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309 lines
11 KiB
309 lines
11 KiB
//===--- FormatToken.cpp - Format C++ code --------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// This file implements specific functions of \c FormatTokens and their
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/// roles.
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///
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//===----------------------------------------------------------------------===//
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#include "FormatToken.h"
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#include "ContinuationIndenter.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/Debug.h"
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#include <climits>
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namespace clang {
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namespace format {
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const char *getTokenTypeName(TokenType Type) {
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static const char *const TokNames[] = {
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#define TYPE(X) #X,
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LIST_TOKEN_TYPES
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#undef TYPE
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nullptr};
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if (Type < NUM_TOKEN_TYPES)
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return TokNames[Type];
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llvm_unreachable("unknown TokenType");
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return nullptr;
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}
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// FIXME: This is copy&pasted from Sema. Put it in a common place and remove
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// duplication.
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bool FormatToken::isSimpleTypeSpecifier() const {
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switch (Tok.getKind()) {
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case tok::kw_short:
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case tok::kw_long:
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case tok::kw___int64:
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case tok::kw___int128:
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case tok::kw_signed:
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case tok::kw_unsigned:
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case tok::kw_void:
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case tok::kw_char:
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case tok::kw_int:
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case tok::kw_half:
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case tok::kw_float:
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case tok::kw_double:
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case tok::kw___bf16:
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case tok::kw__Float16:
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case tok::kw___float128:
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case tok::kw_wchar_t:
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case tok::kw_bool:
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case tok::kw___underlying_type:
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case tok::annot_typename:
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case tok::kw_char8_t:
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case tok::kw_char16_t:
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case tok::kw_char32_t:
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case tok::kw_typeof:
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case tok::kw_decltype:
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case tok::kw__Atomic:
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return true;
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default:
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return false;
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}
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}
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TokenRole::~TokenRole() {}
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void TokenRole::precomputeFormattingInfos(const FormatToken *Token) {}
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unsigned CommaSeparatedList::formatAfterToken(LineState &State,
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ContinuationIndenter *Indenter,
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bool DryRun) {
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if (State.NextToken == nullptr || !State.NextToken->Previous)
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return 0;
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if (Formats.size() == 1)
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return 0; // Handled by formatFromToken
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// Ensure that we start on the opening brace.
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const FormatToken *LBrace =
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State.NextToken->Previous->getPreviousNonComment();
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if (!LBrace || !LBrace->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) ||
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LBrace->is(BK_Block) || LBrace->is(TT_DictLiteral) ||
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LBrace->Next->is(TT_DesignatedInitializerPeriod))
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return 0;
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// Calculate the number of code points we have to format this list. As the
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// first token is already placed, we have to subtract it.
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unsigned RemainingCodePoints =
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Style.ColumnLimit - State.Column + State.NextToken->Previous->ColumnWidth;
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// Find the best ColumnFormat, i.e. the best number of columns to use.
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const ColumnFormat *Format = getColumnFormat(RemainingCodePoints);
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// If no ColumnFormat can be used, the braced list would generally be
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// bin-packed. Add a severe penalty to this so that column layouts are
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// preferred if possible.
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if (!Format)
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return 10000;
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// Format the entire list.
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unsigned Penalty = 0;
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unsigned Column = 0;
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unsigned Item = 0;
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while (State.NextToken != LBrace->MatchingParen) {
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bool NewLine = false;
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unsigned ExtraSpaces = 0;
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// If the previous token was one of our commas, we are now on the next item.
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if (Item < Commas.size() && State.NextToken->Previous == Commas[Item]) {
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if (!State.NextToken->isTrailingComment()) {
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ExtraSpaces += Format->ColumnSizes[Column] - ItemLengths[Item];
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++Column;
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}
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++Item;
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}
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if (Column == Format->Columns || State.NextToken->MustBreakBefore) {
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Column = 0;
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NewLine = true;
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}
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// Place token using the continuation indenter and store the penalty.
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Penalty += Indenter->addTokenToState(State, NewLine, DryRun, ExtraSpaces);
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}
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return Penalty;
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}
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unsigned CommaSeparatedList::formatFromToken(LineState &State,
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ContinuationIndenter *Indenter,
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bool DryRun) {
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// Formatting with 1 Column isn't really a column layout, so we don't need the
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// special logic here. We can just avoid bin packing any of the parameters.
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if (Formats.size() == 1 || HasNestedBracedList)
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State.Stack.back().AvoidBinPacking = true;
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return 0;
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}
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// Returns the lengths in code points between Begin and End (both included),
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// assuming that the entire sequence is put on a single line.
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static unsigned CodePointsBetween(const FormatToken *Begin,
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const FormatToken *End) {
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assert(End->TotalLength >= Begin->TotalLength);
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return End->TotalLength - Begin->TotalLength + Begin->ColumnWidth;
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}
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void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) {
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// FIXME: At some point we might want to do this for other lists, too.
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if (!Token->MatchingParen ||
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!Token->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare))
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return;
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// In C++11 braced list style, we should not format in columns unless they
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// have many items (20 or more) or we allow bin-packing of function call
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// arguments.
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if (Style.Cpp11BracedListStyle && !Style.BinPackArguments &&
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Commas.size() < 19)
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return;
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// Limit column layout for JavaScript array initializers to 20 or more items
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// for now to introduce it carefully. We can become more aggressive if this
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// necessary.
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if (Token->is(TT_ArrayInitializerLSquare) && Commas.size() < 19)
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return;
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// Column format doesn't really make sense if we don't align after brackets.
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if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign)
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return;
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FormatToken *ItemBegin = Token->Next;
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while (ItemBegin->isTrailingComment())
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ItemBegin = ItemBegin->Next;
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SmallVector<bool, 8> MustBreakBeforeItem;
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// The lengths of an item if it is put at the end of the line. This includes
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// trailing comments which are otherwise ignored for column alignment.
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SmallVector<unsigned, 8> EndOfLineItemLength;
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bool HasSeparatingComment = false;
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for (unsigned i = 0, e = Commas.size() + 1; i != e; ++i) {
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// Skip comments on their own line.
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while (ItemBegin->HasUnescapedNewline && ItemBegin->isTrailingComment()) {
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ItemBegin = ItemBegin->Next;
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HasSeparatingComment = i > 0;
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}
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MustBreakBeforeItem.push_back(ItemBegin->MustBreakBefore);
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if (ItemBegin->is(tok::l_brace))
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HasNestedBracedList = true;
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const FormatToken *ItemEnd = nullptr;
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if (i == Commas.size()) {
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ItemEnd = Token->MatchingParen;
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const FormatToken *NonCommentEnd = ItemEnd->getPreviousNonComment();
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ItemLengths.push_back(CodePointsBetween(ItemBegin, NonCommentEnd));
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if (Style.Cpp11BracedListStyle &&
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!ItemEnd->Previous->isTrailingComment()) {
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// In Cpp11 braced list style, the } and possibly other subsequent
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// tokens will need to stay on a line with the last element.
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while (ItemEnd->Next && !ItemEnd->Next->CanBreakBefore)
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ItemEnd = ItemEnd->Next;
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} else {
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// In other braced lists styles, the "}" can be wrapped to the new line.
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ItemEnd = Token->MatchingParen->Previous;
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}
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} else {
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ItemEnd = Commas[i];
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// The comma is counted as part of the item when calculating the length.
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ItemLengths.push_back(CodePointsBetween(ItemBegin, ItemEnd));
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// Consume trailing comments so the are included in EndOfLineItemLength.
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if (ItemEnd->Next && !ItemEnd->Next->HasUnescapedNewline &&
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ItemEnd->Next->isTrailingComment())
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ItemEnd = ItemEnd->Next;
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}
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EndOfLineItemLength.push_back(CodePointsBetween(ItemBegin, ItemEnd));
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// If there is a trailing comma in the list, the next item will start at the
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// closing brace. Don't create an extra item for this.
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if (ItemEnd->getNextNonComment() == Token->MatchingParen)
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break;
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ItemBegin = ItemEnd->Next;
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}
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// Don't use column layout for lists with few elements and in presence of
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// separating comments.
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if (Commas.size() < 5 || HasSeparatingComment)
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return;
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if (Token->NestingLevel != 0 && Token->is(tok::l_brace) && Commas.size() < 19)
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return;
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// We can never place more than ColumnLimit / 3 items in a row (because of the
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// spaces and the comma).
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unsigned MaxItems = Style.ColumnLimit / 3;
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std::vector<unsigned> MinSizeInColumn;
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MinSizeInColumn.reserve(MaxItems);
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for (unsigned Columns = 1; Columns <= MaxItems; ++Columns) {
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ColumnFormat Format;
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Format.Columns = Columns;
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Format.ColumnSizes.resize(Columns);
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MinSizeInColumn.assign(Columns, UINT_MAX);
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Format.LineCount = 1;
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bool HasRowWithSufficientColumns = false;
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unsigned Column = 0;
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for (unsigned i = 0, e = ItemLengths.size(); i != e; ++i) {
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assert(i < MustBreakBeforeItem.size());
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if (MustBreakBeforeItem[i] || Column == Columns) {
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++Format.LineCount;
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Column = 0;
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}
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if (Column == Columns - 1)
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HasRowWithSufficientColumns = true;
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unsigned Length =
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(Column == Columns - 1) ? EndOfLineItemLength[i] : ItemLengths[i];
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Format.ColumnSizes[Column] = std::max(Format.ColumnSizes[Column], Length);
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MinSizeInColumn[Column] = std::min(MinSizeInColumn[Column], Length);
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++Column;
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}
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// If all rows are terminated early (e.g. by trailing comments), we don't
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// need to look further.
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if (!HasRowWithSufficientColumns)
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break;
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Format.TotalWidth = Columns - 1; // Width of the N-1 spaces.
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for (unsigned i = 0; i < Columns; ++i)
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Format.TotalWidth += Format.ColumnSizes[i];
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// Don't use this Format, if the difference between the longest and shortest
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// element in a column exceeds a threshold to avoid excessive spaces.
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if ([&] {
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for (unsigned i = 0; i < Columns - 1; ++i)
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if (Format.ColumnSizes[i] - MinSizeInColumn[i] > 10)
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return true;
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return false;
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}())
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continue;
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// Ignore layouts that are bound to violate the column limit.
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if (Format.TotalWidth > Style.ColumnLimit && Columns > 1)
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continue;
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Formats.push_back(Format);
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}
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}
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const CommaSeparatedList::ColumnFormat *
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CommaSeparatedList::getColumnFormat(unsigned RemainingCharacters) const {
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const ColumnFormat *BestFormat = nullptr;
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for (SmallVector<ColumnFormat, 4>::const_reverse_iterator
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I = Formats.rbegin(),
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E = Formats.rend();
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I != E; ++I) {
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if (I->TotalWidth <= RemainingCharacters || I->Columns == 1) {
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if (BestFormat && I->LineCount > BestFormat->LineCount)
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break;
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BestFormat = &*I;
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}
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}
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return BestFormat;
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}
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} // namespace format
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} // namespace clang
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