1 //===--- WhitespaceManager.h - Format C++ code ------------------*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
10 /// WhitespaceManager class manages whitespace around tokens and their
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_LIB_FORMAT_WHITESPACEMANAGER_H
16 #define LLVM_CLANG_LIB_FORMAT_WHITESPACEMANAGER_H
18 #include "TokenAnnotator.h"
19 #include "clang/Basic/SourceManager.h"
20 #include "clang/Format/Format.h"
26 /// Manages the whitespaces around tokens and their replacements.
28 /// This includes special handling for certain constructs, e.g. the alignment of
29 /// trailing line comments.
31 /// To guarantee correctness of alignment operations, the \c WhitespaceManager
32 /// must be informed about every token in the source file; for each token, there
33 /// must be exactly one call to either \c replaceWhitespace or
34 /// \c addUntouchableToken.
36 /// There may be multiple calls to \c breakToken for a given token.
37 class WhitespaceManager {
39 WhitespaceManager(const SourceManager &SourceMgr, const FormatStyle &Style,
41 : SourceMgr(SourceMgr), Style(Style), UseCRLF(UseCRLF) {}
43 bool useCRLF() const { return UseCRLF; }
45 /// Replaces the whitespace in front of \p Tok. Only call once for
46 /// each \c AnnotatedToken.
48 /// \p StartOfTokenColumn is the column at which the token will start after
49 /// this replacement. It is needed for determining how \p Spaces is turned
50 /// into tabs and spaces for some format styles.
51 void replaceWhitespace(FormatToken &Tok, unsigned Newlines, unsigned Spaces,
52 unsigned StartOfTokenColumn,
53 bool InPPDirective = false);
55 /// Adds information about an unchangeable token's whitespace.
57 /// Needs to be called for every token for which \c replaceWhitespace
59 void addUntouchableToken(const FormatToken &Tok, bool InPPDirective);
61 llvm::Error addReplacement(const tooling::Replacement &Replacement);
63 /// Inserts or replaces whitespace in the middle of a token.
65 /// Inserts \p PreviousPostfix, \p Newlines, \p Spaces and \p CurrentPrefix
66 /// (in this order) at \p Offset inside \p Tok, replacing \p ReplaceChars
69 /// Note: \p Spaces can be negative to retain information about initial
70 /// relative column offset between a line of a block comment and the start of
71 /// the comment. This negative offset may be compensated by trailing comment
72 /// alignment here. In all other cases negative \p Spaces will be truncated to
75 /// When \p InPPDirective is true, escaped newlines are inserted. \p Spaces is
76 /// used to align backslashes correctly.
77 void replaceWhitespaceInToken(const FormatToken &Tok, unsigned Offset,
78 unsigned ReplaceChars,
79 StringRef PreviousPostfix,
80 StringRef CurrentPrefix, bool InPPDirective,
81 unsigned Newlines, int Spaces);
83 /// Returns all the \c Replacements created during formatting.
84 const tooling::Replacements &generateReplacements();
86 /// Represents a change before a token, a break inside a token,
87 /// or the layout of an unchanged token (or whitespace within).
89 /// Functor to sort changes in original source order.
90 class IsBeforeInFile {
92 IsBeforeInFile(const SourceManager &SourceMgr) : SourceMgr(SourceMgr) {}
93 bool operator()(const Change &C1, const Change &C2) const;
96 const SourceManager &SourceMgr;
99 /// 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(const FormatToken &Tok, bool CreateReplacement,
109 SourceRange OriginalWhitespaceRange, int Spaces,
110 unsigned StartOfTokenColumn, unsigned NewlinesBefore,
111 StringRef PreviousLinePostfix, StringRef CurrentLinePrefix,
112 bool ContinuesPPDirective, bool IsInsideToken);
114 // The kind of the token whose whitespace this change replaces, or in which
115 // this change inserts whitespace.
116 // FIXME: Currently this is not set correctly for breaks inside comments, as
117 // the \c BreakableToken is still doing its own alignment.
118 const FormatToken *Tok;
120 bool CreateReplacement;
121 // Changes might be in the middle of a token, so we cannot just keep the
122 // FormatToken around to query its information.
123 SourceRange OriginalWhitespaceRange;
124 unsigned StartOfTokenColumn;
125 unsigned NewlinesBefore;
126 std::string PreviousLinePostfix;
127 std::string CurrentLinePrefix;
128 bool ContinuesPPDirective;
130 // The number of spaces in front of the token or broken part of the token.
131 // This will be adapted when aligning tokens.
132 // Can be negative to retain information about the initial relative offset
133 // of the lines in a block comment. This is used when aligning trailing
134 // comments. Uncompensated negative offset is truncated to 0.
137 // If this change is inside of a token but not at the start of the token or
138 // directly after a newline.
141 // \c IsTrailingComment, \c TokenLength, \c PreviousEndOfTokenColumn and
142 // \c EscapedNewlineColumn will be calculated in
143 // \c calculateLineBreakInformation.
144 bool IsTrailingComment;
145 unsigned TokenLength;
146 unsigned PreviousEndOfTokenColumn;
147 unsigned EscapedNewlineColumn;
149 // These fields are used to retain correct relative line indentation in a
150 // block comment when aligning trailing comments.
152 // If this Change represents a continuation of a block comment,
153 // \c StartOfBlockComment is pointer to the first Change in the block
154 // comment. \c IndentationOffset is a relative column offset to this
155 // change, so that the correct column can be reconstructed at the end of
156 // the alignment process.
157 const Change *StartOfBlockComment;
158 int IndentationOffset;
160 // A combination of indent level and nesting level, which are used in
161 // tandem to compute lexical scope, for the purposes of deciding
162 // when to stop consecutive alignment runs.
163 std::pair<unsigned, unsigned> indentAndNestingLevel() const {
164 return std::make_pair(Tok->IndentLevel, Tok->NestingLevel);
169 /// Calculate \c IsTrailingComment, \c TokenLength for the last tokens
170 /// or token parts in a line and \c PreviousEndOfTokenColumn and
171 /// \c EscapedNewlineColumn for the first tokens or token parts in a line.
172 void calculateLineBreakInformation();
174 /// \brief Align consecutive C/C++ preprocessor macros over all \c Changes.
175 void alignConsecutiveMacros();
177 /// Align consecutive assignments over all \c Changes.
178 void alignConsecutiveAssignments();
180 /// Align consecutive declarations over all \c Changes.
181 void alignConsecutiveDeclarations();
183 /// Align trailing comments over all \c Changes.
184 void alignTrailingComments();
186 /// Align trailing comments from change \p Start to change \p End at
187 /// the specified \p Column.
188 void alignTrailingComments(unsigned Start, unsigned End, unsigned Column);
190 /// Align escaped newlines over all \c Changes.
191 void alignEscapedNewlines();
193 /// Align escaped newlines from change \p Start to change \p End at
194 /// the specified \p Column.
195 void alignEscapedNewlines(unsigned Start, unsigned End, unsigned Column);
197 /// Fill \c Replaces with the replacements for all effective changes.
198 void generateChanges();
200 /// Stores \p Text as the replacement for the whitespace in \p Range.
201 void storeReplacement(SourceRange Range, StringRef Text);
202 void appendNewlineText(std::string &Text, unsigned Newlines);
203 void appendEscapedNewlineText(std::string &Text, unsigned Newlines,
204 unsigned PreviousEndOfTokenColumn,
205 unsigned EscapedNewlineColumn);
206 void appendIndentText(std::string &Text, unsigned IndentLevel,
207 unsigned Spaces, unsigned WhitespaceStartColumn);
209 SmallVector<Change, 16> Changes;
210 const SourceManager &SourceMgr;
211 tooling::Replacements Replaces;
212 const FormatStyle &Style;
216 } // namespace format