Split UnwrappedLineFormatter into individual components.

Goals: Structure code better and make components easier to use for
future features (e.g. column layout for long braced initializers).

No functional changes intended.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188543 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Format/ContinuationIndenter.cpp b/lib/Format/ContinuationIndenter.cpp
new file mode 100644
index 0000000..b26d453
--- /dev/null
+++ b/lib/Format/ContinuationIndenter.cpp
@@ -0,0 +1,670 @@
+//===--- ContinuationIndenter.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 the continuation indenter.
+///
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "format-formatter"
+
+#include "BreakableToken.h"
+#include "ContinuationIndenter.h"
+#include "WhitespaceManager.h"
+#include "clang/Basic/OperatorPrecedence.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Format/Format.h"
+#include "llvm/Support/Debug.h"
+#include <string>
+
+namespace clang {
+namespace format {
+
+// Returns the length of everything up to the first possible line break after
+// the ), ], } or > matching \c Tok.
+static unsigned getLengthToMatchingParen(const FormatToken &Tok) {
+  if (Tok.MatchingParen == NULL)
+    return 0;
+  FormatToken *End = Tok.MatchingParen;
+  while (End->Next && !End->Next->CanBreakBefore) {
+    End = End->Next;
+  }
+  return End->TotalLength - Tok.TotalLength + 1;
+}
+
+ContinuationIndenter::ContinuationIndenter(const FormatStyle &Style,
+                                           SourceManager &SourceMgr,
+                                           const AnnotatedLine &Line,
+                                           unsigned FirstIndent,
+                                           WhitespaceManager &Whitespaces,
+                                           encoding::Encoding Encoding,
+                                           bool BinPackInconclusiveFunctions)
+    : Style(Style), SourceMgr(SourceMgr), Line(Line), FirstIndent(FirstIndent),
+      Whitespaces(Whitespaces), Encoding(Encoding),
+      BinPackInconclusiveFunctions(BinPackInconclusiveFunctions) {}
+
+LineState ContinuationIndenter::getInitialState() {
+  // Initialize state dependent on indent.
+  LineState State;
+  State.Column = FirstIndent;
+  State.NextToken = Line.First;
+  State.Stack.push_back(ParenState(FirstIndent, FirstIndent,
+                                   /*AvoidBinPacking=*/false,
+                                   /*NoLineBreak=*/false));
+  State.LineContainsContinuedForLoopSection = false;
+  State.ParenLevel = 0;
+  State.StartOfStringLiteral = 0;
+  State.StartOfLineLevel = State.ParenLevel;
+  State.LowestLevelOnLine = State.ParenLevel;
+  State.IgnoreStackForComparison = false;
+
+  // The first token has already been indented and thus consumed.
+  moveStateToNextToken(State, /*DryRun=*/false,
+                       /*Newline=*/false);
+  return State;
+}
+
+bool ContinuationIndenter::canBreak(const LineState &State) {
+  const FormatToken &Current = *State.NextToken;
+  const FormatToken &Previous = *Current.Previous;
+  assert(&Previous == Current.Previous);
+  if (!Current.CanBreakBefore &&
+      !(Current.is(tok::r_brace) && State.Stack.back().BreakBeforeClosingBrace))
+    return false;
+  // The opening "{" of a braced list has to be on the same line as the first
+  // element if it is nested in another braced init list or function call.
+  if (!Current.MustBreakBefore && Previous.is(tok::l_brace) &&
+      Previous.Previous &&
+      Previous.Previous->isOneOf(tok::l_brace, tok::l_paren, tok::comma))
+    return false;
+  // This prevents breaks like:
+  //   ...
+  //   SomeParameter, OtherParameter).DoSomething(
+  //   ...
+  // As they hide "DoSomething" and are generally bad for readability.
+  if (Previous.opensScope() && State.LowestLevelOnLine < State.StartOfLineLevel)
+    return false;
+  return !State.Stack.back().NoLineBreak;
+}
+
+bool ContinuationIndenter::mustBreak(const LineState &State) {
+  const FormatToken &Current = *State.NextToken;
+  const FormatToken &Previous = *Current.Previous;
+  if (Current.MustBreakBefore || Current.Type == TT_InlineASMColon)
+    return true;
+  if (!Style.Cpp11BracedListStyle && Current.is(tok::r_brace) &&
+      State.Stack.back().BreakBeforeClosingBrace)
+    return true;
+  if (Previous.is(tok::semi) && State.LineContainsContinuedForLoopSection)
+    return true;
+  if (Style.BreakConstructorInitializersBeforeComma) {
+    if (Previous.Type == TT_CtorInitializerComma)
+      return false;
+    if (Current.Type == TT_CtorInitializerComma)
+      return true;
+  }
+  if ((Previous.isOneOf(tok::comma, tok::semi) || Current.is(tok::question) ||
+       (Current.Type == TT_ConditionalExpr &&
+        !(Current.is(tok::colon) && Previous.is(tok::question)))) &&
+      State.Stack.back().BreakBeforeParameter && !Current.isTrailingComment() &&
+      !Current.isOneOf(tok::r_paren, tok::r_brace))
+    return true;
+  if (Style.AlwaysBreakBeforeMultilineStrings &&
+      State.Column > State.Stack.back().Indent &&
+      Current.is(tok::string_literal) && Previous.isNot(tok::lessless) &&
+      Previous.Type != TT_InlineASMColon &&
+      ((Current.getNextNonComment() &&
+        Current.getNextNonComment()->is(tok::string_literal)) ||
+       (Current.TokenText.find("\\\n") != StringRef::npos)))
+    return true;
+
+  if (!Style.BreakBeforeBinaryOperators) {
+    // If we need to break somewhere inside the LHS of a binary expression, we
+    // should also break after the operator. Otherwise, the formatting would
+    // hide the operator precedence, e.g. in:
+    //   if (aaaaaaaaaaaaaa ==
+    //           bbbbbbbbbbbbbb && c) {..
+    // For comparisons, we only apply this rule, if the LHS is a binary
+    // expression itself as otherwise, the line breaks seem superfluous.
+    // We need special cases for ">>" which we have split into two ">" while
+    // lexing in order to make template parsing easier.
+    //
+    // FIXME: We'll need something similar for styles that break before binary
+    // operators.
+    bool IsComparison = (Previous.getPrecedence() == prec::Relational ||
+                         Previous.getPrecedence() == prec::Equality) &&
+                        Previous.Previous &&
+                        Previous.Previous->Type != TT_BinaryOperator; // For >>.
+    bool LHSIsBinaryExpr =
+        Previous.Previous && Previous.Previous->FakeRParens > 0;
+    if (Previous.Type == TT_BinaryOperator &&
+        (!IsComparison || LHSIsBinaryExpr) &&
+        Current.Type != TT_BinaryOperator && // For >>.
+        !Current.isTrailingComment() &&
+        !Previous.isOneOf(tok::lessless, tok::question) &&
+        Previous.getPrecedence() != prec::Assignment &&
+        State.Stack.back().BreakBeforeParameter)
+      return true;
+  }
+
+  // Same as above, but for the first "<<" operator.
+  if (Current.is(tok::lessless) && State.Stack.back().BreakBeforeParameter &&
+      State.Stack.back().FirstLessLess == 0)
+    return true;
+
+  // FIXME: Comparing LongestObjCSelectorName to 0 is a hacky way of finding
+  // out whether it is the first parameter. Clean this up.
+  if (Current.Type == TT_ObjCSelectorName &&
+      Current.LongestObjCSelectorName == 0 &&
+      State.Stack.back().BreakBeforeParameter)
+    return true;
+  if ((Current.Type == TT_CtorInitializerColon ||
+       (Previous.ClosesTemplateDeclaration && State.ParenLevel == 0)))
+    return true;
+
+  if ((Current.Type == TT_StartOfName || Current.is(tok::kw_operator)) &&
+      Line.MightBeFunctionDecl && State.Stack.back().BreakBeforeParameter &&
+      State.ParenLevel == 0)
+    return true;
+  return false;
+}
+
+unsigned ContinuationIndenter::addTokenToState(LineState &State, bool Newline,
+                                               bool DryRun) {
+  const FormatToken &Current = *State.NextToken;
+  const FormatToken &Previous = *State.NextToken->Previous;
+
+  // Extra penalty that needs to be added because of the way certain line
+  // breaks are chosen.
+  unsigned ExtraPenalty = 0;
+
+  if (State.Stack.size() == 0 || Current.Type == TT_ImplicitStringLiteral) {
+    // FIXME: Is this correct?
+    int WhitespaceLength = SourceMgr.getSpellingColumnNumber(
+                               State.NextToken->WhitespaceRange.getEnd()) -
+                           SourceMgr.getSpellingColumnNumber(
+                               State.NextToken->WhitespaceRange.getBegin());
+    State.Column += WhitespaceLength + State.NextToken->CodePointCount;
+    State.NextToken = State.NextToken->Next;
+    return 0;
+  }
+
+  // If we are continuing an expression, we want to indent an extra 4 spaces.
+  unsigned ContinuationIndent =
+      std::max(State.Stack.back().LastSpace, State.Stack.back().Indent) + 4;
+  if (Newline) {
+    // Breaking before the first "<<" is generally not desirable if the LHS is
+    // short.
+    if (Current.is(tok::lessless) && State.Stack.back().FirstLessLess == 0 &&
+        State.Column <= Style.ColumnLimit / 2)
+      ExtraPenalty += Style.PenaltyBreakFirstLessLess;
+
+    State.Stack.back().ContainsLineBreak = true;
+    if (Current.is(tok::r_brace)) {
+      if (Current.BlockKind == BK_BracedInit)
+        State.Column = State.Stack[State.Stack.size() - 2].LastSpace;
+      else
+        State.Column = FirstIndent;
+    } else if (Current.is(tok::string_literal) &&
+               State.StartOfStringLiteral != 0) {
+      State.Column = State.StartOfStringLiteral;
+      State.Stack.back().BreakBeforeParameter = true;
+    } else if (Current.is(tok::lessless) &&
+               State.Stack.back().FirstLessLess != 0) {
+      State.Column = State.Stack.back().FirstLessLess;
+    } else if (Current.isOneOf(tok::period, tok::arrow) &&
+               Current.Type != TT_DesignatedInitializerPeriod) {
+      if (State.Stack.back().CallContinuation == 0) {
+        State.Column = ContinuationIndent;
+        State.Stack.back().CallContinuation = State.Column;
+      } else {
+        State.Column = State.Stack.back().CallContinuation;
+      }
+    } else if (Current.Type == TT_ConditionalExpr) {
+      State.Column = State.Stack.back().QuestionColumn;
+    } else if (Previous.is(tok::comma) && State.Stack.back().VariablePos != 0) {
+      State.Column = State.Stack.back().VariablePos;
+    } else if (Previous.ClosesTemplateDeclaration ||
+               ((Current.Type == TT_StartOfName ||
+                 Current.is(tok::kw_operator)) &&
+                State.ParenLevel == 0 &&
+                (!Style.IndentFunctionDeclarationAfterType ||
+                 Line.StartsDefinition))) {
+      State.Column = State.Stack.back().Indent;
+    } else if (Current.Type == TT_ObjCSelectorName) {
+      if (State.Stack.back().ColonPos > Current.CodePointCount) {
+        State.Column = State.Stack.back().ColonPos - Current.CodePointCount;
+      } else {
+        State.Column = State.Stack.back().Indent;
+        State.Stack.back().ColonPos = State.Column + Current.CodePointCount;
+      }
+    } else if (Current.is(tok::l_square) && Current.Type != TT_ObjCMethodExpr) {
+      if (State.Stack.back().StartOfArraySubscripts != 0)
+        State.Column = State.Stack.back().StartOfArraySubscripts;
+      else
+        State.Column = ContinuationIndent;
+    } else if (Current.Type == TT_StartOfName ||
+               Previous.isOneOf(tok::coloncolon, tok::equal) ||
+               Previous.Type == TT_ObjCMethodExpr) {
+      State.Column = ContinuationIndent;
+    } else if (Current.Type == TT_CtorInitializerColon) {
+      State.Column = FirstIndent + Style.ConstructorInitializerIndentWidth;
+    } else if (Current.Type == TT_CtorInitializerComma) {
+      State.Column = State.Stack.back().Indent;
+    } else {
+      State.Column = State.Stack.back().Indent;
+      // Ensure that we fall back to indenting 4 spaces instead of just
+      // flushing continuations left.
+      if (State.Column == FirstIndent)
+        State.Column += 4;
+    }
+
+    if (Current.is(tok::question))
+      State.Stack.back().BreakBeforeParameter = true;
+    if ((Previous.isOneOf(tok::comma, tok::semi) &&
+         !State.Stack.back().AvoidBinPacking) ||
+        Previous.Type == TT_BinaryOperator)
+      State.Stack.back().BreakBeforeParameter = false;
+    if (Previous.Type == TT_TemplateCloser && State.ParenLevel == 0)
+      State.Stack.back().BreakBeforeParameter = false;
+
+    if (!DryRun) {
+      unsigned NewLines = 1;
+      if (Current.is(tok::comment))
+        NewLines = std::max(NewLines, std::min(Current.NewlinesBefore,
+                                               Style.MaxEmptyLinesToKeep + 1));
+      Whitespaces.replaceWhitespace(Current, NewLines, State.Column,
+                                    State.Column, Line.InPPDirective);
+    }
+
+    if (!Current.isTrailingComment())
+      State.Stack.back().LastSpace = State.Column;
+    if (Current.isOneOf(tok::arrow, tok::period) &&
+        Current.Type != TT_DesignatedInitializerPeriod)
+      State.Stack.back().LastSpace += Current.CodePointCount;
+    State.StartOfLineLevel = State.ParenLevel;
+    State.LowestLevelOnLine = State.ParenLevel;
+
+    // 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) {
+      State.Stack[i].BreakBeforeParameter = true;
+    }
+    const FormatToken *TokenBefore = Current.getPreviousNonComment();
+    if (TokenBefore && !TokenBefore->isOneOf(tok::comma, tok::semi) &&
+        TokenBefore->Type != TT_TemplateCloser &&
+        TokenBefore->Type != TT_BinaryOperator && !TokenBefore->opensScope())
+      State.Stack.back().BreakBeforeParameter = true;
+
+    // If we break after {, we should also break before the corresponding }.
+    if (Previous.is(tok::l_brace))
+      State.Stack.back().BreakBeforeClosingBrace = true;
+
+    if (State.Stack.back().AvoidBinPacking) {
+      // If we are breaking after '(', '{', '<', this is not bin packing
+      // unless AllowAllParametersOfDeclarationOnNextLine is false.
+      if (!(Previous.isOneOf(tok::l_paren, tok::l_brace) ||
+            Previous.Type == TT_BinaryOperator) ||
+          (!Style.AllowAllParametersOfDeclarationOnNextLine &&
+           Line.MustBeDeclaration))
+        State.Stack.back().BreakBeforeParameter = true;
+    }
+
+  } else {
+    if (Current.is(tok::equal) &&
+        (Line.First->is(tok::kw_for) || State.ParenLevel == 0) &&
+        State.Stack.back().VariablePos == 0) {
+      State.Stack.back().VariablePos = State.Column;
+      // Move over * and & if they are bound to the variable name.
+      const FormatToken *Tok = &Previous;
+      while (Tok && State.Stack.back().VariablePos >= Tok->CodePointCount) {
+        State.Stack.back().VariablePos -= Tok->CodePointCount;
+        if (Tok->SpacesRequiredBefore != 0)
+          break;
+        Tok = Tok->Previous;
+      }
+      if (Previous.PartOfMultiVariableDeclStmt)
+        State.Stack.back().LastSpace = State.Stack.back().VariablePos;
+    }
+
+    unsigned Spaces = State.NextToken->SpacesRequiredBefore;
+
+    if (!DryRun)
+      Whitespaces.replaceWhitespace(Current, 0, Spaces, State.Column + Spaces);
+
+    if (Current.Type == TT_ObjCSelectorName &&
+        State.Stack.back().ColonPos == 0) {
+      if (State.Stack.back().Indent + Current.LongestObjCSelectorName >
+          State.Column + Spaces + Current.CodePointCount)
+        State.Stack.back().ColonPos =
+            State.Stack.back().Indent + Current.LongestObjCSelectorName;
+      else
+        State.Stack.back().ColonPos =
+            State.Column + Spaces + Current.CodePointCount;
+    }
+
+    if (Previous.opensScope() && Previous.Type != TT_ObjCMethodExpr &&
+        Current.Type != TT_LineComment)
+      State.Stack.back().Indent = State.Column + Spaces;
+    if (Previous.is(tok::comma) && !Current.isTrailingComment() &&
+        State.Stack.back().AvoidBinPacking)
+      State.Stack.back().NoLineBreak = true;
+
+    State.Column += Spaces;
+    if (Current.is(tok::l_paren) && Previous.isOneOf(tok::kw_if, tok::kw_for))
+      // 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.Stack.back().LastSpace = State.Column;
+    else if ((Previous.Type == TT_BinaryOperator ||
+              Previous.Type == TT_ConditionalExpr ||
+              Previous.Type == TT_CtorInitializerColon) &&
+             !(Previous.getPrecedence() == prec::Assignment &&
+               Current.FakeLParens.empty()))
+      // Always indent relative to the RHS of the expression unless this is a
+      // simple assignment without binary expression on the RHS.
+      State.Stack.back().LastSpace = State.Column;
+    else if (Previous.Type == TT_InheritanceColon)
+      State.Stack.back().Indent = State.Column;
+    else if (Previous.opensScope()) {
+      // If a function has multiple parameters (including a single parameter
+      // that is a binary expression) or a trailing call, indent all
+      // parameters from the opening parenthesis. This avoids confusing
+      // indents like:
+      //   OuterFunction(InnerFunctionCall(
+      //       ParameterToInnerFunction),
+      //                 SecondParameterToOuterFunction);
+      bool HasMultipleParameters = !Current.FakeLParens.empty();
+      bool HasTrailingCall = false;
+      if (Previous.MatchingParen) {
+        const FormatToken *Next = Previous.MatchingParen->getNextNonComment();
+        if (Next && Next->isOneOf(tok::period, tok::arrow))
+          HasTrailingCall = true;
+      }
+      if (HasMultipleParameters || HasTrailingCall)
+        State.Stack.back().LastSpace = State.Column;
+    }
+  }
+
+  return moveStateToNextToken(State, DryRun, Newline) + ExtraPenalty;
+}
+
+unsigned ContinuationIndenter::moveStateToNextToken(LineState &State,
+                                                    bool DryRun, bool Newline) {
+  const FormatToken &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::l_square) &&
+      State.Stack.back().StartOfArraySubscripts == 0)
+    State.Stack.back().StartOfArraySubscripts = State.Column;
+  if (Current.is(tok::question))
+    State.Stack.back().QuestionColumn = State.Column;
+  if (!Current.opensScope() && !Current.closesScope())
+    State.LowestLevelOnLine =
+        std::min(State.LowestLevelOnLine, State.ParenLevel);
+  if (Current.isOneOf(tok::period, tok::arrow) &&
+      Line.Type == LT_BuilderTypeCall && State.ParenLevel == 0)
+    State.Stack.back().StartOfFunctionCall =
+        Current.LastInChainOfCalls ? 0 : State.Column + Current.CodePointCount;
+  if (Current.Type == TT_CtorInitializerColon) {
+    // Indent 2 from the column, so:
+    // SomeClass::SomeClass()
+    //     : First(...), ...
+    //       Next(...)
+    //       ^ line up here.
+    State.Stack.back().Indent =
+        State.Column + (Style.BreakConstructorInitializersBeforeComma ? 0 : 2);
+    if (Style.ConstructorInitializerAllOnOneLineOrOnePerLine)
+      State.Stack.back().AvoidBinPacking = true;
+    State.Stack.back().BreakBeforeParameter = false;
+  }
+
+  // If return returns a binary expression, align after it.
+  if (Current.is(tok::kw_return) && !Current.FakeLParens.empty())
+    State.Stack.back().LastSpace = State.Column + 7;
+
+  // In ObjC method declaration we align on the ":" of parameters, but we need
+  // to ensure that we indent parameters on subsequent lines by at least 4.
+  if (Current.Type == TT_ObjCMethodSpecifier)
+    State.Stack.back().Indent += 4;
+
+  // Insert scopes created by fake parenthesis.
+  const FormatToken *Previous = Current.getPreviousNonComment();
+  // Don't add extra indentation for the first fake parenthesis after
+  // 'return', assignements or opening <({[. The indentation for these cases
+  // is special cased.
+  bool SkipFirstExtraIndent =
+      Current.is(tok::kw_return) ||
+      (Previous && (Previous->opensScope() ||
+                    Previous->getPrecedence() == prec::Assignment));
+  for (SmallVectorImpl<prec::Level>::const_reverse_iterator
+           I = Current.FakeLParens.rbegin(),
+           E = Current.FakeLParens.rend();
+       I != E; ++I) {
+    ParenState NewParenState = State.Stack.back();
+    NewParenState.ContainsLineBreak = false;
+    NewParenState.Indent =
+        std::max(std::max(State.Column, NewParenState.Indent),
+                 State.Stack.back().LastSpace);
+
+    // Always indent conditional expressions. Never indent expression where
+    // the 'operator' is ',', ';' or an assignment (i.e. *I <=
+    // prec::Assignment) as those have different indentation rules. Indent
+    // other expression, unless the indentation needs to be skipped.
+    if (*I == prec::Conditional ||
+        (!SkipFirstExtraIndent && *I > prec::Assignment &&
+         !Style.BreakBeforeBinaryOperators))
+      NewParenState.Indent += 4;
+    if (Previous && !Previous->opensScope())
+      NewParenState.BreakBeforeParameter = false;
+    State.Stack.push_back(NewParenState);
+    SkipFirstExtraIndent = false;
+  }
+
+  // If we encounter an opening (, [, { or <, we add a level to our stacks to
+  // prepare for the following tokens.
+  if (Current.opensScope()) {
+    unsigned NewIndent;
+    unsigned LastSpace = State.Stack.back().LastSpace;
+    bool AvoidBinPacking;
+    if (Current.is(tok::l_brace)) {
+      NewIndent =
+          LastSpace + (Style.Cpp11BracedListStyle ? 4 : Style.IndentWidth);
+      const FormatToken *NextNoComment = Current.getNextNonComment();
+      AvoidBinPacking = NextNoComment &&
+                        NextNoComment->Type == TT_DesignatedInitializerPeriod;
+    } else {
+      NewIndent =
+          4 + std::max(LastSpace, State.Stack.back().StartOfFunctionCall);
+      AvoidBinPacking = !Style.BinPackParameters ||
+                        (Style.ExperimentalAutoDetectBinPacking &&
+                         (Current.PackingKind == PPK_OnePerLine ||
+                          (!BinPackInconclusiveFunctions &&
+                           Current.PackingKind == PPK_Inconclusive)));
+    }
+
+    State.Stack.push_back(ParenState(NewIndent, LastSpace, AvoidBinPacking,
+                                     State.Stack.back().NoLineBreak));
+    ++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.isOneOf(tok::r_paren, tok::r_square) ||
+      (Current.is(tok::r_brace) && State.NextToken != Line.First) ||
+      State.NextToken->Type == TT_TemplateCloser) {
+    State.Stack.pop_back();
+    --State.ParenLevel;
+  }
+  if (Current.is(tok::r_square)) {
+    // If this ends the array subscript expr, reset the corresponding value.
+    const FormatToken *NextNonComment = Current.getNextNonComment();
+    if (NextNonComment && NextNonComment->isNot(tok::l_square))
+      State.Stack.back().StartOfArraySubscripts = 0;
+  }
+
+  // Remove scopes created by fake parenthesis.
+  for (unsigned i = 0, e = Current.FakeRParens; i != e; ++i) {
+    unsigned VariablePos = State.Stack.back().VariablePos;
+    State.Stack.pop_back();
+    State.Stack.back().VariablePos = VariablePos;
+  }
+
+  if (Current.is(tok::string_literal) && State.StartOfStringLiteral == 0) {
+    State.StartOfStringLiteral = State.Column;
+  } else if (!Current.isOneOf(tok::comment, tok::identifier, tok::hash,
+                              tok::string_literal)) {
+    State.StartOfStringLiteral = 0;
+  }
+
+  State.Column += Current.CodePointCount;
+
+  State.NextToken = State.NextToken->Next;
+
+  if (!Newline && Style.AlwaysBreakBeforeMultilineStrings &&
+      Current.is(tok::string_literal) && Current.CanBreakBefore)
+    return 0;
+
+  return breakProtrudingToken(Current, State, DryRun);
+}
+
+unsigned ContinuationIndenter::breakProtrudingToken(const FormatToken &Current,
+                                                    LineState &State,
+                                                    bool DryRun) {
+  llvm::OwningPtr<BreakableToken> Token;
+  unsigned StartColumn = State.Column - Current.CodePointCount;
+  unsigned OriginalStartColumn =
+      SourceMgr.getSpellingColumnNumber(Current.getStartOfNonWhitespace()) - 1;
+
+  if (Current.is(tok::string_literal) &&
+      Current.Type != TT_ImplicitStringLiteral) {
+    // Only break up default narrow strings.
+    if (!Current.TokenText.startswith("\""))
+      return 0;
+    // Don't break string literals with escaped newlines. As clang-format must
+    // not change the string's content, it is unlikely that we'll end up with
+    // a better format.
+    if (Current.TokenText.find("\\\n") != StringRef::npos)
+      return 0;
+    // Exempts unterminated string literals from line breaking. The user will
+    // likely want to terminate the string before any line breaking is done.
+    if (Current.IsUnterminatedLiteral)
+      return 0;
+
+    Token.reset(new BreakableStringLiteral(Current, StartColumn,
+                                           Line.InPPDirective, Encoding));
+  } else if (Current.Type == TT_BlockComment && Current.isTrailingComment()) {
+    Token.reset(new BreakableBlockComment(
+        Style, Current, StartColumn, OriginalStartColumn, !Current.Previous,
+        Line.InPPDirective, Encoding));
+  } else if (Current.Type == TT_LineComment &&
+             (Current.Previous == NULL ||
+              Current.Previous->Type != TT_ImplicitStringLiteral)) {
+    // Don't break line comments with escaped newlines. These look like
+    // separate line comments, but in fact contain a single line comment with
+    // multiple lines including leading whitespace and the '//' markers.
+    //
+    // FIXME: If we want to handle them correctly, we'll need to adjust
+    // leading whitespace in consecutive lines when changing indentation of
+    // the first line similar to what we do with block comments.
+    StringRef::size_type EscapedNewlinePos = Current.TokenText.find("\\\n");
+    if (EscapedNewlinePos != StringRef::npos) {
+      State.Column =
+          StartColumn +
+          encoding::getCodePointCount(
+              Current.TokenText.substr(0, EscapedNewlinePos), Encoding) +
+          1;
+      return 0;
+    }
+
+    Token.reset(new BreakableLineComment(Current, StartColumn,
+                                         Line.InPPDirective, Encoding));
+  } else {
+    return 0;
+  }
+  if (Current.UnbreakableTailLength >= getColumnLimit())
+    return 0;
+
+  unsigned RemainingSpace = getColumnLimit() - Current.UnbreakableTailLength;
+  bool BreakInserted = false;
+  unsigned Penalty = 0;
+  unsigned RemainingTokenColumns = 0;
+  for (unsigned LineIndex = 0, EndIndex = Token->getLineCount();
+       LineIndex != EndIndex; ++LineIndex) {
+    if (!DryRun)
+      Token->replaceWhitespaceBefore(LineIndex, Whitespaces);
+    unsigned TailOffset = 0;
+    RemainingTokenColumns =
+        Token->getLineLengthAfterSplit(LineIndex, TailOffset, StringRef::npos);
+    while (RemainingTokenColumns > RemainingSpace) {
+      BreakableToken::Split Split =
+          Token->getSplit(LineIndex, TailOffset, getColumnLimit());
+      if (Split.first == StringRef::npos) {
+        // The last line's penalty is handled in addNextStateToQueue().
+        if (LineIndex < EndIndex - 1)
+          Penalty += Style.PenaltyExcessCharacter *
+                     (RemainingTokenColumns - RemainingSpace);
+        break;
+      }
+      assert(Split.first != 0);
+      unsigned NewRemainingTokenColumns = Token->getLineLengthAfterSplit(
+          LineIndex, TailOffset + Split.first + Split.second, StringRef::npos);
+      assert(NewRemainingTokenColumns < RemainingTokenColumns);
+      if (!DryRun)
+        Token->insertBreak(LineIndex, TailOffset, Split, Whitespaces);
+      Penalty += Current.is(tok::string_literal) ? Style.PenaltyBreakString
+                                                 : Style.PenaltyBreakComment;
+      unsigned ColumnsUsed =
+          Token->getLineLengthAfterSplit(LineIndex, TailOffset, Split.first);
+      if (ColumnsUsed > getColumnLimit()) {
+        Penalty +=
+            Style.PenaltyExcessCharacter * (ColumnsUsed - getColumnLimit());
+      }
+      TailOffset += Split.first + Split.second;
+      RemainingTokenColumns = NewRemainingTokenColumns;
+      BreakInserted = true;
+    }
+  }
+
+  State.Column = RemainingTokenColumns;
+
+  if (BreakInserted) {
+    // If we break the token inside a parameter list, we need to break before
+    // the next parameter on all levels, so that the next parameter is clearly
+    // visible. Line comments already introduce a break.
+    if (Current.Type != TT_LineComment) {
+      for (unsigned i = 0, e = State.Stack.size(); i != e; ++i)
+        State.Stack[i].BreakBeforeParameter = true;
+    }
+
+    State.Stack.back().LastSpace = StartColumn;
+  }
+  return Penalty;
+}
+
+unsigned ContinuationIndenter::getColumnLimit() const {
+  // In preprocessor directives reserve two chars for trailing " \"
+  return Style.ColumnLimit - (Line.InPPDirective ? 2 : 0);
+}
+
+} // namespace format
+} // namespace clang