1 //===--- BreakableToken.cpp - Format C++ code -----------------------------===//
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 Contains implementation of BreakableToken class and classes derived
14 //===----------------------------------------------------------------------===//
16 #include "BreakableToken.h"
17 #include "clang/Basic/CharInfo.h"
18 #include "clang/Format/Format.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/Support/Debug.h"
23 #define DEBUG_TYPE "format-token-breaker"
28 static const char *const Blanks = " \t\v\f\r";
29 static bool IsBlank(char C) {
42 static BreakableToken::Split getCommentSplit(StringRef Text,
43 unsigned ContentStartColumn,
46 encoding::Encoding Encoding) {
47 if (ColumnLimit <= ContentStartColumn + 1)
48 return BreakableToken::Split(StringRef::npos, 0);
50 unsigned MaxSplit = ColumnLimit - ContentStartColumn + 1;
51 unsigned MaxSplitBytes = 0;
53 for (unsigned NumChars = 0;
54 NumChars < MaxSplit && MaxSplitBytes < Text.size();) {
55 unsigned BytesInChar =
56 encoding::getCodePointNumBytes(Text[MaxSplitBytes], Encoding);
58 encoding::columnWidthWithTabs(Text.substr(MaxSplitBytes, BytesInChar),
59 ContentStartColumn, TabWidth, Encoding);
60 MaxSplitBytes += BytesInChar;
63 StringRef::size_type SpaceOffset = Text.find_last_of(Blanks, MaxSplitBytes);
64 if (SpaceOffset == StringRef::npos ||
65 // Don't break at leading whitespace.
66 Text.find_last_not_of(Blanks, SpaceOffset) == StringRef::npos) {
67 // Make sure that we don't break at leading whitespace that
68 // reaches past MaxSplit.
69 StringRef::size_type FirstNonWhitespace = Text.find_first_not_of(Blanks);
70 if (FirstNonWhitespace == StringRef::npos)
71 // If the comment is only whitespace, we cannot split.
72 return BreakableToken::Split(StringRef::npos, 0);
73 SpaceOffset = Text.find_first_of(
74 Blanks, std::max<unsigned>(MaxSplitBytes, FirstNonWhitespace));
76 if (SpaceOffset != StringRef::npos && SpaceOffset != 0) {
77 StringRef BeforeCut = Text.substr(0, SpaceOffset).rtrim(Blanks);
78 StringRef AfterCut = Text.substr(SpaceOffset).ltrim(Blanks);
79 return BreakableToken::Split(BeforeCut.size(),
80 AfterCut.begin() - BeforeCut.end());
82 return BreakableToken::Split(StringRef::npos, 0);
85 static BreakableToken::Split
86 getStringSplit(StringRef Text, unsigned UsedColumns, unsigned ColumnLimit,
87 unsigned TabWidth, encoding::Encoding Encoding) {
88 // FIXME: Reduce unit test case.
90 return BreakableToken::Split(StringRef::npos, 0);
91 if (ColumnLimit <= UsedColumns)
92 return BreakableToken::Split(StringRef::npos, 0);
93 unsigned MaxSplit = ColumnLimit - UsedColumns;
94 StringRef::size_type SpaceOffset = 0;
95 StringRef::size_type SlashOffset = 0;
96 StringRef::size_type WordStartOffset = 0;
97 StringRef::size_type SplitPoint = 0;
98 for (unsigned Chars = 0;;) {
100 if (Text[0] == '\\') {
101 Advance = encoding::getEscapeSequenceLength(Text);
104 Advance = encoding::getCodePointNumBytes(Text[0], Encoding);
105 Chars += encoding::columnWidthWithTabs(
106 Text.substr(0, Advance), UsedColumns + Chars, TabWidth, Encoding);
109 if (Chars > MaxSplit || Text.size() == Advance)
112 if (IsBlank(Text[0]))
113 SpaceOffset = SplitPoint;
115 SlashOffset = SplitPoint;
116 if (Advance == 1 && !isAlphanumeric(Text[0]))
117 WordStartOffset = SplitPoint;
119 SplitPoint += Advance;
120 Text = Text.substr(Advance);
123 if (SpaceOffset != 0)
124 return BreakableToken::Split(SpaceOffset + 1, 0);
125 if (SlashOffset != 0)
126 return BreakableToken::Split(SlashOffset + 1, 0);
127 if (WordStartOffset != 0)
128 return BreakableToken::Split(WordStartOffset + 1, 0);
130 return BreakableToken::Split(SplitPoint, 0);
131 return BreakableToken::Split(StringRef::npos, 0);
134 unsigned BreakableSingleLineToken::getLineCount() const { return 1; }
136 unsigned BreakableSingleLineToken::getLineLengthAfterSplit(
137 unsigned LineIndex, unsigned Offset, StringRef::size_type Length) const {
138 return StartColumn + Prefix.size() + Postfix.size() +
139 encoding::columnWidthWithTabs(Line.substr(Offset, Length),
140 StartColumn + Prefix.size(),
141 Style.TabWidth, Encoding);
144 BreakableSingleLineToken::BreakableSingleLineToken(
145 const FormatToken &Tok, unsigned IndentLevel, unsigned StartColumn,
146 StringRef Prefix, StringRef Postfix, bool InPPDirective,
147 encoding::Encoding Encoding, const FormatStyle &Style)
148 : BreakableToken(Tok, IndentLevel, InPPDirective, Encoding, Style),
149 StartColumn(StartColumn), Prefix(Prefix), Postfix(Postfix) {
150 assert(Tok.TokenText.endswith(Postfix));
151 Line = Tok.TokenText.substr(
152 Prefix.size(), Tok.TokenText.size() - Prefix.size() - Postfix.size());
155 BreakableStringLiteral::BreakableStringLiteral(
156 const FormatToken &Tok, unsigned IndentLevel, unsigned StartColumn,
157 StringRef Prefix, StringRef Postfix, bool InPPDirective,
158 encoding::Encoding Encoding, const FormatStyle &Style)
159 : BreakableSingleLineToken(Tok, IndentLevel, StartColumn, Prefix, Postfix,
160 InPPDirective, Encoding, Style) {}
162 BreakableToken::Split
163 BreakableStringLiteral::getSplit(unsigned LineIndex, unsigned TailOffset,
164 unsigned ColumnLimit) const {
165 return getStringSplit(Line.substr(TailOffset),
166 StartColumn + Prefix.size() + Postfix.size(),
167 ColumnLimit, Style.TabWidth, Encoding);
170 void BreakableStringLiteral::insertBreak(unsigned LineIndex,
171 unsigned TailOffset, Split Split,
172 WhitespaceManager &Whitespaces) {
173 unsigned LeadingSpaces = StartColumn;
174 // The '@' of an ObjC string literal (@"Test") does not become part of the
176 // FIXME: It might be a cleaner solution to merge the tokens as a
177 // precomputation step.
178 if (Prefix.startswith("@"))
180 Whitespaces.replaceWhitespaceInToken(
181 Tok, Prefix.size() + TailOffset + Split.first, Split.second, Postfix,
182 Prefix, InPPDirective, 1, IndentLevel, LeadingSpaces);
185 static StringRef getLineCommentIndentPrefix(StringRef Comment) {
186 static const char *const KnownPrefixes[] = { "///", "//" };
187 StringRef LongestPrefix;
188 for (StringRef KnownPrefix : KnownPrefixes) {
189 if (Comment.startswith(KnownPrefix)) {
190 size_t PrefixLength = KnownPrefix.size();
191 while (PrefixLength < Comment.size() && Comment[PrefixLength] == ' ')
193 if (PrefixLength > LongestPrefix.size())
194 LongestPrefix = Comment.substr(0, PrefixLength);
197 return LongestPrefix;
200 BreakableLineComment::BreakableLineComment(
201 const FormatToken &Token, unsigned IndentLevel, unsigned StartColumn,
202 bool InPPDirective, encoding::Encoding Encoding, const FormatStyle &Style)
203 : BreakableSingleLineToken(Token, IndentLevel, StartColumn,
204 getLineCommentIndentPrefix(Token.TokenText), "",
205 InPPDirective, Encoding, Style) {
206 OriginalPrefix = Prefix;
207 if (Token.TokenText.size() > Prefix.size() &&
208 isAlphanumeric(Token.TokenText[Prefix.size()])) {
211 else if (Prefix == "///")
216 BreakableToken::Split
217 BreakableLineComment::getSplit(unsigned LineIndex, unsigned TailOffset,
218 unsigned ColumnLimit) const {
219 return getCommentSplit(Line.substr(TailOffset), StartColumn + Prefix.size(),
220 ColumnLimit, Style.TabWidth, Encoding);
223 void BreakableLineComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
225 WhitespaceManager &Whitespaces) {
226 Whitespaces.replaceWhitespaceInToken(
227 Tok, OriginalPrefix.size() + TailOffset + Split.first, Split.second,
228 Postfix, Prefix, InPPDirective, /*Newlines=*/1, IndentLevel, StartColumn);
231 void BreakableLineComment::replaceWhitespace(unsigned LineIndex,
232 unsigned TailOffset, Split Split,
233 WhitespaceManager &Whitespaces) {
234 Whitespaces.replaceWhitespaceInToken(
235 Tok, OriginalPrefix.size() + TailOffset + Split.first, Split.second, "",
236 "", /*InPPDirective=*/false, /*Newlines=*/0, /*IndentLevel=*/0,
241 BreakableLineComment::replaceWhitespaceBefore(unsigned LineIndex,
242 WhitespaceManager &Whitespaces) {
243 if (OriginalPrefix != Prefix) {
244 Whitespaces.replaceWhitespaceInToken(Tok, OriginalPrefix.size(), 0, "", "",
245 /*InPPDirective=*/false,
246 /*Newlines=*/0, /*IndentLevel=*/0,
251 BreakableBlockComment::BreakableBlockComment(
252 const FormatToken &Token, unsigned IndentLevel, unsigned StartColumn,
253 unsigned OriginalStartColumn, bool FirstInLine, bool InPPDirective,
254 encoding::Encoding Encoding, const FormatStyle &Style)
255 : BreakableToken(Token, IndentLevel, InPPDirective, Encoding, Style) {
256 StringRef TokenText(Token.TokenText);
257 assert(TokenText.startswith("/*") && TokenText.endswith("*/"));
258 TokenText.substr(2, TokenText.size() - 4).split(Lines, "\n");
260 int IndentDelta = StartColumn - OriginalStartColumn;
261 LeadingWhitespace.resize(Lines.size());
262 StartOfLineColumn.resize(Lines.size());
263 StartOfLineColumn[0] = StartColumn + 2;
264 for (size_t i = 1; i < Lines.size(); ++i)
265 adjustWhitespace(i, IndentDelta);
268 if (Lines.size() == 1 && !FirstInLine) {
269 // Comments for which FirstInLine is false can start on arbitrary column,
270 // and available horizontal space can be too small to align consecutive
271 // lines with the first one.
272 // FIXME: We could, probably, align them to current indentation level, but
273 // now we just wrap them without stars.
276 for (size_t i = 1, e = Lines.size(); i < e && !Decoration.empty(); ++i) {
277 // If the last line is empty, the closing "*/" will have a star.
278 if (i + 1 == e && Lines[i].empty())
280 while (!Lines[i].startswith(Decoration))
281 Decoration = Decoration.substr(0, Decoration.size() - 1);
284 LastLineNeedsDecoration = true;
285 IndentAtLineBreak = StartOfLineColumn[0] + 1;
286 for (size_t i = 1; i < Lines.size(); ++i) {
287 if (Lines[i].empty()) {
288 if (i + 1 == Lines.size()) {
289 // Empty last line means that we already have a star as a part of the
290 // trailing */. We also need to preserve whitespace, so that */ is
291 // correctly indented.
292 LastLineNeedsDecoration = false;
293 } else if (Decoration.empty()) {
294 // For all other lines, set the start column to 0 if they're empty, so
295 // we do not insert trailing whitespace anywhere.
296 StartOfLineColumn[i] = 0;
300 // The first line already excludes the star.
301 // For all other lines, adjust the line to exclude the star and
302 // (optionally) the first whitespace.
303 StartOfLineColumn[i] += Decoration.size();
304 Lines[i] = Lines[i].substr(Decoration.size());
305 LeadingWhitespace[i] += Decoration.size();
306 IndentAtLineBreak = std::min<int>(IndentAtLineBreak, StartOfLineColumn[i]);
308 IndentAtLineBreak = std::max<unsigned>(IndentAtLineBreak, Decoration.size());
310 llvm::dbgs() << "IndentAtLineBreak " << IndentAtLineBreak << "\n";
311 for (size_t i = 0; i < Lines.size(); ++i) {
312 llvm::dbgs() << i << " |" << Lines[i] << "| " << LeadingWhitespace[i]
318 void BreakableBlockComment::adjustWhitespace(unsigned LineIndex,
320 // When in a preprocessor directive, the trailing backslash in a block comment
321 // is not needed, but can serve a purpose of uniformity with necessary escaped
322 // newlines outside the comment. In this case we remove it here before
323 // trimming the trailing whitespace. The backslash will be re-added later when
324 // inserting a line break.
325 size_t EndOfPreviousLine = Lines[LineIndex - 1].size();
326 if (InPPDirective && Lines[LineIndex - 1].endswith("\\"))
329 // Calculate the end of the non-whitespace text in the previous line.
331 Lines[LineIndex - 1].find_last_not_of(Blanks, EndOfPreviousLine);
332 if (EndOfPreviousLine == StringRef::npos)
333 EndOfPreviousLine = 0;
336 // Calculate the start of the non-whitespace text in the current line.
337 size_t StartOfLine = Lines[LineIndex].find_first_not_of(Blanks);
338 if (StartOfLine == StringRef::npos)
339 StartOfLine = Lines[LineIndex].size();
341 StringRef Whitespace = Lines[LineIndex].substr(0, StartOfLine);
342 // Adjust Lines to only contain relevant text.
343 Lines[LineIndex - 1] = Lines[LineIndex - 1].substr(0, EndOfPreviousLine);
344 Lines[LineIndex] = Lines[LineIndex].substr(StartOfLine);
345 // Adjust LeadingWhitespace to account all whitespace between the lines
346 // to the current line.
347 LeadingWhitespace[LineIndex] =
348 Lines[LineIndex].begin() - Lines[LineIndex - 1].end();
350 // Adjust the start column uniformly across all lines.
351 StartOfLineColumn[LineIndex] =
352 encoding::columnWidthWithTabs(Whitespace, 0, Style.TabWidth, Encoding) +
356 unsigned BreakableBlockComment::getLineCount() const { return Lines.size(); }
358 unsigned BreakableBlockComment::getLineLengthAfterSplit(
359 unsigned LineIndex, unsigned Offset, StringRef::size_type Length) const {
360 unsigned ContentStartColumn = getContentStartColumn(LineIndex, Offset);
361 return ContentStartColumn +
362 encoding::columnWidthWithTabs(Lines[LineIndex].substr(Offset, Length),
363 ContentStartColumn, Style.TabWidth,
365 // The last line gets a "*/" postfix.
366 (LineIndex + 1 == Lines.size() ? 2 : 0);
369 BreakableToken::Split
370 BreakableBlockComment::getSplit(unsigned LineIndex, unsigned TailOffset,
371 unsigned ColumnLimit) const {
372 return getCommentSplit(Lines[LineIndex].substr(TailOffset),
373 getContentStartColumn(LineIndex, TailOffset),
374 ColumnLimit, Style.TabWidth, Encoding);
377 void BreakableBlockComment::insertBreak(unsigned LineIndex, unsigned TailOffset,
379 WhitespaceManager &Whitespaces) {
380 StringRef Text = Lines[LineIndex].substr(TailOffset);
381 StringRef Prefix = Decoration;
382 if (LineIndex + 1 == Lines.size() &&
383 Text.size() == Split.first + Split.second) {
384 // For the last line we need to break before "*/", but not to add "* ".
388 unsigned BreakOffsetInToken =
389 Text.data() - Tok.TokenText.data() + Split.first;
390 unsigned CharsToRemove = Split.second;
391 assert(IndentAtLineBreak >= Decoration.size());
392 Whitespaces.replaceWhitespaceInToken(
393 Tok, BreakOffsetInToken, CharsToRemove, "", Prefix, InPPDirective, 1,
394 IndentLevel, IndentAtLineBreak - Decoration.size());
397 void BreakableBlockComment::replaceWhitespace(unsigned LineIndex,
398 unsigned TailOffset, Split Split,
399 WhitespaceManager &Whitespaces) {
400 StringRef Text = Lines[LineIndex].substr(TailOffset);
401 unsigned BreakOffsetInToken =
402 Text.data() - Tok.TokenText.data() + Split.first;
403 unsigned CharsToRemove = Split.second;
404 Whitespaces.replaceWhitespaceInToken(
405 Tok, BreakOffsetInToken, CharsToRemove, "", "", /*InPPDirective=*/false,
406 /*Newlines=*/0, /*IndentLevel=*/0, /*Spaces=*/1);
410 BreakableBlockComment::replaceWhitespaceBefore(unsigned LineIndex,
411 WhitespaceManager &Whitespaces) {
414 StringRef Prefix = Decoration;
415 if (Lines[LineIndex].empty()) {
416 if (LineIndex + 1 == Lines.size()) {
417 if (!LastLineNeedsDecoration) {
418 // If the last line was empty, we don't need a prefix, as the */ will
419 // line up with the decoration (if it exists).
422 } else if (!Decoration.empty()) {
423 // For other empty lines, if we do have a decoration, adapt it to not
424 // contain a trailing whitespace.
425 Prefix = Prefix.substr(0, 1);
428 if (StartOfLineColumn[LineIndex] == 1) {
429 // This line starts immediately after the decorating *.
430 Prefix = Prefix.substr(0, 1);
434 unsigned WhitespaceOffsetInToken = Lines[LineIndex].data() -
435 Tok.TokenText.data() -
436 LeadingWhitespace[LineIndex];
437 Whitespaces.replaceWhitespaceInToken(
438 Tok, WhitespaceOffsetInToken, LeadingWhitespace[LineIndex], "", Prefix,
439 InPPDirective, 1, IndentLevel,
440 StartOfLineColumn[LineIndex] - Prefix.size());
444 BreakableBlockComment::getContentStartColumn(unsigned LineIndex,
445 unsigned TailOffset) const {
446 // If we break, we always break at the predefined indent.
448 return IndentAtLineBreak;
449 return std::max(0, StartOfLineColumn[LineIndex]);
452 } // namespace format