FormatToken.cpp revision 3c6aea7ac63265c769b5fe09e213ab1c4cee111e
1//===--- FormatToken.cpp - 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 This file implements specific functions of \c FormatTokens and their 12/// roles. 13/// 14//===----------------------------------------------------------------------===// 15 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" 21 22namespace clang { 23namespace format { 24 25TokenRole::~TokenRole() {} 26 27void TokenRole::precomputeFormattingInfos(const FormatToken *Token) {} 28 29unsigned CommaSeparatedList::format(LineState &State, 30 ContinuationIndenter *Indenter, 31 bool DryRun) { 32 if (!State.NextToken->Previous || !State.NextToken->Previous->Previous || 33 Commas.size() <= 2) 34 return 0; 35 36 // Ensure that we start on the opening brace. 37 const FormatToken *LBrace = State.NextToken->Previous->Previous; 38 if (LBrace->isNot(tok::l_brace) || 39 LBrace->BlockKind == BK_Block || 40 LBrace->Type == TT_DictLiteral || 41 LBrace->Next->Type == TT_DesignatedInitializerPeriod) 42 return 0; 43 44 // Calculate the number of code points we have to format this list. As the 45 // first token is already placed, we have to subtract it. 46 unsigned RemainingCodePoints = Style.ColumnLimit - State.Column + 47 State.NextToken->Previous->ColumnWidth; 48 49 // Find the best ColumnFormat, i.e. the best number of columns to use. 50 const ColumnFormat *Format = getColumnFormat(RemainingCodePoints); 51 if (!Format) 52 return 0; 53 54 // Format the entire list. 55 unsigned Penalty = 0; 56 unsigned Column = 0; 57 unsigned Item = 0; 58 while (State.NextToken != LBrace->MatchingParen) { 59 bool NewLine = false; 60 unsigned ExtraSpaces = 0; 61 62 // If the previous token was one of our commas, we are now on the next item. 63 if (Item < Commas.size() && State.NextToken->Previous == Commas[Item]) { 64 if (!State.NextToken->isTrailingComment()) { 65 ExtraSpaces += Format->ColumnSizes[Column] - ItemLengths[Item]; 66 ++Column; 67 } 68 ++Item; 69 } 70 71 if (Column == Format->Columns || State.NextToken->MustBreakBefore) { 72 Column = 0; 73 NewLine = true; 74 } 75 76 // Place token using the continuation indenter and store the penalty. 77 Penalty += Indenter->addTokenToState(State, NewLine, DryRun, ExtraSpaces); 78 } 79 return Penalty; 80} 81 82// Returns the lengths in code points between Begin and End (both included), 83// assuming that the entire sequence is put on a single line. 84static unsigned CodePointsBetween(const FormatToken *Begin, 85 const FormatToken *End) { 86 assert(End->TotalLength >= Begin->TotalLength); 87 return End->TotalLength - Begin->TotalLength + Begin->ColumnWidth; 88} 89 90void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) { 91 // FIXME: At some point we might want to do this for other lists, too. 92 if (!Token->MatchingParen || Token->isNot(tok::l_brace)) 93 return; 94 95 FormatToken *ItemBegin = Token->Next; 96 SmallVector<bool, 8> MustBreakBeforeItem; 97 98 // The lengths of an item if it is put at the end of the line. This includes 99 // trailing comments which are otherwise ignored for column alignment. 100 SmallVector<unsigned, 8> EndOfLineItemLength; 101 102 for (unsigned i = 0, e = Commas.size() + 1; i != e; ++i) { 103 // Skip comments on their own line. 104 while (ItemBegin->HasUnescapedNewline && ItemBegin->isTrailingComment()) 105 ItemBegin = ItemBegin->Next; 106 107 MustBreakBeforeItem.push_back(ItemBegin->MustBreakBefore); 108 const FormatToken *ItemEnd = NULL; 109 if (i == Commas.size()) { 110 ItemEnd = Token->MatchingParen; 111 const FormatToken *NonCommentEnd = ItemEnd->getPreviousNonComment(); 112 ItemLengths.push_back(CodePointsBetween(ItemBegin, NonCommentEnd)); 113 if (Style.Cpp11BracedListStyle) { 114 // In Cpp11 braced list style, the } and possibly other subsequent 115 // tokens will need to stay on a line with the last element. 116 while (ItemEnd->Next && !ItemEnd->Next->CanBreakBefore) 117 ItemEnd = ItemEnd->Next; 118 } else { 119 // In other braced lists styles, the "}" can be wrapped to the new line. 120 ItemEnd = Token->MatchingParen->Previous; 121 } 122 } else { 123 ItemEnd = Commas[i]; 124 // The comma is counted as part of the item when calculating the length. 125 ItemLengths.push_back(CodePointsBetween(ItemBegin, ItemEnd)); 126 // Consume trailing comments so the are included in EndOfLineItemLength. 127 if (ItemEnd->Next && !ItemEnd->Next->HasUnescapedNewline && 128 ItemEnd->Next->isTrailingComment()) 129 ItemEnd = ItemEnd->Next; 130 } 131 EndOfLineItemLength.push_back(CodePointsBetween(ItemBegin, ItemEnd)); 132 // If there is a trailing comma in the list, the next item will start at the 133 // closing brace. Don't create an extra item for this. 134 if (ItemEnd->getNextNonComment() == Token->MatchingParen) 135 break; 136 ItemBegin = ItemEnd->Next; 137 } 138 139 // We can never place more than ColumnLimit / 3 items in a row (because of the 140 // spaces and the comma). 141 for (unsigned Columns = 1; Columns <= Style.ColumnLimit / 3; ++Columns) { 142 ColumnFormat Format; 143 Format.Columns = Columns; 144 Format.ColumnSizes.resize(Columns); 145 Format.LineCount = 0; 146 bool HasRowWithSufficientColumns = false; 147 unsigned Column = 0; 148 for (unsigned i = 0, e = ItemLengths.size(); i != e; ++i) { 149 assert(i < MustBreakBeforeItem.size()); 150 if (MustBreakBeforeItem[i] || Column == Columns) { 151 ++Format.LineCount; 152 Column = 0; 153 } 154 if (Column == Columns - 1) 155 HasRowWithSufficientColumns = true; 156 unsigned length = 157 (Column == Columns - 1) ? EndOfLineItemLength[i] : ItemLengths[i]; 158 Format.ColumnSizes[Column] = 159 std::max(Format.ColumnSizes[Column], length); 160 ++Column; 161 } 162 // If all rows are terminated early (e.g. by trailing comments), we don't 163 // need to look further. 164 if (!HasRowWithSufficientColumns) 165 break; 166 Format.TotalWidth = Columns - 1; // Width of the N-1 spaces. 167 for (unsigned i = 0; i < Columns; ++i) { 168 Format.TotalWidth += Format.ColumnSizes[i]; 169 } 170 171 // Ignore layouts that are bound to violate the column limit. 172 if (Format.TotalWidth > Style.ColumnLimit) 173 continue; 174 175 Formats.push_back(Format); 176 } 177} 178 179const CommaSeparatedList::ColumnFormat * 180CommaSeparatedList::getColumnFormat(unsigned RemainingCharacters) const { 181 const ColumnFormat *BestFormat = NULL; 182 for (SmallVector<ColumnFormat, 4>::const_reverse_iterator 183 I = Formats.rbegin(), 184 E = Formats.rend(); 185 I != E; ++I) { 186 if (I->TotalWidth <= RemainingCharacters) { 187 if (BestFormat && I->LineCount > BestFormat->LineCount) 188 break; 189 BestFormat = &*I; 190 } 191 } 192 return BestFormat; 193} 194 195} // namespace format 196} // namespace clang 197