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//===--- Format.cpp - Format C++ code -------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief This file implements functions declared in Format.h. This will be
/// split into separate files as we go.
///
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "format-formatter"
#include "TokenAnnotator.h"
#include "UnwrappedLineParser.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/OperatorPrecedence.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Format/Format.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Lex/Lexer.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Debug.h"
#include <queue>
#include <string>
namespace clang {
namespace format {
FormatStyle getLLVMStyle() {
FormatStyle LLVMStyle;
LLVMStyle.ColumnLimit = 80;
LLVMStyle.MaxEmptyLinesToKeep = 1;
LLVMStyle.PointerBindsToType = false;
LLVMStyle.DerivePointerBinding = false;
LLVMStyle.AccessModifierOffset = -2;
LLVMStyle.Standard = FormatStyle::LS_Cpp03;
LLVMStyle.IndentCaseLabels = false;
LLVMStyle.SpacesBeforeTrailingComments = 1;
LLVMStyle.BinPackParameters = true;
LLVMStyle.AllowAllParametersOfDeclarationOnNextLine = true;
LLVMStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = false;
LLVMStyle.AllowShortIfStatementsOnASingleLine = false;
LLVMStyle.ObjCSpaceBeforeProtocolList = true;
LLVMStyle.PenaltyExcessCharacter = 1000000;
LLVMStyle.PenaltyReturnTypeOnItsOwnLine = 5;
return LLVMStyle;
}
FormatStyle getGoogleStyle() {
FormatStyle GoogleStyle;
GoogleStyle.ColumnLimit = 80;
GoogleStyle.MaxEmptyLinesToKeep = 1;
GoogleStyle.PointerBindsToType = true;
GoogleStyle.DerivePointerBinding = true;
GoogleStyle.AccessModifierOffset = -1;
GoogleStyle.Standard = FormatStyle::LS_Auto;
GoogleStyle.IndentCaseLabels = true;
GoogleStyle.SpacesBeforeTrailingComments = 2;
GoogleStyle.BinPackParameters = false;
GoogleStyle.AllowAllParametersOfDeclarationOnNextLine = true;
GoogleStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = true;
GoogleStyle.AllowShortIfStatementsOnASingleLine = false;
GoogleStyle.ObjCSpaceBeforeProtocolList = false;
GoogleStyle.PenaltyExcessCharacter = 1000000;
GoogleStyle.PenaltyReturnTypeOnItsOwnLine = 100;
return GoogleStyle;
}
FormatStyle getChromiumStyle() {
FormatStyle ChromiumStyle = getGoogleStyle();
ChromiumStyle.AllowAllParametersOfDeclarationOnNextLine = false;
ChromiumStyle.Standard = FormatStyle::LS_Cpp03;
ChromiumStyle.DerivePointerBinding = false;
return ChromiumStyle;
}
static bool isTrailingComment(const AnnotatedToken &Tok) {
return Tok.is(tok::comment) &&
(Tok.Children.empty() || Tok.Children[0].MustBreakBefore);
}
// Returns the length of everything up to the first possible line break after
// the ), ], } or > matching \c Tok.
static unsigned getLengthToMatchingParen(const AnnotatedToken &Tok) {
if (Tok.MatchingParen == NULL)
return 0;
AnnotatedToken *End = Tok.MatchingParen;
while (!End->Children.empty() && !End->Children[0].CanBreakBefore) {
End = &End->Children[0];
}
return End->TotalLength - Tok.TotalLength + 1;
}
/// \brief Manages the whitespaces around tokens and their replacements.
///
/// This includes special handling for certain constructs, e.g. the alignment of
/// trailing line comments.
class WhitespaceManager {
public:
WhitespaceManager(SourceManager &SourceMgr) : SourceMgr(SourceMgr) {}
/// \brief Replaces the whitespace in front of \p Tok. Only call once for
/// each \c AnnotatedToken.
void replaceWhitespace(const AnnotatedToken &Tok, unsigned NewLines,
unsigned Spaces, unsigned WhitespaceStartColumn,
const FormatStyle &Style) {
// 2+ newlines mean an empty line separating logic scopes.
if (NewLines >= 2)
alignComments();
// Align line comments if they are trailing or if they continue other
// trailing comments.
if (isTrailingComment(Tok) && (Tok.Parent != NULL || !Comments.empty())) {
if (Style.ColumnLimit >=
Spaces + WhitespaceStartColumn + Tok.FormatTok.TokenLength) {
Comments.push_back(StoredComment());
Comments.back().Tok = Tok.FormatTok;
Comments.back().Spaces = Spaces;
Comments.back().NewLines = NewLines;
if (NewLines == 0)
Comments.back().MinColumn = WhitespaceStartColumn + Spaces;
else
Comments.back().MinColumn = Spaces;
Comments.back().MaxColumn =
Style.ColumnLimit - Tok.FormatTok.TokenLength;
return;
}
}
// If this line does not have a trailing comment, align the stored comments.
if (Tok.Children.empty() && !isTrailingComment(Tok))
alignComments();
storeReplacement(Tok.FormatTok,
std::string(NewLines, '\n') + std::string(Spaces, ' '));
}
/// \brief Like \c replaceWhitespace, but additionally adds right-aligned
/// backslashes to escape newlines inside a preprocessor directive.
///
/// This function and \c replaceWhitespace have the same behavior if
/// \c Newlines == 0.
void replacePPWhitespace(const AnnotatedToken &Tok, unsigned NewLines,
unsigned Spaces, unsigned WhitespaceStartColumn,
const FormatStyle &Style) {
std::string NewLineText;
if (NewLines > 0) {
unsigned Offset =
std::min<int>(Style.ColumnLimit - 1, WhitespaceStartColumn);
for (unsigned i = 0; i < NewLines; ++i) {
NewLineText += std::string(Style.ColumnLimit - Offset - 1, ' ');
NewLineText += "\\\n";
Offset = 0;
}
}
storeReplacement(Tok.FormatTok, NewLineText + std::string(Spaces, ' '));
}
/// \brief Returns all the \c Replacements created during formatting.
const tooling::Replacements &generateReplacements() {
alignComments();
return Replaces;
}
private:
/// \brief Structure to store a comment for later layout and alignment.
struct StoredComment {
FormatToken Tok;
unsigned MinColumn;
unsigned MaxColumn;
unsigned NewLines;
unsigned Spaces;
};
SmallVector<StoredComment, 16> Comments;
typedef SmallVector<StoredComment, 16>::iterator comment_iterator;
/// \brief Try to align all stashed comments.
void alignComments() {
unsigned MinColumn = 0;
unsigned MaxColumn = UINT_MAX;
comment_iterator Start = Comments.begin();
for (comment_iterator I = Comments.begin(), E = Comments.end(); I != E;
++I) {
if (I->MinColumn > MaxColumn || I->MaxColumn < MinColumn) {
alignComments(Start, I, MinColumn);
MinColumn = I->MinColumn;
MaxColumn = I->MaxColumn;
Start = I;
} else {
MinColumn = std::max(MinColumn, I->MinColumn);
MaxColumn = std::min(MaxColumn, I->MaxColumn);
}
}
alignComments(Start, Comments.end(), MinColumn);
Comments.clear();
}
/// \brief Put all the comments between \p I and \p E into \p Column.
void alignComments(comment_iterator I, comment_iterator E, unsigned Column) {
while (I != E) {
unsigned Spaces = I->Spaces + Column - I->MinColumn;
storeReplacement(I->Tok, std::string(I->NewLines, '\n') +
std::string(Spaces, ' '));
++I;
}
}
/// \brief Stores \p Text as the replacement for the whitespace in front of
/// \p Tok.
void storeReplacement(const FormatToken &Tok, const std::string Text) {
// Don't create a replacement, if it does not change anything.
if (StringRef(SourceMgr.getCharacterData(Tok.WhiteSpaceStart),
Tok.WhiteSpaceLength) == Text)
return;
Replaces.insert(tooling::Replacement(SourceMgr, Tok.WhiteSpaceStart,
Tok.WhiteSpaceLength, Text));
}
SourceManager &SourceMgr;
tooling::Replacements Replaces;
};
class UnwrappedLineFormatter {
public:
UnwrappedLineFormatter(const FormatStyle &Style, SourceManager &SourceMgr,
const AnnotatedLine &Line, unsigned FirstIndent,
const AnnotatedToken &RootToken,
WhitespaceManager &Whitespaces, bool StructuralError)
: Style(Style), SourceMgr(SourceMgr), Line(Line),
FirstIndent(FirstIndent), RootToken(RootToken),
Whitespaces(Whitespaces), Count(0) {
}
/// \brief Formats an \c UnwrappedLine.
///
/// \returns The column after the last token in the last line of the
/// \c UnwrappedLine.
unsigned format() {
// Initialize state dependent on indent.
LineState State;
State.Column = FirstIndent;
State.NextToken = &RootToken;
State.Stack.push_back(
ParenState(FirstIndent + 4, FirstIndent, !Style.BinPackParameters,
/*HasMultiParameterLine=*/ false));
State.VariablePos = 0;
State.LineContainsContinuedForLoopSection = false;
State.ParenLevel = 0;
DEBUG({
DebugTokenState(*State.NextToken);
});
// The first token has already been indented and thus consumed.
moveStateToNextToken(State);
// If everything fits on a single line, just put it there.
if (Line.Last->TotalLength <= getColumnLimit() - FirstIndent) {
while (State.NextToken != NULL) {
addTokenToState(false, false, State);
}
return State.Column;
}
// If the ObjC method declaration does not fit on a line, we should format
// it with one arg per line.
if (Line.Type == LT_ObjCMethodDecl)
State.Stack.back().BreakBeforeParameter = true;
// Find best solution in solution space.
return analyzeSolutionSpace(State);
}
private:
void DebugTokenState(const AnnotatedToken &AnnotatedTok) {
const Token &Tok = AnnotatedTok.FormatTok.Tok;
llvm::errs() << StringRef(SourceMgr.getCharacterData(Tok.getLocation()),
Tok.getLength());
llvm::errs();
}
struct ParenState {
ParenState(unsigned Indent, unsigned LastSpace, bool AvoidBinPacking,
bool HasMultiParameterLine)
: Indent(Indent), LastSpace(LastSpace), FirstLessLess(0),
BreakBeforeClosingBrace(false), QuestionColumn(0),
AvoidBinPacking(AvoidBinPacking), BreakBeforeParameter(false),
HasMultiParameterLine(HasMultiParameterLine), ColonPos(0) {
}
/// \brief The position to which a specific parenthesis level needs to be
/// indented.
unsigned Indent;
/// \brief The position of the last space on each level.
///
/// Used e.g. to break like:
/// functionCall(Parameter, otherCall(
/// OtherParameter));
unsigned LastSpace;
/// \brief The position the first "<<" operator encountered on each level.
///
/// Used to align "<<" operators. 0 if no such operator has been encountered
/// on a level.
unsigned FirstLessLess;
/// \brief Whether a newline needs to be inserted before the block's closing
/// brace.
///
/// We only want to insert a newline before the closing brace if there also
/// was a newline after the beginning left brace.
bool BreakBeforeClosingBrace;
/// \brief The column of a \c ? in a conditional expression;
unsigned QuestionColumn;
/// \brief Avoid bin packing, i.e. multiple parameters/elements on multiple
/// lines, in this context.
bool AvoidBinPacking;
/// \brief Break after the next comma (or all the commas in this context if
/// \c AvoidBinPacking is \c true).
bool BreakBeforeParameter;
/// \brief This context already has a line with more than one parameter.
bool HasMultiParameterLine;
/// \brief The position of the colon in an ObjC method declaration/call.
unsigned ColonPos;
bool operator<(const ParenState &Other) const {
if (Indent != Other.Indent)
return Indent < Other.Indent;
if (LastSpace != Other.LastSpace)
return LastSpace < Other.LastSpace;
if (FirstLessLess != Other.FirstLessLess)
return FirstLessLess < Other.FirstLessLess;
if (BreakBeforeClosingBrace != Other.BreakBeforeClosingBrace)
return BreakBeforeClosingBrace;
if (QuestionColumn != Other.QuestionColumn)
return QuestionColumn < Other.QuestionColumn;
if (AvoidBinPacking != Other.AvoidBinPacking)
return AvoidBinPacking;
if (BreakBeforeParameter != Other.BreakBeforeParameter)
return BreakBeforeParameter;
if (HasMultiParameterLine != Other.HasMultiParameterLine)
return HasMultiParameterLine;
if (ColonPos != Other.ColonPos)
return ColonPos < Other.ColonPos;
return false;
}
};
/// \brief The current state when indenting a unwrapped line.
///
/// As the indenting tries different combinations this is copied by value.
struct LineState {
/// \brief The number of used columns in the current line.
unsigned Column;
/// \brief The token that needs to be next formatted.
const AnnotatedToken *NextToken;
/// \brief The column of the first variable name in a variable declaration.
///
/// Used to align further variables if necessary.
unsigned VariablePos;
/// \brief \c true if this line contains a continued for-loop section.
bool LineContainsContinuedForLoopSection;
/// \brief The level of nesting inside (), [], <> and {}.
unsigned ParenLevel;
/// \brief A stack keeping track of properties applying to parenthesis
/// levels.
std::vector<ParenState> Stack;
/// \brief Comparison operator to be able to used \c LineState in \c map.
bool operator<(const LineState &Other) const {
if (Other.NextToken != NextToken)
return Other.NextToken > NextToken;
if (Other.Column != Column)
return Other.Column > Column;
if (Other.VariablePos != VariablePos)
return Other.VariablePos < VariablePos;
if (Other.LineContainsContinuedForLoopSection !=
LineContainsContinuedForLoopSection)
return LineContainsContinuedForLoopSection;
if (Other.ParenLevel != ParenLevel)
return Other.ParenLevel < ParenLevel;
return Other.Stack < Stack;
}
};
/// \brief Appends the next token to \p State and updates information
/// necessary for indentation.
///
/// Puts the token on the current line if \p Newline is \c true and adds a
/// line break and necessary indentation otherwise.
///
/// If \p DryRun is \c false, also creates and stores the required
/// \c Replacement.
void addTokenToState(bool Newline, bool DryRun, LineState &State) {
const AnnotatedToken &Current = *State.NextToken;
const AnnotatedToken &Previous = *State.NextToken->Parent;
assert(State.Stack.size());
if (Current.Type == TT_ImplicitStringLiteral) {
State.Column += State.NextToken->FormatTok.WhiteSpaceLength +
State.NextToken->FormatTok.TokenLength;
if (State.NextToken->Children.empty())
State.NextToken = NULL;
else
State.NextToken = &State.NextToken->Children[0];
return;
}
if (Newline) {
unsigned WhitespaceStartColumn = State.Column;
if (Current.is(tok::r_brace)) {
State.Column = Line.Level * 2;
} else if (Current.is(tok::string_literal) &&
Previous.is(tok::string_literal)) {
State.Column = State.Column - Previous.FormatTok.TokenLength;
} else if (Current.is(tok::lessless) &&
State.Stack.back().FirstLessLess != 0) {
State.Column = State.Stack.back().FirstLessLess;
} else if (State.ParenLevel != 0 &&
(Previous.is(tok::equal) || Previous.is(tok::coloncolon) ||
Current.is(tok::period) || Current.is(tok::arrow) ||
Current.is(tok::question))) {
// Indent and extra 4 spaces after if we know the current expression is
// continued. Don't do that on the top level, as we already indent 4
// there.
State.Column = std::max(State.Stack.back().LastSpace,
State.Stack.back().Indent) + 4;
} else if (Current.Type == TT_ConditionalExpr) {
State.Column = State.Stack.back().QuestionColumn;
} else if (Previous.is(tok::comma) && State.VariablePos != 0 &&
((RootToken.is(tok::kw_for) && State.ParenLevel == 1) ||
State.ParenLevel == 0)) {
State.Column = State.VariablePos;
} else if (State.NextToken->Parent->ClosesTemplateDeclaration ||
Current.Type == TT_StartOfName) {
State.Column = State.Stack.back().Indent - 4;
} else if (Current.Type == TT_ObjCSelectorName) {
if (State.Stack.back().ColonPos > Current.FormatTok.TokenLength) {
State.Column =
State.Stack.back().ColonPos - Current.FormatTok.TokenLength;
} else {
State.Column = State.Stack.back().Indent;
State.Stack.back().ColonPos =
State.Column + Current.FormatTok.TokenLength;
}
} else if (Previous.Type == TT_ObjCMethodExpr) {
State.Column = State.Stack.back().Indent + 4;
} else {
State.Column = State.Stack.back().Indent;
}
if (Previous.is(tok::comma) && !State.Stack.back().AvoidBinPacking)
State.Stack.back().BreakBeforeParameter = false;
if (RootToken.is(tok::kw_for))
State.LineContainsContinuedForLoopSection = Previous.isNot(tok::semi);
if (!DryRun) {
if (!Line.InPPDirective)
Whitespaces.replaceWhitespace(Current, 1, State.Column,
WhitespaceStartColumn, Style);
else
Whitespaces.replacePPWhitespace(Current, 1, State.Column,
WhitespaceStartColumn, Style);
}
State.Stack.back().LastSpace = State.Column;
if (Current.is(tok::colon) && Current.Type != TT_ConditionalExpr)
State.Stack.back().Indent += 2;
} else {
if (Current.is(tok::equal) &&
(RootToken.is(tok::kw_for) || State.ParenLevel == 0))
State.VariablePos = State.Column - Previous.FormatTok.TokenLength;
unsigned Spaces = State.NextToken->SpacesRequiredBefore;
if (!DryRun)
Whitespaces.replaceWhitespace(Current, 0, Spaces, State.Column, Style);
if (Current.Type == TT_ObjCSelectorName &&
State.Stack.back().ColonPos == 0) {
if (State.Stack.back().Indent + Current.LongestObjCSelectorName >
State.Column + Spaces + Current.FormatTok.TokenLength)
State.Stack.back().ColonPos =
State.Stack.back().Indent + Current.LongestObjCSelectorName;
else
State.Stack.back().ColonPos =
State.Column + Spaces + Current.FormatTok.TokenLength;
}
if (Current.Type != TT_LineComment &&
(Previous.is(tok::l_paren) || Previous.is(tok::l_brace) ||
State.NextToken->Parent->Type == TT_TemplateOpener))
State.Stack.back().Indent = State.Column + Spaces;
if (Previous.is(tok::comma) && !isTrailingComment(Current))
State.Stack.back().HasMultiParameterLine = true;
State.Column += Spaces;
if (Current.is(tok::l_paren) && Previous.is(tok::kw_if))
// Treat the condition inside an if as if it was a second function
// parameter, i.e. let nested calls have an indent of 4.
State.Stack.back().LastSpace = State.Column + 1; // 1 is length of "(".
else if (Previous.is(tok::comma) && State.ParenLevel != 0)
// Top-level spaces are exempt as that mostly leads to better results.
State.Stack.back().LastSpace = State.Column;
else if ((Previous.Type == TT_BinaryOperator ||
Previous.Type == TT_ConditionalExpr ||
Previous.Type == TT_CtorInitializerColon) &&
getPrecedence(Previous) != prec::Assignment)
State.Stack.back().LastSpace = State.Column;
else if (Previous.Type == TT_InheritanceColon)
State.Stack.back().Indent = State.Column;
else if (Previous.ParameterCount > 1 &&
(Previous.is(tok::l_paren) || Previous.is(tok::l_square) ||
Previous.is(tok::l_brace) ||
Previous.Type == TT_TemplateOpener))
// If this function has multiple parameters, indent nested calls from
// the start of the first parameter.
State.Stack.back().LastSpace = State.Column;
}
// If we break after an {, we should also break before the corresponding }.
if (Newline && Previous.is(tok::l_brace))
State.Stack.back().BreakBeforeClosingBrace = true;
if (State.Stack.back().AvoidBinPacking && Newline &&
(Line.First.isNot(tok::kw_for) || State.ParenLevel != 1)) {
// If we are breaking after '(', '{', '<', this is not bin packing unless
// AllowAllParametersOfDeclarationOnNextLine is false.
if ((Previous.isNot(tok::l_paren) && Previous.isNot(tok::l_brace) &&
Previous.Type != TT_TemplateOpener) ||
(!Style.AllowAllParametersOfDeclarationOnNextLine &&
Line.MustBeDeclaration))
State.Stack.back().BreakBeforeParameter = true;
// Any break on this level means that the parent level has been broken
// and we need to avoid bin packing there.
for (unsigned i = 0, e = State.Stack.size() - 1; i != e; ++i) {
if (Line.First.isNot(tok::kw_for) || i != 1)
State.Stack[i].BreakBeforeParameter = true;
}
}
moveStateToNextToken(State);
}
/// \brief Mark the next token as consumed in \p State and modify its stacks
/// accordingly.
void moveStateToNextToken(LineState &State) {
const AnnotatedToken &Current = *State.NextToken;
assert(State.Stack.size());
if (Current.Type == TT_InheritanceColon)
State.Stack.back().AvoidBinPacking = true;
if (Current.is(tok::lessless) && State.Stack.back().FirstLessLess == 0)
State.Stack.back().FirstLessLess = State.Column;
if (Current.is(tok::question))
State.Stack.back().QuestionColumn = State.Column;
if (Current.is(tok::l_brace) && Current.MatchingParen != NULL &&
!Current.MatchingParen->MustBreakBefore) {
if (getLengthToMatchingParen(Current) + State.Column > getColumnLimit())
State.Stack.back().BreakBeforeParameter = true;
}
// Insert scopes created by fake parenthesis.
for (unsigned i = 0, e = Current.FakeLParens; i != e; ++i) {
ParenState NewParenState = State.Stack.back();
NewParenState.Indent = std::max(State.Column, State.Stack.back().Indent);
State.Stack.push_back(NewParenState);
}
// If we encounter an opening (, [, { or <, we add a level to our stacks to
// prepare for the following tokens.
if (Current.is(tok::l_paren) || Current.is(tok::l_square) ||
Current.is(tok::l_brace) ||
State.NextToken->Type == TT_TemplateOpener) {
unsigned NewIndent;
bool AvoidBinPacking;
if (Current.is(tok::l_brace)) {
NewIndent = 2 + State.Stack.back().LastSpace;
AvoidBinPacking = false;
} else {
NewIndent = 4 + State.Stack.back().LastSpace;
AvoidBinPacking = !Style.BinPackParameters;
}
State.Stack.push_back(
ParenState(NewIndent, State.Stack.back().LastSpace, AvoidBinPacking,
State.Stack.back().HasMultiParameterLine));
++State.ParenLevel;
}
// If this '[' opens an ObjC call, determine whether all parameters fit into
// one line and put one per line if they don't.
if (Current.is(tok::l_square) && Current.Type == TT_ObjCMethodExpr &&
Current.MatchingParen != NULL) {
if (getLengthToMatchingParen(Current) + State.Column > getColumnLimit())
State.Stack.back().BreakBeforeParameter = true;
}
// If we encounter a closing ), ], } or >, we can remove a level from our
// stacks.
if (Current.is(tok::r_paren) || Current.is(tok::r_square) ||
(Current.is(tok::r_brace) && State.NextToken != &RootToken) ||
State.NextToken->Type == TT_TemplateCloser) {
State.Stack.pop_back();
--State.ParenLevel;
}
// Remove scopes created by fake parenthesis.
for (unsigned i = 0, e = Current.FakeRParens; i != e; ++i) {
State.Stack.pop_back();
}
if (State.NextToken->Children.empty())
State.NextToken = NULL;
else
State.NextToken = &State.NextToken->Children[0];
State.Column += Current.FormatTok.TokenLength;
}
unsigned getColumnLimit() {
return Style.ColumnLimit - (Line.InPPDirective ? 1 : 0);
}
/// \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 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.
unsigned analyzeSolutionSpace(LineState &InitialState) {
std::set<LineState> Seen;
// Insert start element into queue.
StateNode *Node=
new (Allocator.Allocate()) StateNode(InitialState, false, NULL);
Queue.push(QueueItem(OrderedPenalty(0, Count), Node));
++Count;
// While not empty, take first element and follow edges.
while (!Queue.empty()) {
unsigned Penalty = Queue.top().first.first;
StateNode *Node= Queue.top().second;
if (Node->State.NextToken == NULL) {
DEBUG(llvm::errs() << "\n---\nPenalty for line: " << Penalty << "\n");
break;
}
Queue.pop();
if (!Seen.insert(Node->State).second)
// State already examined with lower penalty.
continue;
addNextStateToQueue(Penalty, Node, /*NewLine=*/ false);
addNextStateToQueue(Penalty, Node, /*NewLine=*/ true);
}
if (Queue.empty())
// We were unable to find a solution, do nothing.
// FIXME: Add diagnostic?
return 0;
// Reconstruct the solution.
reconstructPath(InitialState, Queue.top().second);
DEBUG(llvm::errs() << "---\n");
// Return the column after the last token of the solution.
return Queue.top().second->State.Column;
}
void reconstructPath(LineState &State, StateNode *Current) {
// FIXME: This recursive implementation limits the possible number
// of tokens per line if compiled into a binary with small stack space.
// To become more independent of stack frame limitations we would need
// to also change the TokenAnnotator.
if (Current->Previous == NULL)
return;
reconstructPath(State, Current->Previous);
DEBUG({
if (Current->NewLine) {
llvm::errs()
<< "Penalty for splitting before "
<< Current->Previous->State.NextToken->FormatTok.Tok.getName()
<< ": " << Current->Previous->State.NextToken->SplitPenalty << "\n";
}
});
addTokenToState(Current->NewLine, false, State);
}
/// \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) {
if (NewLine && !canBreak(PreviousNode->State))
return;
if (!NewLine && mustBreak(PreviousNode->State))
return;
if (NewLine)
Penalty += PreviousNode->State.NextToken->SplitPenalty;
StateNode *Node = new (Allocator.Allocate())
StateNode(PreviousNode->State, NewLine, PreviousNode);
addTokenToState(NewLine, true, Node->State);
if (Node->State.Column > getColumnLimit()) {
unsigned ExcessCharacters = Node->State.Column - getColumnLimit();
Penalty += Style.PenaltyExcessCharacter * ExcessCharacters;
}
Queue.push(QueueItem(OrderedPenalty(Penalty, Count), Node));
++Count;
}
/// \brief Returns \c true, if a line break after \p State is allowed.
bool canBreak(const LineState &State) {
if (!State.NextToken->CanBreakBefore &&
!(State.NextToken->is(tok::r_brace) &&
State.Stack.back().BreakBeforeClosingBrace))
return false;
// Trying to insert a parameter on a new line if there are already more than
// one parameter on the current line is bin packing.
if (State.Stack.back().HasMultiParameterLine &&
State.Stack.back().AvoidBinPacking)
return false;
return true;
}
/// \brief Returns \c true, if a line break after \p State is mandatory.
bool mustBreak(const LineState &State) {
if (State.NextToken->MustBreakBefore)
return true;
if (State.NextToken->is(tok::r_brace) &&
State.Stack.back().BreakBeforeClosingBrace)
return true;
if (State.NextToken->Parent->is(tok::semi) &&
State.LineContainsContinuedForLoopSection)
return true;
if (State.NextToken->Parent->is(tok::comma) &&
State.Stack.back().BreakBeforeParameter &&
!isTrailingComment(*State.NextToken) &&
State.NextToken->isNot(tok::r_paren))
return true;
// FIXME: Comparing LongestObjCSelectorName to 0 is a hacky way of finding
// out whether it is the first parameter. Clean this up.
if (State.NextToken->Type == TT_ObjCSelectorName &&
State.NextToken->LongestObjCSelectorName == 0 &&
State.Stack.back().BreakBeforeParameter)
return true;
if ((State.NextToken->Type == TT_CtorInitializerColon ||
(State.NextToken->Parent->ClosesTemplateDeclaration &&
State.ParenLevel == 0)))
return true;
return false;
}
FormatStyle Style;
SourceManager &SourceMgr;
const AnnotatedLine &Line;
const unsigned FirstIndent;
const AnnotatedToken &RootToken;
WhitespaceManager &Whitespaces;
llvm::SpecificBumpPtrAllocator<StateNode> Allocator;
QueueType Queue;
// Increasing count of \c StateNode items we have created. This is used
// to create a deterministic order independent of the container.
unsigned Count;
};
class LexerBasedFormatTokenSource : public FormatTokenSource {
public:
LexerBasedFormatTokenSource(Lexer &Lex, SourceManager &SourceMgr)
: GreaterStashed(false), Lex(Lex), SourceMgr(SourceMgr),
IdentTable(Lex.getLangOpts()) {
Lex.SetKeepWhitespaceMode(true);
}
virtual FormatToken getNextToken() {
if (GreaterStashed) {
FormatTok.NewlinesBefore = 0;
FormatTok.WhiteSpaceStart =
FormatTok.Tok.getLocation().getLocWithOffset(1);
FormatTok.WhiteSpaceLength = 0;
GreaterStashed = false;
return FormatTok;
}
FormatTok = FormatToken();
Lex.LexFromRawLexer(FormatTok.Tok);
StringRef Text = rawTokenText(FormatTok.Tok);
FormatTok.WhiteSpaceStart = FormatTok.Tok.getLocation();
if (SourceMgr.getFileOffset(FormatTok.WhiteSpaceStart) == 0)
FormatTok.IsFirst = true;
// Consume and record whitespace until we find a significant token.
while (FormatTok.Tok.is(tok::unknown)) {
unsigned Newlines = Text.count('\n');
unsigned EscapedNewlines = Text.count("\\\n");
FormatTok.NewlinesBefore += Newlines;
FormatTok.HasUnescapedNewline |= EscapedNewlines != Newlines;
FormatTok.WhiteSpaceLength += FormatTok.Tok.getLength();
if (FormatTok.Tok.is(tok::eof))
return FormatTok;
Lex.LexFromRawLexer(FormatTok.Tok);
Text = rawTokenText(FormatTok.Tok);
}
// Now FormatTok is the next non-whitespace token.
FormatTok.TokenLength = Text.size();
// In case the token starts with escaped newlines, we want to
// take them into account as whitespace - this pattern is quite frequent
// in macro definitions.
// FIXME: What do we want to do with other escaped spaces, and escaped
// spaces or newlines in the middle of tokens?
// FIXME: Add a more explicit test.
unsigned i = 0;
while (i + 1 < Text.size() && Text[i] == '\\' && Text[i + 1] == '\n') {
// FIXME: ++FormatTok.NewlinesBefore is missing...
FormatTok.WhiteSpaceLength += 2;
FormatTok.TokenLength -= 2;
i += 2;
}
if (FormatTok.Tok.is(tok::raw_identifier)) {
IdentifierInfo &Info = IdentTable.get(Text);
FormatTok.Tok.setIdentifierInfo(&Info);
FormatTok.Tok.setKind(Info.getTokenID());
}
if (FormatTok.Tok.is(tok::greatergreater)) {
FormatTok.Tok.setKind(tok::greater);
GreaterStashed = true;
}
return FormatTok;
}
IdentifierTable &getIdentTable() { return IdentTable; }
private:
FormatToken FormatTok;
bool GreaterStashed;
Lexer &Lex;
SourceManager &SourceMgr;
IdentifierTable IdentTable;
/// Returns the text of \c FormatTok.
StringRef rawTokenText(Token &Tok) {
return StringRef(SourceMgr.getCharacterData(Tok.getLocation()),
Tok.getLength());
}
};
class Formatter : public UnwrappedLineConsumer {
public:
Formatter(DiagnosticsEngine &Diag, const FormatStyle &Style, Lexer &Lex,
SourceManager &SourceMgr,
const std::vector<CharSourceRange> &Ranges)
: Diag(Diag), Style(Style), Lex(Lex), SourceMgr(SourceMgr),
Whitespaces(SourceMgr), Ranges(Ranges) {
}
virtual ~Formatter() {}
void deriveLocalStyle() {
unsigned CountBoundToVariable = 0;
unsigned CountBoundToType = 0;
bool HasCpp03IncompatibleFormat = false;
for (unsigned i = 0, e = AnnotatedLines.size(); i != e; ++i) {
if (AnnotatedLines[i].First.Children.empty())
continue;
AnnotatedToken *Tok = &AnnotatedLines[i].First.Children[0];
while (!Tok->Children.empty()) {
if (Tok->Type == TT_PointerOrReference) {
bool SpacesBefore = Tok->FormatTok.WhiteSpaceLength > 0;
bool SpacesAfter = Tok->Children[0].FormatTok.WhiteSpaceLength > 0;
if (SpacesBefore && !SpacesAfter)
++CountBoundToVariable;
else if (!SpacesBefore && SpacesAfter)
++CountBoundToType;
}
if (Tok->Type == TT_TemplateCloser &&
Tok->Parent->Type == TT_TemplateCloser &&
Tok->FormatTok.WhiteSpaceLength == 0)
HasCpp03IncompatibleFormat = true;
Tok = &Tok->Children[0];
}
}
if (Style.DerivePointerBinding) {
if (CountBoundToType > CountBoundToVariable)
Style.PointerBindsToType = true;
else if (CountBoundToType < CountBoundToVariable)
Style.PointerBindsToType = false;
}
if (Style.Standard == FormatStyle::LS_Auto) {
Style.Standard = HasCpp03IncompatibleFormat ? FormatStyle::LS_Cpp11
: FormatStyle::LS_Cpp03;
}
}
tooling::Replacements format() {
LexerBasedFormatTokenSource Tokens(Lex, SourceMgr);
UnwrappedLineParser Parser(Diag, Style, Tokens, *this);
StructuralError = Parser.parse();
unsigned PreviousEndOfLineColumn = 0;
TokenAnnotator Annotator(Style, SourceMgr, Lex,
Tokens.getIdentTable().get("in"));
for (unsigned i = 0, e = AnnotatedLines.size(); i != e; ++i) {
Annotator.annotate(AnnotatedLines[i]);
}
deriveLocalStyle();
for (unsigned i = 0, e = AnnotatedLines.size(); i != e; ++i) {
Annotator.calculateFormattingInformation(AnnotatedLines[i]);
}
std::vector<int> IndentForLevel;
bool PreviousLineWasTouched = false;
for (std::vector<AnnotatedLine>::iterator I = AnnotatedLines.begin(),
E = AnnotatedLines.end();
I != E; ++I) {
const AnnotatedLine &TheLine = *I;
int Offset = getIndentOffset(TheLine.First);
while (IndentForLevel.size() <= TheLine.Level)
IndentForLevel.push_back(-1);
IndentForLevel.resize(TheLine.Level + 1);
if (touchesRanges(TheLine) && TheLine.Type != LT_Invalid) {
unsigned LevelIndent = getIndent(IndentForLevel, TheLine.Level);
unsigned Indent = LevelIndent;
if (static_cast<int>(Indent) + Offset >= 0)
Indent += Offset;
if (!TheLine.First.FormatTok.WhiteSpaceStart.isValid() ||
StructuralError) {
Indent = LevelIndent = SourceMgr.getSpellingColumnNumber(
TheLine.First.FormatTok.Tok.getLocation()) - 1;
} else {
formatFirstToken(TheLine.First, Indent, TheLine.InPPDirective,
PreviousEndOfLineColumn);
}
tryFitMultipleLinesInOne(Indent, I, E);
UnwrappedLineFormatter Formatter(Style, SourceMgr, TheLine, Indent,
TheLine.First, Whitespaces,
StructuralError);
PreviousEndOfLineColumn = Formatter.format();
IndentForLevel[TheLine.Level] = LevelIndent;
PreviousLineWasTouched = true;
} else {
if (TheLine.First.FormatTok.NewlinesBefore > 0 ||
TheLine.First.FormatTok.IsFirst) {
unsigned Indent = SourceMgr.getSpellingColumnNumber(
TheLine.First.FormatTok.Tok.getLocation()) - 1;
unsigned LevelIndent = Indent;
if (static_cast<int>(LevelIndent) - Offset >= 0)
LevelIndent -= Offset;
IndentForLevel[TheLine.Level] = LevelIndent;
// Remove trailing whitespace of the previous line if it was touched.
if (PreviousLineWasTouched)
formatFirstToken(TheLine.First, Indent, TheLine.InPPDirective,
PreviousEndOfLineColumn);
}
// If we did not reformat this unwrapped line, the column at the end of
// the last token is unchanged - thus, we can calculate the end of the
// last token.
PreviousEndOfLineColumn =
SourceMgr.getSpellingColumnNumber(
TheLine.Last->FormatTok.Tok.getLocation()) +
Lex.MeasureTokenLength(TheLine.Last->FormatTok.Tok.getLocation(),
SourceMgr, Lex.getLangOpts()) - 1;
PreviousLineWasTouched = false;
}
}
return Whitespaces.generateReplacements();
}
private:
/// \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(const std::vector<int> IndentForLevel,
unsigned Level) {
if (IndentForLevel[Level] != -1)
return IndentForLevel[Level];
if (Level == 0)
return 0;
return getIndent(IndentForLevel, Level - 1) + 2;
}
/// \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 AnnotatedToken &RootToken) {
bool IsAccessModifier = false;
if (RootToken.is(tok::kw_public) || RootToken.is(tok::kw_protected) ||
RootToken.is(tok::kw_private))
IsAccessModifier = true;
else if (RootToken.is(tok::at) && !RootToken.Children.empty() &&
(RootToken.Children[0].isObjCAtKeyword(tok::objc_public) ||
RootToken.Children[0].isObjCAtKeyword(tok::objc_protected) ||
RootToken.Children[0].isObjCAtKeyword(tok::objc_package) ||
RootToken.Children[0].isObjCAtKeyword(tok::objc_private)))
IsAccessModifier = true;
if (IsAccessModifier)
return Style.AccessModifierOffset;
return 0;
}
/// \brief Tries to merge lines into one.
///
/// This will change \c Line and \c AnnotatedLine to contain the merged line,
/// if possible; note that \c I will be incremented when lines are merged.
///
/// Returns whether the resulting \c Line can fit in a single line.
void tryFitMultipleLinesInOne(unsigned Indent,
std::vector<AnnotatedLine>::iterator &I,
std::vector<AnnotatedLine>::iterator E) {
unsigned Limit = Style.ColumnLimit - (I->InPPDirective ? 1 : 0) - Indent;
// We can never merge stuff if there are trailing line comments.
if (I->Last->Type == TT_LineComment)
return;
// Check whether the UnwrappedLine can be put onto a single line. If
// so, this is bound to be the optimal solution (by definition) and we
// don't need to analyze the entire solution space.
if (I->Last->TotalLength > Limit)
return;
Limit -= I->Last->TotalLength;
if (I + 1 == E || (I + 1)->Type == LT_Invalid)
return;
if (I->Last->is(tok::l_brace)) {
tryMergeSimpleBlock(I, E, Limit);
} else if (I->First.is(tok::kw_if)) {
tryMergeSimpleIf(I, E, Limit);
} else if (I->InPPDirective && (I->First.FormatTok.HasUnescapedNewline ||
I->First.FormatTok.IsFirst)) {
tryMergeSimplePPDirective(I, E, Limit);
}
return;
}
void tryMergeSimplePPDirective(std::vector<AnnotatedLine>::iterator &I,
std::vector<AnnotatedLine>::iterator E,
unsigned Limit) {
AnnotatedLine &Line = *I;
if (!(I + 1)->InPPDirective || (I + 1)->First.FormatTok.HasUnescapedNewline)
return;
if (I + 2 != E && (I + 2)->InPPDirective &&
!(I + 2)->First.FormatTok.HasUnescapedNewline)
return;
if (1 + (I + 1)->Last->TotalLength > Limit)
return;
join(Line, *(++I));
}
void tryMergeSimpleIf(std::vector<AnnotatedLine>::iterator &I,
std::vector<AnnotatedLine>::iterator E,
unsigned Limit) {
if (!Style.AllowShortIfStatementsOnASingleLine)
return;
if ((I + 1)->InPPDirective != I->InPPDirective ||
((I + 1)->InPPDirective &&
(I + 1)->First.FormatTok.HasUnescapedNewline))
return;
AnnotatedLine &Line = *I;
if (Line.Last->isNot(tok::r_paren))
return;
if (1 + (I + 1)->Last->TotalLength > Limit)
return;
if ((I + 1)->First.is(tok::kw_if) || (I + 1)->First.Type == TT_LineComment)
return;
// Only inline simple if's (no nested if or else).
if (I + 2 != E && (I + 2)->First.is(tok::kw_else))
return;
join(Line, *(++I));
}
void tryMergeSimpleBlock(std::vector<AnnotatedLine>::iterator &I,
std::vector<AnnotatedLine>::iterator E,
unsigned Limit) {
// First, check that the current line allows merging. This is the case if
// we're not in a control flow statement and the last token is an opening
// brace.
AnnotatedLine &Line = *I;
bool AllowedTokens =
Line.First.isNot(tok::kw_if) && Line.First.isNot(tok::kw_while) &&
Line.First.isNot(tok::kw_do) && Line.First.isNot(tok::r_brace) &&
Line.First.isNot(tok::kw_else) && Line.First.isNot(tok::kw_try) &&
Line.First.isNot(tok::kw_catch) && Line.First.isNot(tok::kw_for) &&
// This gets rid of all ObjC @ keywords and methods.
Line.First.isNot(tok::at) && Line.First.isNot(tok::minus) &&
Line.First.isNot(tok::plus);
if (!AllowedTokens)
return;
AnnotatedToken *Tok = &(I + 1)->First;
if (Tok->Children.empty() && Tok->is(tok::r_brace) &&
!Tok->MustBreakBefore && Tok->TotalLength <= Limit) {
Tok->SpacesRequiredBefore = 0;
join(Line, *(I + 1));
I += 1;
} else {
// Check that we still have three lines and they fit into the limit.
if (I + 2 == E || (I + 2)->Type == LT_Invalid ||
!nextTwoLinesFitInto(I, Limit))
return;
// 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->Type == TT_LineComment || Tok->MustBreakBefore)
return;
do {
if (Tok->is(tok::l_brace) || Tok->is(tok::r_brace))
return;
Tok = Tok->Children.empty() ? NULL : &Tok->Children.back();
} while (Tok != NULL);
// Last, check that the third line contains a single closing brace.
Tok = &(I + 2)->First;
if (!Tok->Children.empty() || Tok->isNot(tok::r_brace) ||
Tok->MustBreakBefore)
return;
join(Line, *(I + 1));
join(Line, *(I + 2));
I += 2;
}
}
bool nextTwoLinesFitInto(std::vector<AnnotatedLine>::iterator I,
unsigned Limit) {
return 1 + (I + 1)->Last->TotalLength + 1 + (I + 2)->Last->TotalLength <=
Limit;
}
void join(AnnotatedLine &A, const AnnotatedLine &B) {
A.Last->Children.push_back(B.First);
while (!A.Last->Children.empty()) {
A.Last->Children[0].Parent = A.Last;
A.Last = &A.Last->Children[0];
}
}
bool touchesRanges(const AnnotatedLine &TheLine) {
const FormatToken *First = &TheLine.First.FormatTok;
const FormatToken *Last = &TheLine.Last->FormatTok;
CharSourceRange LineRange = CharSourceRange::getTokenRange(
First->Tok.getLocation(), Last->Tok.getLocation());
for (unsigned i = 0, e = Ranges.size(); i != e; ++i) {
if (!SourceMgr.isBeforeInTranslationUnit(LineRange.getEnd(),
Ranges[i].getBegin()) &&
!SourceMgr.isBeforeInTranslationUnit(Ranges[i].getEnd(),
LineRange.getBegin()))
return true;
}
return false;
}
virtual void consumeUnwrappedLine(const UnwrappedLine &TheLine) {
AnnotatedLines.push_back(AnnotatedLine(TheLine));
}
/// \brief Add a new line and the required indent before the first Token
/// of the \c UnwrappedLine if there was no structural parsing error.
/// Returns the indent level of the \c UnwrappedLine.
void formatFirstToken(const AnnotatedToken &RootToken, unsigned Indent,
bool InPPDirective, unsigned PreviousEndOfLineColumn) {
const FormatToken &Tok = RootToken.FormatTok;
unsigned Newlines =
std::min(Tok.NewlinesBefore, Style.MaxEmptyLinesToKeep + 1);
if (Newlines == 0 && !Tok.IsFirst)
Newlines = 1;
if (!InPPDirective || Tok.HasUnescapedNewline) {
Whitespaces.replaceWhitespace(RootToken, Newlines, Indent, 0, Style);
} else {
Whitespaces.replacePPWhitespace(RootToken, Newlines, Indent,
PreviousEndOfLineColumn, Style);
}
}
DiagnosticsEngine &Diag;
FormatStyle Style;
Lexer &Lex;
SourceManager &SourceMgr;
WhitespaceManager Whitespaces;
std::vector<CharSourceRange> Ranges;
std::vector<AnnotatedLine> AnnotatedLines;
bool StructuralError;
};
tooling::Replacements
reformat(const FormatStyle &Style, Lexer &Lex, SourceManager &SourceMgr,
std::vector<CharSourceRange> Ranges, DiagnosticConsumer *DiagClient) {
IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
OwningPtr<DiagnosticConsumer> DiagPrinter;
if (DiagClient == 0) {
DiagPrinter.reset(new TextDiagnosticPrinter(llvm::errs(), &*DiagOpts));
DiagPrinter->BeginSourceFile(Lex.getLangOpts(), Lex.getPP());
DiagClient = DiagPrinter.get();
}
DiagnosticsEngine Diagnostics(
IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs()), &*DiagOpts,
DiagClient, false);
Diagnostics.setSourceManager(&SourceMgr);
Formatter formatter(Diagnostics, Style, Lex, SourceMgr, Ranges);
return formatter.format();
}
LangOptions getFormattingLangOpts() {
LangOptions LangOpts;
LangOpts.CPlusPlus = 1;
LangOpts.CPlusPlus11 = 1;
LangOpts.Bool = 1;
LangOpts.ObjC1 = 1;
LangOpts.ObjC2 = 1;
return LangOpts;
}
} // namespace format
} // namespace clang