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

989 lines
38 KiB
C++

//===--- WhitespaceManager.cpp - Format C++ code --------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// 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(const FormatToken &Tok,
bool CreateReplacement,
SourceRange OriginalWhitespaceRange,
int Spaces, unsigned StartOfTokenColumn,
unsigned NewlinesBefore,
StringRef PreviousLinePostfix,
StringRef CurrentLinePrefix, bool IsAligned,
bool ContinuesPPDirective, bool IsInsideToken)
: Tok(&Tok), CreateReplacement(CreateReplacement),
OriginalWhitespaceRange(OriginalWhitespaceRange),
StartOfTokenColumn(StartOfTokenColumn), NewlinesBefore(NewlinesBefore),
PreviousLinePostfix(PreviousLinePostfix),
CurrentLinePrefix(CurrentLinePrefix), IsAligned(IsAligned),
ContinuesPPDirective(ContinuesPPDirective), Spaces(Spaces),
IsInsideToken(IsInsideToken), IsTrailingComment(false), TokenLength(0),
PreviousEndOfTokenColumn(0), EscapedNewlineColumn(0),
StartOfBlockComment(nullptr), IndentationOffset(0), ConditionalsLevel(0) {
}
void WhitespaceManager::replaceWhitespace(FormatToken &Tok, unsigned Newlines,
unsigned Spaces,
unsigned StartOfTokenColumn,
bool IsAligned, bool InPPDirective) {
if (Tok.Finalized)
return;
Tok.Decision = (Newlines > 0) ? FD_Break : FD_Continue;
Changes.push_back(Change(Tok, /*CreateReplacement=*/true, Tok.WhitespaceRange,
Spaces, StartOfTokenColumn, Newlines, "", "",
IsAligned, InPPDirective && !Tok.IsFirst,
/*IsInsideToken=*/false));
}
void WhitespaceManager::addUntouchableToken(const FormatToken &Tok,
bool InPPDirective) {
if (Tok.Finalized)
return;
Changes.push_back(Change(Tok, /*CreateReplacement=*/false,
Tok.WhitespaceRange, /*Spaces=*/0,
Tok.OriginalColumn, Tok.NewlinesBefore, "", "",
/*IsAligned=*/false, InPPDirective && !Tok.IsFirst,
/*IsInsideToken=*/false));
}
llvm::Error
WhitespaceManager::addReplacement(const tooling::Replacement &Replacement) {
return Replaces.add(Replacement);
}
void WhitespaceManager::replaceWhitespaceInToken(
const FormatToken &Tok, unsigned Offset, unsigned ReplaceChars,
StringRef PreviousPostfix, StringRef CurrentPrefix, bool InPPDirective,
unsigned Newlines, int Spaces) {
if (Tok.Finalized)
return;
SourceLocation Start = Tok.getStartOfNonWhitespace().getLocWithOffset(Offset);
Changes.push_back(
Change(Tok, /*CreateReplacement=*/true,
SourceRange(Start, Start.getLocWithOffset(ReplaceChars)), Spaces,
std::max(0, Spaces), Newlines, PreviousPostfix, CurrentPrefix,
/*IsAligned=*/true, InPPDirective && !Tok.IsFirst,
/*IsInsideToken=*/true));
}
const tooling::Replacements &WhitespaceManager::generateReplacements() {
if (Changes.empty())
return Replaces;
llvm::sort(Changes, Change::IsBeforeInFile(SourceMgr));
calculateLineBreakInformation();
alignConsecutiveMacros();
alignConsecutiveDeclarations();
alignConsecutiveBitFields();
alignConsecutiveAssignments();
alignChainedConditionals();
alignTrailingComments();
alignEscapedNewlines();
generateChanges();
return Replaces;
}
void WhitespaceManager::calculateLineBreakInformation() {
Changes[0].PreviousEndOfTokenColumn = 0;
Change *LastOutsideTokenChange = &Changes[0];
for (unsigned i = 1, e = Changes.size(); i != e; ++i) {
SourceLocation OriginalWhitespaceStart =
Changes[i].OriginalWhitespaceRange.getBegin();
SourceLocation PreviousOriginalWhitespaceEnd =
Changes[i - 1].OriginalWhitespaceRange.getEnd();
unsigned OriginalWhitespaceStartOffset =
SourceMgr.getFileOffset(OriginalWhitespaceStart);
unsigned PreviousOriginalWhitespaceEndOffset =
SourceMgr.getFileOffset(PreviousOriginalWhitespaceEnd);
assert(PreviousOriginalWhitespaceEndOffset <=
OriginalWhitespaceStartOffset);
const char *const PreviousOriginalWhitespaceEndData =
SourceMgr.getCharacterData(PreviousOriginalWhitespaceEnd);
StringRef Text(PreviousOriginalWhitespaceEndData,
SourceMgr.getCharacterData(OriginalWhitespaceStart) -
PreviousOriginalWhitespaceEndData);
// Usually consecutive changes would occur in consecutive tokens. This is
// not the case however when analyzing some preprocessor runs of the
// annotated lines. For example, in this code:
//
// #if A // line 1
// int i = 1;
// #else B // line 2
// int i = 2;
// #endif // line 3
//
// one of the runs will produce the sequence of lines marked with line 1, 2
// and 3. So the two consecutive whitespace changes just before '// line 2'
// and before '#endif // line 3' span multiple lines and tokens:
//
// #else B{change X}[// line 2
// int i = 2;
// ]{change Y}#endif // line 3
//
// For this reason, if the text between consecutive changes spans multiple
// newlines, the token length must be adjusted to the end of the original
// line of the token.
auto NewlinePos = Text.find_first_of('\n');
if (NewlinePos == StringRef::npos) {
Changes[i - 1].TokenLength = OriginalWhitespaceStartOffset -
PreviousOriginalWhitespaceEndOffset +
Changes[i].PreviousLinePostfix.size() +
Changes[i - 1].CurrentLinePrefix.size();
} else {
Changes[i - 1].TokenLength =
NewlinePos + Changes[i - 1].CurrentLinePrefix.size();
}
// If there are multiple changes in this token, sum up all the changes until
// the end of the line.
if (Changes[i - 1].IsInsideToken && Changes[i - 1].NewlinesBefore == 0)
LastOutsideTokenChange->TokenLength +=
Changes[i - 1].TokenLength + Changes[i - 1].Spaces;
else
LastOutsideTokenChange = &Changes[i - 1];
Changes[i].PreviousEndOfTokenColumn =
Changes[i - 1].StartOfTokenColumn + Changes[i - 1].TokenLength;
Changes[i - 1].IsTrailingComment =
(Changes[i].NewlinesBefore > 0 || Changes[i].Tok->is(tok::eof) ||
(Changes[i].IsInsideToken && Changes[i].Tok->is(tok::comment))) &&
Changes[i - 1].Tok->is(tok::comment) &&
// FIXME: This is a dirty hack. The problem is that
// BreakableLineCommentSection does comment reflow changes and here is
// the aligning of trailing comments. Consider the case where we reflow
// the second line up in this example:
//
// // line 1
// // line 2
//
// That amounts to 2 changes by BreakableLineCommentSection:
// - the first, delimited by (), for the whitespace between the tokens,
// - and second, delimited by [], for the whitespace at the beginning
// of the second token:
//
// // line 1(
// )[// ]line 2
//
// So in the end we have two changes like this:
//
// // line1()[ ]line 2
//
// Note that the OriginalWhitespaceStart of the second change is the
// same as the PreviousOriginalWhitespaceEnd of the first change.
// In this case, the below check ensures that the second change doesn't
// get treated as a trailing comment change here, since this might
// trigger additional whitespace to be wrongly inserted before "line 2"
// by the comment aligner here.
//
// For a proper solution we need a mechanism to say to WhitespaceManager
// that a particular change breaks the current sequence of trailing
// comments.
OriginalWhitespaceStart != PreviousOriginalWhitespaceEnd;
}
// 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().Tok->is(tok::comment);
const WhitespaceManager::Change *LastBlockComment = nullptr;
for (auto &Change : Changes) {
// Reset the IsTrailingComment flag for changes inside of trailing comments
// so they don't get realigned later. Comment line breaks however still need
// to be aligned.
if (Change.IsInsideToken && Change.NewlinesBefore == 0)
Change.IsTrailingComment = false;
Change.StartOfBlockComment = nullptr;
Change.IndentationOffset = 0;
if (Change.Tok->is(tok::comment)) {
if (Change.Tok->is(TT_LineComment) || !Change.IsInsideToken)
LastBlockComment = &Change;
else {
if ((Change.StartOfBlockComment = LastBlockComment))
Change.IndentationOffset =
Change.StartOfTokenColumn -
Change.StartOfBlockComment->StartOfTokenColumn;
}
} else {
LastBlockComment = nullptr;
}
}
// Compute conditional nesting level
// Level is increased for each conditional, unless this conditional continues
// a chain of conditional, i.e. starts immediately after the colon of another
// conditional.
SmallVector<bool, 16> ScopeStack;
int ConditionalsLevel = 0;
for (auto &Change : Changes) {
for (unsigned i = 0, e = Change.Tok->FakeLParens.size(); i != e; ++i) {
bool isNestedConditional =
Change.Tok->FakeLParens[e - 1 - i] == prec::Conditional &&
!(i == 0 && Change.Tok->Previous &&
Change.Tok->Previous->is(TT_ConditionalExpr) &&
Change.Tok->Previous->is(tok::colon));
if (isNestedConditional)
++ConditionalsLevel;
ScopeStack.push_back(isNestedConditional);
}
Change.ConditionalsLevel = ConditionalsLevel;
for (unsigned i = Change.Tok->FakeRParens; i > 0 && ScopeStack.size();
--i) {
if (ScopeStack.pop_back_val())
--ConditionalsLevel;
}
}
}
// Align a single sequence of tokens, see AlignTokens below.
template <typename F>
static void
AlignTokenSequence(unsigned Start, unsigned End, unsigned Column, F &&Matches,
SmallVector<WhitespaceManager::Change, 16> &Changes) {
bool FoundMatchOnLine = false;
int Shift = 0;
// ScopeStack keeps track of the current scope depth. It contains indices of
// the first token on each scope.
// We only run the "Matches" function on tokens from the outer-most scope.
// However, we do need to pay special attention to one class of tokens
// that are not in the outer-most scope, and that is function parameters
// which are split across multiple lines, as illustrated by this example:
// double a(int x);
// int b(int y,
// double z);
// In the above example, we need to take special care to ensure that
// 'double z' is indented along with it's owning function 'b'.
// Special handling is required for 'nested' ternary operators.
SmallVector<unsigned, 16> ScopeStack;
for (unsigned i = Start; i != End; ++i) {
if (ScopeStack.size() != 0 &&
Changes[i].indentAndNestingLevel() <
Changes[ScopeStack.back()].indentAndNestingLevel())
ScopeStack.pop_back();
// Compare current token to previous non-comment token to ensure whether
// it is in a deeper scope or not.
unsigned PreviousNonComment = i - 1;
while (PreviousNonComment > Start &&
Changes[PreviousNonComment].Tok->is(tok::comment))
PreviousNonComment--;
if (i != Start && Changes[i].indentAndNestingLevel() >
Changes[PreviousNonComment].indentAndNestingLevel())
ScopeStack.push_back(i);
bool InsideNestedScope = ScopeStack.size() != 0;
if (Changes[i].NewlinesBefore > 0 && !InsideNestedScope) {
Shift = 0;
FoundMatchOnLine = false;
}
// If this is the first matching token to be aligned, remember by how many
// spaces it has to be shifted, so the rest of the changes on the line are
// shifted by the same amount
if (!FoundMatchOnLine && !InsideNestedScope && Matches(Changes[i])) {
FoundMatchOnLine = true;
Shift = Column - Changes[i].StartOfTokenColumn;
Changes[i].Spaces += Shift;
}
// This is for function parameters that are split across multiple lines,
// as mentioned in the ScopeStack comment.
if (InsideNestedScope && Changes[i].NewlinesBefore > 0) {
unsigned ScopeStart = ScopeStack.back();
if (Changes[ScopeStart - 1].Tok->is(TT_FunctionDeclarationName) ||
(ScopeStart > Start + 1 &&
Changes[ScopeStart - 2].Tok->is(TT_FunctionDeclarationName)) ||
Changes[i].Tok->is(TT_ConditionalExpr) ||
(Changes[i].Tok->Previous &&
Changes[i].Tok->Previous->is(TT_ConditionalExpr)))
Changes[i].Spaces += Shift;
}
assert(Shift >= 0);
Changes[i].StartOfTokenColumn += Shift;
if (i + 1 != Changes.size())
Changes[i + 1].PreviousEndOfTokenColumn += Shift;
}
}
// Walk through a subset of the changes, starting at StartAt, and find
// sequences of matching tokens to align. To do so, keep track of the lines and
// whether or not a matching token was found on a line. If a matching token is
// found, extend the current sequence. If the current line cannot be part of a
// sequence, e.g. because there is an empty line before it or it contains only
// non-matching tokens, finalize the previous sequence.
// The value returned is the token on which we stopped, either because we
// exhausted all items inside Changes, or because we hit a scope level higher
// than our initial scope.
// This function is recursive. Each invocation processes only the scope level
// equal to the initial level, which is the level of Changes[StartAt].
// If we encounter a scope level greater than the initial level, then we call
// ourselves recursively, thereby avoiding the pollution of the current state
// with the alignment requirements of the nested sub-level. This recursive
// behavior is necessary for aligning function prototypes that have one or more
// arguments.
// If this function encounters a scope level less than the initial level,
// it returns the current position.
// There is a non-obvious subtlety in the recursive behavior: Even though we
// defer processing of nested levels to recursive invocations of this
// function, when it comes time to align a sequence of tokens, we run the
// alignment on the entire sequence, including the nested levels.
// When doing so, most of the nested tokens are skipped, because their
// alignment was already handled by the recursive invocations of this function.
// However, the special exception is that we do NOT skip function parameters
// that are split across multiple lines. See the test case in FormatTest.cpp
// that mentions "split function parameter alignment" for an example of this.
template <typename F>
static unsigned AlignTokens(const FormatStyle &Style, F &&Matches,
SmallVector<WhitespaceManager::Change, 16> &Changes,
unsigned StartAt) {
unsigned MinColumn = 0;
unsigned MaxColumn = UINT_MAX;
// Line number of the start and the end of the current token sequence.
unsigned StartOfSequence = 0;
unsigned EndOfSequence = 0;
// Measure the scope level (i.e. depth of (), [], {}) of the first token, and
// abort when we hit any token in a higher scope than the starting one.
auto IndentAndNestingLevel = StartAt < Changes.size()
? Changes[StartAt].indentAndNestingLevel()
: std::tuple<unsigned, unsigned, unsigned>();
// Keep track of the number of commas before the matching tokens, we will only
// align a sequence of matching tokens if they are preceded by the same number
// of commas.
unsigned CommasBeforeLastMatch = 0;
unsigned CommasBeforeMatch = 0;
// Whether a matching token has been found on the current line.
bool FoundMatchOnLine = false;
// Aligns a sequence of matching tokens, on the MinColumn column.
//
// Sequences start from the first matching token to align, and end at the
// first token of the first line that doesn't need to be aligned.
//
// We need to adjust the StartOfTokenColumn of each Change that is on a line
// containing any matching token to be aligned and located after such token.
auto AlignCurrentSequence = [&] {
if (StartOfSequence > 0 && StartOfSequence < EndOfSequence)
AlignTokenSequence(StartOfSequence, EndOfSequence, MinColumn, Matches,
Changes);
MinColumn = 0;
MaxColumn = UINT_MAX;
StartOfSequence = 0;
EndOfSequence = 0;
};
unsigned i = StartAt;
for (unsigned e = Changes.size(); i != e; ++i) {
if (Changes[i].indentAndNestingLevel() < IndentAndNestingLevel)
break;
if (Changes[i].NewlinesBefore != 0) {
CommasBeforeMatch = 0;
EndOfSequence = i;
// If there is a blank line, there is a forced-align-break (eg,
// preprocessor), or if the last line didn't contain any matching token,
// the sequence ends here.
if (Changes[i].NewlinesBefore > 1 ||
Changes[i].Tok->MustBreakAlignBefore || !FoundMatchOnLine)
AlignCurrentSequence();
FoundMatchOnLine = false;
}
if (Changes[i].Tok->is(tok::comma)) {
++CommasBeforeMatch;
} else if (Changes[i].indentAndNestingLevel() > IndentAndNestingLevel) {
// Call AlignTokens recursively, skipping over this scope block.
unsigned StoppedAt = AlignTokens(Style, Matches, Changes, i);
i = StoppedAt - 1;
continue;
}
if (!Matches(Changes[i]))
continue;
// If there is more than one matching token per line, or if the number of
// preceding commas, do not match anymore, end the sequence.
if (FoundMatchOnLine || CommasBeforeMatch != CommasBeforeLastMatch)
AlignCurrentSequence();
CommasBeforeLastMatch = CommasBeforeMatch;
FoundMatchOnLine = true;
if (StartOfSequence == 0)
StartOfSequence = i;
unsigned ChangeMinColumn = Changes[i].StartOfTokenColumn;
int LineLengthAfter = Changes[i].TokenLength;
for (unsigned j = i + 1; j != e && Changes[j].NewlinesBefore == 0; ++j) {
LineLengthAfter += Changes[j].Spaces;
// Changes are generally 1:1 with the tokens, but a change could also be
// inside of a token, in which case it's counted more than once: once for
// the whitespace surrounding the token (!IsInsideToken) and once for
// each whitespace change within it (IsInsideToken).
// Therefore, changes inside of a token should only count the space.
if (!Changes[j].IsInsideToken)
LineLengthAfter += Changes[j].TokenLength;
}
unsigned ChangeMaxColumn = Style.ColumnLimit - LineLengthAfter;
// If we are restricted by the maximum column width, end the sequence.
if (ChangeMinColumn > MaxColumn || ChangeMaxColumn < MinColumn ||
CommasBeforeLastMatch != CommasBeforeMatch) {
AlignCurrentSequence();
StartOfSequence = i;
}
MinColumn = std::max(MinColumn, ChangeMinColumn);
MaxColumn = std::min(MaxColumn, ChangeMaxColumn);
}
EndOfSequence = i;
AlignCurrentSequence();
return i;
}
// Aligns a sequence of matching tokens, on the MinColumn column.
//
// Sequences start from the first matching token to align, and end at the
// first token of the first line that doesn't need to be aligned.
//
// We need to adjust the StartOfTokenColumn of each Change that is on a line
// containing any matching token to be aligned and located after such token.
static void AlignMacroSequence(
unsigned &StartOfSequence, unsigned &EndOfSequence, unsigned &MinColumn,
unsigned &MaxColumn, bool &FoundMatchOnLine,
std::function<bool(const WhitespaceManager::Change &C)> AlignMacrosMatches,
SmallVector<WhitespaceManager::Change, 16> &Changes) {
if (StartOfSequence > 0 && StartOfSequence < EndOfSequence) {
FoundMatchOnLine = false;
int Shift = 0;
for (unsigned I = StartOfSequence; I != EndOfSequence; ++I) {
if (Changes[I].NewlinesBefore > 0) {
Shift = 0;
FoundMatchOnLine = false;
}
// If this is the first matching token to be aligned, remember by how many
// spaces it has to be shifted, so the rest of the changes on the line are
// shifted by the same amount
if (!FoundMatchOnLine && AlignMacrosMatches(Changes[I])) {
FoundMatchOnLine = true;
Shift = MinColumn - Changes[I].StartOfTokenColumn;
Changes[I].Spaces += Shift;
}
assert(Shift >= 0);
Changes[I].StartOfTokenColumn += Shift;
if (I + 1 != Changes.size())
Changes[I + 1].PreviousEndOfTokenColumn += Shift;
}
}
MinColumn = 0;
MaxColumn = UINT_MAX;
StartOfSequence = 0;
EndOfSequence = 0;
}
void WhitespaceManager::alignConsecutiveMacros() {
if (!Style.AlignConsecutiveMacros)
return;
auto AlignMacrosMatches = [](const Change &C) {
const FormatToken *Current = C.Tok;
unsigned SpacesRequiredBefore = 1;
if (Current->SpacesRequiredBefore == 0 || !Current->Previous)
return false;
Current = Current->Previous;
// If token is a ")", skip over the parameter list, to the
// token that precedes the "("
if (Current->is(tok::r_paren) && Current->MatchingParen) {
Current = Current->MatchingParen->Previous;
SpacesRequiredBefore = 0;
}
if (!Current || !Current->is(tok::identifier))
return false;
if (!Current->Previous || !Current->Previous->is(tok::pp_define))
return false;
// For a macro function, 0 spaces are required between the
// identifier and the lparen that opens the parameter list.
// For a simple macro, 1 space is required between the
// identifier and the first token of the defined value.
return Current->Next->SpacesRequiredBefore == SpacesRequiredBefore;
};
unsigned MinColumn = 0;
unsigned MaxColumn = UINT_MAX;
// Start and end of the token sequence we're processing.
unsigned StartOfSequence = 0;
unsigned EndOfSequence = 0;
// Whether a matching token has been found on the current line.
bool FoundMatchOnLine = false;
unsigned I = 0;
for (unsigned E = Changes.size(); I != E; ++I) {
if (Changes[I].NewlinesBefore != 0) {
EndOfSequence = I;
// If there is a blank line, or if the last line didn't contain any
// matching token, the sequence ends here.
if (Changes[I].NewlinesBefore > 1 || !FoundMatchOnLine)
AlignMacroSequence(StartOfSequence, EndOfSequence, MinColumn, MaxColumn,
FoundMatchOnLine, AlignMacrosMatches, Changes);
FoundMatchOnLine = false;
}
if (!AlignMacrosMatches(Changes[I]))
continue;
FoundMatchOnLine = true;
if (StartOfSequence == 0)
StartOfSequence = I;
unsigned ChangeMinColumn = Changes[I].StartOfTokenColumn;
int LineLengthAfter = -Changes[I].Spaces;
for (unsigned j = I; j != E && Changes[j].NewlinesBefore == 0; ++j)
LineLengthAfter += Changes[j].Spaces + Changes[j].TokenLength;
unsigned ChangeMaxColumn = Style.ColumnLimit - LineLengthAfter;
MinColumn = std::max(MinColumn, ChangeMinColumn);
MaxColumn = std::min(MaxColumn, ChangeMaxColumn);
}
EndOfSequence = I;
AlignMacroSequence(StartOfSequence, EndOfSequence, MinColumn, MaxColumn,
FoundMatchOnLine, AlignMacrosMatches, Changes);
}
void WhitespaceManager::alignConsecutiveAssignments() {
if (!Style.AlignConsecutiveAssignments)
return;
AlignTokens(
Style,
[&](const Change &C) {
// Do not align on equal signs that are first on a line.
if (C.NewlinesBefore > 0)
return false;
// Do not align on equal signs that are last on a line.
if (&C != &Changes.back() && (&C + 1)->NewlinesBefore > 0)
return false;
return C.Tok->is(tok::equal);
},
Changes, /*StartAt=*/0);
}
void WhitespaceManager::alignConsecutiveBitFields() {
if (!Style.AlignConsecutiveBitFields)
return;
AlignTokens(
Style,
[&](Change const &C) {
// Do not align on ':' that is first on a line.
if (C.NewlinesBefore > 0)
return false;
// Do not align on ':' that is last on a line.
if (&C != &Changes.back() && (&C + 1)->NewlinesBefore > 0)
return false;
return C.Tok->is(TT_BitFieldColon);
},
Changes, /*StartAt=*/0);
}
void WhitespaceManager::alignConsecutiveDeclarations() {
if (!Style.AlignConsecutiveDeclarations)
return;
// FIXME: Currently we don't handle properly the PointerAlignment: Right
// The * and & are not aligned and are left dangling. Something has to be done
// about it, but it raises the question of alignment of code like:
// const char* const* v1;
// float const* v2;
// SomeVeryLongType const& v3;
AlignTokens(
Style,
[](Change const &C) {
// tok::kw_operator is necessary for aligning operator overload
// definitions.
if (C.Tok->isOneOf(TT_FunctionDeclarationName, tok::kw_operator))
return true;
if (C.Tok->isNot(TT_StartOfName))
return false;
// Check if there is a subsequent name that starts the same declaration.
for (FormatToken *Next = C.Tok->Next; Next; Next = Next->Next) {
if (Next->is(tok::comment))
continue;
if (!Next->Tok.getIdentifierInfo())
break;
if (Next->isOneOf(TT_StartOfName, TT_FunctionDeclarationName,
tok::kw_operator))
return false;
}
return true;
},
Changes, /*StartAt=*/0);
}
void WhitespaceManager::alignChainedConditionals() {
if (Style.BreakBeforeTernaryOperators) {
AlignTokens(
Style,
[](Change const &C) {
// Align question operators and last colon
return C.Tok->is(TT_ConditionalExpr) &&
((C.Tok->is(tok::question) && !C.NewlinesBefore) ||
(C.Tok->is(tok::colon) && C.Tok->Next &&
(C.Tok->Next->FakeLParens.size() == 0 ||
C.Tok->Next->FakeLParens.back() != prec::Conditional)));
},
Changes, /*StartAt=*/0);
} else {
static auto AlignWrappedOperand = [](Change const &C) {
auto Previous = C.Tok->getPreviousNonComment(); // Previous;
return C.NewlinesBefore && Previous && Previous->is(TT_ConditionalExpr) &&
(Previous->is(tok::question) ||
(Previous->is(tok::colon) &&
(C.Tok->FakeLParens.size() == 0 ||
C.Tok->FakeLParens.back() != prec::Conditional)));
};
// Ensure we keep alignment of wrapped operands with non-wrapped operands
// Since we actually align the operators, the wrapped operands need the
// extra offset to be properly aligned.
for (Change &C : Changes) {
if (AlignWrappedOperand(C))
C.StartOfTokenColumn -= 2;
}
AlignTokens(
Style,
[this](Change const &C) {
// Align question operators if next operand is not wrapped, as
// well as wrapped operands after question operator or last
// colon in conditional sequence
return (C.Tok->is(TT_ConditionalExpr) && C.Tok->is(tok::question) &&
&C != &Changes.back() && (&C + 1)->NewlinesBefore == 0 &&
!(&C + 1)->IsTrailingComment) ||
AlignWrappedOperand(C);
},
Changes, /*StartAt=*/0);
}
}
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].Tok->MustBreakAlignBefore)
BreakBeforeNext = true;
if (!Changes[i].IsTrailingComment)
continue;
unsigned ChangeMinColumn = Changes[i].StartOfTokenColumn;
unsigned ChangeMaxColumn;
if (Style.ColumnLimit == 0)
ChangeMaxColumn = UINT_MAX;
else if (Style.ColumnLimit >= Changes[i].TokenLength)
ChangeMaxColumn = Style.ColumnLimit - Changes[i].TokenLength;
else
ChangeMaxColumn = ChangeMinColumn;
// If we don't create a replacement for this change, we have to consider
// it to be immovable.
if (!Changes[i].CreateReplacement)
ChangeMaxColumn = ChangeMinColumn;
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].Tok->is(tok::r_brace) &&
Changes[i - 1].StartOfTokenColumn == 0;
bool WasAlignedWithStartOfNextLine = false;
if (Changes[i].NewlinesBefore == 1) { // A comment on its own line.
unsigned CommentColumn = SourceMgr.getSpellingColumnNumber(
Changes[i].OriginalWhitespaceRange.getEnd());
for (unsigned j = i + 1; j != e; ++j) {
if (Changes[j].Tok->is(tok::comment))
continue;
unsigned NextColumn = SourceMgr.getSpellingColumnNumber(
Changes[j].OriginalWhitespaceRange.getEnd());
// The start of the next token was previously aligned with the
// start of this comment.
WasAlignedWithStartOfNextLine =
CommentColumn == NextColumn ||
CommentColumn == NextColumn + Style.IndentWidth;
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 != Changes.size())
Changes[i + 1].PreviousEndOfTokenColumn += Shift;
Changes[i].StartOfTokenColumn += Shift;
}
}
void WhitespaceManager::alignEscapedNewlines() {
if (Style.AlignEscapedNewlines == FormatStyle::ENAS_DontAlign)
return;
bool AlignLeft = Style.AlignEscapedNewlines == FormatStyle::ENAS_Left;
unsigned MaxEndOfLine = AlignLeft ? 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 = AlignLeft ? 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 (i > 0) {
assert(Changes[i - 1].OriginalWhitespaceRange.getBegin() !=
C.OriginalWhitespaceRange.getBegin() &&
"Generating two replacements for the same location");
}
if (C.CreateReplacement) {
std::string ReplacementText = C.PreviousLinePostfix;
if (C.ContinuesPPDirective)
appendEscapedNewlineText(ReplacementText, C.NewlinesBefore,
C.PreviousEndOfTokenColumn,
C.EscapedNewlineColumn);
else
appendNewlineText(ReplacementText, C.NewlinesBefore);
appendIndentText(
ReplacementText, C.Tok->IndentLevel, std::max(0, C.Spaces),
C.StartOfTokenColumn - std::max(0, C.Spaces), C.IsAligned);
ReplacementText.append(C.CurrentLinePrefix);
storeReplacement(C.OriginalWhitespaceRange, ReplacementText);
}
}
}
void WhitespaceManager::storeReplacement(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;
auto Err = Replaces.add(tooling::Replacement(
SourceMgr, CharSourceRange::getCharRange(Range), Text));
// FIXME: better error handling. For now, just print an error message in the
// release version.
if (Err) {
llvm::errs() << llvm::toString(std::move(Err)) << "\n";
assert(false);
}
}
void WhitespaceManager::appendNewlineText(std::string &Text,
unsigned Newlines) {
for (unsigned i = 0; i < Newlines; ++i)
Text.append(UseCRLF ? "\r\n" : "\n");
}
void WhitespaceManager::appendEscapedNewlineText(
std::string &Text, unsigned Newlines, unsigned PreviousEndOfTokenColumn,
unsigned EscapedNewlineColumn) {
if (Newlines > 0) {
unsigned Spaces =
std::max<int>(1, EscapedNewlineColumn - PreviousEndOfTokenColumn - 1);
for (unsigned i = 0; i < Newlines; ++i) {
Text.append(Spaces, ' ');
Text.append(UseCRLF ? "\\\r\n" : "\\\n");
Spaces = std::max<int>(0, EscapedNewlineColumn - 1);
}
}
}
void WhitespaceManager::appendIndentText(std::string &Text,
unsigned IndentLevel, unsigned Spaces,
unsigned WhitespaceStartColumn,
bool IsAligned) {
switch (Style.UseTab) {
case FormatStyle::UT_Never:
Text.append(Spaces, ' ');
break;
case FormatStyle::UT_Always: {
if (Style.TabWidth) {
unsigned FirstTabWidth =
Style.TabWidth - WhitespaceStartColumn % Style.TabWidth;
// Insert only spaces when we want to end up before the next tab.
if (Spaces < FirstTabWidth || Spaces == 1) {
Text.append(Spaces, ' ');
break;
}
// Align to the next tab.
Spaces -= FirstTabWidth;
Text.append("\t");
Text.append(Spaces / Style.TabWidth, '\t');
Text.append(Spaces % Style.TabWidth, ' ');
} else if (Spaces == 1) {
Text.append(Spaces, ' ');
}
break;
}
case FormatStyle::UT_ForIndentation:
if (WhitespaceStartColumn == 0) {
unsigned Indentation = IndentLevel * Style.IndentWidth;
Spaces = appendTabIndent(Text, Spaces, Indentation);
}
Text.append(Spaces, ' ');
break;
case FormatStyle::UT_ForContinuationAndIndentation:
if (WhitespaceStartColumn == 0)
Spaces = appendTabIndent(Text, Spaces, Spaces);
Text.append(Spaces, ' ');
break;
case FormatStyle::UT_AlignWithSpaces:
if (WhitespaceStartColumn == 0) {
unsigned Indentation =
IsAligned ? IndentLevel * Style.IndentWidth : Spaces;
Spaces = appendTabIndent(Text, Spaces, Indentation);
}
Text.append(Spaces, ' ');
break;
}
}
unsigned WhitespaceManager::appendTabIndent(std::string &Text, unsigned Spaces,
unsigned Indentation) {
// This happens, e.g. when a line in a block comment is indented less than the
// first one.
if (Indentation > Spaces)
Indentation = Spaces;
if (Style.TabWidth) {
unsigned Tabs = Indentation / Style.TabWidth;
Text.append(Tabs, '\t');
Spaces -= Tabs * Style.TabWidth;
}
return Spaces;
}
} // namespace format
} // namespace clang