1 //===--- BreakableToken.h - Format C++ code -------------------------------===// 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 Declares BreakableToken, BreakableStringLiteral, and 12 /// BreakableBlockComment classes, that contain token type-specific logic to 13 /// break long lines in tokens. 14 /// 15 //===----------------------------------------------------------------------===// 16 17 #ifndef LLVM_CLANG_FORMAT_BREAKABLETOKEN_H 18 #define LLVM_CLANG_FORMAT_BREAKABLETOKEN_H 19 20 #include "Encoding.h" 21 #include "TokenAnnotator.h" 22 #include "WhitespaceManager.h" 23 #include <utility> 24 25 namespace clang { 26 namespace format { 27 28 struct FormatStyle; 29 30 /// \brief Base class for strategies on how to break tokens. 31 /// 32 /// FIXME: The interface seems set in stone, so we might want to just pull the 33 /// strategy into the class, instead of controlling it from the outside. 34 class BreakableToken { 35 public: 36 /// \brief Contains starting character index and length of split. 37 typedef std::pair<StringRef::size_type, unsigned> Split; 38 ~BreakableToken()39 virtual ~BreakableToken() {} 40 41 /// \brief Returns the number of lines in this token in the original code. 42 virtual unsigned getLineCount() const = 0; 43 44 /// \brief Returns the number of columns required to format the piece of line 45 /// at \p LineIndex, from byte offset \p Offset with length \p Length. 46 /// 47 /// Note that previous breaks are not taken into account. \p Offset is always 48 /// specified from the start of the (original) line. 49 /// \p Length can be set to StringRef::npos, which means "to the end of line". 50 virtual unsigned 51 getLineLengthAfterSplit(unsigned LineIndex, unsigned Offset, 52 StringRef::size_type Length) const = 0; 53 54 /// \brief Returns a range (offset, length) at which to break the line at 55 /// \p LineIndex, if previously broken at \p TailOffset. If possible, do not 56 /// violate \p ColumnLimit. 57 virtual Split getSplit(unsigned LineIndex, unsigned TailOffset, 58 unsigned ColumnLimit) const = 0; 59 60 /// \brief Emits the previously retrieved \p Split via \p Whitespaces. 61 virtual void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split, 62 WhitespaceManager &Whitespaces) = 0; 63 64 /// \brief Replaces the whitespace range described by \p Split with a single 65 /// space. 66 virtual void replaceWhitespace(unsigned LineIndex, unsigned TailOffset, 67 Split Split, 68 WhitespaceManager &Whitespaces) = 0; 69 70 /// \brief Replaces the whitespace between \p LineIndex-1 and \p LineIndex. replaceWhitespaceBefore(unsigned LineIndex,WhitespaceManager & Whitespaces)71 virtual void replaceWhitespaceBefore(unsigned LineIndex, 72 WhitespaceManager &Whitespaces) {} 73 74 protected: BreakableToken(const FormatToken & Tok,unsigned IndentLevel,bool InPPDirective,encoding::Encoding Encoding,const FormatStyle & Style)75 BreakableToken(const FormatToken &Tok, unsigned IndentLevel, 76 bool InPPDirective, encoding::Encoding Encoding, 77 const FormatStyle &Style) 78 : Tok(Tok), IndentLevel(IndentLevel), InPPDirective(InPPDirective), 79 Encoding(Encoding), Style(Style) {} 80 81 const FormatToken &Tok; 82 const unsigned IndentLevel; 83 const bool InPPDirective; 84 const encoding::Encoding Encoding; 85 const FormatStyle &Style; 86 }; 87 88 /// \brief Base class for single line tokens that can be broken. 89 /// 90 /// \c getSplit() needs to be implemented by child classes. 91 class BreakableSingleLineToken : public BreakableToken { 92 public: 93 unsigned getLineCount() const override; 94 unsigned getLineLengthAfterSplit(unsigned LineIndex, unsigned TailOffset, 95 StringRef::size_type Length) const override; 96 97 protected: 98 BreakableSingleLineToken(const FormatToken &Tok, unsigned IndentLevel, 99 unsigned StartColumn, StringRef Prefix, 100 StringRef Postfix, bool InPPDirective, 101 encoding::Encoding Encoding, 102 const FormatStyle &Style); 103 104 // The column in which the token starts. 105 unsigned StartColumn; 106 // The prefix a line needs after a break in the token. 107 StringRef Prefix; 108 // The postfix a line needs before introducing a break. 109 StringRef Postfix; 110 // The token text excluding the prefix and postfix. 111 StringRef Line; 112 }; 113 114 class BreakableStringLiteral : public BreakableSingleLineToken { 115 public: 116 /// \brief Creates a breakable token for a single line string literal. 117 /// 118 /// \p StartColumn specifies the column in which the token will start 119 /// after formatting. 120 BreakableStringLiteral(const FormatToken &Tok, unsigned IndentLevel, 121 unsigned StartColumn, StringRef Prefix, 122 StringRef Postfix, bool InPPDirective, 123 encoding::Encoding Encoding, const FormatStyle &Style); 124 125 Split getSplit(unsigned LineIndex, unsigned TailOffset, 126 unsigned ColumnLimit) const override; 127 void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split, 128 WhitespaceManager &Whitespaces) override; replaceWhitespace(unsigned LineIndex,unsigned TailOffset,Split Split,WhitespaceManager & Whitespaces)129 void replaceWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split, 130 WhitespaceManager &Whitespaces) override {} 131 }; 132 133 class BreakableLineComment : public BreakableSingleLineToken { 134 public: 135 /// \brief Creates a breakable token for a line comment. 136 /// 137 /// \p StartColumn specifies the column in which the comment will start 138 /// after formatting. 139 BreakableLineComment(const FormatToken &Token, unsigned IndentLevel, 140 unsigned StartColumn, bool InPPDirective, 141 encoding::Encoding Encoding, const FormatStyle &Style); 142 143 Split getSplit(unsigned LineIndex, unsigned TailOffset, 144 unsigned ColumnLimit) const override; 145 void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split, 146 WhitespaceManager &Whitespaces) override; 147 void replaceWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split, 148 WhitespaceManager &Whitespaces) override; 149 void replaceWhitespaceBefore(unsigned LineIndex, 150 WhitespaceManager &Whitespaces) override; 151 152 private: 153 // The prefix without an additional space if one was added. 154 StringRef OriginalPrefix; 155 }; 156 157 class BreakableBlockComment : public BreakableToken { 158 public: 159 /// \brief Creates a breakable token for a block comment. 160 /// 161 /// \p StartColumn specifies the column in which the comment will start 162 /// after formatting, while \p OriginalStartColumn specifies in which 163 /// column the comment started before formatting. 164 /// If the comment starts a line after formatting, set \p FirstInLine to true. 165 BreakableBlockComment(const FormatToken &Token, unsigned IndentLevel, 166 unsigned StartColumn, unsigned OriginaStartColumn, 167 bool FirstInLine, bool InPPDirective, 168 encoding::Encoding Encoding, const FormatStyle &Style); 169 170 unsigned getLineCount() const override; 171 unsigned getLineLengthAfterSplit(unsigned LineIndex, unsigned TailOffset, 172 StringRef::size_type Length) const override; 173 Split getSplit(unsigned LineIndex, unsigned TailOffset, 174 unsigned ColumnLimit) const override; 175 void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split, 176 WhitespaceManager &Whitespaces) override; 177 void replaceWhitespace(unsigned LineIndex, unsigned TailOffset, Split Split, 178 WhitespaceManager &Whitespaces) override; 179 void replaceWhitespaceBefore(unsigned LineIndex, 180 WhitespaceManager &Whitespaces) override; 181 182 private: 183 // Rearranges the whitespace between Lines[LineIndex-1] and Lines[LineIndex], 184 // so that all whitespace between the lines is accounted to Lines[LineIndex] 185 // as leading whitespace: 186 // - Lines[LineIndex] points to the text after that whitespace 187 // - Lines[LineIndex-1] shrinks by its trailing whitespace 188 // - LeadingWhitespace[LineIndex] is updated with the complete whitespace 189 // between the end of the text of Lines[LineIndex-1] and Lines[LineIndex] 190 // 191 // Sets StartOfLineColumn to the intended column in which the text at 192 // Lines[LineIndex] starts (note that the decoration, if present, is not 193 // considered part of the text). 194 void adjustWhitespace(unsigned LineIndex, int IndentDelta); 195 196 // Returns the column at which the text in line LineIndex starts, when broken 197 // at TailOffset. Note that the decoration (if present) is not considered part 198 // of the text. 199 unsigned getContentStartColumn(unsigned LineIndex, unsigned TailOffset) const; 200 201 // Contains the text of the lines of the block comment, excluding the leading 202 // /* in the first line and trailing */ in the last line, and excluding all 203 // trailing whitespace between the lines. Note that the decoration (if 204 // present) is also not considered part of the text. 205 SmallVector<StringRef, 16> Lines; 206 207 // LeadingWhitespace[i] is the number of characters regarded as whitespace in 208 // front of Lines[i]. Note that this can include "* " sequences, which we 209 // regard as whitespace when all lines have a "*" prefix. 210 SmallVector<unsigned, 16> LeadingWhitespace; 211 212 // StartOfLineColumn[i] is the target column at which Line[i] should be. 213 // Note that this excludes a leading "* " or "*" in case all lines have 214 // a "*" prefix. 215 SmallVector<int, 16> StartOfLineColumn; 216 217 // The column at which the text of a broken line should start. 218 // Note that an optional decoration would go before that column. 219 // IndentAtLineBreak is a uniform position for all lines in a block comment, 220 // regardless of their relative position. 221 // FIXME: Revisit the decision to do this; the main reason was to support 222 // patterns like 223 // /**************//** 224 // * Comment 225 // We could also support such patterns by special casing the first line 226 // instead. 227 unsigned IndentAtLineBreak; 228 229 // This is to distinguish between the case when the last line was empty and 230 // the case when it started with a decoration ("*" or "* "). 231 bool LastLineNeedsDecoration; 232 233 // Either "* " if all lines begin with a "*", or empty. 234 StringRef Decoration; 235 }; 236 237 } // namespace format 238 } // namespace clang 239 240 #endif // LLVM_CLANG_FORMAT_BREAKABLETOKEN_H 241