WhitespaceManager.h revision e573c3f7fc40e813559ab4ff1e7eec4f66f1a50f 
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_FORMAT_WHITESPACEMANAGER_H
17#define LLVM_CLANG_FORMAT_WHITESPACEMANAGER_H
18
19#include "TokenAnnotator.h"
20#include "clang/Basic/SourceManager.h"
21#include "clang/Format/Format.h"
22#include <string>
23
24namespace clang {
25namespace 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.
38class WhitespaceManager {
39public:
40  WhitespaceManager(SourceManager &SourceMgr, const FormatStyle &Style)
41      : SourceMgr(SourceMgr), Style(Style) {}
42
43  /// \brief Replaces the whitespace in front of \p Tok. Only call once for
44  /// each \c AnnotatedToken.
45  void replaceWhitespace(const AnnotatedToken &Tok, unsigned Newlines,
46                         unsigned Spaces, unsigned StartOfTokenColumn,
47                         bool InPPDirective = false);
48
49  /// \brief Adds information about an unchangable token's whitespace.
50  ///
51  /// Needs to be called for every token for which \c replaceWhitespace
52  /// was not called.
53  void addUntouchableToken(const FormatToken &Tok, bool InPPDirective);
54
55  /// \brief Inserts a line break into the middle of a token.
56  ///
57  /// Will break at \p Offset inside \p Tok, putting \p PreviousPostfix before
58  /// the line break and \p CurrentPrefix before the rest of the token starts in
59  /// the next line.
60  ///
61  /// \p InPPDirective and \p Spaces are used to generate the correct line
62  /// break.
63  void breakToken(const FormatToken &Tok, unsigned Offset,
64                  unsigned ReplaceChars, StringRef PreviousPostfix,
65                  StringRef CurrentPrefix, bool InPPDirective, unsigned Spaces);
66
67  /// \brief Returns all the \c Replacements created during formatting.
68  const tooling::Replacements &generateReplacements();
69
70  /// \brief Replaces \p ReplaceChars after \p SourceLoc with \p Text.
71  ///
72  /// FIXME: This is currently used to align comments outside of the \c
73  /// WhitespaceManager. Once this has been moved inside, get rid of this
74  /// method.
75  void addReplacement(const SourceLocation &SourceLoc, unsigned ReplaceChars,
76                      StringRef Text);
77
78private:
79  /// \brief Represents a change before a token, a break inside a token,
80  /// or the layout of an unchanged token (or whitespace within).
81  struct Change {
82    /// \brief Functor to sort changes in original source order.
83    class IsBeforeInFile {
84     public:
85      IsBeforeInFile(const SourceManager &SourceMgr) : SourceMgr(SourceMgr) {}
86      bool operator()(const Change &C1, const Change &C2) const;
87
88     private:
89      const SourceManager &SourceMgr;
90    };
91
92    Change() {}
93
94    /// \brief Creates a \c Change.
95    ///
96    /// The generated \c Change will replace the characters at
97    /// \p OriginalWhitespaceRange with a concatenation of
98    /// \p PreviousLinePostfix, \p NewlinesBefore line breaks, \p Spaces spaces
99    /// and \p CurrentLinePrefix.
100    ///
101    /// \p StartOfTokenColumn and \p InPPDirective will be used to lay out
102    /// trailing comments and escaped newlines.
103    Change(bool CreateReplacement, const SourceRange &OriginalWhitespaceRange,
104           unsigned Spaces, unsigned StartOfTokenColumn,
105           unsigned NewlinesBefore, StringRef PreviousLinePostfix,
106           StringRef CurrentLinePrefix, tok::TokenKind Kind,
107           bool ContinuesPPDirective);
108
109    bool CreateReplacement;
110    // Changes might be in the middle of a token, so we cannot just keep the
111    // FormatToken around to query its information.
112    SourceRange OriginalWhitespaceRange;
113    unsigned StartOfTokenColumn;
114    unsigned NewlinesBefore;
115    std::string PreviousLinePostfix;
116    std::string CurrentLinePrefix;
117    // The kind of the token whose whitespace this change replaces, or in which
118    // this change inserts whitespace.
119    // FIXME: Currently this is not set correctly for breaks inside comments, as
120    // the \c BreakableToken is still doing its own alignment.
121    tok::TokenKind Kind;
122    bool ContinuesPPDirective;
123
124    // The number of spaces in front of the token or broken part of the token.
125    // This will be adapted when aligning tokens.
126    unsigned Spaces;
127
128    // \c IsTrailingComment, \c TokenLength, \c PreviousEndOfTokenColumn and
129    // \c EscapedNewlineColumn will be calculated in
130    // \c calculateLineBreakInformation.
131    bool IsTrailingComment;
132    unsigned TokenLength;
133    unsigned PreviousEndOfTokenColumn;
134    unsigned EscapedNewlineColumn;
135
136  };
137
138  /// \brief Calculate \c IsTrailingComment, \c TokenLength for the last tokens
139  /// or token parts in a line and \c PreviousEndOfTokenColumn and
140  /// \c EscapedNewlineColumn for the first tokens or token parts in a line.
141  void calculateLineBreakInformation();
142
143  /// \brief Align trailing comments over all \c Changes.
144  void alignTrailingComments();
145
146  /// \brief Align trailing comments from change \p Start to change \p End at
147  /// the specified \p Column.
148  void alignTrailingComments(unsigned Start, unsigned End, unsigned Column);
149
150  /// \brief Align escaped newlines over all \c Changes.
151  void alignEscapedNewlines();
152
153  /// \brief Align escaped newlines from change \p Start to change \p End at
154  /// the specified \p Column.
155  void alignEscapedNewlines(unsigned Start, unsigned End, unsigned Column);
156
157  /// \brief Fill \c Replaces with the replacements for all effective changes.
158  void generateChanges();
159
160  /// \brief Stores \p Text as the replacement for the whitespace in \p Range.
161  void storeReplacement(const SourceRange &Range, StringRef Text);
162  std::string getNewLineText(unsigned NewLines, unsigned Spaces);
163  std::string getNewLineText(unsigned NewLines, unsigned Spaces,
164                             unsigned PreviousEndOfTokenColumn,
165                             unsigned EscapedNewlineColumn);
166  std::string getIndentText(unsigned Spaces);
167
168  SmallVector<Change, 16> Changes;
169  SourceManager &SourceMgr;
170  tooling::Replacements Replaces;
171  const FormatStyle &Style;
172};
173
174} // namespace format
175} // namespace clang
176
177#endif // LLVM_CLANG_FORMAT_WHITESPACEMANAGER_H
178