blob: 029f4159b748ab799aea7be148729ce462d998bc [file] [log] [blame]
//===--- WhitespaceManager.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
/// WhitespaceManager class manages whitespace around tokens and their
/// replacements.
#include "TokenAnnotator.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Format/Format.h"
#include "llvm/ADT/SmallVector.h"
#include <algorithm>
#include <string>
#include <tuple>
namespace clang {
namespace format {
/// Manages the whitespaces around tokens and their replacements.
/// This includes special handling for certain constructs, e.g. the alignment of
/// trailing line comments.
/// To guarantee correctness of alignment operations, the \c WhitespaceManager
/// must be informed about every token in the source file; for each token, there
/// must be exactly one call to either \c replaceWhitespace or
/// \c addUntouchableToken.
/// There may be multiple calls to \c breakToken for a given token.
class WhitespaceManager {
WhitespaceManager(const SourceManager &SourceMgr, const FormatStyle &Style,
bool UseCRLF)
: SourceMgr(SourceMgr), Style(Style), UseCRLF(UseCRLF) {}
bool useCRLF() const { return UseCRLF; }
/// Replaces the whitespace in front of \p Tok. Only call once for
/// each \c AnnotatedToken.
/// \p StartOfTokenColumn is the column at which the token will start after
/// this replacement. It is needed for determining how \p Spaces is turned
/// into tabs and spaces for some format styles.
void replaceWhitespace(FormatToken &Tok, unsigned Newlines, unsigned Spaces,
unsigned StartOfTokenColumn, bool isAligned = false,
bool InPPDirective = false);
/// Adds information about an unchangeable token's whitespace.
/// Needs to be called for every token for which \c replaceWhitespace
/// was not called.
void addUntouchableToken(const FormatToken &Tok, bool InPPDirective);
llvm::Error addReplacement(const tooling::Replacement &Replacement);
/// Inserts or replaces whitespace in the middle of a token.
/// Inserts \p PreviousPostfix, \p Newlines, \p Spaces and \p CurrentPrefix
/// (in this order) at \p Offset inside \p Tok, replacing \p ReplaceChars
/// characters.
/// Note: \p Spaces can be negative to retain information about initial
/// relative column offset between a line of a block comment and the start of
/// the comment. This negative offset may be compensated by trailing comment
/// alignment here. In all other cases negative \p Spaces will be truncated to
/// 0.
/// When \p InPPDirective is true, escaped newlines are inserted. \p Spaces is
/// used to align backslashes correctly.
void replaceWhitespaceInToken(const FormatToken &Tok, unsigned Offset,
unsigned ReplaceChars,
StringRef PreviousPostfix,
StringRef CurrentPrefix, bool InPPDirective,
unsigned Newlines, int Spaces);
/// Returns all the \c Replacements created during formatting.
const tooling::Replacements &generateReplacements();
/// Represents a change before a token, a break inside a token,
/// or the layout of an unchanged token (or whitespace within).
struct Change {
/// Functor to sort changes in original source order.
class IsBeforeInFile {
IsBeforeInFile(const SourceManager &SourceMgr) : SourceMgr(SourceMgr) {}
bool operator()(const Change &C1, const Change &C2) const;
const SourceManager &SourceMgr;
/// Creates a \c Change.
/// The generated \c Change will replace the characters at
/// \p OriginalWhitespaceRange with a concatenation of
/// \p PreviousLinePostfix, \p NewlinesBefore line breaks, \p Spaces spaces
/// and \p CurrentLinePrefix.
/// \p StartOfTokenColumn and \p InPPDirective will be used to lay out
/// trailing comments and escaped newlines.
Change(const FormatToken &Tok, bool CreateReplacement,
SourceRange OriginalWhitespaceRange, int Spaces,
unsigned StartOfTokenColumn, unsigned NewlinesBefore,
StringRef PreviousLinePostfix, StringRef CurrentLinePrefix,
bool IsAligned, bool ContinuesPPDirective, bool IsInsideToken);
// The kind of the token whose whitespace this change replaces, or in which
// this change inserts whitespace.
// FIXME: Currently this is not set correctly for breaks inside comments, as
// the \c BreakableToken is still doing its own alignment.
const FormatToken *Tok;
bool CreateReplacement;
// Changes might be in the middle of a token, so we cannot just keep the
// FormatToken around to query its information.
SourceRange OriginalWhitespaceRange;
unsigned StartOfTokenColumn;
unsigned NewlinesBefore;
std::string PreviousLinePostfix;
std::string CurrentLinePrefix;
bool IsAligned;
bool ContinuesPPDirective;
// The number of spaces in front of the token or broken part of the token.
// This will be adapted when aligning tokens.
// Can be negative to retain information about the initial relative offset
// of the lines in a block comment. This is used when aligning trailing
// comments. Uncompensated negative offset is truncated to 0.
int Spaces;
// If this change is inside of a token but not at the start of the token or
// directly after a newline.
bool IsInsideToken;
// \c IsTrailingComment, \c TokenLength, \c PreviousEndOfTokenColumn and
// \c EscapedNewlineColumn will be calculated in
// \c calculateLineBreakInformation.
bool IsTrailingComment;
unsigned TokenLength;
unsigned PreviousEndOfTokenColumn;
unsigned EscapedNewlineColumn;
// These fields are used to retain correct relative line indentation in a
// block comment when aligning trailing comments.
// If this Change represents a continuation of a block comment,
// \c StartOfBlockComment is pointer to the first Change in the block
// comment. \c IndentationOffset is a relative column offset to this
// change, so that the correct column can be reconstructed at the end of
// the alignment process.
const Change *StartOfBlockComment;
int IndentationOffset;
// Depth of conditionals. Computed from tracking fake parenthesis, except
// it does not increase the indent for "chained" conditionals.
int ConditionalsLevel;
// A combination of indent, nesting and conditionals levels, which are used
// in tandem to compute lexical scope, for the purposes of deciding
// when to stop consecutive alignment runs.
std::tuple<unsigned, unsigned, unsigned> indentAndNestingLevel() const {
return std::make_tuple(Tok->IndentLevel, Tok->NestingLevel,
struct CellDescription {
unsigned Index = 0;
unsigned Cell = 0;
unsigned EndIndex = 0;
bool HasSplit = false;
CellDescription *NextColumnElement = nullptr;
constexpr bool operator==(const CellDescription &Other) const {
return Index == Other.Index && Cell == Other.Cell &&
EndIndex == Other.EndIndex;
constexpr bool operator!=(const CellDescription &Other) const {
return !(*this == Other);
struct CellDescriptions {
SmallVector<CellDescription> Cells;
unsigned CellCount = 0;
unsigned InitialSpaces = 0;
/// Calculate \c IsTrailingComment, \c TokenLength for the last tokens
/// or token parts in a line and \c PreviousEndOfTokenColumn and
/// \c EscapedNewlineColumn for the first tokens or token parts in a line.
void calculateLineBreakInformation();
/// \brief Align consecutive C/C++ preprocessor macros over all \c Changes.
void alignConsecutiveMacros();
/// Align consecutive assignments over all \c Changes.
void alignConsecutiveAssignments();
/// Align consecutive bitfields over all \c Changes.
void alignConsecutiveBitFields();
/// Align consecutive declarations over all \c Changes.
void alignConsecutiveDeclarations();
/// Align consecutive declarations over all \c Changes.
void alignChainedConditionals();
/// Align trailing comments over all \c Changes.
void alignTrailingComments();
/// Align trailing comments from change \p Start to change \p End at
/// the specified \p Column.
void alignTrailingComments(unsigned Start, unsigned End, unsigned Column);
/// Align escaped newlines over all \c Changes.
void alignEscapedNewlines();
/// Align escaped newlines from change \p Start to change \p End at
/// the specified \p Column.
void alignEscapedNewlines(unsigned Start, unsigned End, unsigned Column);
/// Align Array Initializers over all \c Changes.
void alignArrayInitializers();
/// Align Array Initializers from change \p Start to change \p End at
/// the specified \p Column.
void alignArrayInitializers(unsigned Start, unsigned End);
/// Align Array Initializers being careful to right justify the columns
/// as described by \p CellDescs.
void alignArrayInitializersRightJustified(CellDescriptions &&CellDescs);
/// Align Array Initializers being careful to leftt justify the columns
/// as described by \p CellDescs.
void alignArrayInitializersLeftJustified(CellDescriptions &&CellDescs);
/// Calculate the cell width between two indexes.
unsigned calculateCellWidth(unsigned Start, unsigned End,
bool WithSpaces = false) const;
/// Get a set of fully specified CellDescriptions between \p Start and
/// \p End of the change list.
CellDescriptions getCells(unsigned Start, unsigned End);
/// Does this \p Cell contain a split element?
static bool isSplitCell(const CellDescription &Cell);
/// Get the width of the preceding cells from \p Start to \p End.
template <typename I>
auto getNetWidth(const I &Start, const I &End, unsigned InitialSpaces) const {
auto NetWidth = InitialSpaces;
for (auto PrevIter = Start; PrevIter != End; ++PrevIter) {
// If we broke the line the initial spaces are already
// accounted for.
if (Changes[PrevIter->Index].NewlinesBefore > 0)
NetWidth = 0;
NetWidth +=
calculateCellWidth(PrevIter->Index, PrevIter->EndIndex, true) + 1;
return NetWidth;
/// Get the maximum width of a cell in a sequence of columns.
template <typename I>
unsigned getMaximumCellWidth(I CellIter, unsigned NetWidth) const {
unsigned CellWidth =
calculateCellWidth(CellIter->Index, CellIter->EndIndex, true);
if (Changes[CellIter->Index].NewlinesBefore == 0)
CellWidth += NetWidth;
for (const auto *Next = CellIter->NextColumnElement; Next != nullptr;
Next = Next->NextColumnElement) {
auto ThisWidth = calculateCellWidth(Next->Index, Next->EndIndex, true);
if (Changes[Next->Index].NewlinesBefore == 0)
ThisWidth += NetWidth;
CellWidth = std::max(CellWidth, ThisWidth);
return CellWidth;
/// Get The maximum width of all columns to a given cell.
template <typename I>
unsigned getMaximumNetWidth(const I &CellStart, const I &CellStop,
unsigned InitialSpaces,
unsigned CellCount) const {
auto MaxNetWidth = getNetWidth(CellStart, CellStop, InitialSpaces);
auto RowCount = 1U;
auto Offset = std::distance(CellStart, CellStop);
for (const auto *Next = CellStop->NextColumnElement; Next != nullptr;
Next = Next->NextColumnElement) {
auto Start = (CellStart + RowCount * CellCount);
auto End = Start + Offset;
MaxNetWidth =
std::max(MaxNetWidth, getNetWidth(Start, End, InitialSpaces));
return MaxNetWidth;
/// Align a split cell with a newline to the first element in the cell.
void alignToStartOfCell(unsigned Start, unsigned End);
/// Link the Cell pointers in the list of Cells.
static CellDescriptions linkCells(CellDescriptions &&CellDesc);
/// Fill \c Replaces with the replacements for all effective changes.
void generateChanges();
/// Stores \p Text as the replacement for the whitespace in \p Range.
void storeReplacement(SourceRange Range, StringRef Text);
void appendNewlineText(std::string &Text, unsigned Newlines);
void appendEscapedNewlineText(std::string &Text, unsigned Newlines,
unsigned PreviousEndOfTokenColumn,
unsigned EscapedNewlineColumn);
void appendIndentText(std::string &Text, unsigned IndentLevel,
unsigned Spaces, unsigned WhitespaceStartColumn,
bool IsAligned);
unsigned appendTabIndent(std::string &Text, unsigned Spaces,
unsigned Indentation);
SmallVector<Change, 16> Changes;
const SourceManager &SourceMgr;
tooling::Replacements Replaces;
const FormatStyle &Style;
bool UseCRLF;
} // namespace format
} // namespace clang