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 "FormatToken.h"
17 #include "ContinuationIndenter.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:
58 case tok::kw___underlying_type:
59 case tok::annot_typename:
60 case tok::kw_char16_t:
61 case tok::kw_char32_t:
63 case tok::kw_decltype:
70 TokenRole::~TokenRole() {}
72 void TokenRole::precomputeFormattingInfos(const FormatToken *Token) {}
74 unsigned CommaSeparatedList::formatAfterToken(LineState &State,
75 ContinuationIndenter *Indenter,
77 if (State.NextToken == nullptr || !State.NextToken->Previous)
80 // Ensure that we start on the opening brace.
81 const FormatToken *LBrace =
82 State.NextToken->Previous->getPreviousNonComment();
83 if (!LBrace || LBrace->isNot(tok::l_brace) || LBrace->BlockKind == BK_Block ||
84 LBrace->Type == TT_DictLiteral ||
85 LBrace->Next->Type == TT_DesignatedInitializerPeriod)
88 // Calculate the number of code points we have to format this list. As the
89 // first token is already placed, we have to subtract it.
90 unsigned RemainingCodePoints =
91 Style.ColumnLimit - State.Column + State.NextToken->Previous->ColumnWidth;
93 // Find the best ColumnFormat, i.e. the best number of columns to use.
94 const ColumnFormat *Format = getColumnFormat(RemainingCodePoints);
95 // If no ColumnFormat can be used, the braced list would generally be
96 // bin-packed. Add a severe penalty to this so that column layouts are
97 // preferred if possible.
101 // Format the entire list.
102 unsigned Penalty = 0;
105 while (State.NextToken != LBrace->MatchingParen) {
106 bool NewLine = false;
107 unsigned ExtraSpaces = 0;
109 // If the previous token was one of our commas, we are now on the next item.
110 if (Item < Commas.size() && State.NextToken->Previous == Commas[Item]) {
111 if (!State.NextToken->isTrailingComment()) {
112 ExtraSpaces += Format->ColumnSizes[Column] - ItemLengths[Item];
118 if (Column == Format->Columns || State.NextToken->MustBreakBefore) {
123 // Place token using the continuation indenter and store the penalty.
124 Penalty += Indenter->addTokenToState(State, NewLine, DryRun, ExtraSpaces);
129 unsigned CommaSeparatedList::formatFromToken(LineState &State,
130 ContinuationIndenter *Indenter,
132 if (HasNestedBracedList)
133 State.Stack.back().AvoidBinPacking = true;
137 // Returns the lengths in code points between Begin and End (both included),
138 // assuming that the entire sequence is put on a single line.
139 static unsigned CodePointsBetween(const FormatToken *Begin,
140 const FormatToken *End) {
141 assert(End->TotalLength >= Begin->TotalLength);
142 return End->TotalLength - Begin->TotalLength + Begin->ColumnWidth;
145 void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) {
146 // FIXME: At some point we might want to do this for other lists, too.
147 if (!Token->MatchingParen || Token->isNot(tok::l_brace))
150 // In C++11 braced list style, we should not format in columns unless they
151 // have many items (20 or more) or we allow bin-packing of function call
153 if (Style.Cpp11BracedListStyle && !Style.BinPackArguments &&
157 // Column format doesn't really make sense if we don't align after brackets.
158 if (!Style.AlignAfterOpenBracket)
161 FormatToken *ItemBegin = Token->Next;
162 while (ItemBegin->isTrailingComment())
163 ItemBegin = ItemBegin->Next;
164 SmallVector<bool, 8> MustBreakBeforeItem;
166 // The lengths of an item if it is put at the end of the line. This includes
167 // trailing comments which are otherwise ignored for column alignment.
168 SmallVector<unsigned, 8> EndOfLineItemLength;
170 bool HasSeparatingComment = false;
171 for (unsigned i = 0, e = Commas.size() + 1; i != e; ++i) {
172 // Skip comments on their own line.
173 while (ItemBegin->HasUnescapedNewline && ItemBegin->isTrailingComment()) {
174 ItemBegin = ItemBegin->Next;
175 HasSeparatingComment = i > 0;
178 MustBreakBeforeItem.push_back(ItemBegin->MustBreakBefore);
179 if (ItemBegin->is(tok::l_brace))
180 HasNestedBracedList = true;
181 const FormatToken *ItemEnd = nullptr;
182 if (i == Commas.size()) {
183 ItemEnd = Token->MatchingParen;
184 const FormatToken *NonCommentEnd = ItemEnd->getPreviousNonComment();
185 ItemLengths.push_back(CodePointsBetween(ItemBegin, NonCommentEnd));
186 if (Style.Cpp11BracedListStyle) {
187 // In Cpp11 braced list style, the } and possibly other subsequent
188 // tokens will need to stay on a line with the last element.
189 while (ItemEnd->Next && !ItemEnd->Next->CanBreakBefore)
190 ItemEnd = ItemEnd->Next;
192 // In other braced lists styles, the "}" can be wrapped to the new line.
193 ItemEnd = Token->MatchingParen->Previous;
197 // The comma is counted as part of the item when calculating the length.
198 ItemLengths.push_back(CodePointsBetween(ItemBegin, ItemEnd));
200 // Consume trailing comments so the are included in EndOfLineItemLength.
201 if (ItemEnd->Next && !ItemEnd->Next->HasUnescapedNewline &&
202 ItemEnd->Next->isTrailingComment())
203 ItemEnd = ItemEnd->Next;
205 EndOfLineItemLength.push_back(CodePointsBetween(ItemBegin, ItemEnd));
206 // If there is a trailing comma in the list, the next item will start at the
207 // closing brace. Don't create an extra item for this.
208 if (ItemEnd->getNextNonComment() == Token->MatchingParen)
210 ItemBegin = ItemEnd->Next;
213 // Don't use column layout for nested lists, lists with few elements and in
214 // presence of separating comments.
215 if (Token->NestingLevel != 0 || Commas.size() < 5 || HasSeparatingComment)
218 // We can never place more than ColumnLimit / 3 items in a row (because of the
219 // spaces and the comma).
220 unsigned MaxItems = Style.ColumnLimit / 3;
221 std::vector<unsigned> MinSizeInColumn;
222 MinSizeInColumn.reserve(MaxItems);
223 for (unsigned Columns = 1; Columns <= MaxItems; ++Columns) {
225 Format.Columns = Columns;
226 Format.ColumnSizes.resize(Columns);
227 MinSizeInColumn.assign(Columns, UINT_MAX);
228 Format.LineCount = 1;
229 bool HasRowWithSufficientColumns = false;
231 for (unsigned i = 0, e = ItemLengths.size(); i != e; ++i) {
232 assert(i < MustBreakBeforeItem.size());
233 if (MustBreakBeforeItem[i] || Column == Columns) {
237 if (Column == Columns - 1)
238 HasRowWithSufficientColumns = true;
240 (Column == Columns - 1) ? EndOfLineItemLength[i] : ItemLengths[i];
241 Format.ColumnSizes[Column] = std::max(Format.ColumnSizes[Column], Length);
242 MinSizeInColumn[Column] = std::min(MinSizeInColumn[Column], Length);
245 // If all rows are terminated early (e.g. by trailing comments), we don't
246 // need to look further.
247 if (!HasRowWithSufficientColumns)
249 Format.TotalWidth = Columns - 1; // Width of the N-1 spaces.
251 for (unsigned i = 0; i < Columns; ++i)
252 Format.TotalWidth += Format.ColumnSizes[i];
254 // Don't use this Format, if the difference between the longest and shortest
255 // element in a column exceeds a threshold to avoid excessive spaces.
257 for (unsigned i = 0; i < Columns - 1; ++i)
258 if (Format.ColumnSizes[i] - MinSizeInColumn[i] > 10)
264 // Ignore layouts that are bound to violate the column limit.
265 if (Format.TotalWidth > Style.ColumnLimit)
268 Formats.push_back(Format);
272 const CommaSeparatedList::ColumnFormat *
273 CommaSeparatedList::getColumnFormat(unsigned RemainingCharacters) const {
274 const ColumnFormat *BestFormat = nullptr;
275 for (SmallVector<ColumnFormat, 4>::const_reverse_iterator
276 I = Formats.rbegin(),
279 if (I->TotalWidth <= RemainingCharacters) {
280 if (BestFormat && I->LineCount > BestFormat->LineCount)
288 } // namespace format