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

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//===--- UnwrappedLineFormatter.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.
//
//===----------------------------------------------------------------------===//
#include "UnwrappedLineFormatter.h"
#include "WhitespaceManager.h"
#include "llvm/Support/Debug.h"
#include <queue>
#define DEBUG_TYPE "format-formatter"
namespace clang {
namespace format {
namespace {
bool startsExternCBlock(const AnnotatedLine &Line) {
const FormatToken *Next = Line.First->getNextNonComment();
const FormatToken *NextNext = Next ? Next->getNextNonComment() : nullptr;
return Line.startsWith(tok::kw_extern) && Next && Next->isStringLiteral() &&
NextNext && NextNext->is(tok::l_brace);
}
/// \brief Tracks the indent level of \c AnnotatedLines across levels.
///
/// \c nextLine must be called for each \c AnnotatedLine, after which \c
/// getIndent() will return the indent for the last line \c nextLine was called
/// with.
/// If the line is not formatted (and thus the indent does not change), calling
/// \c adjustToUnmodifiedLine after the call to \c nextLine will cause
/// subsequent lines on the same level to be indented at the same level as the
/// given line.
class LevelIndentTracker {
public:
LevelIndentTracker(const FormatStyle &Style,
const AdditionalKeywords &Keywords, unsigned StartLevel,
int AdditionalIndent)
: Style(Style), Keywords(Keywords), AdditionalIndent(AdditionalIndent) {
for (unsigned i = 0; i != StartLevel; ++i)
IndentForLevel.push_back(Style.IndentWidth * i + AdditionalIndent);
}
/// \brief Returns the indent for the current line.
unsigned getIndent() const { return Indent; }
/// \brief Update the indent state given that \p Line is going to be formatted
/// next.
void nextLine(const AnnotatedLine &Line) {
Offset = getIndentOffset(*Line.First);
// Update the indent level cache size so that we can rely on it
// having the right size in adjustToUnmodifiedline.
while (IndentForLevel.size() <= Line.Level)
IndentForLevel.push_back(-1);
if (Line.InPPDirective) {
Indent = Line.Level * Style.IndentWidth + AdditionalIndent;
} else {
IndentForLevel.resize(Line.Level + 1);
Indent = getIndent(IndentForLevel, Line.Level);
}
if (static_cast<int>(Indent) + Offset >= 0)
Indent += Offset;
}
/// \brief Update the indent state given that \p Line indent should be
/// skipped.
void skipLine(const AnnotatedLine &Line) {
while (IndentForLevel.size() <= Line.Level)
IndentForLevel.push_back(Indent);
}
/// \brief Update the level indent to adapt to the given \p Line.
///
/// When a line is not formatted, we move the subsequent lines on the same
/// level to the same indent.
/// Note that \c nextLine must have been called before this method.
void adjustToUnmodifiedLine(const AnnotatedLine &Line) {
unsigned LevelIndent = Line.First->OriginalColumn;
if (static_cast<int>(LevelIndent) - Offset >= 0)
LevelIndent -= Offset;
if ((!Line.First->is(tok::comment) || IndentForLevel[Line.Level] == -1) &&
!Line.InPPDirective)
IndentForLevel[Line.Level] = LevelIndent;
}
private:
/// \brief Get the offset of the line relatively to the level.
///
/// For example, 'public:' labels in classes are offset by 1 or 2
/// characters to the left from their level.
int getIndentOffset(const FormatToken &RootToken) {
if (Style.Language == FormatStyle::LK_Java ||
Style.Language == FormatStyle::LK_JavaScript)
return 0;
if (RootToken.isAccessSpecifier(false) ||
RootToken.isObjCAccessSpecifier() ||
(RootToken.isOneOf(Keywords.kw_signals, Keywords.kw_qsignals) &&
RootToken.Next && RootToken.Next->is(tok::colon)))
return Style.AccessModifierOffset;
return 0;
}
/// \brief Get the indent of \p Level from \p IndentForLevel.
///
/// \p IndentForLevel must contain the indent for the level \c l
/// at \p IndentForLevel[l], or a value < 0 if the indent for
/// that level is unknown.
unsigned getIndent(ArrayRef<int> IndentForLevel, unsigned Level) {
if (IndentForLevel[Level] != -1)
return IndentForLevel[Level];
if (Level == 0)
return 0;
return getIndent(IndentForLevel, Level - 1) + Style.IndentWidth;
}
const FormatStyle &Style;
const AdditionalKeywords &Keywords;
const unsigned AdditionalIndent;
/// \brief The indent in characters for each level.
std::vector<int> IndentForLevel;
/// \brief Offset of the current line relative to the indent level.
///
/// For example, the 'public' keywords is often indented with a negative
/// offset.
int Offset = 0;
/// \brief The current line's indent.
unsigned Indent = 0;
};
bool isNamespaceDeclaration(const AnnotatedLine *Line) {
const FormatToken *NamespaceTok = Line->First;
return NamespaceTok && NamespaceTok->getNamespaceToken();
}
bool isEndOfNamespace(const AnnotatedLine *Line,
const SmallVectorImpl<AnnotatedLine *> &AnnotatedLines) {
if (!Line->startsWith(tok::r_brace))
return false;
size_t StartLineIndex = Line->MatchingOpeningBlockLineIndex;
if (StartLineIndex == UnwrappedLine::kInvalidIndex)
return false;
assert(StartLineIndex < AnnotatedLines.size());
return isNamespaceDeclaration(AnnotatedLines[StartLineIndex]);
}
class LineJoiner {
public:
LineJoiner(const FormatStyle &Style, const AdditionalKeywords &Keywords,
const SmallVectorImpl<AnnotatedLine *> &Lines)
: Style(Style), Keywords(Keywords), End(Lines.end()), Next(Lines.begin()),
AnnotatedLines(Lines) {}
/// \brief Returns the next line, merging multiple lines into one if possible.
const AnnotatedLine *getNextMergedLine(bool DryRun,
LevelIndentTracker &IndentTracker) {
if (Next == End)
return nullptr;
const AnnotatedLine *Current = *Next;
IndentTracker.nextLine(*Current);
unsigned MergedLines =
tryFitMultipleLinesInOne(IndentTracker, Next, End);
if (MergedLines > 0 && Style.ColumnLimit == 0)
// Disallow line merging if there is a break at the start of one of the
// input lines.
for (unsigned i = 0; i < MergedLines; ++i)
if (Next[i + 1]->First->NewlinesBefore > 0)
MergedLines = 0;
if (!DryRun)
for (unsigned i = 0; i < MergedLines; ++i)
join(*Next[0], *Next[i + 1]);
Next = Next + MergedLines + 1;
return Current;
}
private:
/// \brief Calculates how many lines can be merged into 1 starting at \p I.
unsigned
tryFitMultipleLinesInOne(LevelIndentTracker &IndentTracker,
SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E) {
const unsigned Indent = IndentTracker.getIndent();
// Can't join the last line with anything.
if (I + 1 == E)
return 0;
// We can never merge stuff if there are trailing line comments.
const AnnotatedLine *TheLine = *I;
if (TheLine->Last->is(TT_LineComment))
return 0;
if (I[1]->Type == LT_Invalid || I[1]->First->MustBreakBefore)
return 0;
if (TheLine->InPPDirective &&
(!I[1]->InPPDirective || I[1]->First->HasUnescapedNewline))
return 0;
if (Style.ColumnLimit > 0 && Indent > Style.ColumnLimit)
return 0;
unsigned Limit =
Style.ColumnLimit == 0 ? UINT_MAX : Style.ColumnLimit - Indent;
// If we already exceed the column limit, we set 'Limit' to 0. The different
// tryMerge..() functions can then decide whether to still do merging.
Limit = TheLine->Last->TotalLength > Limit
? 0
: Limit - TheLine->Last->TotalLength;
if (TheLine->Last->is(TT_FunctionLBrace) &&
TheLine->First == TheLine->Last &&
!Style.BraceWrapping.SplitEmptyFunction &&
I[1]->First->is(tok::r_brace))
return tryMergeSimpleBlock(I, E, Limit);
// Handle empty record blocks where the brace has already been wrapped
if (TheLine->Last->is(tok::l_brace) && TheLine->First == TheLine->Last &&
I != AnnotatedLines.begin()) {
bool EmptyBlock = I[1]->First->is(tok::r_brace);
const FormatToken *Tok = I[-1]->First;
if (Tok && Tok->is(tok::comment))
Tok = Tok->getNextNonComment();
if (Tok && Tok->getNamespaceToken())
return !Style.BraceWrapping.SplitEmptyNamespace && EmptyBlock
? tryMergeSimpleBlock(I, E, Limit) : 0;
if (Tok && Tok->is(tok::kw_typedef))
Tok = Tok->getNextNonComment();
if (Tok && Tok->isOneOf(tok::kw_class, tok::kw_struct, tok::kw_union,
Keywords.kw_interface))
return !Style.BraceWrapping.SplitEmptyRecord && EmptyBlock
? tryMergeSimpleBlock(I, E, Limit) : 0;
}
// FIXME: TheLine->Level != 0 might or might not be the right check to do.
// If necessary, change to something smarter.
bool MergeShortFunctions =
Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_All ||
(Style.AllowShortFunctionsOnASingleLine >= FormatStyle::SFS_Empty &&
I[1]->First->is(tok::r_brace)) ||
(Style.AllowShortFunctionsOnASingleLine & FormatStyle::SFS_InlineOnly &&
TheLine->Level != 0);
if (Style.CompactNamespaces) {
if (isNamespaceDeclaration(TheLine)) {
int i = 0;
unsigned closingLine = TheLine->MatchingOpeningBlockLineIndex - 1;
for (; I + 1 + i != E && isNamespaceDeclaration(I[i + 1]) &&
closingLine == I[i + 1]->MatchingOpeningBlockLineIndex &&
I[i + 1]->Last->TotalLength < Limit;
i++, closingLine--) {
// No extra indent for compacted namespaces
IndentTracker.skipLine(*I[i + 1]);
Limit -= I[i + 1]->Last->TotalLength;
}
return i;
}
if (isEndOfNamespace(TheLine, AnnotatedLines)) {
int i = 0;
unsigned openingLine = TheLine->MatchingOpeningBlockLineIndex - 1;
for (; I + 1 + i != E && isEndOfNamespace(I[i + 1], AnnotatedLines) &&
openingLine == I[i + 1]->MatchingOpeningBlockLineIndex;
i++, openingLine--) {
// No space between consecutive braces
I[i + 1]->First->SpacesRequiredBefore = !I[i]->Last->is(tok::r_brace);
// Indent like the outer-most namespace
IndentTracker.nextLine(*I[i + 1]);
}
return i;
}
}
if (TheLine->Last->is(TT_FunctionLBrace) &&
TheLine->First != TheLine->Last) {
return MergeShortFunctions ? tryMergeSimpleBlock(I, E, Limit) : 0;
}
if (TheLine->Last->is(tok::l_brace)) {
return !Style.BraceWrapping.AfterFunction
? tryMergeSimpleBlock(I, E, Limit)
: 0;
}
if (I[1]->First->is(TT_FunctionLBrace) &&
Style.BraceWrapping.AfterFunction) {
if (I[1]->Last->is(TT_LineComment))
return 0;
// Check for Limit <= 2 to account for the " {".
if (Limit <= 2 || (Style.ColumnLimit == 0 && containsMustBreak(TheLine)))
return 0;
Limit -= 2;
unsigned MergedLines = 0;
if (MergeShortFunctions ||
(Style.AllowShortFunctionsOnASingleLine >= FormatStyle::SFS_Empty &&
I[1]->First == I[1]->Last && I + 2 != E &&
I[2]->First->is(tok::r_brace))) {
MergedLines = tryMergeSimpleBlock(I + 1, E, Limit);
// If we managed to merge the block, count the function header, which is
// on a separate line.
if (MergedLines > 0)
++MergedLines;
}
return MergedLines;
}
if (TheLine->First->is(tok::kw_if)) {
return Style.AllowShortIfStatementsOnASingleLine
? tryMergeSimpleControlStatement(I, E, Limit)
: 0;
}
if (TheLine->First->isOneOf(tok::kw_for, tok::kw_while)) {
return Style.AllowShortLoopsOnASingleLine
? tryMergeSimpleControlStatement(I, E, Limit)
: 0;
}
if (TheLine->First->isOneOf(tok::kw_case, tok::kw_default)) {
return Style.AllowShortCaseLabelsOnASingleLine
? tryMergeShortCaseLabels(I, E, Limit)
: 0;
}
if (TheLine->InPPDirective &&
(TheLine->First->HasUnescapedNewline || TheLine->First->IsFirst)) {
return tryMergeSimplePPDirective(I, E, Limit);
}
return 0;
}
unsigned
tryMergeSimplePPDirective(SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E,
unsigned Limit) {
if (Limit == 0)
return 0;
if (I + 2 != E && I[2]->InPPDirective && !I[2]->First->HasUnescapedNewline)
return 0;
if (1 + I[1]->Last->TotalLength > Limit)
return 0;
return 1;
}
unsigned tryMergeSimpleControlStatement(
SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E, unsigned Limit) {
if (Limit == 0)
return 0;
if (Style.BraceWrapping.AfterControlStatement &&
(I[1]->First->is(tok::l_brace) && !Style.AllowShortBlocksOnASingleLine))
return 0;
if (I[1]->InPPDirective != (*I)->InPPDirective ||
(I[1]->InPPDirective && I[1]->First->HasUnescapedNewline))
return 0;
Limit = limitConsideringMacros(I + 1, E, Limit);
AnnotatedLine &Line = **I;
if (Line.Last->isNot(tok::r_paren))
return 0;
if (1 + I[1]->Last->TotalLength > Limit)
return 0;
if (I[1]->First->isOneOf(tok::semi, tok::kw_if, tok::kw_for, tok::kw_while,
TT_LineComment))
return 0;
// Only inline simple if's (no nested if or else).
if (I + 2 != E && Line.startsWith(tok::kw_if) &&
I[2]->First->is(tok::kw_else))
return 0;
return 1;
}
unsigned
tryMergeShortCaseLabels(SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E,
unsigned Limit) {
if (Limit == 0 || I + 1 == E ||
I[1]->First->isOneOf(tok::kw_case, tok::kw_default))
return 0;
unsigned NumStmts = 0;
unsigned Length = 0;
bool InPPDirective = I[0]->InPPDirective;
for (; NumStmts < 3; ++NumStmts) {
if (I + 1 + NumStmts == E)
break;
const AnnotatedLine *Line = I[1 + NumStmts];
if (Line->InPPDirective != InPPDirective)
break;
if (Line->First->isOneOf(tok::kw_case, tok::kw_default, tok::r_brace))
break;
if (Line->First->isOneOf(tok::kw_if, tok::kw_for, tok::kw_switch,
tok::kw_while, tok::comment) ||
Line->Last->is(tok::comment))
return 0;
Length += I[1 + NumStmts]->Last->TotalLength + 1; // 1 for the space.
}
if (NumStmts == 0 || NumStmts == 3 || Length > Limit)
return 0;
return NumStmts;
}
unsigned
tryMergeSimpleBlock(SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E,
unsigned Limit) {
AnnotatedLine &Line = **I;
// Don't merge ObjC @ keywords and methods.
// FIXME: If an option to allow short exception handling clauses on a single
// line is added, change this to not return for @try and friends.
if (Style.Language != FormatStyle::LK_Java &&
Line.First->isOneOf(tok::at, tok::minus, tok::plus))
return 0;
// Check that the current line allows merging. This depends on whether we
// are in a control flow statements as well as several style flags.
if (Line.First->isOneOf(tok::kw_else, tok::kw_case) ||
(Line.First->Next && Line.First->Next->is(tok::kw_else)))
return 0;
if (Line.First->isOneOf(tok::kw_if, tok::kw_while, tok::kw_do, tok::kw_try,
tok::kw___try, tok::kw_catch, tok::kw___finally,
tok::kw_for, tok::r_brace, Keywords.kw___except)) {
if (!Style.AllowShortBlocksOnASingleLine)
return 0;
if (!Style.AllowShortIfStatementsOnASingleLine &&
Line.startsWith(tok::kw_if))
return 0;
if (!Style.AllowShortLoopsOnASingleLine &&
Line.First->isOneOf(tok::kw_while, tok::kw_do, tok::kw_for))
return 0;
// FIXME: Consider an option to allow short exception handling clauses on
// a single line.
// FIXME: This isn't covered by tests.
// FIXME: For catch, __except, __finally the first token on the line
// is '}', so this isn't correct here.
if (Line.First->isOneOf(tok::kw_try, tok::kw___try, tok::kw_catch,
Keywords.kw___except, tok::kw___finally))
return 0;
}
FormatToken *Tok = I[1]->First;
if (Tok->is(tok::r_brace) && !Tok->MustBreakBefore &&
(Tok->getNextNonComment() == nullptr ||
Tok->getNextNonComment()->is(tok::semi))) {
// We merge empty blocks even if the line exceeds the column limit.
Tok->SpacesRequiredBefore = 0;
Tok->CanBreakBefore = true;
return 1;
} else if (Limit != 0 && !Line.startsWith(tok::kw_namespace) &&
!startsExternCBlock(Line)) {
// We don't merge short records.
FormatToken *RecordTok =
Line.First->is(tok::kw_typedef) ? Line.First->Next : Line.First;
if (RecordTok &&
RecordTok->isOneOf(tok::kw_class, tok::kw_union, tok::kw_struct,
Keywords.kw_interface))
return 0;
// Check that we still have three lines and they fit into the limit.
if (I + 2 == E || I[2]->Type == LT_Invalid)
return 0;
Limit = limitConsideringMacros(I + 2, E, Limit);
if (!nextTwoLinesFitInto(I, Limit))
return 0;
// Second, check that the next line does not contain any braces - if it
// does, readability declines when putting it into a single line.
if (I[1]->Last->is(TT_LineComment))
return 0;
do {
if (Tok->is(tok::l_brace) && Tok->BlockKind != BK_BracedInit)
return 0;
Tok = Tok->Next;
} while (Tok);
// Last, check that the third line starts with a closing brace.
Tok = I[2]->First;
if (Tok->isNot(tok::r_brace))
return 0;
// Don't merge "if (a) { .. } else {".
if (Tok->Next && Tok->Next->is(tok::kw_else))
return 0;
return 2;
}
return 0;
}
/// Returns the modified column limit for \p I if it is inside a macro and
/// needs a trailing '\'.
unsigned
limitConsideringMacros(SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E,
unsigned Limit) {
if (I[0]->InPPDirective && I + 1 != E &&
!I[1]->First->HasUnescapedNewline && !I[1]->First->is(tok::eof)) {
return Limit < 2 ? 0 : Limit - 2;
}
return Limit;
}
bool nextTwoLinesFitInto(SmallVectorImpl<AnnotatedLine *>::const_iterator I,
unsigned Limit) {
if (I[1]->First->MustBreakBefore || I[2]->First->MustBreakBefore)
return false;
return 1 + I[1]->Last->TotalLength + 1 + I[2]->Last->TotalLength <= Limit;
}
bool containsMustBreak(const AnnotatedLine *Line) {
for (const FormatToken *Tok = Line->First; Tok; Tok = Tok->Next) {
if (Tok->MustBreakBefore)
return true;
}
return false;
}
void join(AnnotatedLine &A, const AnnotatedLine &B) {
assert(!A.Last->Next);
assert(!B.First->Previous);
if (B.Affected)
A.Affected = true;
A.Last->Next = B.First;
B.First->Previous = A.Last;
B.First->CanBreakBefore = true;
unsigned LengthA = A.Last->TotalLength + B.First->SpacesRequiredBefore;
for (FormatToken *Tok = B.First; Tok; Tok = Tok->Next) {
Tok->TotalLength += LengthA;
A.Last = Tok;
}
}
const FormatStyle &Style;
const AdditionalKeywords &Keywords;
const SmallVectorImpl<AnnotatedLine *>::const_iterator End;
SmallVectorImpl<AnnotatedLine *>::const_iterator Next;
const SmallVectorImpl<AnnotatedLine *> &AnnotatedLines;
};
static void markFinalized(FormatToken *Tok) {
for (; Tok; Tok = Tok->Next) {
Tok->Finalized = true;
for (AnnotatedLine *Child : Tok->Children)
markFinalized(Child->First);
}
}
#ifndef NDEBUG
static void printLineState(const LineState &State) {
llvm::dbgs() << "State: ";
for (const ParenState &P : State.Stack) {
llvm::dbgs() << P.Indent << "|" << P.LastSpace << "|" << P.NestedBlockIndent
<< " ";
}
llvm::dbgs() << State.NextToken->TokenText << "\n";
}
#endif
/// \brief Base class for classes that format one \c AnnotatedLine.
class LineFormatter {
public:
LineFormatter(ContinuationIndenter *Indenter, WhitespaceManager *Whitespaces,
const FormatStyle &Style,
UnwrappedLineFormatter *BlockFormatter)
: Indenter(Indenter), Whitespaces(Whitespaces), Style(Style),
BlockFormatter(BlockFormatter) {}
virtual ~LineFormatter() {}
/// \brief Formats an \c AnnotatedLine and returns the penalty.
///
/// If \p DryRun is \c false, directly applies the changes.
virtual unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent,
bool DryRun) = 0;
protected:
/// \brief If the \p State's next token is an r_brace closing a nested block,
/// format the nested block before it.
///
/// Returns \c true if all children could be placed successfully and adapts
/// \p Penalty as well as \p State. If \p DryRun is false, also directly
/// creates changes using \c Whitespaces.
///
/// The crucial idea here is that children always get formatted upon
/// encountering the closing brace right after the nested block. Now, if we
/// are currently trying to keep the "}" on the same line (i.e. \p NewLine is
/// \c false), the entire block has to be kept on the same line (which is only
/// possible if it fits on the line, only contains a single statement, etc.
///
/// If \p NewLine is true, we format the nested block on separate lines, i.e.
/// break after the "{", format all lines with correct indentation and the put
/// the closing "}" on yet another new line.
///
/// This enables us to keep the simple structure of the
/// \c UnwrappedLineFormatter, where we only have two options for each token:
/// break or don't break.
bool formatChildren(LineState &State, bool NewLine, bool DryRun,
unsigned &Penalty) {
const FormatToken *LBrace = State.NextToken->getPreviousNonComment();
FormatToken &Previous = *State.NextToken->Previous;
if (!LBrace || LBrace->isNot(tok::l_brace) ||
LBrace->BlockKind != BK_Block || Previous.Children.size() == 0)
// The previous token does not open a block. Nothing to do. We don't
// assert so that we can simply call this function for all tokens.
return true;
if (NewLine) {
int AdditionalIndent = State.Stack.back().Indent -
Previous.Children[0]->Level * Style.IndentWidth;
Penalty +=
BlockFormatter->format(Previous.Children, DryRun, AdditionalIndent,
/*FixBadIndentation=*/true);
return true;
}
if (Previous.Children[0]->First->MustBreakBefore)
return false;
// Cannot merge into one line if this line ends on a comment.
if (Previous.is(tok::comment))
return false;
// Cannot merge multiple statements into a single line.
if (Previous.Children.size() > 1)
return false;
const AnnotatedLine *Child = Previous.Children[0];
// We can't put the closing "}" on a line with a trailing comment.
if (Child->Last->isTrailingComment())
return false;
// If the child line exceeds the column limit, we wouldn't want to merge it.
// We add +2 for the trailing " }".
if (Style.ColumnLimit > 0 &&
Child->Last->TotalLength + State.Column + 2 > Style.ColumnLimit)
return false;
if (!DryRun) {
Whitespaces->replaceWhitespace(
*Child->First, /*Newlines=*/0, /*Spaces=*/1,
/*StartOfTokenColumn=*/State.Column, State.Line->InPPDirective);
}
Penalty += formatLine(*Child, State.Column + 1, DryRun);
State.Column += 1 + Child->Last->TotalLength;
return true;
}
ContinuationIndenter *Indenter;
private:
WhitespaceManager *Whitespaces;
const FormatStyle &Style;
UnwrappedLineFormatter *BlockFormatter;
};
/// \brief Formatter that keeps the existing line breaks.
class NoColumnLimitLineFormatter : public LineFormatter {
public:
NoColumnLimitLineFormatter(ContinuationIndenter *Indenter,
WhitespaceManager *Whitespaces,
const FormatStyle &Style,
UnwrappedLineFormatter *BlockFormatter)
: LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {}
/// \brief Formats the line, simply keeping all of the input's line breaking
/// decisions.
unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent,
bool DryRun) override {
assert(!DryRun);
LineState State =
Indenter->getInitialState(FirstIndent, &Line, /*DryRun=*/false);
while (State.NextToken) {
bool Newline =
Indenter->mustBreak(State) ||
(Indenter->canBreak(State) && State.NextToken->NewlinesBefore > 0);
unsigned Penalty = 0;
formatChildren(State, Newline, /*DryRun=*/false, Penalty);
Indenter->addTokenToState(State, Newline, /*DryRun=*/false);
}
return 0;
}
};
/// \brief Formatter that puts all tokens into a single line without breaks.
class NoLineBreakFormatter : public LineFormatter {
public:
NoLineBreakFormatter(ContinuationIndenter *Indenter,
WhitespaceManager *Whitespaces, const FormatStyle &Style,
UnwrappedLineFormatter *BlockFormatter)
: LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {}
/// \brief Puts all tokens into a single line.
unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent,
bool DryRun) override {
unsigned Penalty = 0;
LineState State = Indenter->getInitialState(FirstIndent, &Line, DryRun);
while (State.NextToken) {
formatChildren(State, /*Newline=*/false, DryRun, Penalty);
Indenter->addTokenToState(
State, /*Newline=*/State.NextToken->MustBreakBefore, DryRun);
}
return Penalty;
}
};
/// \brief Finds the best way to break lines.
class OptimizingLineFormatter : public LineFormatter {
public:
OptimizingLineFormatter(ContinuationIndenter *Indenter,
WhitespaceManager *Whitespaces,
const FormatStyle &Style,
UnwrappedLineFormatter *BlockFormatter)
: LineFormatter(Indenter, Whitespaces, Style, BlockFormatter) {}
/// \brief Formats the line by finding the best line breaks with line lengths
/// below the column limit.
unsigned formatLine(const AnnotatedLine &Line, unsigned FirstIndent,
bool DryRun) override {
LineState State = Indenter->getInitialState(FirstIndent, &Line, DryRun);
// If the ObjC method declaration does not fit on a line, we should format
// it with one arg per line.
if (State.Line->Type == LT_ObjCMethodDecl)
State.Stack.back().BreakBeforeParameter = true;
// Find best solution in solution space.
return analyzeSolutionSpace(State, DryRun);
}
private:
struct CompareLineStatePointers {
bool operator()(LineState *obj1, LineState *obj2) const {
return *obj1 < *obj2;
}
};
/// \brief A pair of <penalty, count> that is used to prioritize the BFS on.
///
/// In case of equal penalties, we want to prefer states that were inserted
/// first. During state generation we make sure that we insert states first
/// that break the line as late as possible.
typedef std::pair<unsigned, unsigned> OrderedPenalty;
/// \brief An edge in the solution space from \c Previous->State to \c State,
/// inserting a newline dependent on the \c NewLine.
struct StateNode {
StateNode(const LineState &State, bool NewLine, StateNode *Previous)
: State(State), NewLine(NewLine), Previous(Previous) {}
LineState State;
bool NewLine;
StateNode *Previous;
};
/// \brief An item in the prioritized BFS search queue. The \c StateNode's
/// \c State has the given \c OrderedPenalty.
typedef std::pair<OrderedPenalty, StateNode *> QueueItem;
/// \brief The BFS queue type.
typedef std::priority_queue<QueueItem, std::vector<QueueItem>,
std::greater<QueueItem>> QueueType;
/// \brief Analyze the entire solution space starting from \p InitialState.
///
/// This implements a variant of Dijkstra's algorithm on the graph that spans
/// the solution space (\c LineStates are the nodes). The algorithm tries to
/// find the shortest path (the one with lowest penalty) from \p InitialState
/// to a state where all tokens are placed. Returns the penalty.
///
/// If \p DryRun is \c false, directly applies the changes.
unsigned analyzeSolutionSpace(LineState &InitialState, bool DryRun) {
std::set<LineState *, CompareLineStatePointers> Seen;
// Increasing count of \c StateNode items we have created. This is used to
// create a deterministic order independent of the container.
unsigned Count = 0;
QueueType Queue;
// Insert start element into queue.
StateNode *Node =
new (Allocator.Allocate()) StateNode(InitialState, false, nullptr);
Queue.push(QueueItem(OrderedPenalty(0, Count), Node));
++Count;
unsigned Penalty = 0;
// While not empty, take first element and follow edges.
while (!Queue.empty()) {
Penalty = Queue.top().first.first;
StateNode *Node = Queue.top().second;
if (!Node->State.NextToken) {
DEBUG(llvm::dbgs() << "\n---\nPenalty for line: " << Penalty << "\n");
break;
}
Queue.pop();
// Cut off the analysis of certain solutions if the analysis gets too
// complex. See description of IgnoreStackForComparison.
if (Count > 50000)
Node->State.IgnoreStackForComparison = true;
if (!Seen.insert(&Node->State).second)
// State already examined with lower penalty.
continue;
FormatDecision LastFormat = Node->State.NextToken->Decision;
if (LastFormat == FD_Unformatted || LastFormat == FD_Continue)
addNextStateToQueue(Penalty, Node, /*NewLine=*/false, &Count, &Queue);
if (LastFormat == FD_Unformatted || LastFormat == FD_Break)
addNextStateToQueue(Penalty, Node, /*NewLine=*/true, &Count, &Queue);
}
if (Queue.empty()) {
// We were unable to find a solution, do nothing.
// FIXME: Add diagnostic?
DEBUG(llvm::dbgs() << "Could not find a solution.\n");
return 0;
}
// Reconstruct the solution.
if (!DryRun)
reconstructPath(InitialState, Queue.top().second);
DEBUG(llvm::dbgs() << "Total number of analyzed states: " << Count << "\n");
DEBUG(llvm::dbgs() << "---\n");
return Penalty;
}
/// \brief Add the following state to the analysis queue \c Queue.
///
/// Assume the current state is \p PreviousNode and has been reached with a
/// penalty of \p Penalty. Insert a line break if \p NewLine is \c true.
void addNextStateToQueue(unsigned Penalty, StateNode *PreviousNode,
bool NewLine, unsigned *Count, QueueType *Queue) {
if (NewLine && !Indenter->canBreak(PreviousNode->State))
return;
if (!NewLine && Indenter->mustBreak(PreviousNode->State))
return;
StateNode *Node = new (Allocator.Allocate())
StateNode(PreviousNode->State, NewLine, PreviousNode);
if (!formatChildren(Node->State, NewLine, /*DryRun=*/true, Penalty))
return;
Penalty += Indenter->addTokenToState(Node->State, NewLine, true);
Queue->push(QueueItem(OrderedPenalty(Penalty, *Count), Node));
++(*Count);
}
/// \brief Applies the best formatting by reconstructing the path in the
/// solution space that leads to \c Best.
void reconstructPath(LineState &State, StateNode *Best) {
std::deque<StateNode *> Path;
// We do not need a break before the initial token.
while (Best->Previous) {
Path.push_front(Best);
Best = Best->Previous;
}
for (std::deque<StateNode *>::iterator I = Path.begin(), E = Path.end();
I != E; ++I) {
unsigned Penalty = 0;
formatChildren(State, (*I)->NewLine, /*DryRun=*/false, Penalty);
Penalty += Indenter->addTokenToState(State, (*I)->NewLine, false);
DEBUG({
printLineState((*I)->Previous->State);
if ((*I)->NewLine) {
llvm::dbgs() << "Penalty for placing "
<< (*I)->Previous->State.NextToken->Tok.getName() << ": "
<< Penalty << "\n";
}
});
}
}
llvm::SpecificBumpPtrAllocator<StateNode> Allocator;
};
} // anonymous namespace
unsigned
UnwrappedLineFormatter::format(const SmallVectorImpl<AnnotatedLine *> &Lines,
bool DryRun, int AdditionalIndent,
bool FixBadIndentation) {
LineJoiner Joiner(Style, Keywords, Lines);
// Try to look up already computed penalty in DryRun-mode.
std::pair<const SmallVectorImpl<AnnotatedLine *> *, unsigned> CacheKey(
&Lines, AdditionalIndent);
auto CacheIt = PenaltyCache.find(CacheKey);
if (DryRun && CacheIt != PenaltyCache.end())
return CacheIt->second;
assert(!Lines.empty());
unsigned Penalty = 0;
LevelIndentTracker IndentTracker(Style, Keywords, Lines[0]->Level,
AdditionalIndent);
const AnnotatedLine *PreviousLine = nullptr;
const AnnotatedLine *NextLine = nullptr;
// The minimum level of consecutive lines that have been formatted.
unsigned RangeMinLevel = UINT_MAX;
for (const AnnotatedLine *Line =
Joiner.getNextMergedLine(DryRun, IndentTracker);
Line; Line = NextLine) {
const AnnotatedLine &TheLine = *Line;
unsigned Indent = IndentTracker.getIndent();
// We continue formatting unchanged lines to adjust their indent, e.g. if a
// scope was added. However, we need to carefully stop doing this when we
// exit the scope of affected lines to prevent indenting a the entire
// remaining file if it currently missing a closing brace.
bool ContinueFormatting =
TheLine.Level > RangeMinLevel ||
(TheLine.Level == RangeMinLevel && !TheLine.startsWith(tok::r_brace));
bool FixIndentation = (FixBadIndentation || ContinueFormatting) &&
Indent != TheLine.First->OriginalColumn;
bool ShouldFormat = TheLine.Affected || FixIndentation;
// We cannot format this line; if the reason is that the line had a
// parsing error, remember that.
if (ShouldFormat && TheLine.Type == LT_Invalid && Status) {
Status->FormatComplete = false;
Status->Line =
SourceMgr.getSpellingLineNumber(TheLine.First->Tok.getLocation());
}
if (ShouldFormat && TheLine.Type != LT_Invalid) {
if (!DryRun)
formatFirstToken(TheLine, PreviousLine, Indent);
NextLine = Joiner.getNextMergedLine(DryRun, IndentTracker);
unsigned ColumnLimit = getColumnLimit(TheLine.InPPDirective, NextLine);
bool FitsIntoOneLine =
TheLine.Last->TotalLength + Indent <= ColumnLimit ||
(TheLine.Type == LT_ImportStatement &&
(Style.Language != FormatStyle::LK_JavaScript ||
!Style.JavaScriptWrapImports));
if (Style.ColumnLimit == 0)
NoColumnLimitLineFormatter(Indenter, Whitespaces, Style, this)
.formatLine(TheLine, Indent, DryRun);
else if (FitsIntoOneLine)
Penalty += NoLineBreakFormatter(Indenter, Whitespaces, Style, this)
.formatLine(TheLine, Indent, DryRun);
else
Penalty += OptimizingLineFormatter(Indenter, Whitespaces, Style, this)
.formatLine(TheLine, Indent, DryRun);
RangeMinLevel = std::min(RangeMinLevel, TheLine.Level);
} else {
// If no token in the current line is affected, we still need to format
// affected children.
if (TheLine.ChildrenAffected)
for (const FormatToken *Tok = TheLine.First; Tok; Tok = Tok->Next)
if (!Tok->Children.empty())
format(Tok->Children, DryRun);
// Adapt following lines on the current indent level to the same level
// unless the current \c AnnotatedLine is not at the beginning of a line.
bool StartsNewLine =
TheLine.First->NewlinesBefore > 0 || TheLine.First->IsFirst;
if (StartsNewLine)
IndentTracker.adjustToUnmodifiedLine(TheLine);
if (!DryRun) {
bool ReformatLeadingWhitespace =
StartsNewLine && ((PreviousLine && PreviousLine->Affected) ||
TheLine.LeadingEmptyLinesAffected);
// Format the first token.
if (ReformatLeadingWhitespace)
formatFirstToken(TheLine, PreviousLine,
TheLine.First->OriginalColumn);
else
Whitespaces->addUntouchableToken(*TheLine.First,
TheLine.InPPDirective);
// Notify the WhitespaceManager about the unchanged whitespace.
for (FormatToken *Tok = TheLine.First->Next; Tok; Tok = Tok->Next)
Whitespaces->addUntouchableToken(*Tok, TheLine.InPPDirective);
}
NextLine = Joiner.getNextMergedLine(DryRun, IndentTracker);
RangeMinLevel = UINT_MAX;
}
if (!DryRun)
markFinalized(TheLine.First);
PreviousLine = &TheLine;
}
PenaltyCache[CacheKey] = Penalty;
return Penalty;
}
void UnwrappedLineFormatter::formatFirstToken(const AnnotatedLine &Line,
const AnnotatedLine *PreviousLine,
unsigned Indent) {
FormatToken& RootToken = *Line.First;
if (RootToken.is(tok::eof)) {
unsigned Newlines = std::min(RootToken.NewlinesBefore, 1u);
Whitespaces->replaceWhitespace(RootToken, Newlines, /*Spaces=*/0,
/*StartOfTokenColumn=*/0);
return;
}
unsigned Newlines =
std::min(RootToken.NewlinesBefore, Style.MaxEmptyLinesToKeep + 1);
// Remove empty lines before "}" where applicable.
if (RootToken.is(tok::r_brace) &&
(!RootToken.Next ||
(RootToken.Next->is(tok::semi) && !RootToken.Next->Next)))
Newlines = std::min(Newlines, 1u);
if (Newlines == 0 && !RootToken.IsFirst)
Newlines = 1;
if (RootToken.IsFirst && !RootToken.HasUnescapedNewline)
Newlines = 0;
// Remove empty lines after "{".
if (!Style.KeepEmptyLinesAtTheStartOfBlocks && PreviousLine &&
PreviousLine->Last->is(tok::l_brace) &&
PreviousLine->First->isNot(tok::kw_namespace) &&
!startsExternCBlock(*PreviousLine))
Newlines = 1;
// Insert extra new line before access specifiers.
if (PreviousLine && PreviousLine->Last->isOneOf(tok::semi, tok::r_brace) &&
RootToken.isAccessSpecifier() && RootToken.NewlinesBefore == 1)
++Newlines;
// Remove empty lines after access specifiers.
if (PreviousLine && PreviousLine->First->isAccessSpecifier() &&
(!PreviousLine->InPPDirective || !RootToken.HasUnescapedNewline))
Newlines = std::min(1u, Newlines);
Whitespaces->replaceWhitespace(RootToken, Newlines, Indent, Indent,
Line.InPPDirective &&
!RootToken.HasUnescapedNewline);
}
unsigned
UnwrappedLineFormatter::getColumnLimit(bool InPPDirective,
const AnnotatedLine *NextLine) const {
// In preprocessor directives reserve two chars for trailing " \" if the
// next line continues the preprocessor directive.
bool ContinuesPPDirective =
InPPDirective &&
// If there is no next line, this is likely a child line and the parent
// continues the preprocessor directive.
(!NextLine ||
(NextLine->InPPDirective &&
// If there is an unescaped newline between this line and the next, the
// next line starts a new preprocessor directive.
!NextLine->First->HasUnescapedNewline));
return Style.ColumnLimit - (ContinuesPPDirective ? 2 : 0);
}
} // namespace format
} // namespace clang
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