//===--- ContinuationIndenter.h - Format C++ code ---------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

///

/// \file

/// This file implements an indenter that manages the indentation of

/// continuations.

///

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LIB_FORMAT_CONTINUATIONINDENTER_H

#define LLVM_CLANG_LIB_FORMAT_CONTINUATIONINDENTER_H

#include "Encoding.h"

#include "FormatToken.h"

#include "clang/Format/Format.h"

#include "llvm/Support/Regex.h"

#include <map>

#include <optional>

#include <tuple>

namespace clang {

class SourceManager;

namespace format {

class AnnotatedLine;

class BreakableToken;

struct FormatToken;

struct LineState;

struct ParenState;

struct RawStringFormatStyleManager;

class WhitespaceManager;

struct RawStringFormatStyleManager {

  llvm::StringMap<FormatStyle> DelimiterStyle;

  llvm::StringMap<FormatStyle> EnclosingFunctionStyle;

  RawStringFormatStyleManager(const FormatStyle &CodeStyle);

  std::optional<FormatStyle> getDelimiterStyle(StringRef Delimiter) const;

  std::optional<FormatStyle>

  getEnclosingFunctionStyle(StringRef EnclosingFunction) const;

};

class ContinuationIndenter {

public:

  /// Constructs a \c ContinuationIndenter to format \p Line starting in

  /// column \p FirstIndent.

  ContinuationIndenter(const FormatStyle &Style,

                       const AdditionalKeywords &Keywords,

                       const SourceManager &SourceMgr,

                       WhitespaceManager &Whitespaces,

                       encoding::Encoding Encoding,

                       bool BinPackInconclusiveFunctions);

  /// Get the initial state, i.e. the state after placing \p Line's

  /// first token at \p FirstIndent. When reformatting a fragment of code, as in

  /// the case of formatting inside raw string literals, \p FirstStartColumn is

  /// the column at which the state of the parent formatter is.

  LineState getInitialState(unsigned FirstIndent, unsigned FirstStartColumn,

                            const AnnotatedLine *Line, bool DryRun);

  // FIXME: canBreak and mustBreak aren't strictly indentation-related. Find a

  // better home.

  /// Returns \c true, if a line break after \p State is allowed.

  bool canBreak(const LineState &State);

  /// Returns \c true, if a line break after \p State is mandatory.

  bool mustBreak(const LineState &State);

  /// Appends the next token to \p State and updates information

  /// necessary for indentation.

  ///

  /// Puts the token on the current line if \p Newline is \c false and adds a

  /// line break and necessary indentation otherwise.

  ///

  /// If \p DryRun is \c false, also creates and stores the required

  /// \c Replacement.

  unsigned addTokenToState(LineState &State, bool Newline, bool DryRun,

                           unsigned ExtraSpaces = 0);

  /// Get the column limit for this line. This is the style's column

  /// limit, potentially reduced for preprocessor definitions.

  unsigned getColumnLimit(const LineState &State) const;

private:

  /// Mark the next token as consumed in \p State and modify its stacks

  /// accordingly.

  unsigned moveStateToNextToken(LineState &State, bool DryRun, bool Newline);

  /// Update 'State' according to the next token's fake left parentheses.

  void moveStatePastFakeLParens(LineState &State, bool Newline);

  /// Update 'State' according to the next token's fake r_parens.

  void moveStatePastFakeRParens(LineState &State);

  /// Update 'State' according to the next token being one of "(<{[".

  void moveStatePastScopeOpener(LineState &State, bool Newline);

  /// Update 'State' according to the next token being one of ")>}]".

  void moveStatePastScopeCloser(LineState &State);

  /// Update 'State' with the next token opening a nested block.

  void moveStateToNewBlock(LineState &State);

  /// Reformats a raw string literal.

  ///

  /// \returns An extra penalty induced by reformatting the token.

  unsigned reformatRawStringLiteral(const FormatToken &Current,

                                    LineState &State,

                                    const FormatStyle &RawStringStyle,

                                    bool DryRun, bool Newline);

  /// If the current token is at the end of the current line, handle

  /// the transition to the next line.

  unsigned handleEndOfLine(const FormatToken &Current, LineState &State,

                           bool DryRun, bool AllowBreak, bool Newline);

  /// If \p Current is a raw string that is configured to be reformatted,

  /// return the style to be used.

  std::optional<FormatStyle> getRawStringStyle(const FormatToken &Current,

                                               const LineState &State);

  /// If the current token sticks out over the end of the line, break

  /// it if possible.

  ///

  /// \returns A pair (penalty, exceeded), where penalty is the extra penalty

  /// when tokens are broken or lines exceed the column limit, and exceeded

  /// indicates whether the algorithm purposefully left lines exceeding the

  /// column limit.

  ///

  /// The returned penalty will cover the cost of the additional line breaks

  /// and column limit violation in all lines except for the last one. The

  /// penalty for the column limit violation in the last line (and in single

  /// line tokens) is handled in \c addNextStateToQueue.

  ///

  /// \p Strict indicates whether reflowing is allowed to leave characters

  /// protruding the column limit; if true, lines will be split strictly within

  /// the column limit where possible; if false, words are allowed to protrude

  /// over the column limit as long as the penalty is less than the penalty

  /// of a break.

  std::pair<unsigned, bool> breakProtrudingToken(const FormatToken &Current,

                                                 LineState &State,

                                                 bool AllowBreak, bool DryRun,

                                                 bool Strict);

  /// Returns the \c BreakableToken starting at \p Current, or nullptr

  /// if the current token cannot be broken.

  std::unique_ptr<BreakableToken>

  createBreakableToken(const FormatToken &Current, LineState &State,

                       bool AllowBreak);

  /// Appends the next token to \p State and updates information

  /// necessary for indentation.

  ///

  /// Puts the token on the current line.

  ///

  /// If \p DryRun is \c false, also creates and stores the required

  /// \c Replacement.

  void addTokenOnCurrentLine(LineState &State, bool DryRun,

                             unsigned ExtraSpaces);

  /// Appends the next token to \p State and updates information

  /// necessary for indentation.

  ///

  /// Adds a line break and necessary indentation.

  ///

  /// If \p DryRun is \c false, also creates and stores the required

  /// \c Replacement.

  unsigned addTokenOnNewLine(LineState &State, bool DryRun);

  /// Calculate the new column for a line wrap before the next token.

  unsigned getNewLineColumn(const LineState &State);

  /// Adds a multiline token to the \p State.

  ///

  /// \returns Extra penalty for the first line of the literal: last line is

  /// handled in \c addNextStateToQueue, and the penalty for other lines doesn't

  /// matter, as we don't change them.

  unsigned addMultilineToken(const FormatToken &Current, LineState &State);

  /// Returns \c true if the next token starts a multiline string

  /// literal.

  ///

  /// This includes implicitly concatenated strings, strings that will be broken

  /// by clang-format and string literals with escaped newlines.

  bool nextIsMultilineString(const LineState &State);

  FormatStyle Style;

  const AdditionalKeywords &Keywords;

  const SourceManager &SourceMgr;

  WhitespaceManager &Whitespaces;

  encoding::Encoding Encoding;

  bool BinPackInconclusiveFunctions;

  llvm::Regex CommentPragmasRegex;

  const RawStringFormatStyleManager RawStringFormats;

};

struct ParenState {

  ParenState(const FormatToken *Tok, unsigned Indent, unsigned LastSpace,

             bool AvoidBinPacking, bool NoLineBreak)

      : Tok(Tok), Indent(Indent), LastSpace(LastSpace),

        NestedBlockIndent(Indent), IsAligned(false),

        BreakBeforeClosingBrace(false), BreakBeforeClosingParen(false),

        AvoidBinPacking(AvoidBinPacking), BreakBeforeParameter(false),

        NoLineBreak(NoLineBreak), NoLineBreakInOperand(false),

        LastOperatorWrapped(true), ContainsLineBreak(false),

        ContainsUnwrappedBuilder(false), AlignColons(true),

        ObjCSelectorNameFound(false), HasMultipleNestedBlocks(false),

        NestedBlockInlined(false), IsInsideObjCArrayLiteral(false),

        IsCSharpGenericTypeConstraint(false), IsChainedConditional(false),

        IsWrappedConditional(false), UnindentOperator(false) {}

  /// \brief The token opening this parenthesis level, or nullptr if this level

  /// is opened by fake parenthesis.

  ///

  /// Not considered for memoization as it will always have the same value at

  /// the same token.

  const FormatToken *Tok;

  /// The position to which a specific parenthesis level needs to be

  /// indented.

  unsigned Indent;

  /// The position of the last space on each level.

  ///

  /// Used e.g. to break like:

  /// functionCall(Parameter, otherCall(

  ///                             OtherParameter));

  unsigned LastSpace;

  /// If a block relative to this parenthesis level gets wrapped, indent

  /// it this much.

  unsigned NestedBlockIndent;

  /// The position the first "<<" operator encountered on each level.

  ///

  /// Used to align "<<" operators. 0 if no such operator has been encountered

  /// on a level.

  unsigned FirstLessLess = 0;

  /// The column of a \c ? in a conditional expression;

  unsigned QuestionColumn = 0;

  /// The position of the colon in an ObjC method declaration/call.

  unsigned ColonPos = 0;

  /// The start of the most recent function in a builder-type call.

  unsigned StartOfFunctionCall = 0;

  /// Contains the start of array subscript expressions, so that they

  /// can be aligned.

  unsigned StartOfArraySubscripts = 0;

  /// If a nested name specifier was broken over multiple lines, this

  /// contains the start column of the second line. Otherwise 0.

  unsigned NestedNameSpecifierContinuation = 0;

  /// If a call expression was broken over multiple lines, this

  /// contains the start column of the second line. Otherwise 0.

  unsigned CallContinuation = 0;

  /// The column of the first variable name in a variable declaration.

  ///

  /// Used to align further variables if necessary.

  unsigned VariablePos = 0;

  /// Whether this block's indentation is used for alignment.

  bool IsAligned : 1;

  /// Whether a newline needs to be inserted before the block's closing

  /// brace.

  ///

  /// We only want to insert a newline before the closing brace if there also

  /// was a newline after the beginning left brace.

  bool BreakBeforeClosingBrace : 1;

  /// Whether a newline needs to be inserted before the block's closing

  /// paren.

  ///

  /// We only want to insert a newline before the closing paren if there also

  /// was a newline after the beginning left paren.

  bool BreakBeforeClosingParen : 1;

  /// Avoid bin packing, i.e. multiple parameters/elements on multiple

  /// lines, in this context.

  bool AvoidBinPacking : 1;

  /// Break after the next comma (or all the commas in this context if

  /// \c AvoidBinPacking is \c true).

  bool BreakBeforeParameter : 1;

  /// Line breaking in this context would break a formatting rule.

  bool NoLineBreak : 1;

  /// Same as \c NoLineBreak, but is restricted until the end of the

  /// operand (including the next ",").

  bool NoLineBreakInOperand : 1;

  /// True if the last binary operator on this level was wrapped to the

  /// next line.

  bool LastOperatorWrapped : 1;

  /// \c true if this \c ParenState already contains a line-break.

  ///

  /// The first line break in a certain \c ParenState causes extra penalty so

  /// that clang-format prefers similar breaks, i.e. breaks in the same

  /// parenthesis.

  bool ContainsLineBreak : 1;

  /// \c true if this \c ParenState contains multiple segments of a

  /// builder-type call on one line.

  bool ContainsUnwrappedBuilder : 1;

  /// \c true if the colons of the curren ObjC method expression should

  /// be aligned.

  ///

  /// Not considered for memoization as it will always have the same value at

  /// the same token.

  bool AlignColons : 1;

  /// \c true if at least one selector name was found in the current

  /// ObjC method expression.

  ///

  /// Not considered for memoization as it will always have the same value at

  /// the same token.

  bool ObjCSelectorNameFound : 1;

  /// \c true if there are multiple nested blocks inside these parens.

  ///

  /// Not considered for memoization as it will always have the same value at

  /// the same token.

  bool HasMultipleNestedBlocks : 1;

  /// The start of a nested block (e.g. lambda introducer in C++ or

  /// "function" in JavaScript) is not wrapped to a new line.

  bool NestedBlockInlined : 1;

  /// \c true if the current \c ParenState represents an Objective-C

  /// array literal.

  bool IsInsideObjCArrayLiteral : 1;

  bool IsCSharpGenericTypeConstraint : 1;

  /// \brief true if the current \c ParenState represents the false branch of

  /// a chained conditional expression (e.g. else-if)

  bool IsChainedConditional : 1;

  /// \brief true if there conditionnal was wrapped on the first operator (the

  /// question mark)

  bool IsWrappedConditional : 1;

  /// \brief Indicates the indent should be reduced by the length of the

  /// operator.

  bool UnindentOperator : 1;

  bool operator<(const ParenState &Other) const {

    if (Indent != Other.Indent)

      return Indent < Other.Indent;

    if (LastSpace != Other.LastSpace)

      return LastSpace < Other.LastSpace;

    if (NestedBlockIndent != Other.NestedBlockIndent)

      return NestedBlockIndent < Other.NestedBlockIndent;

    if (FirstLessLess != Other.FirstLessLess)

      return FirstLessLess < Other.FirstLessLess;

    if (IsAligned != Other.IsAligned)

      return IsAligned;

    if (BreakBeforeClosingBrace != Other.BreakBeforeClosingBrace)

      return BreakBeforeClosingBrace;

    if (BreakBeforeClosingParen != Other.BreakBeforeClosingParen)

      return BreakBeforeClosingParen;

    if (QuestionColumn != Other.QuestionColumn)

      return QuestionColumn < Other.QuestionColumn;

    if (AvoidBinPacking != Other.AvoidBinPacking)

      return AvoidBinPacking;

    if (BreakBeforeParameter != Other.BreakBeforeParameter)

      return BreakBeforeParameter;

    if (NoLineBreak != Other.NoLineBreak)

      return NoLineBreak;

    if (LastOperatorWrapped != Other.LastOperatorWrapped)

      return LastOperatorWrapped;

    if (ColonPos != Other.ColonPos)

      return ColonPos < Other.ColonPos;

    if (StartOfFunctionCall != Other.StartOfFunctionCall)

      return StartOfFunctionCall < Other.StartOfFunctionCall;

    if (StartOfArraySubscripts != Other.StartOfArraySubscripts)

      return StartOfArraySubscripts < Other.StartOfArraySubscripts;

    if (CallContinuation != Other.CallContinuation)

      return CallContinuation < Other.CallContinuation;

    if (VariablePos != Other.VariablePos)

      return VariablePos < Other.VariablePos;

    if (ContainsLineBreak != Other.ContainsLineBreak)

      return ContainsLineBreak;

    if (ContainsUnwrappedBuilder != Other.ContainsUnwrappedBuilder)

      return ContainsUnwrappedBuilder;

    if (NestedBlockInlined != Other.NestedBlockInlined)

      return NestedBlockInlined;

    if (IsCSharpGenericTypeConstraint != Other.IsCSharpGenericTypeConstraint)

      return IsCSharpGenericTypeConstraint;

    if (IsChainedConditional != Other.IsChainedConditional)

      return IsChainedConditional;

    if (IsWrappedConditional != Other.IsWrappedConditional)

      return IsWrappedConditional;

    if (UnindentOperator != Other.UnindentOperator)

      return UnindentOperator;

    return false;

  }

};

/// The current state when indenting a unwrapped line.

///

/// As the indenting tries different combinations this is copied by value.

struct LineState {

  /// The number of used columns in the current line.

  unsigned Column;

  /// The token that needs to be next formatted.

  FormatToken *NextToken;

  /// \c true if \p NextToken should not continue this line.

  bool NoContinuation;

  /// The \c NestingLevel at the start of this line.

  unsigned StartOfLineLevel;

  /// The lowest \c NestingLevel on the current line.

  unsigned LowestLevelOnLine;

  /// The start column of the string literal, if we're in a string

  /// literal sequence, 0 otherwise.

  unsigned StartOfStringLiteral;

  /// Disallow line breaks for this line.

  bool NoLineBreak;

  /// A stack keeping track of properties applying to parenthesis

  /// levels.

  SmallVector<ParenState> Stack;

  /// Ignore the stack of \c ParenStates for state comparison.

  ///

  /// In long and deeply nested unwrapped lines, the current algorithm can

  /// be insufficient for finding the best formatting with a reasonable amount

  /// of time and memory. Setting this flag will effectively lead to the

  /// algorithm not analyzing some combinations. However, these combinations

  /// rarely contain the optimal solution: In short, accepting a higher

  /// penalty early would need to lead to different values in the \c

  /// ParenState stack (in an otherwise identical state) and these different

  /// values would need to lead to a significant amount of avoided penalty

  /// later.

  ///

  /// FIXME: Come up with a better algorithm instead.

  bool IgnoreStackForComparison;

  /// The indent of the first token.

  unsigned FirstIndent;

  /// The line that is being formatted.

  ///

  /// Does not need to be considered for memoization because it doesn't change.

  const AnnotatedLine *Line;

  /// Comparison operator to be able to used \c LineState in \c map.

  bool operator<(const LineState &Other) const {

    if (NextToken != Other.NextToken)

      return NextToken < Other.NextToken;

    if (Column != Other.Column)

      return Column < Other.Column;

    if (NoContinuation != Other.NoContinuation)

      return NoContinuation;

    if (StartOfLineLevel != Other.StartOfLineLevel)

      return StartOfLineLevel < Other.StartOfLineLevel;

    if (LowestLevelOnLine != Other.LowestLevelOnLine)

      return LowestLevelOnLine < Other.LowestLevelOnLine;

    if (StartOfStringLiteral != Other.StartOfStringLiteral)

      return StartOfStringLiteral < Other.StartOfStringLiteral;

    if (IgnoreStackForComparison || Other.IgnoreStackForComparison)

      return false;

    return Stack < Other.Stack;

  }

};

} // end namespace format

} // end namespace clang

#endif