llvm-project/clang/lib/Format/WhitespaceManager.cpp

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//===--- WhitespaceManager.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 WhitespaceManager class.
///
//===----------------------------------------------------------------------===//
#include "WhitespaceManager.h"
#include "llvm/ADT/STLExtras.h"
namespace clang {
namespace format {
bool WhitespaceManager::Change::IsBeforeInFile::
operator()(const Change &C1, const Change &C2) const {
return SourceMgr.isBeforeInTranslationUnit(
C1.OriginalWhitespaceRange.getBegin(),
C2.OriginalWhitespaceRange.getBegin());
}
WhitespaceManager::Change::Change(
bool CreateReplacement, const SourceRange &OriginalWhitespaceRange,
unsigned IndentLevel, int Spaces, unsigned StartOfTokenColumn,
unsigned NewlinesBefore, StringRef PreviousLinePostfix,
StringRef CurrentLinePrefix, tok::TokenKind Kind, bool ContinuesPPDirective)
: CreateReplacement(CreateReplacement),
OriginalWhitespaceRange(OriginalWhitespaceRange),
StartOfTokenColumn(StartOfTokenColumn), NewlinesBefore(NewlinesBefore),
PreviousLinePostfix(PreviousLinePostfix),
CurrentLinePrefix(CurrentLinePrefix), Kind(Kind),
ContinuesPPDirective(ContinuesPPDirective), IndentLevel(IndentLevel),
Spaces(Spaces) {}
void WhitespaceManager::reset() {
Changes.clear();
Replaces.clear();
}
void WhitespaceManager::replaceWhitespace(FormatToken &Tok, unsigned Newlines,
unsigned IndentLevel, unsigned Spaces,
unsigned StartOfTokenColumn,
bool InPPDirective) {
if (Tok.Finalized)
return;
Tok.Decision = (Newlines > 0) ? FD_Break : FD_Continue;
Changes.push_back(Change(true, Tok.WhitespaceRange, IndentLevel, Spaces,
StartOfTokenColumn, Newlines, "", "",
Tok.Tok.getKind(), InPPDirective && !Tok.IsFirst));
}
void WhitespaceManager::addUntouchableToken(const FormatToken &Tok,
bool InPPDirective) {
if (Tok.Finalized)
return;
Changes.push_back(Change(false, Tok.WhitespaceRange, /*IndentLevel=*/0,
/*Spaces=*/0, Tok.OriginalColumn, Tok.NewlinesBefore,
"", "", Tok.Tok.getKind(),
InPPDirective && !Tok.IsFirst));
}
void WhitespaceManager::replaceWhitespaceInToken(
const FormatToken &Tok, unsigned Offset, unsigned ReplaceChars,
StringRef PreviousPostfix, StringRef CurrentPrefix, bool InPPDirective,
unsigned Newlines, unsigned IndentLevel, int Spaces) {
if (Tok.Finalized)
return;
SourceLocation Start = Tok.getStartOfNonWhitespace().getLocWithOffset(Offset);
Changes.push_back(Change(
true, SourceRange(Start, Start.getLocWithOffset(ReplaceChars)),
IndentLevel, Spaces, std::max(0, Spaces), Newlines, PreviousPostfix,
CurrentPrefix,
// If we don't add a newline this change doesn't start a comment. Thus,
// when we align line comments, we don't need to treat this change as one.
// FIXME: We still need to take this change in account to properly
// calculate the new length of the comment and to calculate the changes
// for which to do the alignment when aligning comments.
Tok.Type == TT_LineComment && Newlines > 0 ? tok::comment : tok::unknown,
InPPDirective && !Tok.IsFirst));
}
const tooling::Replacements &WhitespaceManager::generateReplacements() {
if (Changes.empty())
return Replaces;
std::sort(Changes.begin(), Changes.end(), Change::IsBeforeInFile(SourceMgr));
calculateLineBreakInformation();
alignTrailingComments();
alignEscapedNewlines();
generateChanges();
return Replaces;
}
void WhitespaceManager::calculateLineBreakInformation() {
Changes[0].PreviousEndOfTokenColumn = 0;
for (unsigned i = 1, e = Changes.size(); i != e; ++i) {
unsigned OriginalWhitespaceStart =
SourceMgr.getFileOffset(Changes[i].OriginalWhitespaceRange.getBegin());
unsigned PreviousOriginalWhitespaceEnd = SourceMgr.getFileOffset(
Changes[i - 1].OriginalWhitespaceRange.getEnd());
Changes[i - 1].TokenLength = OriginalWhitespaceStart -
PreviousOriginalWhitespaceEnd +
Changes[i].PreviousLinePostfix.size() +
Changes[i - 1].CurrentLinePrefix.size();
Changes[i].PreviousEndOfTokenColumn =
Changes[i - 1].StartOfTokenColumn + Changes[i - 1].TokenLength;
Changes[i - 1].IsTrailingComment =
(Changes[i].NewlinesBefore > 0 || Changes[i].Kind == tok::eof) &&
Changes[i - 1].Kind == tok::comment;
}
// FIXME: The last token is currently not always an eof token; in those
// cases, setting TokenLength of the last token to 0 is wrong.
Changes.back().TokenLength = 0;
Changes.back().IsTrailingComment = Changes.back().Kind == tok::comment;
const WhitespaceManager::Change *LastBlockComment = nullptr;
for (auto &Change : Changes) {
Change.StartOfBlockComment = nullptr;
Change.IndentationOffset = 0;
if (Change.Kind == tok::comment) {
LastBlockComment = &Change;
} else if (Change.Kind == tok::unknown) {
if ((Change.StartOfBlockComment = LastBlockComment))
Change.IndentationOffset =
Change.StartOfTokenColumn -
Change.StartOfBlockComment->StartOfTokenColumn;
} else {
LastBlockComment = nullptr;
}
}
}
void WhitespaceManager::alignTrailingComments() {
unsigned MinColumn = 0;
unsigned MaxColumn = UINT_MAX;
unsigned StartOfSequence = 0;
bool BreakBeforeNext = false;
unsigned Newlines = 0;
for (unsigned i = 0, e = Changes.size(); i != e; ++i) {
if (Changes[i].StartOfBlockComment)
continue;
Newlines += Changes[i].NewlinesBefore;
if (!Changes[i].IsTrailingComment)
continue;
unsigned ChangeMinColumn = Changes[i].StartOfTokenColumn;
unsigned ChangeMaxColumn = Style.ColumnLimit - Changes[i].TokenLength;
if (i + 1 != e && Changes[i + 1].ContinuesPPDirective)
ChangeMaxColumn -= 2;
// If this comment follows an } in column 0, it probably documents the
// closing of a namespace and we don't want to align it.
bool FollowsRBraceInColumn0 = i > 0 && Changes[i].NewlinesBefore == 0 &&
Changes[i - 1].Kind == tok::r_brace &&
Changes[i - 1].StartOfTokenColumn == 0;
bool WasAlignedWithStartOfNextLine = false;
if (Changes[i].NewlinesBefore == 1) { // A comment on its own line.
for (unsigned j = i + 1; j != e; ++j) {
if (Changes[j].Kind != tok::comment) { // Skip over comments.
// The start of the next token was previously aligned with the
// start of this comment.
WasAlignedWithStartOfNextLine =
(SourceMgr.getSpellingColumnNumber(
Changes[i].OriginalWhitespaceRange.getEnd()) ==
SourceMgr.getSpellingColumnNumber(
Changes[j].OriginalWhitespaceRange.getEnd()));
break;
}
}
}
if (!Style.AlignTrailingComments || FollowsRBraceInColumn0) {
alignTrailingComments(StartOfSequence, i, MinColumn);
MinColumn = ChangeMinColumn;
MaxColumn = ChangeMinColumn;
StartOfSequence = i;
} else if (BreakBeforeNext || Newlines > 1 ||
(ChangeMinColumn > MaxColumn || ChangeMaxColumn < MinColumn) ||
// Break the comment sequence if the previous line did not end
// in a trailing comment.
(Changes[i].NewlinesBefore == 1 && i > 0 &&
!Changes[i - 1].IsTrailingComment) ||
WasAlignedWithStartOfNextLine) {
alignTrailingComments(StartOfSequence, i, MinColumn);
MinColumn = ChangeMinColumn;
MaxColumn = ChangeMaxColumn;
StartOfSequence = i;
} else {
MinColumn = std::max(MinColumn, ChangeMinColumn);
MaxColumn = std::min(MaxColumn, ChangeMaxColumn);
}
BreakBeforeNext =
(i == 0) || (Changes[i].NewlinesBefore > 1) ||
// Never start a sequence with a comment at the beginning of
// the line.
(Changes[i].NewlinesBefore == 1 && StartOfSequence == i);
Newlines = 0;
}
alignTrailingComments(StartOfSequence, Changes.size(), MinColumn);
}
void WhitespaceManager::alignTrailingComments(unsigned Start, unsigned End,
unsigned Column) {
for (unsigned i = Start; i != End; ++i) {
int Shift = 0;
if (Changes[i].IsTrailingComment) {
Shift = Column - Changes[i].StartOfTokenColumn;
}
if (Changes[i].StartOfBlockComment) {
Shift = Changes[i].IndentationOffset +
Changes[i].StartOfBlockComment->StartOfTokenColumn -
Changes[i].StartOfTokenColumn;
}
assert(Shift >= 0);
Changes[i].Spaces += Shift;
if (i + 1 != End)
Changes[i + 1].PreviousEndOfTokenColumn += Shift;
Changes[i].StartOfTokenColumn += Shift;
}
}
void WhitespaceManager::alignEscapedNewlines() {
unsigned MaxEndOfLine =
Style.AlignEscapedNewlinesLeft ? 0 : Style.ColumnLimit;
unsigned StartOfMacro = 0;
for (unsigned i = 1, e = Changes.size(); i < e; ++i) {
Change &C = Changes[i];
if (C.NewlinesBefore > 0) {
if (C.ContinuesPPDirective) {
MaxEndOfLine = std::max(C.PreviousEndOfTokenColumn + 2, MaxEndOfLine);
} else {
alignEscapedNewlines(StartOfMacro + 1, i, MaxEndOfLine);
MaxEndOfLine = Style.AlignEscapedNewlinesLeft ? 0 : Style.ColumnLimit;
StartOfMacro = i;
}
}
}
alignEscapedNewlines(StartOfMacro + 1, Changes.size(), MaxEndOfLine);
}
void WhitespaceManager::alignEscapedNewlines(unsigned Start, unsigned End,
unsigned Column) {
for (unsigned i = Start; i < End; ++i) {
Change &C = Changes[i];
if (C.NewlinesBefore > 0) {
assert(C.ContinuesPPDirective);
if (C.PreviousEndOfTokenColumn + 1 > Column)
C.EscapedNewlineColumn = 0;
else
C.EscapedNewlineColumn = Column;
}
}
}
void WhitespaceManager::generateChanges() {
for (unsigned i = 0, e = Changes.size(); i != e; ++i) {
const Change &C = Changes[i];
if (C.CreateReplacement) {
std::string ReplacementText = C.PreviousLinePostfix;
if (C.ContinuesPPDirective)
appendNewlineText(ReplacementText, C.NewlinesBefore,
C.PreviousEndOfTokenColumn, C.EscapedNewlineColumn);
else
appendNewlineText(ReplacementText, C.NewlinesBefore);
appendIndentText(ReplacementText, C.IndentLevel, std::max(0, C.Spaces),
C.StartOfTokenColumn - std::max(0, C.Spaces));
ReplacementText.append(C.CurrentLinePrefix);
storeReplacement(C.OriginalWhitespaceRange, ReplacementText);
}
}
}
void WhitespaceManager::storeReplacement(const SourceRange &Range,
StringRef Text) {
unsigned WhitespaceLength = SourceMgr.getFileOffset(Range.getEnd()) -
SourceMgr.getFileOffset(Range.getBegin());
// Don't create a replacement, if it does not change anything.
if (StringRef(SourceMgr.getCharacterData(Range.getBegin()),
WhitespaceLength) == Text)
return;
Replaces.insert(tooling::Replacement(
SourceMgr, CharSourceRange::getCharRange(Range), Text));
}
void WhitespaceManager::appendNewlineText(std::string &Text,
unsigned Newlines) {
for (unsigned i = 0; i < Newlines; ++i)
Text.append(UseCRLF ? "\r\n" : "\n");
}
void WhitespaceManager::appendNewlineText(std::string &Text, unsigned Newlines,
unsigned PreviousEndOfTokenColumn,
unsigned EscapedNewlineColumn) {
if (Newlines > 0) {
unsigned Offset =
std::min<int>(EscapedNewlineColumn - 1, PreviousEndOfTokenColumn);
for (unsigned i = 0; i < Newlines; ++i) {
Text.append(std::string(EscapedNewlineColumn - Offset - 1, ' '));
Text.append(UseCRLF ? "\\\r\n" : "\\\n");
Offset = 0;
}
}
}
void WhitespaceManager::appendIndentText(std::string &Text,
unsigned IndentLevel, unsigned Spaces,
unsigned WhitespaceStartColumn) {
switch (Style.UseTab) {
case FormatStyle::UT_Never:
Text.append(std::string(Spaces, ' '));
break;
case FormatStyle::UT_Always: {
unsigned FirstTabWidth =
Style.TabWidth - WhitespaceStartColumn % Style.TabWidth;
// Indent with tabs only when there's at least one full tab.
if (FirstTabWidth + Style.TabWidth <= Spaces) {
Spaces -= FirstTabWidth;
Text.append("\t");
}
Text.append(std::string(Spaces / Style.TabWidth, '\t'));
Text.append(std::string(Spaces % Style.TabWidth, ' '));
break;
}
case FormatStyle::UT_ForIndentation:
if (WhitespaceStartColumn == 0) {
unsigned Indentation = IndentLevel * Style.IndentWidth;
// This happens, e.g. when a line in a block comment is indented less than
// the first one.
if (Indentation > Spaces)
Indentation = Spaces;
unsigned Tabs = Indentation / Style.TabWidth;
Text.append(std::string(Tabs, '\t'));
Spaces -= Tabs * Style.TabWidth;
}
Text.append(std::string(Spaces, ' '));
break;
}
}
} // namespace format
} // namespace clang