1 //===--- FormatToken.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 This file implements specific functions of \c FormatTokens and their
14 //===----------------------------------------------------------------------===//
16 #include "ContinuationIndenter.h"
17 #include "FormatToken.h"
18 #include "clang/Format/Format.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/Support/Debug.h"
26 const char *getTokenTypeName(TokenType Type) {
27 static const char *const TokNames[] = {
34 if (Type < NUM_TOKEN_TYPES)
35 return TokNames[Type];
36 llvm_unreachable("unknown TokenType");
40 // FIXME: This is copy&pasted from Sema. Put it in a common place and remove
42 bool FormatToken::isSimpleTypeSpecifier() const {
43 switch (Tok.getKind()) {
47 case tok::kw___int128:
49 case tok::kw_unsigned:
56 case tok::kw___float128:
59 case tok::kw___underlying_type:
60 case tok::annot_typename:
61 case tok::kw_char16_t:
62 case tok::kw_char32_t:
64 case tok::kw_decltype:
71 TokenRole::~TokenRole() {}
73 void TokenRole::precomputeFormattingInfos(const FormatToken *Token) {}
75 unsigned CommaSeparatedList::formatAfterToken(LineState &State,
76 ContinuationIndenter *Indenter,
78 if (State.NextToken == nullptr || !State.NextToken->Previous)
81 // Ensure that we start on the opening brace.
82 const FormatToken *LBrace =
83 State.NextToken->Previous->getPreviousNonComment();
84 if (!LBrace || !LBrace->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) ||
85 LBrace->BlockKind == BK_Block || LBrace->Type == TT_DictLiteral ||
86 LBrace->Next->Type == TT_DesignatedInitializerPeriod)
89 // Calculate the number of code points we have to format this list. As the
90 // first token is already placed, we have to subtract it.
91 unsigned RemainingCodePoints =
92 Style.ColumnLimit - State.Column + State.NextToken->Previous->ColumnWidth;
94 // Find the best ColumnFormat, i.e. the best number of columns to use.
95 const ColumnFormat *Format = getColumnFormat(RemainingCodePoints);
96 // If no ColumnFormat can be used, the braced list would generally be
97 // bin-packed. Add a severe penalty to this so that column layouts are
98 // preferred if possible.
102 // Format the entire list.
103 unsigned Penalty = 0;
106 while (State.NextToken != LBrace->MatchingParen) {
107 bool NewLine = false;
108 unsigned ExtraSpaces = 0;
110 // If the previous token was one of our commas, we are now on the next item.
111 if (Item < Commas.size() && State.NextToken->Previous == Commas[Item]) {
112 if (!State.NextToken->isTrailingComment()) {
113 ExtraSpaces += Format->ColumnSizes[Column] - ItemLengths[Item];
119 if (Column == Format->Columns || State.NextToken->MustBreakBefore) {
124 // Place token using the continuation indenter and store the penalty.
125 Penalty += Indenter->addTokenToState(State, NewLine, DryRun, ExtraSpaces);
130 unsigned CommaSeparatedList::formatFromToken(LineState &State,
131 ContinuationIndenter *Indenter,
133 if (HasNestedBracedList)
134 State.Stack.back().AvoidBinPacking = true;
138 // Returns the lengths in code points between Begin and End (both included),
139 // assuming that the entire sequence is put on a single line.
140 static unsigned CodePointsBetween(const FormatToken *Begin,
141 const FormatToken *End) {
142 assert(End->TotalLength >= Begin->TotalLength);
143 return End->TotalLength - Begin->TotalLength + Begin->ColumnWidth;
146 void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) {
147 // FIXME: At some point we might want to do this for other lists, too.
148 if (!Token->MatchingParen ||
149 !Token->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare))
152 // In C++11 braced list style, we should not format in columns unless they
153 // have many items (20 or more) or we allow bin-packing of function call
155 if (Style.Cpp11BracedListStyle && !Style.BinPackArguments &&
159 // Limit column layout for JavaScript array initializers to 20 or more items
160 // for now to introduce it carefully. We can become more aggressive if this
162 if (Token->is(TT_ArrayInitializerLSquare) && Commas.size() < 19)
165 // Column format doesn't really make sense if we don't align after brackets.
166 if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign)
169 FormatToken *ItemBegin = Token->Next;
170 while (ItemBegin->isTrailingComment())
171 ItemBegin = ItemBegin->Next;
172 SmallVector<bool, 8> MustBreakBeforeItem;
174 // The lengths of an item if it is put at the end of the line. This includes
175 // trailing comments which are otherwise ignored for column alignment.
176 SmallVector<unsigned, 8> EndOfLineItemLength;
178 bool HasSeparatingComment = false;
179 for (unsigned i = 0, e = Commas.size() + 1; i != e; ++i) {
180 // Skip comments on their own line.
181 while (ItemBegin->HasUnescapedNewline && ItemBegin->isTrailingComment()) {
182 ItemBegin = ItemBegin->Next;
183 HasSeparatingComment = i > 0;
186 MustBreakBeforeItem.push_back(ItemBegin->MustBreakBefore);
187 if (ItemBegin->is(tok::l_brace))
188 HasNestedBracedList = true;
189 const FormatToken *ItemEnd = nullptr;
190 if (i == Commas.size()) {
191 ItemEnd = Token->MatchingParen;
192 const FormatToken *NonCommentEnd = ItemEnd->getPreviousNonComment();
193 ItemLengths.push_back(CodePointsBetween(ItemBegin, NonCommentEnd));
194 if (Style.Cpp11BracedListStyle &&
195 !ItemEnd->Previous->isTrailingComment()) {
196 // In Cpp11 braced list style, the } and possibly other subsequent
197 // tokens will need to stay on a line with the last element.
198 while (ItemEnd->Next && !ItemEnd->Next->CanBreakBefore)
199 ItemEnd = ItemEnd->Next;
201 // In other braced lists styles, the "}" can be wrapped to the new line.
202 ItemEnd = Token->MatchingParen->Previous;
206 // The comma is counted as part of the item when calculating the length.
207 ItemLengths.push_back(CodePointsBetween(ItemBegin, ItemEnd));
209 // Consume trailing comments so the are included in EndOfLineItemLength.
210 if (ItemEnd->Next && !ItemEnd->Next->HasUnescapedNewline &&
211 ItemEnd->Next->isTrailingComment())
212 ItemEnd = ItemEnd->Next;
214 EndOfLineItemLength.push_back(CodePointsBetween(ItemBegin, ItemEnd));
215 // If there is a trailing comma in the list, the next item will start at the
216 // closing brace. Don't create an extra item for this.
217 if (ItemEnd->getNextNonComment() == Token->MatchingParen)
219 ItemBegin = ItemEnd->Next;
222 // Don't use column layout for lists with few elements and in presence of
223 // separating comments.
224 if (Commas.size() < 5 || HasSeparatingComment)
227 if (Token->NestingLevel != 0 && Token->is(tok::l_brace) && Commas.size() < 19)
230 // We can never place more than ColumnLimit / 3 items in a row (because of the
231 // spaces and the comma).
232 unsigned MaxItems = Style.ColumnLimit / 3;
233 std::vector<unsigned> MinSizeInColumn;
234 MinSizeInColumn.reserve(MaxItems);
235 for (unsigned Columns = 1; Columns <= MaxItems; ++Columns) {
237 Format.Columns = Columns;
238 Format.ColumnSizes.resize(Columns);
239 MinSizeInColumn.assign(Columns, UINT_MAX);
240 Format.LineCount = 1;
241 bool HasRowWithSufficientColumns = false;
243 for (unsigned i = 0, e = ItemLengths.size(); i != e; ++i) {
244 assert(i < MustBreakBeforeItem.size());
245 if (MustBreakBeforeItem[i] || Column == Columns) {
249 if (Column == Columns - 1)
250 HasRowWithSufficientColumns = true;
252 (Column == Columns - 1) ? EndOfLineItemLength[i] : ItemLengths[i];
253 Format.ColumnSizes[Column] = std::max(Format.ColumnSizes[Column], Length);
254 MinSizeInColumn[Column] = std::min(MinSizeInColumn[Column], Length);
257 // If all rows are terminated early (e.g. by trailing comments), we don't
258 // need to look further.
259 if (!HasRowWithSufficientColumns)
261 Format.TotalWidth = Columns - 1; // Width of the N-1 spaces.
263 for (unsigned i = 0; i < Columns; ++i)
264 Format.TotalWidth += Format.ColumnSizes[i];
266 // Don't use this Format, if the difference between the longest and shortest
267 // element in a column exceeds a threshold to avoid excessive spaces.
269 for (unsigned i = 0; i < Columns - 1; ++i)
270 if (Format.ColumnSizes[i] - MinSizeInColumn[i] > 10)
276 // Ignore layouts that are bound to violate the column limit.
277 if (Format.TotalWidth > Style.ColumnLimit)
280 Formats.push_back(Format);
284 const CommaSeparatedList::ColumnFormat *
285 CommaSeparatedList::getColumnFormat(unsigned RemainingCharacters) const {
286 const ColumnFormat *BestFormat = nullptr;
287 for (SmallVector<ColumnFormat, 4>::const_reverse_iterator
288 I = Formats.rbegin(),
291 if (I->TotalWidth <= RemainingCharacters) {
292 if (BestFormat && I->LineCount > BestFormat->LineCount)
300 } // namespace format