[clang-format] Add option to break before inheritance separation operator in class declaration.

Differential Revision: https://reviews.llvm.org/D30487

llvm-svn: 297467

clang/docs/ClangFormatStyleOptions.rst

@@ -528,6 +528,10 @@ the configuration (without a prefix: ``Auto``).
 
 
 
+**BreakBeforeInheritanceComma** (``bool``)
+  If ``true``, in the class inheritance expression clang-format will
+  break before ``:`` and ``,`` if there is multiple inheritance.
+
 **BreakBeforeTernaryOperators** (``bool``)
   If ``true``, ternary operators will be placed after line breaks.
 

clang/include/clang/Format/Format.h

@@ -422,6 +422,10 @@ struct FormatStyle {
   /// which should not be split into lines or otherwise changed.
   std::string CommentPragmas;
 
+  /// \brief If ``true``, in the class inheritance expression clang-format will
+  /// break before ``:`` and ``,`` if there is multiple inheritance.
+  bool BreakBeforeInheritanceComma;
+
   /// \brief If the constructor initializers don't fit on a line, put each
   /// initializer on its own line.
   bool ConstructorInitializerAllOnOneLineOrOnePerLine;
@@ -844,6 +848,7 @@ struct FormatStyle {
            BreakAfterJavaFieldAnnotations == R.BreakAfterJavaFieldAnnotations &&
            BreakStringLiterals == R.BreakStringLiterals &&
            ColumnLimit == R.ColumnLimit && CommentPragmas == R.CommentPragmas &&
+           BreakBeforeInheritanceComma == R.BreakBeforeInheritanceComma &&
            ConstructorInitializerAllOnOneLineOrOnePerLine ==
                R.ConstructorInitializerAllOnOneLineOrOnePerLine &&
            ConstructorInitializerIndentWidth ==

clang/lib/Format/ContinuationIndenter.cpp

@@ -57,8 +57,10 @@ static bool startsNextParameter(const FormatToken &Current,
       Style.BreakConstructorInitializersBeforeComma)
     return true;
   return Previous.is(tok::comma) && !Current.isTrailingComment() &&
-         (Previous.isNot(TT_CtorInitializerComma) ||
-          !Style.BreakConstructorInitializersBeforeComma);
+         ((Previous.isNot(TT_CtorInitializerComma) ||
+          !Style.BreakConstructorInitializersBeforeComma) &&
+          (Previous.isNot(TT_InheritanceComma) ||
+          !Style.BreakBeforeInheritanceComma));
 }
 
 ContinuationIndenter::ContinuationIndenter(const FormatStyle &Style,
@@ -350,6 +352,11 @@ void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
     Whitespaces.replaceWhitespace(Current, /*Newlines=*/0, Spaces,
                                   State.Column + Spaces);
 
+  // If "BreakBeforeInheritanceComma" mode, don't break within the inheritance
+  // declaration unless there is multiple inheritance.
+  if (Style.BreakBeforeInheritanceComma && Current.is(TT_InheritanceColon))
+    State.Stack.back().NoLineBreak = true;
+
   if (Current.is(TT_SelectorName) &&
       !State.Stack.back().ObjCSelectorNameFound) {
     unsigned MinIndent =
@@ -737,10 +744,11 @@ unsigned ContinuationIndenter::getNewLineColumn(const LineState &State) {
   if (PreviousNonComment && PreviousNonComment->is(tok::colon) &&
       PreviousNonComment->isOneOf(TT_ObjCMethodExpr, TT_DictLiteral))
     return ContinuationIndent;
-  if (NextNonComment->is(TT_CtorInitializerColon))
-    return State.FirstIndent + Style.ConstructorInitializerIndentWidth;
   if (NextNonComment->is(TT_CtorInitializerComma))
     return State.Stack.back().Indent;
+  if (NextNonComment->isOneOf(TT_CtorInitializerColon, TT_InheritanceColon,
+                              TT_InheritanceComma))
+    return State.FirstIndent + Style.ConstructorInitializerIndentWidth;
   if (Previous.is(tok::r_paren) && !Current.isBinaryOperator() &&
       !Current.isOneOf(tok::colon, tok::comment))
     return ContinuationIndent;
@@ -810,6 +818,9 @@ unsigned ContinuationIndenter::moveStateToNextToken(LineState &State,
       State.Stack.back().AvoidBinPacking = true;
     State.Stack.back().BreakBeforeParameter = false;
   }
+  if (Current.is(TT_InheritanceColon))
+    State.Stack.back().Indent =
+        State.FirstIndent + Style.ContinuationIndentWidth;
   if (Current.isOneOf(TT_BinaryOperator, TT_ConditionalExpr) && Newline)
     State.Stack.back().NestedBlockIndent =
         State.Column + Current.ColumnWidth + 1;

clang/lib/Format/Format.cpp

@@ -298,6 +298,8 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("BreakStringLiterals", Style.BreakStringLiterals);
     IO.mapOptional("ColumnLimit", Style.ColumnLimit);
     IO.mapOptional("CommentPragmas", Style.CommentPragmas);
+    IO.mapOptional("BreakBeforeInheritanceComma",
+                   Style.BreakBeforeInheritanceComma);
     IO.mapOptional("ConstructorInitializerAllOnOneLineOrOnePerLine",
                    Style.ConstructorInitializerAllOnOneLineOrOnePerLine);
     IO.mapOptional("ConstructorInitializerIndentWidth",
@@ -521,6 +523,7 @@ FormatStyle getLLVMStyle() {
                              false, false, false, false, false};
   LLVMStyle.BreakAfterJavaFieldAnnotations = false;
   LLVMStyle.BreakConstructorInitializersBeforeComma = false;
+  LLVMStyle.BreakBeforeInheritanceComma = false;
   LLVMStyle.BreakStringLiterals = true;
   LLVMStyle.ColumnLimit = 80;
   LLVMStyle.CommentPragmas = "^ IWYU pragma:";
@@ -674,6 +677,7 @@ FormatStyle getMozillaStyle() {
   MozillaStyle.BinPackArguments = false;
   MozillaStyle.BreakBeforeBraces = FormatStyle::BS_Mozilla;
   MozillaStyle.BreakConstructorInitializersBeforeComma = true;
+  MozillaStyle.BreakBeforeInheritanceComma = true;
   MozillaStyle.ConstructorInitializerIndentWidth = 2;
   MozillaStyle.ContinuationIndentWidth = 2;
   MozillaStyle.Cpp11BracedListStyle = false;

clang/lib/Format/FormatToken.h

@@ -48,6 +48,7 @@ namespace format {
   TYPE(FunctionTypeLParen) \
   TYPE(ImplicitStringLiteral) \
   TYPE(InheritanceColon) \
+  TYPE(InheritanceComma) \
   TYPE(InlineASMBrace) \
   TYPE(InlineASMColon) \
   TYPE(JavaAnnotation) \

clang/lib/Format/TokenAnnotator.cpp

@@ -676,6 +676,8 @@ private:
     case tok::comma:
       if (Contexts.back().InCtorInitializer)
         Tok->Type = TT_CtorInitializerComma;
+      else if (Contexts.back().InInheritanceList)
+        Tok->Type = TT_InheritanceComma;
       else if (Contexts.back().FirstStartOfName &&
                (Contexts.size() == 1 || Line.startsWith(tok::kw_for))) {
         Contexts.back().FirstStartOfName->PartOfMultiVariableDeclStmt = true;
@@ -945,6 +947,7 @@ private:
     bool CanBeExpression = true;
     bool InTemplateArgument = false;
     bool InCtorInitializer = false;
+    bool InInheritanceList = false;
     bool CaretFound = false;
     bool IsForEachMacro = false;
   };
@@ -1004,6 +1007,9 @@ private:
                Current.Previous->is(TT_CtorInitializerColon)) {
       Contexts.back().IsExpression = true;
       Contexts.back().InCtorInitializer = true;
+    } else if (Current.Previous &&
+               Current.Previous->is(TT_InheritanceColon)) {
+      Contexts.back().InInheritanceList = true;
     } else if (Current.isOneOf(tok::r_paren, tok::greater, tok::comma)) {
       for (FormatToken *Previous = Current.Previous;
            Previous && Previous->isOneOf(tok::star, tok::amp);
@@ -2474,6 +2480,10 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
       Style.BreakConstructorInitializersBeforeComma &&
       !Style.ConstructorInitializerAllOnOneLineOrOnePerLine)
     return true;
+  // Break only if we have multiple inheritance.
+  if (Style.BreakBeforeInheritanceComma &&
+      Right.is(TT_InheritanceComma))
+   return true;
   if (Right.is(tok::string_literal) && Right.TokenText.startswith("R\""))
     // Raw string literals are special wrt. line breaks. The author has made a
     // deliberate choice and might have aligned the contents of the string
@@ -2653,6 +2663,10 @@ bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
   if (Right.is(TT_CtorInitializerComma) &&
       Style.BreakConstructorInitializersBeforeComma)
     return true;
+  if (Left.is(TT_InheritanceComma) && Style.BreakBeforeInheritanceComma)
+    return false;
+  if (Right.is(TT_InheritanceComma) && Style.BreakBeforeInheritanceComma)
+    return true;
   if ((Left.is(tok::greater) && Right.is(tok::greater)) ||
       (Left.is(tok::less) && Right.is(tok::less)))
     return false;

clang/unittests/Format/FormatTest.cpp

@@ -1029,6 +1029,17 @@ TEST_F(FormatTest, FormatsClasses) {
   verifyFormat("class ::A::B {};");
 }
 
+TEST_F(FormatTest, BreakBeforeInheritanceComma) {
+  FormatStyle StyleWithInheritanceBreak = getLLVMStyle();
+  StyleWithInheritanceBreak.BreakBeforeInheritanceComma = true;
+
+  verifyFormat("class MyClass : public X {};", StyleWithInheritanceBreak);
+  verifyFormat("class MyClass\n"
+               "    : public X\n"
+               "    , public Y {};",
+               StyleWithInheritanceBreak);
+}
+
 TEST_F(FormatTest, FormatsVariableDeclarationsAfterStructOrClass) {
   verifyFormat("class A {\n} a, b;");
   verifyFormat("struct A {\n} a, b;");
@@ -8582,6 +8593,7 @@ TEST_F(FormatTest, ParsesConfigurationBools) {
   CHECK_PARSE_BOOL(BreakBeforeTernaryOperators);
   CHECK_PARSE_BOOL(BreakConstructorInitializersBeforeComma);
   CHECK_PARSE_BOOL(BreakStringLiterals);
+  CHECK_PARSE_BOOL(BreakBeforeInheritanceComma)
   CHECK_PARSE_BOOL(ConstructorInitializerAllOnOneLineOrOnePerLine);
   CHECK_PARSE_BOOL(DerivePointerAlignment);
   CHECK_PARSE_BOOL_FIELD(DerivePointerAlignment, "DerivePointerBinding");