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//===--- ContinuationIndenter.h - Format C++ code ---------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
/// \file
/// This file implements an indenter that manages the indentation of
/// continuations.
#include "Encoding.h"
#include "FormatToken.h"
#include "clang/Format/Format.h"
#include "llvm/Support/Regex.h"
#include <map>
#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);
llvm::Optional<FormatStyle> getDelimiterStyle(StringRef Delimiter) const;
getEnclosingFunctionStyle(StringRef EnclosingFunction) const;
class ContinuationIndenter {
/// 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;
/// 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.
llvm::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.
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), 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;
/// 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 (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 this line contains a continued for-loop section.
bool LineContainsContinuedForLoopSection;
/// \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;
/// A stack keeping track of properties applying to parenthesis
/// levels.
std::vector<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 (LineContainsContinuedForLoopSection !=
return LineContainsContinuedForLoopSection;
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