
    158   /// \brief If this is an opening parenthesis, how are the parameters packed?
    159   ParameterPackingKind PackingKind;
    160 
    161   /// \brief The total length of the line up to and including this token.
    162   unsigned TotalLength;
    163 
    164   /// \brief The length of following tokens until the next natural split point,
    165   /// or the next token that can be broken.
    166   unsigned UnbreakableTailLength;
    167 
    168   // FIXME: Come up with a 'cleaner' concept.
    169   /// \brief The binding strength of a token. This is a combined value of
    170   /// operator precedence, parenthesis nesting, etc.
    171   unsigned BindingStrength;
    172 
    173   /// \brief Penalty for inserting a line break before this token.
    174   unsigned SplitPenalty;
    175 
    176   /// \brief If this is the first ObjC selector name in an ObjC method
    177   /// definition or call, this contains the length of the longest name.
    178   unsigned LongestObjCSelectorName;
    179 
    180   /// \brief Stores the number of required fake parentheses and the
    181   /// corresponding operator precedence.
    182   ///
    183   /// If multiple fake parentheses start at a token, this vector stores them in
    184   /// reverse order, i.e. inner fake parenthesis first.
    185   SmallVector<prec::Level, 4> FakeLParens;
    186   /// \brief Insert this many fake ) after this token for correct indentation.
    187   unsigned FakeRParens;
    188 
    189   /// \brief Is this the last "." or "->" in a builder-type call?
    190   bool LastInChainOfCalls;
    191 
    192   /// \brief Is this token part of a \c DeclStmt defining multiple variables?
    193   ///
    194   /// Only set if \c Type == \c TT_StartOfName.
    195   bool PartOfMultiVariableDeclStmt;
    196 
    197   bool is(tok::TokenKind Kind) const { return Tok.is(Kind); }
    198 
    199   bool isOneOf(tok::TokenKind K1, tok::TokenKind K2) const {
    200     return is(K1) || is(K2);
    201   }
    202 
    203   bool isOneOf(tok::TokenKind K1, tok::TokenKind K2, tok::TokenKind K3) const {
    204     return is(K1) || is(K2) || is(K3);
    205   }
    206 
    207   bool isOneOf(tok::TokenKind K1, tok::TokenKind K2, tok::TokenKind K3,
    208                tok::TokenKind K4, tok::TokenKind K5 = tok::NUM_TOKENS,
    209                tok::TokenKind K6 = tok::NUM_TOKENS,
    210                tok::TokenKind K7 = tok::NUM_TOKENS,
    211                tok::TokenKind K8 = tok::NUM_TOKENS,
    212                tok::TokenKind K9 = tok::NUM_TOKENS,
    213                tok::TokenKind K10 = tok::NUM_TOKENS,
    214                tok::TokenKind K11 = tok::NUM_TOKENS,
    215                tok::TokenKind K12 = tok::NUM_TOKENS) const {
    216     return is(K1) || is(K2) || is(K3) || is(K4) || is(K5) || is(K6) || is(K7) ||
    217            is(K8) || is(K9) || is(K10) || is(K11) || is(K12);
    218   }
    219 
    220   bool isNot(tok::TokenKind Kind) const { return Tok.isNot(Kind); }
    221 
    222   bool isObjCAtKeyword(tok::ObjCKeywordKind Kind) const {
    223     return Tok.isObjCAtKeyword(Kind);
    224   }
    225 
    226   bool isAccessSpecifier(bool ColonRequired = true) const {
    227     return isOneOf(tok::kw_public, tok::kw_protected, tok::kw_private) &&
    228            (!ColonRequired || (Next && Next->is(tok::colon)));
    229   }
    230 
    231   bool isObjCAccessSpecifier() const {
    232     return is(tok::at) && Next && (Next->isObjCAtKeyword(tok::objc_public) ||
    233                                    Next->isObjCAtKeyword(tok::objc_protected) ||
    234                                    Next->isObjCAtKeyword(tok::objc_package) ||
    235                                    Next->isObjCAtKeyword(tok::objc_private));
    236   }
    237 
    238   /// \brief Returns whether \p Tok is ([{ or a template opening <.
    239   bool opensScope() const {
    240     return isOneOf(tok::l_paren, tok::l_brace, tok::l_square) ||
    241            Type == TT_TemplateOpener;
    242   }
    243   /// \brief Returns whether \p Tok is )]} or a template closing >.
    244   bool closesScope() const {
    245     return isOneOf(tok::r_paren, tok::r_brace, tok::r_square) ||
    246            Type == TT_TemplateCloser;
    247   }
    248 
    249   bool isUnaryOperator() const {
    250     switch (Tok.getKind()) {
    251     case tok::plus:
    252     case tok::plusplus:
    253     case tok::minus:
    254     case tok::minusminus:
    255     case tok::exclaim:
    256     case tok::tilde:
    257     case tok::kw_sizeof:
    258     case tok::kw_alignof:
    259       return true;
    260     default:
    261       return false;
    262     }
    263   }
    264   bool isBinaryOperator() const {
    265     // Comma is a binary operator, but does not behave as such wrt. formatting.
    266     return getPrecedence() > prec::Comma;
    267   }
    268   bool isTrailingComment() const {
    269     return is(tok::comment) && (!Next || Next->NewlinesBefore > 0);
    270   }
    271 
    272   prec::Level getPrecedence() const {
    273     return getBinOpPrecedence(Tok.getKind(), true, true);
    274   }
    275 
    276   /// \brief Returns the previous token ignoring comments.
    277   FormatToken *getPreviousNonComment() const {
    278     FormatToken *Tok = Previous;
    279     while (Tok != NULL && Tok->is(tok::comment))
    280       Tok = Tok->Previous;
    281     return Tok;
    282   }
    283 
    284   /// \brief Returns the next token ignoring comments.
    285   const FormatToken *getNextNonComment() const {
    286     const FormatToken *Tok = Next;
    287     while (Tok != NULL && Tok->is(tok::comment))
    288       Tok = Tok->Next;
    289     return Tok;
    290   }
    291 
    292   FormatToken *MatchingParen;
    293 
    294   FormatToken *Previous;
    295   FormatToken *Next;
    296 
    297 private:
    298   // Disallow copying.
    299   FormatToken(const FormatToken &) LLVM_DELETED_FUNCTION;
    300   void operator=(const FormatToken &) LLVM_DELETED_FUNCTION;
    301 };
    302 
    303 } // namespace format
    304 } // namespace clang
    305 
    306 #endif // LLVM_CLANG_FORMAT_FORMAT_TOKEN_H
    307