lib/Format/FormatToken.cpp - third_party/swift-clang - Git at Google

 //===--- FormatToken.cpp - Format C++ code --------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// \brief This file implements specific functions of \c FormatTokens and their
 /// roles.
 ///
 //===----------------------------------------------------------------------===//

 #include "ContinuationIndenter.h"
 #include "FormatToken.h"
 #include "clang/Format/Format.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Debug.h"
 #include <climits>

 namespace clang {
 namespace format {

 const char *getTokenTypeName(TokenType Type) {
   static const char *const TokNames[] = {
 #define TYPE(X) #X,
 LIST_TOKEN_TYPES
 #undef TYPE
     nullptr
   };

   if (Type < NUM_TOKEN_TYPES)
     return TokNames[Type];
   llvm_unreachable("unknown TokenType");
   return nullptr;
 }

 // FIXME: This is copy&pasted from Sema. Put it in a common place and remove
 // duplication.
 bool FormatToken::isSimpleTypeSpecifier() const {
   switch (Tok.getKind()) {
   case tok::kw_short:
   case tok::kw_long:
   case tok::kw___int64:
   case tok::kw___int128:
   case tok::kw_signed:
   case tok::kw_unsigned:
   case tok::kw_void:
   case tok::kw_char:
   case tok::kw_int:
   case tok::kw_half:
   case tok::kw_float:
   case tok::kw_double:
   case tok::kw_wchar_t:
   case tok::kw_bool:
   case tok::kw___underlying_type:
   case tok::annot_typename:
   case tok::kw_char16_t:
   case tok::kw_char32_t:
   case tok::kw_typeof:
   case tok::kw_decltype:
     return true;
   default:
     return false;
   }
 }

 TokenRole::~TokenRole() {}

 void TokenRole::precomputeFormattingInfos(const FormatToken *Token) {}

 unsigned CommaSeparatedList::formatAfterToken(LineState &State,
                                               ContinuationIndenter *Indenter,
                                               bool DryRun) {
   if (State.NextToken == nullptr || !State.NextToken->Previous)
     return 0;

   // Ensure that we start on the opening brace.
   const FormatToken *LBrace =
       State.NextToken->Previous->getPreviousNonComment();
   if (!LBrace || !LBrace->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) ||
       LBrace->BlockKind == BK_Block || LBrace->Type == TT_DictLiteral ||
       LBrace->Next->Type == TT_DesignatedInitializerPeriod)
     return 0;

   // Calculate the number of code points we have to format this list. As the
   // first token is already placed, we have to subtract it.
   unsigned RemainingCodePoints =
       Style.ColumnLimit - State.Column + State.NextToken->Previous->ColumnWidth;

   // Find the best ColumnFormat, i.e. the best number of columns to use.
   const ColumnFormat *Format = getColumnFormat(RemainingCodePoints);
   // If no ColumnFormat can be used, the braced list would generally be
   // bin-packed. Add a severe penalty to this so that column layouts are
   // preferred if possible.
   if (!Format)
     return 10000;

   // Format the entire list.
   unsigned Penalty = 0;
   unsigned Column = 0;
   unsigned Item = 0;
   while (State.NextToken != LBrace->MatchingParen) {
     bool NewLine = false;
     unsigned ExtraSpaces = 0;

     // If the previous token was one of our commas, we are now on the next item.
     if (Item < Commas.size() && State.NextToken->Previous == Commas[Item]) {
       if (!State.NextToken->isTrailingComment()) {
         ExtraSpaces += Format->ColumnSizes[Column] - ItemLengths[Item];
         ++Column;
       }
       ++Item;
     }

     if (Column == Format->Columns || State.NextToken->MustBreakBefore) {
       Column = 0;
       NewLine = true;
     }

     // Place token using the continuation indenter and store the penalty.
     Penalty += Indenter->addTokenToState(State, NewLine, DryRun, ExtraSpaces);
   }
   return Penalty;
 }

 unsigned CommaSeparatedList::formatFromToken(LineState &State,
                                              ContinuationIndenter *Indenter,
                                              bool DryRun) {
   if (HasNestedBracedList)
     State.Stack.back().AvoidBinPacking = true;
   return 0;
 }

 // Returns the lengths in code points between Begin and End (both included),
 // assuming that the entire sequence is put on a single line.
 static unsigned CodePointsBetween(const FormatToken *Begin,
                                   const FormatToken *End) {
   assert(End->TotalLength >= Begin->TotalLength);
   return End->TotalLength - Begin->TotalLength + Begin->ColumnWidth;
 }

 void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) {
   // FIXME: At some point we might want to do this for other lists, too.
   if (!Token->MatchingParen ||
       !Token->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare))
     return;

   // In C++11 braced list style, we should not format in columns unless they
   // have many items (20 or more) or we allow bin-packing of function call
   // arguments.
   if (Style.Cpp11BracedListStyle && !Style.BinPackArguments &&
       Commas.size() < 19)
     return;

   // Limit column layout for JavaScript array initializers to 20 or more items
   // for now to introduce it carefully. We can become more aggressive if this
   // necessary.
   if (Token->is(TT_ArrayInitializerLSquare) && Commas.size() < 19)
     return;

   // Column format doesn't really make sense if we don't align after brackets.
   if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign)
     return;

   FormatToken *ItemBegin = Token->Next;
   while (ItemBegin->isTrailingComment())
     ItemBegin = ItemBegin->Next;
   SmallVector<bool, 8> MustBreakBeforeItem;

   // The lengths of an item if it is put at the end of the line. This includes
   // trailing comments which are otherwise ignored for column alignment.
   SmallVector<unsigned, 8> EndOfLineItemLength;

   bool HasSeparatingComment = false;
   for (unsigned i = 0, e = Commas.size() + 1; i != e; ++i) {
     // Skip comments on their own line.
     while (ItemBegin->HasUnescapedNewline && ItemBegin->isTrailingComment()) {
       ItemBegin = ItemBegin->Next;
       HasSeparatingComment = i > 0;
     }

     MustBreakBeforeItem.push_back(ItemBegin->MustBreakBefore);
     if (ItemBegin->is(tok::l_brace))
       HasNestedBracedList = true;
     const FormatToken *ItemEnd = nullptr;
     if (i == Commas.size()) {
       ItemEnd = Token->MatchingParen;
       const FormatToken *NonCommentEnd = ItemEnd->getPreviousNonComment();
       ItemLengths.push_back(CodePointsBetween(ItemBegin, NonCommentEnd));
       if (Style.Cpp11BracedListStyle &&
           !ItemEnd->Previous->isTrailingComment()) {
         // In Cpp11 braced list style, the } and possibly other subsequent
         // tokens will need to stay on a line with the last element.
         while (ItemEnd->Next && !ItemEnd->Next->CanBreakBefore)
           ItemEnd = ItemEnd->Next;
       } else {
         // In other braced lists styles, the "}" can be wrapped to the new line.
         ItemEnd = Token->MatchingParen->Previous;
       }
     } else {
       ItemEnd = Commas[i];
       // The comma is counted as part of the item when calculating the length.
       ItemLengths.push_back(CodePointsBetween(ItemBegin, ItemEnd));

       // Consume trailing comments so the are included in EndOfLineItemLength.
       if (ItemEnd->Next && !ItemEnd->Next->HasUnescapedNewline &&
           ItemEnd->Next->isTrailingComment())
         ItemEnd = ItemEnd->Next;
     }
     EndOfLineItemLength.push_back(CodePointsBetween(ItemBegin, ItemEnd));
     // If there is a trailing comma in the list, the next item will start at the
     // closing brace. Don't create an extra item for this.
     if (ItemEnd->getNextNonComment() == Token->MatchingParen)
       break;
     ItemBegin = ItemEnd->Next;
   }

   // Don't use column layout for lists with few elements and in presence of
   // separating comments.
   if (Commas.size() < 5 || HasSeparatingComment)
     return;

   if (Token->NestingLevel != 0 && Token->is(tok::l_brace) && Commas.size() < 19)
     return;

   // We can never place more than ColumnLimit / 3 items in a row (because of the
   // spaces and the comma).
   unsigned MaxItems = Style.ColumnLimit / 3;
   std::vector<unsigned> MinSizeInColumn;
   MinSizeInColumn.reserve(MaxItems);
   for (unsigned Columns = 1; Columns <= MaxItems; ++Columns) {
     ColumnFormat Format;
     Format.Columns = Columns;
     Format.ColumnSizes.resize(Columns);
     MinSizeInColumn.assign(Columns, UINT_MAX);
     Format.LineCount = 1;
     bool HasRowWithSufficientColumns = false;
     unsigned Column = 0;
     for (unsigned i = 0, e = ItemLengths.size(); i != e; ++i) {
       assert(i < MustBreakBeforeItem.size());
       if (MustBreakBeforeItem[i] || Column == Columns) {
         ++Format.LineCount;
         Column = 0;
       }
       if (Column == Columns - 1)
         HasRowWithSufficientColumns = true;
       unsigned Length =
           (Column == Columns - 1) ? EndOfLineItemLength[i] : ItemLengths[i];
       Format.ColumnSizes[Column] = std::max(Format.ColumnSizes[Column], Length);
       MinSizeInColumn[Column] = std::min(MinSizeInColumn[Column], Length);
       ++Column;
     }
     // If all rows are terminated early (e.g. by trailing comments), we don't
     // need to look further.
     if (!HasRowWithSufficientColumns)
       break;
     Format.TotalWidth = Columns - 1; // Width of the N-1 spaces.

     for (unsigned i = 0; i < Columns; ++i)
       Format.TotalWidth += Format.ColumnSizes[i];

     // Don't use this Format, if the difference between the longest and shortest
     // element in a column exceeds a threshold to avoid excessive spaces.
     if ([&] {
           for (unsigned i = 0; i < Columns - 1; ++i)
             if (Format.ColumnSizes[i] - MinSizeInColumn[i] > 10)
               return true;
           return false;
         }())
       continue;

     // Ignore layouts that are bound to violate the column limit.
     if (Format.TotalWidth > Style.ColumnLimit)
       continue;

     Formats.push_back(Format);
   }
 }

 const CommaSeparatedList::ColumnFormat *
 CommaSeparatedList::getColumnFormat(unsigned RemainingCharacters) const {
   const ColumnFormat *BestFormat = nullptr;
   for (SmallVector<ColumnFormat, 4>::const_reverse_iterator
            I = Formats.rbegin(),
            E = Formats.rend();
        I != E; ++I) {
     if (I->TotalWidth <= RemainingCharacters) {
       if (BestFormat && I->LineCount > BestFormat->LineCount)
         break;
       BestFormat = &*I;
     }
   }
   return BestFormat;
 }

 } // namespace format
 } // namespace clang
	//===--- FormatToken.cpp - Format C++ code --------------------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	///
	/// \file
	/// \brief This file implements specific functions of \c FormatTokens and their
	/// roles.
	///
	//===----------------------------------------------------------------------===//

	#include "ContinuationIndenter.h"
	#include "FormatToken.h"
	#include "clang/Format/Format.h"
	#include "llvm/ADT/SmallVector.h"
	#include "llvm/Support/Debug.h"
	#include <climits>

	namespace clang {
	namespace format {

	const char *getTokenTypeName(TokenType Type) {
	static const char *const TokNames[] = {
	#define TYPE(X) #X,
	LIST_TOKEN_TYPES
	#undef TYPE
	nullptr
	};

	if (Type < NUM_TOKEN_TYPES)
	return TokNames[Type];
	llvm_unreachable("unknown TokenType");
	return nullptr;
	}

	// FIXME: This is copy&pasted from Sema. Put it in a common place and remove
	// duplication.
	bool FormatToken::isSimpleTypeSpecifier() const {
	switch (Tok.getKind()) {
	case tok::kw_short:
	case tok::kw_long:
	case tok::kw___int64:
	case tok::kw___int128:
	case tok::kw_signed:
	case tok::kw_unsigned:
	case tok::kw_void:
	case tok::kw_char:
	case tok::kw_int:
	case tok::kw_half:
	case tok::kw_float:
	case tok::kw_double:
	case tok::kw_wchar_t:
	case tok::kw_bool:
	case tok::kw___underlying_type:
	case tok::annot_typename:
	case tok::kw_char16_t:
	case tok::kw_char32_t:
	case tok::kw_typeof:
	case tok::kw_decltype:
	return true;
	default:
	return false;
	}
	}

	TokenRole::~TokenRole() {}

	void TokenRole::precomputeFormattingInfos(const FormatToken *Token) {}

	unsigned CommaSeparatedList::formatAfterToken(LineState &State,
	ContinuationIndenter *Indenter,
	bool DryRun) {
	if (State.NextToken == nullptr \|\| !State.NextToken->Previous)
	return 0;

	// Ensure that we start on the opening brace.
	const FormatToken *LBrace =
	State.NextToken->Previous->getPreviousNonComment();
	if (!LBrace \|\| !LBrace->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) \|\|
	LBrace->BlockKind == BK_Block \|\| LBrace->Type == TT_DictLiteral \|\|
	LBrace->Next->Type == TT_DesignatedInitializerPeriod)
	return 0;

	// Calculate the number of code points we have to format this list. As the
	// first token is already placed, we have to subtract it.
	unsigned RemainingCodePoints =
	Style.ColumnLimit - State.Column + State.NextToken->Previous->ColumnWidth;

	// Find the best ColumnFormat, i.e. the best number of columns to use.
	const ColumnFormat *Format = getColumnFormat(RemainingCodePoints);
	// If no ColumnFormat can be used, the braced list would generally be
	// bin-packed. Add a severe penalty to this so that column layouts are
	// preferred if possible.
	if (!Format)
	return 10000;

	// Format the entire list.
	unsigned Penalty = 0;
	unsigned Column = 0;
	unsigned Item = 0;
	while (State.NextToken != LBrace->MatchingParen) {
	bool NewLine = false;
	unsigned ExtraSpaces = 0;

	// If the previous token was one of our commas, we are now on the next item.
	if (Item < Commas.size() && State.NextToken->Previous == Commas[Item]) {
	if (!State.NextToken->isTrailingComment()) {
	ExtraSpaces += Format->ColumnSizes[Column] - ItemLengths[Item];
	++Column;
	}
	++Item;
	}

	if (Column == Format->Columns \|\| State.NextToken->MustBreakBefore) {
	Column = 0;
	NewLine = true;
	}

	// Place token using the continuation indenter and store the penalty.
	Penalty += Indenter->addTokenToState(State, NewLine, DryRun, ExtraSpaces);
	}
	return Penalty;
	}

	unsigned CommaSeparatedList::formatFromToken(LineState &State,
	ContinuationIndenter *Indenter,
	bool DryRun) {
	if (HasNestedBracedList)
	State.Stack.back().AvoidBinPacking = true;
	return 0;
	}

	// Returns the lengths in code points between Begin and End (both included),
	// assuming that the entire sequence is put on a single line.
	static unsigned CodePointsBetween(const FormatToken *Begin,
	const FormatToken *End) {
	assert(End->TotalLength >= Begin->TotalLength);
	return End->TotalLength - Begin->TotalLength + Begin->ColumnWidth;
	}

	void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) {
	// FIXME: At some point we might want to do this for other lists, too.
	if (!Token->MatchingParen \|\|
	!Token->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare))
	return;

	// In C++11 braced list style, we should not format in columns unless they
	// have many items (20 or more) or we allow bin-packing of function call
	// arguments.
	if (Style.Cpp11BracedListStyle && !Style.BinPackArguments &&
	Commas.size() < 19)
	return;

	// Limit column layout for JavaScript array initializers to 20 or more items
	// for now to introduce it carefully. We can become more aggressive if this
	// necessary.
	if (Token->is(TT_ArrayInitializerLSquare) && Commas.size() < 19)
	return;

	// Column format doesn't really make sense if we don't align after brackets.
	if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign)
	return;

	FormatToken *ItemBegin = Token->Next;
	while (ItemBegin->isTrailingComment())
	ItemBegin = ItemBegin->Next;
	SmallVector<bool, 8> MustBreakBeforeItem;

	// The lengths of an item if it is put at the end of the line. This includes
	// trailing comments which are otherwise ignored for column alignment.
	SmallVector<unsigned, 8> EndOfLineItemLength;

	bool HasSeparatingComment = false;
	for (unsigned i = 0, e = Commas.size() + 1; i != e; ++i) {
	// Skip comments on their own line.
	while (ItemBegin->HasUnescapedNewline && ItemBegin->isTrailingComment()) {
	ItemBegin = ItemBegin->Next;
	HasSeparatingComment = i > 0;
	}

	MustBreakBeforeItem.push_back(ItemBegin->MustBreakBefore);
	if (ItemBegin->is(tok::l_brace))
	HasNestedBracedList = true;
	const FormatToken *ItemEnd = nullptr;
	if (i == Commas.size()) {
	ItemEnd = Token->MatchingParen;
	const FormatToken *NonCommentEnd = ItemEnd->getPreviousNonComment();
	ItemLengths.push_back(CodePointsBetween(ItemBegin, NonCommentEnd));
	if (Style.Cpp11BracedListStyle &&
	!ItemEnd->Previous->isTrailingComment()) {
	// In Cpp11 braced list style, the } and possibly other subsequent
	// tokens will need to stay on a line with the last element.
	while (ItemEnd->Next && !ItemEnd->Next->CanBreakBefore)
	ItemEnd = ItemEnd->Next;
	} else {
	// In other braced lists styles, the "}" can be wrapped to the new line.
	ItemEnd = Token->MatchingParen->Previous;
	}
	} else {
	ItemEnd = Commas[i];
	// The comma is counted as part of the item when calculating the length.
	ItemLengths.push_back(CodePointsBetween(ItemBegin, ItemEnd));

	// Consume trailing comments so the are included in EndOfLineItemLength.
	if (ItemEnd->Next && !ItemEnd->Next->HasUnescapedNewline &&
	ItemEnd->Next->isTrailingComment())
	ItemEnd = ItemEnd->Next;
	}
	EndOfLineItemLength.push_back(CodePointsBetween(ItemBegin, ItemEnd));
	// If there is a trailing comma in the list, the next item will start at the
	// closing brace. Don't create an extra item for this.
	if (ItemEnd->getNextNonComment() == Token->MatchingParen)
	break;
	ItemBegin = ItemEnd->Next;
	}

	// Don't use column layout for lists with few elements and in presence of
	// separating comments.
	if (Commas.size() < 5 \|\| HasSeparatingComment)
	return;

	if (Token->NestingLevel != 0 && Token->is(tok::l_brace) && Commas.size() < 19)
	return;

	// We can never place more than ColumnLimit / 3 items in a row (because of the
	// spaces and the comma).
	unsigned MaxItems = Style.ColumnLimit / 3;
	std::vector<unsigned> MinSizeInColumn;
	MinSizeInColumn.reserve(MaxItems);
	for (unsigned Columns = 1; Columns <= MaxItems; ++Columns) {
	ColumnFormat Format;
	Format.Columns = Columns;
	Format.ColumnSizes.resize(Columns);
	MinSizeInColumn.assign(Columns, UINT_MAX);
	Format.LineCount = 1;
	bool HasRowWithSufficientColumns = false;
	unsigned Column = 0;
	for (unsigned i = 0, e = ItemLengths.size(); i != e; ++i) {
	assert(i < MustBreakBeforeItem.size());
	if (MustBreakBeforeItem[i] \|\| Column == Columns) {
	++Format.LineCount;
	Column = 0;
	}
	if (Column == Columns - 1)
	HasRowWithSufficientColumns = true;
	unsigned Length =
	(Column == Columns - 1) ? EndOfLineItemLength[i] : ItemLengths[i];
	Format.ColumnSizes[Column] = std::max(Format.ColumnSizes[Column], Length);
	MinSizeInColumn[Column] = std::min(MinSizeInColumn[Column], Length);
	++Column;
	}
	// If all rows are terminated early (e.g. by trailing comments), we don't
	// need to look further.
	if (!HasRowWithSufficientColumns)
	break;
	Format.TotalWidth = Columns - 1; // Width of the N-1 spaces.

	for (unsigned i = 0; i < Columns; ++i)
	Format.TotalWidth += Format.ColumnSizes[i];

	// Don't use this Format, if the difference between the longest and shortest
	// element in a column exceeds a threshold to avoid excessive spaces.
	if ([&] {
	for (unsigned i = 0; i < Columns - 1; ++i)
	if (Format.ColumnSizes[i] - MinSizeInColumn[i] > 10)
	return true;
	return false;
	}())
	continue;

	// Ignore layouts that are bound to violate the column limit.
	if (Format.TotalWidth > Style.ColumnLimit)
	continue;

	Formats.push_back(Format);
	}
	}

	const CommaSeparatedList::ColumnFormat *
	CommaSeparatedList::getColumnFormat(unsigned RemainingCharacters) const {
	const ColumnFormat *BestFormat = nullptr;
	for (SmallVector<ColumnFormat, 4>::const_reverse_iterator
	I = Formats.rbegin(),
	E = Formats.rend();
	I != E; ++I) {
	if (I->TotalWidth <= RemainingCharacters) {
	if (BestFormat && I->LineCount > BestFormat->LineCount)
	break;
	BestFormat = &*I;
	}
	}
	return BestFormat;
	}

	} // namespace format
	} // namespace clang