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//===--- FormatToken.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 contains the declaration of the FormatToken, a wrapper
/// around Token with additional information related to formatting.
#include "clang/Basic/OperatorPrecedence.h"
#include "clang/Format/Format.h"
#include "clang/Lex/Lexer.h"
#include <memory>
namespace clang {
namespace format {
enum TokenType {
// Represents what type of block a set of braces open.
enum BraceBlockKind {
// The packing kind of a function's parameters.
enum ParameterPackingKind {
enum FormatDecision {
class TokenRole;
class AnnotatedLine;
/// \brief A wrapper around a \c Token storing information about the
/// whitespace characters preceding it.
struct FormatToken {
: NewlinesBefore(0), HasUnescapedNewline(false), LastNewlineOffset(0),
ColumnWidth(0), LastLineColumnWidth(0), IsMultiline(false),
IsFirst(false), MustBreakBefore(false), IsUnterminatedLiteral(false),
BlockKind(BK_Unknown), Type(TT_Unknown), SpacesRequiredBefore(0),
CanBreakBefore(false), ClosesTemplateDeclaration(false),
ParameterCount(0), PackingKind(PPK_Inconclusive), TotalLength(0),
UnbreakableTailLength(0), BindingStrength(0), NestingLevel(0),
SplitPenalty(0), LongestObjCSelectorName(0), FakeRParens(0),
StartsBinaryExpression(false), EndsBinaryExpression(false),
OperatorIndex(0), LastOperator(false),
PartOfMultiVariableDeclStmt(false), IsForEachMacro(false),
MatchingParen(NULL), Previous(NULL), Next(NULL),
Decision(FD_Unformatted), Finalized(false) {}
/// \brief The \c Token.
Token Tok;
/// \brief The number of newlines immediately before the \c Token.
/// This can be used to determine what the user wrote in the original code
/// and thereby e.g. leave an empty line between two function definitions.
unsigned NewlinesBefore;
/// \brief Whether there is at least one unescaped newline before the \c
/// Token.
bool HasUnescapedNewline;
/// \brief The range of the whitespace immediately preceding the \c Token.
SourceRange WhitespaceRange;
/// \brief The offset just past the last '\n' in this token's leading
/// whitespace (relative to \c WhiteSpaceStart). 0 if there is no '\n'.
unsigned LastNewlineOffset;
/// \brief The width of the non-whitespace parts of the token (or its first
/// line for multi-line tokens) in columns.
/// We need this to correctly measure number of columns a token spans.
unsigned ColumnWidth;
/// \brief Contains the width in columns of the last line of a multi-line
/// token.
unsigned LastLineColumnWidth;
/// \brief Whether the token text contains newlines (escaped or not).
bool IsMultiline;
/// \brief Indicates that this is the first token.
bool IsFirst;
/// \brief Whether there must be a line break before this token.
/// This happens for example when a preprocessor directive ended directly
/// before the token.
bool MustBreakBefore;
/// \brief Returns actual token start location without leading escaped
/// newlines and whitespace.
/// This can be different to Tok.getLocation(), which includes leading escaped
/// newlines.
SourceLocation getStartOfNonWhitespace() const {
return WhitespaceRange.getEnd();
/// \brief The raw text of the token.
/// Contains the raw token text without leading whitespace and without leading
/// escaped newlines.
StringRef TokenText;
/// \brief Set to \c true if this token is an unterminated literal.
bool IsUnterminatedLiteral;
/// \brief Contains the kind of block if this token is a brace.
BraceBlockKind BlockKind;
TokenType Type;
/// \brief The number of spaces that should be inserted before this token.
unsigned SpacesRequiredBefore;
/// \brief \c true if it is allowed to break before this token.
bool CanBreakBefore;
bool ClosesTemplateDeclaration;
/// \brief Number of parameters, if this is "(", "[" or "<".
/// This is initialized to 1 as we don't need to distinguish functions with
/// 0 parameters from functions with 1 parameter. Thus, we can simply count
/// the number of commas.
unsigned ParameterCount;
/// \brief A token can have a special role that can carry extra information
/// about the token's formatting.
std::unique_ptr<TokenRole> Role;
/// \brief If this is an opening parenthesis, how are the parameters packed?
ParameterPackingKind PackingKind;
/// \brief The total length of the unwrapped line up to and including this
/// token.
unsigned TotalLength;
/// \brief The original 0-based column of this token, including expanded tabs.
/// The configured TabWidth is used as tab width.
unsigned OriginalColumn;
/// \brief The length of following tokens until the next natural split point,
/// or the next token that can be broken.
unsigned UnbreakableTailLength;
// FIXME: Come up with a 'cleaner' concept.
/// \brief The binding strength of a token. This is a combined value of
/// operator precedence, parenthesis nesting, etc.
unsigned BindingStrength;
/// \brief The nesting level of this token, i.e. the number of surrounding (),
/// [], {} or <>.
unsigned NestingLevel;
/// \brief Penalty for inserting a line break before this token.
unsigned SplitPenalty;
/// \brief If this is the first ObjC selector name in an ObjC method
/// definition or call, this contains the length of the longest name.
/// This being set to 0 means that the selectors should not be colon-aligned,
/// e.g. because several of them are block-type.
unsigned LongestObjCSelectorName;
/// \brief Stores the number of required fake parentheses and the
/// corresponding operator precedence.
/// If multiple fake parentheses start at a token, this vector stores them in
/// reverse order, i.e. inner fake parenthesis first.
SmallVector<prec::Level, 4> FakeLParens;
/// \brief Insert this many fake ) after this token for correct indentation.
unsigned FakeRParens;
/// \brief \c true if this token starts a binary expression, i.e. has at least
/// one fake l_paren with a precedence greater than prec::Unknown.
bool StartsBinaryExpression;
/// \brief \c true if this token ends a binary expression.
bool EndsBinaryExpression;
/// \brief Is this is an operator (or "."/"->") in a sequence of operators
/// with the same precedence, contains the 0-based operator index.
unsigned OperatorIndex;
/// \brief Is this the last operator (or "."/"->") in a sequence of operators
/// with the same precedence?
bool LastOperator;
/// \brief Is this token part of a \c DeclStmt defining multiple variables?
/// Only set if \c Type == \c TT_StartOfName.
bool PartOfMultiVariableDeclStmt;
/// \brief Is this a foreach macro?
bool IsForEachMacro;
bool is(tok::TokenKind Kind) const { return; }
bool isOneOf(tok::TokenKind K1, tok::TokenKind K2) const {
return is(K1) || is(K2);
bool isOneOf(tok::TokenKind K1, tok::TokenKind K2, tok::TokenKind K3) const {
return is(K1) || is(K2) || is(K3);
bool isOneOf(tok::TokenKind K1, tok::TokenKind K2, tok::TokenKind K3,
tok::TokenKind K4, tok::TokenKind K5 = tok::NUM_TOKENS,
tok::TokenKind K6 = tok::NUM_TOKENS,
tok::TokenKind K7 = tok::NUM_TOKENS,
tok::TokenKind K8 = tok::NUM_TOKENS,
tok::TokenKind K9 = tok::NUM_TOKENS,
tok::TokenKind K10 = tok::NUM_TOKENS,
tok::TokenKind K11 = tok::NUM_TOKENS,
tok::TokenKind K12 = tok::NUM_TOKENS) const {
return is(K1) || is(K2) || is(K3) || is(K4) || is(K5) || is(K6) || is(K7) ||
is(K8) || is(K9) || is(K10) || is(K11) || is(K12);
bool isNot(tok::TokenKind Kind) const { return Tok.isNot(Kind); }
bool isStringLiteral() const { return tok::isStringLiteral(Tok.getKind()); }
bool isObjCAtKeyword(tok::ObjCKeywordKind Kind) const {
return Tok.isObjCAtKeyword(Kind);
bool isAccessSpecifier(bool ColonRequired = true) const {
return isOneOf(tok::kw_public, tok::kw_protected, tok::kw_private) &&
(!ColonRequired || (Next && Next->is(tok::colon)));
/// \brief Determine whether the token is a simple-type-specifier.
bool isSimpleTypeSpecifier() const;
bool isObjCAccessSpecifier() const {
return is(tok::at) && Next && (Next->isObjCAtKeyword(tok::objc_public) ||
Next->isObjCAtKeyword(tok::objc_protected) ||
Next->isObjCAtKeyword(tok::objc_package) ||
/// \brief Returns whether \p Tok is ([{ or a template opening <.
bool opensScope() const {
return isOneOf(tok::l_paren, tok::l_brace, tok::l_square) ||
Type == TT_TemplateOpener;
/// \brief Returns whether \p Tok is )]} or a template closing >.
bool closesScope() const {
return isOneOf(tok::r_paren, tok::r_brace, tok::r_square) ||
Type == TT_TemplateCloser;
/// \brief Returns \c true if this is a "." or "->" accessing a member.
bool isMemberAccess() const {
return isOneOf(tok::arrow, tok::period) &&
Type != TT_DesignatedInitializerPeriod;
bool isUnaryOperator() const {
switch (Tok.getKind()) {
case tok::plus:
case tok::plusplus:
case tok::minus:
case tok::minusminus:
case tok::exclaim:
case tok::tilde:
case tok::kw_sizeof:
case tok::kw_alignof:
return true;
return false;
bool isBinaryOperator() const {
// Comma is a binary operator, but does not behave as such wrt. formatting.
return getPrecedence() > prec::Comma;
bool isTrailingComment() const {
return is(tok::comment) && (!Next || Next->NewlinesBefore > 0);
prec::Level getPrecedence() const {
return getBinOpPrecedence(Tok.getKind(), true, true);
/// \brief Returns the previous token ignoring comments.
FormatToken *getPreviousNonComment() const {
FormatToken *Tok = Previous;
while (Tok != NULL && Tok->is(tok::comment))
Tok = Tok->Previous;
return Tok;
/// \brief Returns the next token ignoring comments.
const FormatToken *getNextNonComment() const {
const FormatToken *Tok = Next;
while (Tok != NULL && Tok->is(tok::comment))
Tok = Tok->Next;
return Tok;
/// \brief Returns \c true if this tokens starts a block-type list, i.e. a
/// list that should be indented with a block indent.
bool opensBlockTypeList(const FormatStyle &Style) const {
return Type == TT_ArrayInitializerLSquare ||
(is(tok::l_brace) &&
(BlockKind == BK_Block || Type == TT_DictLiteral ||
/// \brief Same as opensBlockTypeList, but for the closing token.
bool closesBlockTypeList(const FormatStyle &Style) const {
return MatchingParen && MatchingParen->opensBlockTypeList(Style);
FormatToken *MatchingParen;
FormatToken *Previous;
FormatToken *Next;
SmallVector<AnnotatedLine *, 1> Children;
/// \brief Stores the formatting decision for the token once it was made.
FormatDecision Decision;
/// \brief If \c true, this token has been fully formatted (indented and
/// potentially re-formatted inside), and we do not allow further formatting
/// changes.
bool Finalized;
// Disallow copying.
FormatToken(const FormatToken &) LLVM_DELETED_FUNCTION;
void operator=(const FormatToken &) LLVM_DELETED_FUNCTION;
class ContinuationIndenter;
struct LineState;
class TokenRole {
TokenRole(const FormatStyle &Style) : Style(Style) {}
virtual ~TokenRole();
/// \brief After the \c TokenAnnotator has finished annotating all the tokens,
/// this function precomputes required information for formatting.
virtual void precomputeFormattingInfos(const FormatToken *Token);
/// \brief Apply the special formatting that the given role demands.
/// Assumes that the token having this role is already formatted.
/// Continues formatting from \p State leaving indentation to \p Indenter and
/// returns the total penalty that this formatting incurs.
virtual unsigned formatFromToken(LineState &State,
ContinuationIndenter *Indenter,
bool DryRun) {
return 0;
/// \brief Same as \c formatFromToken, but assumes that the first token has
/// already been set thereby deciding on the first line break.
virtual unsigned formatAfterToken(LineState &State,
ContinuationIndenter *Indenter,
bool DryRun) {
return 0;
/// \brief Notifies the \c Role that a comma was found.
virtual void CommaFound(const FormatToken *Token) {}
const FormatStyle &Style;
class CommaSeparatedList : public TokenRole {
CommaSeparatedList(const FormatStyle &Style)
: TokenRole(Style), HasNestedBracedList(false) {}
void precomputeFormattingInfos(const FormatToken *Token) override;
unsigned formatAfterToken(LineState &State, ContinuationIndenter *Indenter,
bool DryRun) override;
unsigned formatFromToken(LineState &State, ContinuationIndenter *Indenter,
bool DryRun) override;
/// \brief Adds \p Token as the next comma to the \c CommaSeparated list.
void CommaFound(const FormatToken *Token) override { Commas.push_back(Token);}
/// \brief A struct that holds information on how to format a given list with
/// a specific number of columns.
struct ColumnFormat {
/// \brief The number of columns to use.
unsigned Columns;
/// \brief The total width in characters.
unsigned TotalWidth;
/// \brief The number of lines required for this format.
unsigned LineCount;
/// \brief The size of each column in characters.
SmallVector<unsigned, 8> ColumnSizes;
/// \brief Calculate which \c ColumnFormat fits best into
/// \p RemainingCharacters.
const ColumnFormat *getColumnFormat(unsigned RemainingCharacters) const;
/// \brief The ordered \c FormatTokens making up the commas of this list.
SmallVector<const FormatToken *, 8> Commas;
/// \brief The length of each of the list's items in characters including the
/// trailing comma.
SmallVector<unsigned, 8> ItemLengths;
/// \brief Precomputed formats that can be used for this list.
SmallVector<ColumnFormat, 4> Formats;
bool HasNestedBracedList;
} // namespace format
} // namespace clang