external/bsd/llvm/dist/clang/lib/Format/WhitespaceManager.h

   1 //===--- WhitespaceManager.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 WhitespaceManager class manages whitespace around tokens and their
  12 /// replacements.
  13 ///
  14 //===----------------------------------------------------------------------===//
  15
  16 #ifndef LLVM_CLANG_LIB_FORMAT_WHITESPACEMANAGER_H
  17 #define LLVM_CLANG_LIB_FORMAT_WHITESPACEMANAGER_H
  18
  19 #include "TokenAnnotator.h"
  20 #include "clang/Basic/SourceManager.h"
  21 #include "clang/Format/Format.h"
  22 #include <string>
  23
  24 namespace clang {
  25 namespace format {
  26
  27 /// \brief Manages the whitespaces around tokens and their replacements.
  28 ///
  29 /// This includes special handling for certain constructs, e.g. the alignment of
  30 /// trailing line comments.
  31 ///
  32 /// To guarantee correctness of alignment operations, the \c WhitespaceManager
  33 /// must be informed about every token in the source file; for each token, there
  34 /// must be exactly one call to either \c replaceWhitespace or
  35 /// \c addUntouchableToken.
  36 ///
  37 /// There may be multiple calls to \c breakToken for a given token.
  38 class WhitespaceManager {
  39 public:
  40   WhitespaceManager(SourceManager &SourceMgr, const FormatStyle &Style,
  41                     bool UseCRLF)
  42       : SourceMgr(SourceMgr), Style(Style), UseCRLF(UseCRLF) {}
  43
  44   /// \brief Prepares the \c WhitespaceManager for another run.
  45   void reset();
  46
  47   /// \brief Replaces the whitespace in front of \p Tok. Only call once for
  48   /// each \c AnnotatedToken.
  49   void replaceWhitespace(FormatToken &Tok, unsigned Newlines,
  50                          unsigned IndentLevel, unsigned Spaces,
  51                          unsigned StartOfTokenColumn,
  52                          bool InPPDirective = false);
  53
  54   /// \brief Adds information about an unchangeable token's whitespace.
  55   ///
  56   /// Needs to be called for every token for which \c replaceWhitespace
  57   /// was not called.
  58   void addUntouchableToken(const FormatToken &Tok, bool InPPDirective);
  59
  60   /// \brief Inserts or replaces whitespace in the middle of a token.
  61   ///
  62   /// Inserts \p PreviousPostfix, \p Newlines, \p Spaces and \p CurrentPrefix
  63   /// (in this order) at \p Offset inside \p Tok, replacing \p ReplaceChars
  64   /// characters.
  65   ///
  66   /// Note: \p Spaces can be negative to retain information about initial
  67   /// relative column offset between a line of a block comment and the start of
  68   /// the comment. This negative offset may be compensated by trailing comment
  69   /// alignment here. In all other cases negative \p Spaces will be truncated to
  70   /// 0.
  71   ///
  72   /// When \p InPPDirective is true, escaped newlines are inserted. \p Spaces is
  73   /// used to align backslashes correctly.
  74   void replaceWhitespaceInToken(const FormatToken &Tok, unsigned Offset,
  75                                 unsigned ReplaceChars,
  76                                 StringRef PreviousPostfix,
  77                                 StringRef CurrentPrefix, bool InPPDirective,
  78                                 unsigned Newlines, unsigned IndentLevel,
  79                                 int Spaces);
  80
  81   /// \brief Returns all the \c Replacements created during formatting.
  82   const tooling::Replacements &generateReplacements();
  83
  84 private:
  85   /// \brief Represents a change before a token, a break inside a token,
  86   /// or the layout of an unchanged token (or whitespace within).
  87   struct Change {
  88     /// \brief Functor to sort changes in original source order.
  89     class IsBeforeInFile {
  90     public:
  91       IsBeforeInFile(const SourceManager &SourceMgr) : SourceMgr(SourceMgr) {}
  92       bool operator()(const Change &C1, const Change &C2) const;
  93
  94     private:
  95       const SourceManager &SourceMgr;
  96     };
  97
  98     Change() {}
  99
 100     /// \brief Creates a \c Change.
 101     ///
 102     /// The generated \c Change will replace the characters at
 103     /// \p OriginalWhitespaceRange with a concatenation of
 104     /// \p PreviousLinePostfix, \p NewlinesBefore line breaks, \p Spaces spaces
 105     /// and \p CurrentLinePrefix.
 106     ///
 107     /// \p StartOfTokenColumn and \p InPPDirective will be used to lay out
 108     /// trailing comments and escaped newlines.
 109     Change(bool CreateReplacement, const SourceRange &OriginalWhitespaceRange,
 110            unsigned IndentLevel, int Spaces, unsigned StartOfTokenColumn,
 111            unsigned NewlinesBefore, StringRef PreviousLinePostfix,
 112            StringRef CurrentLinePrefix, tok::TokenKind Kind,
 113            bool ContinuesPPDirective);
 114
 115     bool CreateReplacement;
 116     // Changes might be in the middle of a token, so we cannot just keep the
 117     // FormatToken around to query its information.
 118     SourceRange OriginalWhitespaceRange;
 119     unsigned StartOfTokenColumn;
 120     unsigned NewlinesBefore;
 121     std::string PreviousLinePostfix;
 122     std::string CurrentLinePrefix;
 123     // The kind of the token whose whitespace this change replaces, or in which
 124     // this change inserts whitespace.
 125     // FIXME: Currently this is not set correctly for breaks inside comments, as
 126     // the \c BreakableToken is still doing its own alignment.
 127     tok::TokenKind Kind;
 128     bool ContinuesPPDirective;
 129
 130     // The number of nested blocks the token is in. This is used to add tabs
 131     // only for the indentation, and not for alignment, when
 132     // UseTab = US_ForIndentation.
 133     unsigned IndentLevel;
 134
 135     // The number of spaces in front of the token or broken part of the token.
 136     // This will be adapted when aligning tokens.
 137     // Can be negative to retain information about the initial relative offset
 138     // of the lines in a block comment. This is used when aligning trailing
 139     // comments. Uncompensated negative offset is truncated to 0.
 140     int Spaces;
 141
 142     // \c IsTrailingComment, \c TokenLength, \c PreviousEndOfTokenColumn and
 143     // \c EscapedNewlineColumn will be calculated in
 144     // \c calculateLineBreakInformation.
 145     bool IsTrailingComment;
 146     unsigned TokenLength;
 147     unsigned PreviousEndOfTokenColumn;
 148     unsigned EscapedNewlineColumn;
 149
 150     // These fields are used to retain correct relative line indentation in a
 151     // block comment when aligning trailing comments.
 152     //
 153     // If this Change represents a continuation of a block comment,
 154     // \c StartOfBlockComment is pointer to the first Change in the block
 155     // comment. \c IndentationOffset is a relative column offset to this
 156     // change, so that the correct column can be reconstructed at the end of
 157     // the alignment process.
 158     const Change *StartOfBlockComment;
 159     int IndentationOffset;
 160   };
 161
 162   /// \brief Calculate \c IsTrailingComment, \c TokenLength for the last tokens
 163   /// or token parts in a line and \c PreviousEndOfTokenColumn and
 164   /// \c EscapedNewlineColumn for the first tokens or token parts in a line.
 165   void calculateLineBreakInformation();
 166
 167   /// \brief Align trailing comments over all \c Changes.
 168   void alignTrailingComments();
 169
 170   /// \brief Align trailing comments from change \p Start to change \p End at
 171   /// the specified \p Column.
 172   void alignTrailingComments(unsigned Start, unsigned End, unsigned Column);
 173
 174   /// \brief Align escaped newlines over all \c Changes.
 175   void alignEscapedNewlines();
 176
 177   /// \brief Align escaped newlines from change \p Start to change \p End at
 178   /// the specified \p Column.
 179   void alignEscapedNewlines(unsigned Start, unsigned End, unsigned Column);
 180
 181   /// \brief Fill \c Replaces with the replacements for all effective changes.
 182   void generateChanges();
 183
 184   /// \brief Stores \p Text as the replacement for the whitespace in \p Range.
 185   void storeReplacement(const SourceRange &Range, StringRef Text);
 186   void appendNewlineText(std::string &Text, unsigned Newlines);
 187   void appendNewlineText(std::string &Text, unsigned Newlines,
 188                          unsigned PreviousEndOfTokenColumn,
 189                          unsigned EscapedNewlineColumn);
 190   void appendIndentText(std::string &Text, unsigned IndentLevel,
 191                         unsigned Spaces, unsigned WhitespaceStartColumn);
 192
 193   SmallVector<Change, 16> Changes;
 194   SourceManager &SourceMgr;
 195   tooling::Replacements Replaces;
 196   const FormatStyle &Style;
 197   bool UseCRLF;
 198 };
 199
 200 } // namespace format
 201 } // namespace clang
 202
 203 #endif