Coverage Report

Created: 2020-02-25 14:32

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/Format/ContinuationIndenter.h
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Source (jump to first uncovered line)
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//===--- ContinuationIndenter.h - Format C++ code ---------------*- C++ -*-===//
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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 an indenter that manages the indentation of
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/// continuations.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_LIB_FORMAT_CONTINUATIONINDENTER_H
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#define LLVM_CLANG_LIB_FORMAT_CONTINUATIONINDENTER_H
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#include "Encoding.h"
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#include "FormatToken.h"
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#include "clang/Format/Format.h"
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#include "llvm/Support/Regex.h"
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#include <map>
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#include <tuple>
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namespace clang {
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class SourceManager;
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namespace format {
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class AnnotatedLine;
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class BreakableToken;
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struct FormatToken;
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struct LineState;
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struct ParenState;
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struct RawStringFormatStyleManager;
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class WhitespaceManager;
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struct RawStringFormatStyleManager {
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  llvm::StringMap<FormatStyle> DelimiterStyle;
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  llvm::StringMap<FormatStyle> EnclosingFunctionStyle;
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  RawStringFormatStyleManager(const FormatStyle &CodeStyle);
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  llvm::Optional<FormatStyle> getDelimiterStyle(StringRef Delimiter) const;
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  llvm::Optional<FormatStyle>
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  getEnclosingFunctionStyle(StringRef EnclosingFunction) const;
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};
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class ContinuationIndenter {
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public:
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  /// Constructs a \c ContinuationIndenter to format \p Line starting in
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  /// column \p FirstIndent.
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  ContinuationIndenter(const FormatStyle &Style,
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                       const AdditionalKeywords &Keywords,
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                       const SourceManager &SourceMgr,
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                       WhitespaceManager &Whitespaces,
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                       encoding::Encoding Encoding,
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                       bool BinPackInconclusiveFunctions);
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  /// Get the initial state, i.e. the state after placing \p Line's
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  /// first token at \p FirstIndent. When reformatting a fragment of code, as in
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  /// the case of formatting inside raw string literals, \p FirstStartColumn is
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  /// the column at which the state of the parent formatter is.
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  LineState getInitialState(unsigned FirstIndent, unsigned FirstStartColumn,
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                            const AnnotatedLine *Line, bool DryRun);
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  // FIXME: canBreak and mustBreak aren't strictly indentation-related. Find a
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  // better home.
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  /// Returns \c true, if a line break after \p State is allowed.
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  bool canBreak(const LineState &State);
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  /// Returns \c true, if a line break after \p State is mandatory.
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  bool mustBreak(const LineState &State);
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  /// Appends the next token to \p State and updates information
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  /// necessary for indentation.
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  ///
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  /// Puts the token on the current line if \p Newline is \c false and adds a
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  /// line break and necessary indentation otherwise.
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  ///
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  /// If \p DryRun is \c false, also creates and stores the required
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  /// \c Replacement.
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  unsigned addTokenToState(LineState &State, bool Newline, bool DryRun,
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                           unsigned ExtraSpaces = 0);
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  /// Get the column limit for this line. This is the style's column
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  /// limit, potentially reduced for preprocessor definitions.
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  unsigned getColumnLimit(const LineState &State) const;
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private:
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  /// Mark the next token as consumed in \p State and modify its stacks
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  /// accordingly.
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  unsigned moveStateToNextToken(LineState &State, bool DryRun, bool Newline);
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  /// Update 'State' according to the next token's fake left parentheses.
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  void moveStatePastFakeLParens(LineState &State, bool Newline);
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  /// Update 'State' according to the next token's fake r_parens.
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  void moveStatePastFakeRParens(LineState &State);
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  /// Update 'State' according to the next token being one of "(<{[".
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  void moveStatePastScopeOpener(LineState &State, bool Newline);
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  /// Update 'State' according to the next token being one of ")>}]".
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  void moveStatePastScopeCloser(LineState &State);
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  /// Update 'State' with the next token opening a nested block.
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  void moveStateToNewBlock(LineState &State);
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  /// Reformats a raw string literal.
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  ///
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  /// \returns An extra penalty induced by reformatting the token.
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  unsigned reformatRawStringLiteral(const FormatToken &Current,
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                                    LineState &State,
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                                    const FormatStyle &RawStringStyle,
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                                    bool DryRun, bool Newline);
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  /// If the current token is at the end of the current line, handle
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  /// the transition to the next line.
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  unsigned handleEndOfLine(const FormatToken &Current, LineState &State,
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                           bool DryRun, bool AllowBreak, bool Newline);
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  /// If \p Current is a raw string that is configured to be reformatted,
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  /// return the style to be used.
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  llvm::Optional<FormatStyle> getRawStringStyle(const FormatToken &Current,
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                                                const LineState &State);
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  /// If the current token sticks out over the end of the line, break
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  /// it if possible.
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  ///
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  /// \returns A pair (penalty, exceeded), where penalty is the extra penalty
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  /// when tokens are broken or lines exceed the column limit, and exceeded
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  /// indicates whether the algorithm purposefully left lines exceeding the
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  /// column limit.
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  ///
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  /// The returned penalty will cover the cost of the additional line breaks
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  /// and column limit violation in all lines except for the last one. The
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  /// penalty for the column limit violation in the last line (and in single
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  /// line tokens) is handled in \c addNextStateToQueue.
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  ///
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  /// \p Strict indicates whether reflowing is allowed to leave characters
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  /// protruding the column limit; if true, lines will be split strictly within
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  /// the column limit where possible; if false, words are allowed to protrude
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  /// over the column limit as long as the penalty is less than the penalty
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  /// of a break.
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  std::pair<unsigned, bool> breakProtrudingToken(const FormatToken &Current,
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                                                 LineState &State,
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                                                 bool AllowBreak, bool DryRun,
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                                                 bool Strict);
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  /// Returns the \c BreakableToken starting at \p Current, or nullptr
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  /// if the current token cannot be broken.
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  std::unique_ptr<BreakableToken>
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  createBreakableToken(const FormatToken &Current, LineState &State,
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                       bool AllowBreak);
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  /// Appends the next token to \p State and updates information
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  /// necessary for indentation.
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  ///
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  /// Puts the token on the current line.
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  ///
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  /// If \p DryRun is \c false, also creates and stores the required
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  /// \c Replacement.
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  void addTokenOnCurrentLine(LineState &State, bool DryRun,
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                             unsigned ExtraSpaces);
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  /// Appends the next token to \p State and updates information
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  /// necessary for indentation.
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  ///
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  /// Adds a line break and necessary indentation.
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  ///
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  /// If \p DryRun is \c false, also creates and stores the required
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  /// \c Replacement.
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  unsigned addTokenOnNewLine(LineState &State, bool DryRun);
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  /// Calculate the new column for a line wrap before the next token.
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  unsigned getNewLineColumn(const LineState &State);
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  /// Adds a multiline token to the \p State.
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  ///
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  /// \returns Extra penalty for the first line of the literal: last line is
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  /// handled in \c addNextStateToQueue, and the penalty for other lines doesn't
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  /// matter, as we don't change them.
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  unsigned addMultilineToken(const FormatToken &Current, LineState &State);
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  /// Returns \c true if the next token starts a multiline string
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  /// literal.
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  ///
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  /// This includes implicitly concatenated strings, strings that will be broken
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  /// by clang-format and string literals with escaped newlines.
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  bool nextIsMultilineString(const LineState &State);
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  FormatStyle Style;
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  const AdditionalKeywords &Keywords;
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  const SourceManager &SourceMgr;
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  WhitespaceManager &Whitespaces;
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  encoding::Encoding Encoding;
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  bool BinPackInconclusiveFunctions;
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  llvm::Regex CommentPragmasRegex;
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  const RawStringFormatStyleManager RawStringFormats;
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};
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struct ParenState {
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  ParenState(const FormatToken *Tok, unsigned Indent, unsigned LastSpace,
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             bool AvoidBinPacking, bool NoLineBreak)
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      : Tok(Tok), Indent(Indent), LastSpace(LastSpace),
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        NestedBlockIndent(Indent), BreakBeforeClosingBrace(false),
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        AvoidBinPacking(AvoidBinPacking), BreakBeforeParameter(false),
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        NoLineBreak(NoLineBreak), NoLineBreakInOperand(false),
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        LastOperatorWrapped(true), ContainsLineBreak(false),
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        ContainsUnwrappedBuilder(false), AlignColons(true),
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        ObjCSelectorNameFound(false), HasMultipleNestedBlocks(false),
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224k
        NestedBlockInlined(false), IsInsideObjCArrayLiteral(false) {}
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  /// \brief The token opening this parenthesis level, or nullptr if this level
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  /// is opened by fake parenthesis.
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  ///
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  /// Not considered for memoization as it will always have the same value at
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  /// the same token.
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  const FormatToken *Tok;
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  /// The position to which a specific parenthesis level needs to be
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  /// indented.
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  unsigned Indent;
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  /// The position of the last space on each level.
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  ///
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  /// Used e.g. to break like:
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  /// functionCall(Parameter, otherCall(
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  ///                             OtherParameter));
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  unsigned LastSpace;
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  /// If a block relative to this parenthesis level gets wrapped, indent
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  /// it this much.
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  unsigned NestedBlockIndent;
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  /// The position the first "<<" operator encountered on each level.
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  ///
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  /// Used to align "<<" operators. 0 if no such operator has been encountered
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  /// on a level.
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  unsigned FirstLessLess = 0;
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  /// The column of a \c ? in a conditional expression;
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  unsigned QuestionColumn = 0;
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  /// The position of the colon in an ObjC method declaration/call.
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  unsigned ColonPos = 0;
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  /// The start of the most recent function in a builder-type call.
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  unsigned StartOfFunctionCall = 0;
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  /// Contains the start of array subscript expressions, so that they
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  /// can be aligned.
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  unsigned StartOfArraySubscripts = 0;
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  /// If a nested name specifier was broken over multiple lines, this
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  /// contains the start column of the second line. Otherwise 0.
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  unsigned NestedNameSpecifierContinuation = 0;
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  /// If a call expression was broken over multiple lines, this
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  /// contains the start column of the second line. Otherwise 0.
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  unsigned CallContinuation = 0;
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  /// The column of the first variable name in a variable declaration.
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  ///
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  /// Used to align further variables if necessary.
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  unsigned VariablePos = 0;
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  /// Whether a newline needs to be inserted before the block's closing
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  /// brace.
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  ///
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  /// We only want to insert a newline before the closing brace if there also
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  /// was a newline after the beginning left brace.
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  bool BreakBeforeClosingBrace : 1;
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  /// Avoid bin packing, i.e. multiple parameters/elements on multiple
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  /// lines, in this context.
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  bool AvoidBinPacking : 1;
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  /// Break after the next comma (or all the commas in this context if
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  /// \c AvoidBinPacking is \c true).
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  bool BreakBeforeParameter : 1;
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  /// Line breaking in this context would break a formatting rule.
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  bool NoLineBreak : 1;
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  /// Same as \c NoLineBreak, but is restricted until the end of the
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  /// operand (including the next ",").
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  bool NoLineBreakInOperand : 1;
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  /// True if the last binary operator on this level was wrapped to the
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  /// next line.
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  bool LastOperatorWrapped : 1;
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  /// \c true if this \c ParenState already contains a line-break.
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  ///
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  /// The first line break in a certain \c ParenState causes extra penalty so
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  /// that clang-format prefers similar breaks, i.e. breaks in the same
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  /// parenthesis.
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  bool ContainsLineBreak : 1;
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  /// \c true if this \c ParenState contains multiple segments of a
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  /// builder-type call on one line.
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  bool ContainsUnwrappedBuilder : 1;
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  /// \c true if the colons of the curren ObjC method expression should
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  /// be aligned.
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  ///
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  /// Not considered for memoization as it will always have the same value at
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  /// the same token.
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  bool AlignColons : 1;
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  /// \c true if at least one selector name was found in the current
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  /// ObjC method expression.
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  ///
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  /// Not considered for memoization as it will always have the same value at
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  /// the same token.
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  bool ObjCSelectorNameFound : 1;
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  /// \c true if there are multiple nested blocks inside these parens.
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  ///
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  /// Not considered for memoization as it will always have the same value at
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  /// the same token.
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  bool HasMultipleNestedBlocks : 1;
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  /// The start of a nested block (e.g. lambda introducer in C++ or
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  /// "function" in JavaScript) is not wrapped to a new line.
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  bool NestedBlockInlined : 1;
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  /// \c true if the current \c ParenState represents an Objective-C
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  /// array literal.
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  bool IsInsideObjCArrayLiteral : 1;
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32.1M
  bool operator<(const ParenState &Other) const {
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32.1M
    if (Indent != Other.Indent)
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2.92M
      return Indent < Other.Indent;
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29.2M
    if (LastSpace != Other.LastSpace)
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835k
      return LastSpace < Other.LastSpace;
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28.4M
    if (NestedBlockIndent != Other.NestedBlockIndent)
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480
      return NestedBlockIndent < Other.NestedBlockIndent;
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28.4M
    if (FirstLessLess != Other.FirstLessLess)
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0
      return FirstLessLess < Other.FirstLessLess;
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28.4M
    if (BreakBeforeClosingBrace != Other.BreakBeforeClosingBrace)
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0
      return BreakBeforeClosingBrace;
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28.4M
    if (QuestionColumn != Other.QuestionColumn)
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0
      return QuestionColumn < Other.QuestionColumn;
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28.4M
    if (AvoidBinPacking != Other.AvoidBinPacking)
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0
      return AvoidBinPacking;
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28.4M
    if (BreakBeforeParameter != Other.BreakBeforeParameter)
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1.63k
      return BreakBeforeParameter;
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28.4M
    if (NoLineBreak != Other.NoLineBreak)
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15.3k
      return NoLineBreak;
351
28.3M
    if (LastOperatorWrapped != Other.LastOperatorWrapped)
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3
      return LastOperatorWrapped;
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28.3M
    if (ColonPos != Other.ColonPos)
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6
      return ColonPos < Other.ColonPos;
355
28.3M
    if (StartOfFunctionCall != Other.StartOfFunctionCall)
356
36
      return StartOfFunctionCall < Other.StartOfFunctionCall;
357
28.3M
    if (StartOfArraySubscripts != Other.StartOfArraySubscripts)
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0
      return StartOfArraySubscripts < Other.StartOfArraySubscripts;
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28.3M
    if (CallContinuation != Other.CallContinuation)
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24
      return CallContinuation < Other.CallContinuation;
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28.3M
    if (VariablePos != Other.VariablePos)
362
15.0k
      return VariablePos < Other.VariablePos;
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28.3M
    if (ContainsLineBreak != Other.ContainsLineBreak)
364
369
      return ContainsLineBreak;
365
28.3M
    if (ContainsUnwrappedBuilder != Other.ContainsUnwrappedBuilder)
366
0
      return ContainsUnwrappedBuilder;
367
28.3M
    if (NestedBlockInlined != Other.NestedBlockInlined)
368
970
      return NestedBlockInlined;
369
28.3M
    return false;
370
28.3M
  }
371
};
372
373
/// The current state when indenting a unwrapped line.
374
///
375
/// As the indenting tries different combinations this is copied by value.
376
struct LineState {
377
  /// The number of used columns in the current line.
378
  unsigned Column;
379
380
  /// The token that needs to be next formatted.
381
  FormatToken *NextToken;
382
383
  /// \c true if this line contains a continued for-loop section.
384
  bool LineContainsContinuedForLoopSection;
385
386
  /// \c true if \p NextToken should not continue this line.
387
  bool NoContinuation;
388
389
  /// The \c NestingLevel at the start of this line.
390
  unsigned StartOfLineLevel;
391
392
  /// The lowest \c NestingLevel on the current line.
393
  unsigned LowestLevelOnLine;
394
395
  /// The start column of the string literal, if we're in a string
396
  /// literal sequence, 0 otherwise.
397
  unsigned StartOfStringLiteral;
398
399
  /// A stack keeping track of properties applying to parenthesis
400
  /// levels.
401
  std::vector<ParenState> Stack;
402
403
  /// Ignore the stack of \c ParenStates for state comparison.
404
  ///
405
  /// In long and deeply nested unwrapped lines, the current algorithm can
406
  /// be insufficient for finding the best formatting with a reasonable amount
407
  /// of time and memory. Setting this flag will effectively lead to the
408
  /// algorithm not analyzing some combinations. However, these combinations
409
  /// rarely contain the optimal solution: In short, accepting a higher
410
  /// penalty early would need to lead to different values in the \c
411
  /// ParenState stack (in an otherwise identical state) and these different
412
  /// values would need to lead to a significant amount of avoided penalty
413
  /// later.
414
  ///
415
  /// FIXME: Come up with a better algorithm instead.
416
  bool IgnoreStackForComparison;
417
418
  /// The indent of the first token.
419
  unsigned FirstIndent;
420
421
  /// The line that is being formatted.
422
  ///
423
  /// Does not need to be considered for memoization because it doesn't change.
424
  const AnnotatedLine *Line;
425
426
  /// Comparison operator to be able to used \c LineState in \c map.
427
12.9M
  bool operator<(const LineState &Other) const {
428
12.9M
    if (NextToken != Other.NextToken)
429
4.93M
      return NextToken < Other.NextToken;
430
7.96M
    if (Column != Other.Column)
431
3.46M
      return Column < Other.Column;
432
4.49M
    if (LineContainsContinuedForLoopSection !=
433
4.49M
        Other.LineContainsContinuedForLoopSection)
434
0
      return LineContainsContinuedForLoopSection;
435
4.49M
    if (NoContinuation != Other.NoContinuation)
436
0
      return NoContinuation;
437
4.49M
    if (StartOfLineLevel != Other.StartOfLineLevel)
438
1.49M
      return StartOfLineLevel < Other.StartOfLineLevel;
439
3.00M
    if (LowestLevelOnLine != Other.LowestLevelOnLine)
440
4
      return LowestLevelOnLine < Other.LowestLevelOnLine;
441
3.00M
    if (StartOfStringLiteral != Other.StartOfStringLiteral)
442
117
      return StartOfStringLiteral < Other.StartOfStringLiteral;
443
3.00M
    if (IgnoreStackForComparison || 
Other.IgnoreStackForComparison2.82M
)
444
228k
      return false;
445
2.77M
    return Stack < Other.Stack;
446
2.77M
  }
447
};
448
449
} // end namespace format
450
} // end namespace clang
451
452
#endif