1 //===--- WhitespaceManager.h - Format C++ code ------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// \brief WhitespaceManager class manages whitespace around tokens and their
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_CLANG_LIB_FORMAT_WHITESPACEMANAGER_H
17 #define LLVM_CLANG_LIB_FORMAT_WHITESPACEMANAGER_H
19 #include "TokenAnnotator.h"
20 #include "clang/Basic/SourceManager.h"
21 #include "clang/Format/Format.h"
27 /// \brief Manages the whitespaces around tokens and their replacements.
29 /// This includes special handling for certain constructs, e.g. the alignment of
30 /// trailing line comments.
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.
37 /// There may be multiple calls to \c breakToken for a given token.
38 class WhitespaceManager {
40 WhitespaceManager(SourceManager &SourceMgr, const FormatStyle &Style,
42 : SourceMgr(SourceMgr), Style(Style), UseCRLF(UseCRLF) {}
44 /// \brief Prepares the \c WhitespaceManager for another run.
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);
54 /// \brief Adds information about an unchangeable token's whitespace.
56 /// Needs to be called for every token for which \c replaceWhitespace
58 void addUntouchableToken(const FormatToken &Tok, bool InPPDirective);
60 /// \brief Inserts or replaces whitespace in the middle of a token.
62 /// Inserts \p PreviousPostfix, \p Newlines, \p Spaces and \p CurrentPrefix
63 /// (in this order) at \p Offset inside \p Tok, replacing \p ReplaceChars
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
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,
81 /// \brief Returns all the \c Replacements created during formatting.
82 const tooling::Replacements &generateReplacements();
84 /// \brief Represents a change before a token, a break inside a token,
85 /// or the layout of an unchanged token (or whitespace within).
87 /// \brief Functor to sort changes in original source order.
88 class IsBeforeInFile {
90 IsBeforeInFile(const SourceManager &SourceMgr) : SourceMgr(SourceMgr) {}
91 bool operator()(const Change &C1, const Change &C2) const;
94 const SourceManager &SourceMgr;
99 /// \brief Creates a \c Change.
101 /// The generated \c Change will replace the characters at
102 /// \p OriginalWhitespaceRange with a concatenation of
103 /// \p PreviousLinePostfix, \p NewlinesBefore line breaks, \p Spaces spaces
104 /// and \p CurrentLinePrefix.
106 /// \p StartOfTokenColumn and \p InPPDirective will be used to lay out
107 /// trailing comments and escaped newlines.
108 Change(bool CreateReplacement, SourceRange OriginalWhitespaceRange,
109 unsigned IndentLevel, int Spaces, unsigned StartOfTokenColumn,
110 unsigned NewlinesBefore, StringRef PreviousLinePostfix,
111 StringRef CurrentLinePrefix, tok::TokenKind Kind,
112 bool ContinuesPPDirective, bool IsStartOfDeclName);
114 bool CreateReplacement;
115 // Changes might be in the middle of a token, so we cannot just keep the
116 // FormatToken around to query its information.
117 SourceRange OriginalWhitespaceRange;
118 unsigned StartOfTokenColumn;
119 unsigned NewlinesBefore;
120 std::string PreviousLinePostfix;
121 std::string CurrentLinePrefix;
122 // The kind of the token whose whitespace this change replaces, or in which
123 // this change inserts whitespace.
124 // FIXME: Currently this is not set correctly for breaks inside comments, as
125 // the \c BreakableToken is still doing its own alignment.
127 bool ContinuesPPDirective;
128 bool IsStartOfDeclName;
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;
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.
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;
150 // These fields are used to retain correct relative line indentation in a
151 // block comment when aligning trailing comments.
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;
163 /// \brief Calculate \c IsTrailingComment, \c TokenLength for the last tokens
164 /// or token parts in a line and \c PreviousEndOfTokenColumn and
165 /// \c EscapedNewlineColumn for the first tokens or token parts in a line.
166 void calculateLineBreakInformation();
168 /// \brief Align consecutive assignments over all \c Changes.
169 void alignConsecutiveAssignments();
171 /// \brief Align consecutive declarations over all \c Changes.
172 void alignConsecutiveDeclarations();
174 /// \brief Align trailing comments over all \c Changes.
175 void alignTrailingComments();
177 /// \brief Align trailing comments from change \p Start to change \p End at
178 /// the specified \p Column.
179 void alignTrailingComments(unsigned Start, unsigned End, unsigned Column);
181 /// \brief Align escaped newlines over all \c Changes.
182 void alignEscapedNewlines();
184 /// \brief Align escaped newlines from change \p Start to change \p End at
185 /// the specified \p Column.
186 void alignEscapedNewlines(unsigned Start, unsigned End, unsigned Column);
188 /// \brief Fill \c Replaces with the replacements for all effective changes.
189 void generateChanges();
191 /// \brief Stores \p Text as the replacement for the whitespace in \p Range.
192 void storeReplacement(SourceRange Range, StringRef Text);
193 void appendNewlineText(std::string &Text, unsigned Newlines);
194 void appendNewlineText(std::string &Text, unsigned Newlines,
195 unsigned PreviousEndOfTokenColumn,
196 unsigned EscapedNewlineColumn);
197 void appendIndentText(std::string &Text, unsigned IndentLevel,
198 unsigned Spaces, unsigned WhitespaceStartColumn);
200 SmallVector<Change, 16> Changes;
201 SourceManager &SourceMgr;
202 tooling::Replacements Replaces;
203 const FormatStyle &Style;
207 } // namespace format