path: root/lib/Format/Format.cpp

//===--- Format.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 functions declared in Format.h. This will be
/// split into separate files as we go.
///
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "format-formatter"

#include "TokenAnnotator.h"
#include "UnwrappedLineParser.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/OperatorPrecedence.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Format/Format.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Lex/Lexer.h"
#include "llvm/Support/Debug.h"
#include <string>

// Uncomment to get debug output from tests:
// #define DEBUG_WITH_TYPE(T, X) do { X; } while(0)

namespace clang {
namespace format {

FormatStyle getLLVMStyle() {
  FormatStyle LLVMStyle;
  LLVMStyle.ColumnLimit = 80;
  LLVMStyle.MaxEmptyLinesToKeep = 1;
  LLVMStyle.PointerAndReferenceBindToType = false;
  LLVMStyle.AccessModifierOffset = -2;
  LLVMStyle.SplitTemplateClosingGreater = true;
  LLVMStyle.IndentCaseLabels = false;
  LLVMStyle.SpacesBeforeTrailingComments = 1;
  LLVMStyle.BinPackParameters = true;
  LLVMStyle.AllowAllParametersOfDeclarationOnNextLine = true;
  LLVMStyle.AllowReturnTypeOnItsOwnLine = true;
  LLVMStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = false;
  LLVMStyle.AllowShortIfStatementsOnASingleLine = false;
  LLVMStyle.ObjCSpaceBeforeProtocolList = true;
  return LLVMStyle;
}

FormatStyle getGoogleStyle() {
  FormatStyle GoogleStyle;
  GoogleStyle.ColumnLimit = 80;
  GoogleStyle.MaxEmptyLinesToKeep = 1;
  GoogleStyle.PointerAndReferenceBindToType = true;
  GoogleStyle.AccessModifierOffset = -1;
  GoogleStyle.SplitTemplateClosingGreater = false;
  GoogleStyle.IndentCaseLabels = true;
  GoogleStyle.SpacesBeforeTrailingComments = 2;
  GoogleStyle.BinPackParameters = false;
  GoogleStyle.AllowAllParametersOfDeclarationOnNextLine = true;
  GoogleStyle.AllowReturnTypeOnItsOwnLine = false;
  GoogleStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = true;
  GoogleStyle.AllowShortIfStatementsOnASingleLine = false;
  GoogleStyle.ObjCSpaceBeforeProtocolList = false;
  return GoogleStyle;
}

FormatStyle getChromiumStyle() {
  FormatStyle ChromiumStyle = getGoogleStyle();
  ChromiumStyle.AllowAllParametersOfDeclarationOnNextLine = false;
  ChromiumStyle.SplitTemplateClosingGreater = true;
  return ChromiumStyle;
}

struct OptimizationParameters {
  unsigned PenaltyIndentLevel;
  unsigned PenaltyExcessCharacter;
};

/// \brief Manages the whitespaces around tokens and their replacements.
///
/// This includes special handling for certain constructs, e.g. the alignment of
/// trailing line comments.
class WhitespaceManager {
public:
  WhitespaceManager(SourceManager &SourceMgr) : SourceMgr(SourceMgr) {}

  /// \brief Replaces the whitespace in front of \p Tok. Only call once for
  /// each \c AnnotatedToken.
  void replaceWhitespace(const AnnotatedToken &Tok, unsigned NewLines,
                         unsigned Spaces, unsigned WhitespaceStartColumn,
                         const FormatStyle &Style) {
    // 2+ newlines mean an empty line separating logic scopes.
    if (NewLines >= 2)
      alignComments();

    // Align line comments if they are trailing or if they continue other
    // trailing comments.
    if (Tok.Type == TT_LineComment &&
        (Tok.Parent != NULL || !Comments.empty())) {
      if (Style.ColumnLimit >=
          Spaces + WhitespaceStartColumn + Tok.FormatTok.TokenLength) {
        Comments.push_back(StoredComment());
        Comments.back().Tok = Tok.FormatTok;
        Comments.back().Spaces = Spaces;
        Comments.back().NewLines = NewLines;
        Comments.back().MinColumn = WhitespaceStartColumn + Spaces;
        Comments.back().MaxColumn =
            Style.ColumnLimit - Spaces - Tok.FormatTok.TokenLength;
        return;
      }
    }

    // If this line does not have a trailing comment, align the stored comments.
    if (Tok.Children.empty() && Tok.Type != TT_LineComment)
      alignComments();
    storeReplacement(Tok.FormatTok,
                     std::string(NewLines, '\n') + std::string(Spaces, ' '));
  }

  /// \brief Like \c replaceWhitespace, but additionally adds right-aligned
  /// backslashes to escape newlines inside a preprocessor directive.
  ///