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clang-format: Factor out UnwrappedLineFormatter into a separate file. 

No functional changes intended.

llvm-svn: 223936
This commit is contained in:
Daniel Jasper 2014-12-10 19:00:42 +00:00
parent 76c1d958fb
commit 0df50938be
4 changed files with 869 additions and 773 deletions
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1
clang/lib/Format/CMakeLists.txt
View File

@ -6,6 +6,7 @@ add_clang_library(clangFormat
Format.cpp
FormatToken.cpp
TokenAnnotator.cpp
UnwrappedLineFormatter.cpp
UnwrappedLineParser.cpp
WhitespaceManager.cpp

774
clang/lib/Format/Format.cpp
View File

@ -15,6 +15,7 @@
#include "ContinuationIndenter.h"
#include "TokenAnnotator.h"
#include "UnwrappedLineFormatter.h"
#include "UnwrappedLineParser.h"
#include "WhitespaceManager.h"
#include "clang/Basic/Diagnostic.h"
@ -589,779 +590,6 @@ std::string configurationAsText(const FormatStyle &Style) {
namespace {
bool startsExternCBlock(const AnnotatedLine &Line) {
const FormatToken *Next = Line.First->getNextNonComment();
const FormatToken *NextNext = Next ? Next->getNextNonComment() : nullptr;
return Line.First->is(tok::kw_extern) && Next && Next->isStringLiteral() &&
NextNext && NextNext->is(tok::l_brace);
}
class NoColumnLimitFormatter {
public:
NoColumnLimitFormatter(ContinuationIndenter *Indenter) : Indenter(Indenter) {}
/// \brief Formats the line starting at \p State, simply keeping all of the
/// input's line breaking decisions.
void format(unsigned FirstIndent, const AnnotatedLine *Line) {
LineState State =
Indenter->getInitialState(FirstIndent, Line, /*DryRun=*/false);
while (State.NextToken) {
bool Newline =
Indenter->mustBreak(State) ||
(Indenter->canBreak(State) && State.NextToken->NewlinesBefore > 0);
Indenter->addTokenToState(State, Newline, /*DryRun=*/false);
}
}
private:
ContinuationIndenter *Indenter;
};
class LineJoiner {
public:
LineJoiner(const FormatStyle &Style) : Style(Style) {}
/// \brief Calculates how many lines can be merged into 1 starting at \p I.
unsigned
tryFitMultipleLinesInOne(unsigned Indent,
SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E) {
// We can never merge stuff if there are trailing line comments.
const AnnotatedLine *TheLine = *I;
if (TheLine->Last->is(TT_LineComment))
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 (I + 1 == E || I[1]->Type == LT_Invalid || I[1]->First->MustBreakBefore)
return 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_Inline &&
TheLine->Level != 0);
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.BreakBeforeBraces == FormatStyle::BS_Attach
? tryMergeSimpleBlock(I, E, Limit)
: 0;
}
if (I[1]->First->is(TT_FunctionLBrace) &&
Style.BreakBeforeBraces != FormatStyle::BS_Attach) {
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) {
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;
}
private:
unsigned
tryMergeSimplePPDirective(SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E,
unsigned Limit) {
if (Limit == 0)
return 0;
if (!I[1]->InPPDirective || I[1]->First->HasUnescapedNewline)
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.BreakBeforeBraces == FormatStyle::BS_Allman ||
Style.BreakBeforeBraces == FormatStyle::BS_GNU) &&
(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.First->is(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))
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.
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))
return 0;
if (Line.First->isOneOf(tok::kw_if, tok::kw_while, tok::kw_do, tok::kw_try,
tok::kw_catch, tok::kw_for, tok::r_brace)) {
if (!Style.AllowShortBlocksOnASingleLine)
return 0;
if (!Style.AllowShortIfStatementsOnASingleLine &&
Line.First->is(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.
if (Line.First->isOneOf(tok::kw_try, tok::kw_catch))
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.First->isNot(tok::kw_namespace) &&
!startsExternCBlock(Line)) {
// We don't merge short records.
if (Line.First->isOneOf(tok::kw_class, tok::kw_union, tok::kw_struct))
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;
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;
}
const FormatStyle &Style;
};
class UnwrappedLineFormatter {
public:
UnwrappedLineFormatter(ContinuationIndenter *Indenter,
WhitespaceManager *Whitespaces,
const FormatStyle &Style)
: Indenter(Indenter), Whitespaces(Whitespaces), Style(Style),
Joiner(Style) {}
unsigned format(const SmallVectorImpl<AnnotatedLine *> &Lines, bool DryRun,
int AdditionalIndent = 0, bool FixBadIndentation = false) {
// 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;
std::vector<int> IndentForLevel;
for (unsigned i = 0, e = Lines[0]->Level; i != e; ++i)
IndentForLevel.push_back(Style.IndentWidth * i + AdditionalIndent);
const AnnotatedLine *PreviousLine = nullptr;
for (SmallVectorImpl<AnnotatedLine *>::const_iterator I = Lines.begin(),
E = Lines.end();
I != E; ++I) {
const AnnotatedLine &TheLine = **I;
const FormatToken *FirstTok = TheLine.First;
int Offset = getIndentOffset(*FirstTok);
// Determine indent and try to merge multiple unwrapped lines.
unsigned Indent;
if (TheLine.InPPDirective) {
Indent = TheLine.Level * Style.IndentWidth;
} else {
while (IndentForLevel.size() <= TheLine.Level)
IndentForLevel.push_back(-1);
IndentForLevel.resize(TheLine.Level + 1);
Indent = getIndent(IndentForLevel, TheLine.Level);
}
unsigned LevelIndent = Indent;
if (static_cast<int>(Indent) + Offset >= 0)
Indent += Offset;
// Merge multiple lines if possible.
unsigned MergedLines = Joiner.tryFitMultipleLinesInOne(Indent, I, E);
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 (I[i + 1]->First->NewlinesBefore > 0)
MergedLines = 0;
}
}
if (!DryRun) {
for (unsigned i = 0; i < MergedLines; ++i) {
join(*I[i], *I[i + 1]);
}
}
I += MergedLines;
bool FixIndentation =
FixBadIndentation && (LevelIndent != FirstTok->OriginalColumn);
if (TheLine.First->is(tok::eof)) {
if (PreviousLine && PreviousLine->Affected && !DryRun) {
// Remove the file's trailing whitespace.
unsigned Newlines = std::min(FirstTok->NewlinesBefore, 1u);
Whitespaces->replaceWhitespace(*TheLine.First, Newlines,
/*IndentLevel=*/0, /*Spaces=*/0,
/*TargetColumn=*/0);
}
} else if (TheLine.Type != LT_Invalid &&
(TheLine.Affected || FixIndentation)) {
if (FirstTok->WhitespaceRange.isValid()) {
if (!DryRun)
formatFirstToken(*TheLine.First, PreviousLine, TheLine.Level,
Indent, TheLine.InPPDirective);
} else {
Indent = LevelIndent = FirstTok->OriginalColumn;
}
// If everything fits on a single line, just put it there.
unsigned ColumnLimit = Style.ColumnLimit;
if (I + 1 != E) {
AnnotatedLine *NextLine = I[1];
if (NextLine->InPPDirective && !NextLine->First->HasUnescapedNewline)
ColumnLimit = getColumnLimit(TheLine.InPPDirective);
}
if (TheLine.Last->TotalLength + Indent <= ColumnLimit ||
TheLine.Type == LT_ImportStatement) {
LineState State = Indenter->getInitialState(Indent, &TheLine, DryRun);
while (State.NextToken) {
formatChildren(State, /*Newline=*/false, /*DryRun=*/false, Penalty);
Indenter->addTokenToState(State, /*Newline=*/false, DryRun);
}
} else if (Style.ColumnLimit == 0) {
// FIXME: Implement nested blocks for ColumnLimit = 0.
NoColumnLimitFormatter Formatter(Indenter);
if (!DryRun)
Formatter.format(Indent, &TheLine);
} else {
Penalty += format(TheLine, Indent, DryRun);
}
if (!TheLine.InPPDirective)
IndentForLevel[TheLine.Level] = LevelIndent;
} else if (TheLine.ChildrenAffected) {
format(TheLine.Children, DryRun);
} else {
// Format the first token if necessary, and notify the WhitespaceManager
// about the unchanged whitespace.
for (FormatToken *Tok = TheLine.First; Tok; Tok = Tok->Next) {
if (Tok == TheLine.First &&
(Tok->NewlinesBefore > 0 || Tok->IsFirst)) {
unsigned LevelIndent = Tok->OriginalColumn;
if (!DryRun) {
// Remove trailing whitespace of the previous line.
if ((PreviousLine && PreviousLine->Affected) ||
TheLine.LeadingEmptyLinesAffected) {
formatFirstToken(*Tok, PreviousLine, TheLine.Level, LevelIndent,
TheLine.InPPDirective);
} else {
Whitespaces->addUntouchableToken(*Tok, TheLine.InPPDirective);
}
}
if (static_cast<int>(LevelIndent) - Offset >= 0)
LevelIndent -= Offset;
if (Tok->isNot(tok::comment) && !TheLine.InPPDirective)
IndentForLevel[TheLine.Level] = LevelIndent;
} else if (!DryRun) {
Whitespaces->addUntouchableToken(*Tok, TheLine.InPPDirective);
}
}
}
if (!DryRun) {
for (FormatToken *Tok = TheLine.First; Tok; Tok = Tok->Next) {
Tok->Finalized = true;
}
}
PreviousLine = *I;
}
PenaltyCache[CacheKey] = Penalty;
return Penalty;
}
private:
/// \brief Formats an \c AnnotatedLine and returns the penalty.
///
/// If \p DryRun is \c false, directly applies the changes.
unsigned format(const AnnotatedLine &Line, unsigned FirstIndent,
bool DryRun) {
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);
}
/// \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 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 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 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)
return 0;
if (RootToken.isAccessSpecifier(false) || RootToken.isObjCAccessSpecifier())
return Style.AccessModifierOffset;
return 0;
}
/// \brief Add a new line and the required indent before the first Token
/// of the \c UnwrappedLine if there was no structural parsing error.
void formatFirstToken(FormatToken &RootToken,
const AnnotatedLine *PreviousLine, unsigned IndentLevel,
unsigned Indent, bool InPPDirective) {
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())
Newlines = std::min(1u, Newlines);
Whitespaces->replaceWhitespace(RootToken, Newlines, IndentLevel, Indent,
Indent, InPPDirective &&
!RootToken.HasUnescapedNewline);
}
/// \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;
}
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;
}
}
unsigned getColumnLimit(bool InPPDirective) const {
// In preprocessor directives reserve two chars for trailing " \"
return Style.ColumnLimit - (InPPDirective ? 2 : 0);
}
struct CompareLineStatePointers {
bool operator()(LineState *obj1, LineState *obj2) const {
return *obj1 < *obj2;
}
};
/// \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 = false) {
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 > 10000)
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;
}
void reconstructPath(LineState &State, StateNode *Current) {
std::deque<StateNode *> Path;
// We do not need a break before the initial token.
while (Current->Previous) {
Path.push_front(Current);
Current = Current->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({
if ((*I)->NewLine) {
llvm::dbgs() << "Penalty for placing "
<< (*I)->Previous->State.NextToken->Tok.getName() << ": "
<< Penalty << "\n";
}
});
}
}
/// \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 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) {
FormatToken &Previous = *State.NextToken->Previous;
const FormatToken *LBrace = State.NextToken->getPreviousNonComment();
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.FirstIndent - State.Line->Level * Style.IndentWidth;
if (State.Stack.size() < 2 ||
!State.Stack[State.Stack.size() - 2].NestedBlockInlined) {
AdditionalIndent = State.Stack.back().Indent -
Previous.Children[0]->Level * Style.IndentWidth;
}
Penalty += format(Previous.Children, DryRun, AdditionalIndent,
/*FixBadIndentation=*/true);
return true;
}
if (Previous.Children[0]->First->MustBreakBefore)
return false;
// Cannot merge multiple statements into a single line.
if (Previous.Children.size() > 1)
return false;
// Cannot merge into one line if this line ends on a comment.
if (Previous.is(tok::comment))
return false;
// We can't put the closing "}" on a line with a trailing comment.
if (Previous.Children[0]->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 &&
Previous.Children[0]->Last->TotalLength + State.Column + 2 >
Style.ColumnLimit)
return false;
if (!DryRun) {
Whitespaces->replaceWhitespace(
*Previous.Children[0]->First,
/*Newlines=*/0, /*IndentLevel=*/0, /*Spaces=*/1,
/*StartOfTokenColumn=*/State.Column, State.Line->InPPDirective);
}
Penalty += format(*Previous.Children[0], State.Column + 1, DryRun);
State.Column += 1 + Previous.Children[0]->Last->TotalLength;
return true;
}
ContinuationIndenter *Indenter;
WhitespaceManager *Whitespaces;
FormatStyle Style;
LineJoiner Joiner;
llvm::SpecificBumpPtrAllocator<StateNode> Allocator;
// Cache to store the penalty of formatting a vector of AnnotatedLines
// starting from a specific additional offset. Improves performance if there
// are many nested blocks.
std::map<std::pair<const SmallVectorImpl<AnnotatedLine *> *, unsigned>,
unsigned> PenaltyCache;
};
class FormatTokenLexer {
public:
FormatTokenLexer(SourceManager &SourceMgr, FileID ID, FormatStyle &Style,

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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"
#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.First->is(tok::kw_extern) && Next && Next->isStringLiteral() &&
NextNext && NextNext->is(tok::l_brace);
}
class LineJoiner {
public:
LineJoiner(const FormatStyle &Style) : Style(Style) {}
/// \brief Calculates how many lines can be merged into 1 starting at \p I.
unsigned
tryFitMultipleLinesInOne(unsigned Indent,
SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E) {
// We can never merge stuff if there are trailing line comments.
const AnnotatedLine *TheLine = *I;
if (TheLine->Last->is(TT_LineComment))
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 (I + 1 == E || I[1]->Type == LT_Invalid || I[1]->First->MustBreakBefore)
return 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_Inline &&
TheLine->Level != 0);
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.BreakBeforeBraces == FormatStyle::BS_Attach
? tryMergeSimpleBlock(I, E, Limit)
: 0;
}
if (I[1]->First->is(TT_FunctionLBrace) &&
Style.BreakBeforeBraces != FormatStyle::BS_Attach) {
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) {
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;
}
private:
unsigned
tryMergeSimplePPDirective(SmallVectorImpl<AnnotatedLine *>::const_iterator I,
SmallVectorImpl<AnnotatedLine *>::const_iterator E,
unsigned Limit) {
if (Limit == 0)
return 0;
if (!I[1]->InPPDirective || I[1]->First->HasUnescapedNewline)
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.BreakBeforeBraces == FormatStyle::BS_Allman ||
Style.BreakBeforeBraces == FormatStyle::BS_GNU) &&
(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.First->is(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))
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.
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))
return 0;
if (Line.First->isOneOf(tok::kw_if, tok::kw_while, tok::kw_do, tok::kw_try,
tok::kw_catch, tok::kw_for, tok::r_brace)) {
if (!Style.AllowShortBlocksOnASingleLine)
return 0;
if (!Style.AllowShortIfStatementsOnASingleLine &&
Line.First->is(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.
if (Line.First->isOneOf(tok::kw_try, tok::kw_catch))
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.First->isNot(tok::kw_namespace) &&
!startsExternCBlock(Line)) {
// We don't merge short records.
if (Line.First->isOneOf(tok::kw_class, tok::kw_union, tok::kw_struct))
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;
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;
}
const FormatStyle &Style;
};
class NoColumnLimitFormatter {
public:
NoColumnLimitFormatter(ContinuationIndenter *Indenter) : Indenter(Indenter) {}
/// \brief Formats the line starting at \p State, simply keeping all of the
/// input's line breaking decisions.
void format(unsigned FirstIndent, const AnnotatedLine *Line) {
LineState State =
Indenter->getInitialState(FirstIndent, Line, /*DryRun=*/false);
while (State.NextToken) {
bool Newline =
Indenter->mustBreak(State) ||
(Indenter->canBreak(State) && State.NextToken->NewlinesBefore > 0);
Indenter->addTokenToState(State, Newline, /*DryRun=*/false);
}
}
private:
ContinuationIndenter *Indenter;
};
} // namespace
unsigned
UnwrappedLineFormatter::format(const SmallVectorImpl<AnnotatedLine *> &Lines,
bool DryRun, int AdditionalIndent,
bool FixBadIndentation) {
LineJoiner Joiner(Style);
// 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;
std::vector<int> IndentForLevel;
for (unsigned i = 0, e = Lines[0]->Level; i != e; ++i)
IndentForLevel.push_back(Style.IndentWidth * i + AdditionalIndent);
const AnnotatedLine *PreviousLine = nullptr;
for (SmallVectorImpl<AnnotatedLine *>::const_iterator I = Lines.begin(),
E = Lines.end();
I != E; ++I) {
const AnnotatedLine &TheLine = **I;
const FormatToken *FirstTok = TheLine.First;
int Offset = getIndentOffset(*FirstTok);
// Determine indent and try to merge multiple unwrapped lines.
unsigned Indent;
if (TheLine.InPPDirective) {
Indent = TheLine.Level * Style.IndentWidth;
} else {
while (IndentForLevel.size() <= TheLine.Level)
IndentForLevel.push_back(-1);
IndentForLevel.resize(TheLine.Level + 1);
Indent = getIndent(IndentForLevel, TheLine.Level);
}
unsigned LevelIndent = Indent;
if (static_cast<int>(Indent) + Offset >= 0)
Indent += Offset;
// Merge multiple lines if possible.
unsigned MergedLines = Joiner.tryFitMultipleLinesInOne(Indent, I, E);
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 (I[i + 1]->First->NewlinesBefore > 0)
MergedLines = 0;
}
}
if (!DryRun) {
for (unsigned i = 0; i < MergedLines; ++i) {
join(*I[i], *I[i + 1]);
}
}
I += MergedLines;
bool FixIndentation =
FixBadIndentation && (LevelIndent != FirstTok->OriginalColumn);
if (TheLine.First->is(tok::eof)) {
if (PreviousLine && PreviousLine->Affected && !DryRun) {
// Remove the file's trailing whitespace.
unsigned Newlines = std::min(FirstTok->NewlinesBefore, 1u);
Whitespaces->replaceWhitespace(*TheLine.First, Newlines,
/*IndentLevel=*/0, /*Spaces=*/0,
/*TargetColumn=*/0);
}
} else if (TheLine.Type != LT_Invalid &&
(TheLine.Affected || FixIndentation)) {
if (FirstTok->WhitespaceRange.isValid()) {
if (!DryRun)
formatFirstToken(*TheLine.First, PreviousLine, TheLine.Level, Indent,
TheLine.InPPDirective);
} else {
Indent = LevelIndent = FirstTok->OriginalColumn;
}
// If everything fits on a single line, just put it there.
unsigned ColumnLimit = Style.ColumnLimit;
if (I + 1 != E) {
AnnotatedLine *NextLine = I[1];
if (NextLine->InPPDirective && !NextLine->First->HasUnescapedNewline)
ColumnLimit = getColumnLimit(TheLine.InPPDirective);
}
if (TheLine.Last->TotalLength + Indent <= ColumnLimit ||
TheLine.Type == LT_ImportStatement) {
LineState State = Indenter->getInitialState(Indent, &TheLine, DryRun);
while (State.NextToken) {
formatChildren(State, /*Newline=*/false, /*DryRun=*/false, Penalty);
Indenter->addTokenToState(State, /*Newline=*/false, DryRun);
}
} else if (Style.ColumnLimit == 0) {
// FIXME: Implement nested blocks for ColumnLimit = 0.
NoColumnLimitFormatter Formatter(Indenter);
if (!DryRun)
Formatter.format(Indent, &TheLine);
} else {
Penalty += format(TheLine, Indent, DryRun);
}
if (!TheLine.InPPDirective)
IndentForLevel[TheLine.Level] = LevelIndent;
} else if (TheLine.ChildrenAffected) {
format(TheLine.Children, DryRun);
} else {
// Format the first token if necessary, and notify the WhitespaceManager
// about the unchanged whitespace.
for (FormatToken *Tok = TheLine.First; Tok; Tok = Tok->Next) {
if (Tok == TheLine.First && (Tok->NewlinesBefore > 0 || Tok->IsFirst)) {
unsigned LevelIndent = Tok->OriginalColumn;
if (!DryRun) {
// Remove trailing whitespace of the previous line.
if ((PreviousLine && PreviousLine->Affected) ||
TheLine.LeadingEmptyLinesAffected) {
formatFirstToken(*Tok, PreviousLine, TheLine.Level, LevelIndent,
TheLine.InPPDirective);
} else {
Whitespaces->addUntouchableToken(*Tok, TheLine.InPPDirective);
}
}
if (static_cast<int>(LevelIndent) - Offset >= 0)
LevelIndent -= Offset;
if (Tok->isNot(tok::comment) && !TheLine.InPPDirective)
IndentForLevel[TheLine.Level] = LevelIndent;
} else if (!DryRun) {
Whitespaces->addUntouchableToken(*Tok, TheLine.InPPDirective);
}
}
}
if (!DryRun) {
for (FormatToken *Tok = TheLine.First; Tok; Tok = Tok->Next) {
Tok->Finalized = true;
}
}
PreviousLine = *I;
}
PenaltyCache[CacheKey] = Penalty;
return Penalty;
}
unsigned UnwrappedLineFormatter::format(const AnnotatedLine &Line,
unsigned FirstIndent, bool DryRun) {
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);
}
void UnwrappedLineFormatter::formatFirstToken(FormatToken &RootToken,
const AnnotatedLine *PreviousLine,
unsigned IndentLevel,
unsigned Indent,
bool InPPDirective) {
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())
Newlines = std::min(1u, Newlines);
Whitespaces->replaceWhitespace(RootToken, Newlines, IndentLevel, Indent,
Indent, InPPDirective &&
!RootToken.HasUnescapedNewline);
}
/// \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 UnwrappedLineFormatter::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;
}
void UnwrappedLineFormatter::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;
}
}
unsigned UnwrappedLineFormatter::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 > 10000)
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;
}
void UnwrappedLineFormatter::reconstructPath(LineState &State,
StateNode *Current) {
std::deque<StateNode *> Path;
// We do not need a break before the initial token.
while (Current->Previous) {
Path.push_front(Current);
Current = Current->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({
if ((*I)->NewLine) {
llvm::dbgs() << "Penalty for placing "
<< (*I)->Previous->State.NextToken->Tok.getName() << ": "
<< Penalty << "\n";
}
});
}
}
void UnwrappedLineFormatter::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);
}
bool UnwrappedLineFormatter::formatChildren(LineState &State, bool NewLine,
bool DryRun, unsigned &Penalty) {
FormatToken &Previous = *State.NextToken->Previous;
const FormatToken *LBrace = State.NextToken->getPreviousNonComment();
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.FirstIndent - State.Line->Level * Style.IndentWidth;
if (State.Stack.size() < 2 ||
!State.Stack[State.Stack.size() - 2].NestedBlockInlined) {
AdditionalIndent = State.Stack.back().Indent -
Previous.Children[0]->Level * Style.IndentWidth;
}
Penalty += format(Previous.Children, DryRun, AdditionalIndent,
/*FixBadIndentation=*/true);
return true;
}
if (Previous.Children[0]->First->MustBreakBefore)
return false;
// Cannot merge multiple statements into a single line.
if (Previous.Children.size() > 1)
return false;
// Cannot merge into one line if this line ends on a comment.
if (Previous.is(tok::comment))
return false;
// We can't put the closing "}" on a line with a trailing comment.
if (Previous.Children[0]->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 &&
Previous.Children[0]->Last->TotalLength + State.Column + 2 >
Style.ColumnLimit)
return false;
if (!DryRun) {
Whitespaces->replaceWhitespace(
*Previous.Children[0]->First,
/*Newlines=*/0, /*IndentLevel=*/0, /*Spaces=*/1,
/*StartOfTokenColumn=*/State.Column, State.Line->InPPDirective);
}
Penalty += format(*Previous.Children[0], State.Column + 1, DryRun);
State.Column += 1 + Previous.Children[0]->Last->TotalLength;
return true;
}
} // namespace format
} // namespace clang

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//===--- UnwrappedLineFormatter.h - Format C++ code -------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief Implements a combinartorial exploration of all the different
/// linebreaks unwrapped lines can be formatted in.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEFORMATTER_H
#define LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEFORMATTER_H
#include "ContinuationIndenter.h"
#include "clang/Format/Format.h"
#include <map>
#include <queue>
#include <string>
namespace clang {
namespace format {
class ContinuationIndenter;
class WhitespaceManager;
class UnwrappedLineFormatter {
public:
UnwrappedLineFormatter(ContinuationIndenter *Indenter,
WhitespaceManager *Whitespaces,
const FormatStyle &Style)
: Indenter(Indenter), Whitespaces(Whitespaces), Style(Style) {}
unsigned format(const SmallVectorImpl<AnnotatedLine *> &Lines, bool DryRun,
int AdditionalIndent = 0, bool FixBadIndentation = false);
private:
/// \brief Formats an \c AnnotatedLine and returns the penalty.
///
/// If \p DryRun is \c false, directly applies the changes.
unsigned format(const AnnotatedLine &Line, unsigned FirstIndent,
bool DryRun);
/// \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 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 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 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)
return 0;
if (RootToken.isAccessSpecifier(false) || RootToken.isObjCAccessSpecifier())
return Style.AccessModifierOffset;
return 0;
}
/// \brief Add a new line and the required indent before the first Token
/// of the \c UnwrappedLine if there was no structural parsing error.
void formatFirstToken(FormatToken &RootToken,
const AnnotatedLine *PreviousLine, unsigned IndentLevel,
unsigned Indent, bool InPPDirective);
/// \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);
void join(AnnotatedLine &A, const AnnotatedLine &B);
unsigned getColumnLimit(bool InPPDirective) const {
// In preprocessor directives reserve two chars for trailing " \"
return Style.ColumnLimit - (InPPDirective ? 2 : 0);
}
struct CompareLineStatePointers {
bool operator()(LineState *obj1, LineState *obj2) const {
return *obj1 < *obj2;
}
};
/// \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 = false);
void reconstructPath(LineState &State, StateNode *Current);
/// \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);
/// \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);
ContinuationIndenter *Indenter;
WhitespaceManager *Whitespaces;
FormatStyle Style;
llvm::SpecificBumpPtrAllocator<StateNode> Allocator;
// Cache to store the penalty of formatting a vector of AnnotatedLines
// starting from a specific additional offset. Improves performance if there
// are many nested blocks.
std::map<std::pair<const SmallVectorImpl<AnnotatedLine *> *, unsigned>,
unsigned> PenaltyCache;
};
} // end namespace format
} // end namespace clang
#endif // LLVM_CLANG_LIB_FORMAT_UNWRAPPEDLINEFORMATTER_H