blob: e8a9131e8bc81b48d8a3283178f5487a3939fd24 [file] [log] [blame]
//===--- ContinuationIndenter.h - Format C++ code ---------------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
/// \file
/// \brief This file implements an indenter that manages the indentation of
/// continuations.
#include "Encoding.h"
#include "clang/Format/Format.h"
#include "llvm/Support/Regex.h"
namespace clang {
class SourceManager;
namespace format {
class AnnotatedLine;
struct FormatToken;
struct LineState;
struct ParenState;
class WhitespaceManager;
class ContinuationIndenter {
/// \brief Constructs a \c ContinuationIndenter to format \p Line starting in
/// column \p FirstIndent.
ContinuationIndenter(const FormatStyle &Style, SourceManager &SourceMgr,
WhitespaceManager &Whitespaces,
encoding::Encoding Encoding,
bool BinPackInconclusiveFunctions);
/// \brief Get the initial state, i.e. the state after placing \p Line's
/// first token at \p FirstIndent.
LineState getInitialState(unsigned FirstIndent, const AnnotatedLine *Line,
bool DryRun);
// FIXME: canBreak and mustBreak aren't strictly indentation-related. Find a
// better home.
/// \brief Returns \c true, if a line break after \p State is allowed.
bool canBreak(const LineState &State);
/// \brief Returns \c true, if a line break after \p State is mandatory.
bool mustBreak(const LineState &State);
/// \brief 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);
/// \brief 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;
/// \brief Mark the next token as consumed in \p State and modify its stacks
/// accordingly.
unsigned moveStateToNextToken(LineState &State, bool DryRun, bool Newline);
/// \brief If the current token sticks out over the end of the line, break
/// it if possible.
/// \returns An extra penalty if a token was broken, otherwise 0.
/// 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.
unsigned breakProtrudingToken(const FormatToken &Current, LineState &State,
bool DryRun);
/// \brief 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);
/// \brief 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);
/// \brief Calculate the new column for a line wrap before the next token.
unsigned getNewLineColumn(const LineState &State);
/// \brief 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);
/// \brief 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;
SourceManager &SourceMgr;
WhitespaceManager &Whitespaces;
encoding::Encoding Encoding;
bool BinPackInconclusiveFunctions;
llvm::Regex CommentPragmasRegex;
struct ParenState {
ParenState(unsigned Indent, unsigned IndentLevel, unsigned LastSpace,
bool AvoidBinPacking, bool NoLineBreak)
: Indent(Indent), IndentLevel(IndentLevel), LastSpace(LastSpace),
FirstLessLess(0), BreakBeforeClosingBrace(false), QuestionColumn(0),
AvoidBinPacking(AvoidBinPacking), BreakBeforeParameter(false),
NoLineBreak(NoLineBreak), LastOperatorWrapped(true), ColonPos(0),
StartOfFunctionCall(0), StartOfArraySubscripts(0),
NestedNameSpecifierContinuation(0), CallContinuation(0), VariablePos(0),
ContainsLineBreak(false), ContainsUnwrappedBuilder(0),
AlignColons(true), ObjCSelectorNameFound(false), LambdasFound(0) {}
/// \brief The position to which a specific parenthesis level needs to be
/// indented.
unsigned Indent;
/// \brief The number of indentation levels of the block.
unsigned IndentLevel;
/// \brief The position of the last space on each level.
/// Used e.g. to break like:
/// functionCall(Parameter, otherCall(
/// OtherParameter));
unsigned LastSpace;
/// \brief 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;
/// \brief 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;
/// \brief The column of a \c ? in a conditional expression;
unsigned QuestionColumn;
/// \brief Avoid bin packing, i.e. multiple parameters/elements on multiple
/// lines, in this context.
bool AvoidBinPacking;
/// \brief Break after the next comma (or all the commas in this context if
/// \c AvoidBinPacking is \c true).
bool BreakBeforeParameter;
/// \brief Line breaking in this context would break a formatting rule.
bool NoLineBreak;
/// \brief True if the last binary operator on this level was wrapped to the
/// next line.
bool LastOperatorWrapped;
/// \brief The position of the colon in an ObjC method declaration/call.
unsigned ColonPos;
/// \brief The start of the most recent function in a builder-type call.
unsigned StartOfFunctionCall;
/// \brief Contains the start of array subscript expressions, so that they
/// can be aligned.
unsigned StartOfArraySubscripts;
/// \brief If a nested name specifier was broken over multiple lines, this
/// contains the start column of the second line. Otherwise 0.
unsigned NestedNameSpecifierContinuation;
/// \brief If a call expression was broken over multiple lines, this
/// contains the start column of the second line. Otherwise 0.
unsigned CallContinuation;
/// \brief The column of the first variable name in a variable declaration.
/// Used to align further variables if necessary.
unsigned VariablePos;
/// \brief \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;
/// \brief \c true if this \c ParenState contains multiple segments of a
/// builder-type call on one line.
bool ContainsUnwrappedBuilder;
/// \brief \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;
/// \brief \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;
/// \brief Counts the number of lambda introducers found on this level.
/// Not considered for memoization as it will always have the same value at
/// the same token.
unsigned LambdasFound;
bool operator<(const ParenState &Other) const {
if (Indent != Other.Indent)
return Indent < Other.Indent;
if (LastSpace != Other.LastSpace)
return LastSpace < Other.LastSpace;
if (FirstLessLess != Other.FirstLessLess)
return FirstLessLess < Other.FirstLessLess;
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 < Other.ContainsLineBreak;
if (ContainsUnwrappedBuilder != Other.ContainsUnwrappedBuilder)
return ContainsUnwrappedBuilder < Other.ContainsUnwrappedBuilder;
return false;
/// \brief The current state when indenting a unwrapped line.
/// As the indenting tries different combinations this is copied by value.
struct LineState {
/// \brief The number of used columns in the current line.
unsigned Column;
/// \brief The token that needs to be next formatted.
FormatToken *NextToken;
/// \brief \c true if this line contains a continued for-loop section.
bool LineContainsContinuedForLoopSection;
/// \brief The level of nesting inside (), [], <> and {}.
unsigned ParenLevel;
/// \brief The \c ParenLevel at the start of this line.
unsigned StartOfLineLevel;
/// \brief The lowest \c ParenLevel on the current line.
unsigned LowestLevelOnLine;
/// \brief The start column of the string literal, if we're in a string
/// literal sequence, 0 otherwise.
unsigned StartOfStringLiteral;
/// \brief A stack keeping track of properties applying to parenthesis
/// levels.
std::vector<ParenState> Stack;
/// \brief 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;
/// \brief The indent of the first token.
unsigned FirstIndent;
/// \brief The line that is being formatted.
/// Does not need to be considered for memoization because it doesn't change.
const AnnotatedLine *Line;
/// \brief 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 (ParenLevel != Other.ParenLevel)
return ParenLevel < Other.ParenLevel;
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