clang  3.7.0
WhitespaceManager.h
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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"
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.
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.
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.
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.
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 consecutive assignments over all \c Changes.
168  void alignConsecutiveAssignments();
169 
170  /// \brief Align consecutive assignments from change \p Start to change \p End
171  /// at
172  /// the specified \p Column.
173  void alignConsecutiveAssignments(unsigned Start, unsigned End,
174  unsigned Column);
175 
176  /// \brief Align trailing comments over all \c Changes.
177  void alignTrailingComments();
178 
179  /// \brief Align trailing comments from change \p Start to change \p End at
180  /// the specified \p Column.
181  void alignTrailingComments(unsigned Start, unsigned End, unsigned Column);
182 
183  /// \brief Align escaped newlines over all \c Changes.
184  void alignEscapedNewlines();
185 
186  /// \brief Align escaped newlines from change \p Start to change \p End at
187  /// the specified \p Column.
188  void alignEscapedNewlines(unsigned Start, unsigned End, unsigned Column);
189 
190  /// \brief Fill \c Replaces with the replacements for all effective changes.
191  void generateChanges();
192 
193  /// \brief Stores \p Text as the replacement for the whitespace in \p Range.
194  void storeReplacement(const SourceRange &Range, StringRef Text);
195  void appendNewlineText(std::string &Text, unsigned Newlines);
196  void appendNewlineText(std::string &Text, unsigned Newlines,
197  unsigned PreviousEndOfTokenColumn,
198  unsigned EscapedNewlineColumn);
199  void appendIndentText(std::string &Text, unsigned IndentLevel,
200  unsigned Spaces, unsigned WhitespaceStartColumn);
201 
202  SmallVector<Change, 16> Changes;
203  SourceManager &SourceMgr;
204  tooling::Replacements Replaces;
205  const FormatStyle &Style;
206  bool UseCRLF;
207 };
208 
209 } // namespace format
210 } // namespace clang
211 
212 #endif
Defines the SourceManager interface.
std::set< Replacement > Replacements
A set of Replacements. FIXME: Change to a vector and deduplicate in the RefactoringTool.
Definition: Replacement.h:141
bool operator()(const Change &C1, const Change &C2) const
This file implements a token annotator, i.e. creates AnnotatedTokens out of FormatTokens with require...
Manages the whitespaces around tokens and their replacements.
uint32_t Offset
Definition: CacheTokens.cpp:43
void replaceWhitespace(FormatToken &Tok, unsigned Newlines, unsigned IndentLevel, unsigned Spaces, unsigned StartOfTokenColumn, bool InPPDirective=false)
Replaces the whitespace in front of Tok. Only call once for each AnnotatedToken.
void reset()
Prepares the WhitespaceManager for another run.
const SmallVectorImpl< AnnotatedLine * >::const_iterator End
void replaceWhitespaceInToken(const FormatToken &Tok, unsigned Offset, unsigned ReplaceChars, StringRef PreviousPostfix, StringRef CurrentPrefix, bool InPPDirective, unsigned Newlines, unsigned IndentLevel, int Spaces)
Inserts or replaces whitespace in the middle of a token.
A wrapper around a Token storing information about the whitespace characters preceding it...
Definition: FormatToken.h:112
const tooling::Replacements & generateReplacements()
Returns all the Replacements created during formatting.
Kind
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:25
The FormatStyle is used to configure the formatting to follow specific guidelines.
Definition: Format.h:42
Functor to sort changes in original source order.
void addUntouchableToken(const FormatToken &Tok, bool InPPDirective)
Adds information about an unchangeable token's whitespace.
WhitespaceManager(SourceManager &SourceMgr, const FormatStyle &Style, bool UseCRLF)
A trivial tuple used to represent a source range.
This class handles loading and caching of source files into memory.
unsigned Column
Definition: Format.cpp:1202