path: root/lib/Format/TokenAnnotator.cpp

//===--- TokenAnnotator.cpp - Format C++ code -----------------------------===//
//
//                     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 a token annotator, i.e. creates
/// \c AnnotatedTokens out of \c FormatTokens with required extra information.
///
//===----------------------------------------------------------------------===//

#include "TokenAnnotator.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Lexer.h"

namespace clang {
namespace format {

/// \brief Returns if a token is an Objective-C selector name.
///
/// For example, "bar" is a selector name in [foo bar:(4 + 5)].
static bool isObjCSelectorName(const AnnotatedToken &Tok) {
  return Tok.is(tok::identifier) && !Tok.Children.empty() &&
         Tok.Children[0].is(tok::colon) &&
         Tok.Children[0].Type == TT_ObjCMethodExpr;
}

static bool isBinaryOperator(const AnnotatedToken &Tok) {
  // Comma is a binary operator, but does not behave as such wrt. formatting.
  return getPrecedence(Tok) > prec::Comma;
}

// Returns the previous token ignoring comments.
static const AnnotatedToken *getPreviousToken(const AnnotatedToken &Tok) {
  const AnnotatedToken *PrevToken = Tok.Parent;
  while (PrevToken != NULL && PrevToken->is(tok::comment))
    PrevToken = PrevToken->Parent;
  return PrevToken;
}

// Returns the next token ignoring comments.
static const AnnotatedToken *getNextToken(const AnnotatedToken &Tok) {
  if (Tok.Children.empty())
    return NULL;
  const AnnotatedToken *NextToken = &Tok.Children[0];
  while (NextToken->is(tok::comment)) {
    if (NextToken->Children.empty())
      return NULL;
    NextToken = &NextToken->Children[0];
  }
  return NextToken;
}

/// \brief A parser that gathers additional information about tokens.
///
/// The \c TokenAnnotator tries to matches parenthesis and square brakets and
/// store a parenthesis levels. It also tries to resolve matching "<" and ">"
/// into template parameter lists.
class AnnotatingParser {
public:
  AnnotatingParser(SourceManager &SourceMgr, Lexer &Lex, AnnotatedLine &Line)
      : SourceMgr(SourceMgr), Lex(Lex), Line(Line), CurrentToken(&Line.First),
        KeywordVirtualFound(false), ColonIsObjCMethodExpr(false),
        ColonIsForRangeExpr(false), IsExpression(false),
        LookForFunctionName(Line.MustBeDeclaration), BindingStrength(1) {
  }

  /// \brief A helper class to manage AnnotatingParser::ColonIsObjCMethodExpr.
  struct ObjCSelectorRAII {
    AnnotatingParser &P;
    bool ColonWasObjCMethodExpr;

    ObjCSelectorRAII(AnnotatingParser &P)
        : P(P), ColonWasObjCMethodExpr(P.ColonIsObjCMethodExpr) {
    }

    ~ObjCSelectorRAII() { P.ColonIsObjCMethodExpr = ColonWasObjCMethodExpr; }

    void markStart(AnnotatedToken &Left) {
      P.ColonIsObjCMethodExpr = true;
      Left.Type = TT_ObjCMethodExpr;
    }

    void markEnd(AnnotatedToken &Right) { Right.Type = TT_ObjCMethodExpr; }
  };

  struct ScopedBindingStrengthIncrease {
    AnnotatingParser &P;
    unsigned Increase;

    ScopedBindingStrengthIncrease(AnnotatingParser &P, unsigned Increase)
        : P(P), Increase(Increase) {
      P.BindingStrength += Increase;
    }

    ~ScopedBindingStrengthIncrease() { P.BindingStrength -= Increase; }
  };

  bool parseAngle() {
    if (CurrentToken == NULL)
      return false;
    ScopedBindingStrengthIncrease Increase(*this, 10);
    AnnotatedToken *Left = CurrentToken->Parent;
    while (CurrentToken != NULL) {
      if (CurrentToken->is(tok::greater)) {
        Left->MatchingParen = CurrentToken;
        CurrentToken->MatchingParen = Left;
        CurrentToken->Type = TT_TemplateCloser;
        next();
        return true;
      }
      if (CurrentToken->is(tok::r_paren) || CurrentToken->is(tok::r_square) ||
          CurrentToken->is(tok::r_brace))
        return false;
      if (CurrentToken->is(tok::pipepipe) || CurrentToken->is(tok::ampamp) ||
          CurrentToken->is(tok::question) || CurrentToken->is(tok::colon))
        return false;
      if (CurrentToken->is(tok::comma))
        ++Left->ParameterCount;
      if (!consumeToken())
        return false;
    }
    return false;
  }

  bool parseParens(bool LookForDecls = false) {
    if (CurrentToken == NULL)
      return false;
    ScopedBindingStrengthIncrease Increase(*this, 1);
    bool StartsObjCMethodExpr = false;
    AnnotatedToken *Left = CurrentToken->Parent;
    if (CurrentToken