clang-format: Allow formatting short enums on a single line.

Before:
  enum ShortEnum {
    A,
    B,
    C
  };

After:
  enum ShortEnum { A, B, C };

This seems to be the predominant choice in LLVM/Clang as well as in
Google style.

llvm-svn: 198558

clang/lib/Format/ContinuationIndenter.cpp

@@ -182,10 +182,6 @@ bool ContinuationIndenter::mustBreak(const LineState &State) {
       State.Stack.back().ObjCSelectorNameFound &&
       State.Stack.back().BreakBeforeParameter)
     return true;
-  if (Current.Type == TT_CtorInitializerColon &&
-      (!Style.AllowShortFunctionsOnASingleLine ||
-       Style.BreakConstructorInitializersBeforeComma || Style.ColumnLimit != 0))
-    return true;
   if (Previous.ClosesTemplateDeclaration && State.ParenLevel == 0 &&
       !Current.isTrailingComment())
     return true;
@@ -199,6 +195,18 @@ bool ContinuationIndenter::mustBreak(const LineState &State) {
        (State.Stack.back().BreakBeforeParameter &&
         State.Stack.back().ContainsUnwrappedBuilder)))
     return true;
+
+  // The following could be precomputed as they do not depend on the state.
+  // However, as they should take effect only if the UnwrappedLine does not fit
+  // into the ColumnLimit, they are checked here in the ContinuationIndenter.
+  if (Previous.BlockKind == BK_Block && Previous.is(tok::l_brace) &&
+      !Current.isOneOf(tok::r_brace, tok::comment))
+    return true;
+  if (Current.Type == TT_CtorInitializerColon &&
+      (!Style.AllowShortFunctionsOnASingleLine ||
+       Style.BreakConstructorInitializersBeforeComma || Style.ColumnLimit != 0))
+    return true;
+
   return false;
 }
 

clang/lib/Format/TokenAnnotator.cpp

@@ -1438,9 +1438,6 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
              Style.BreakConstructorInitializersBeforeComma &&
              !Style.ConstructorInitializerAllOnOneLineOrOnePerLine) {
     return true;
-  } else if (Right.Previous->BlockKind == BK_Block &&
-             Right.Previous->isNot(tok::r_brace) && Right.isNot(tok::r_brace)) {
-    return true;
   } else if (Right.is(tok::l_brace) && (Right.BlockKind == BK_Block)) {
     return Style.BreakBeforeBraces == FormatStyle::BS_Allman ||
            Style.BreakBeforeBraces == FormatStyle::BS_GNU;

clang/unittests/Format/FormatTest.cpp

@@ -1650,18 +1650,21 @@ TEST_F(FormatTest, FormatsEnum) {
   verifyFormat("enum X f() {\n  a();\n  return 42;\n}");
   verifyFormat("enum {\n"
                "  Bar = Foo<int, int>::value\n"
-               "};");
+               "};",
+               getLLVMStyleWithColumns(30));
+
+  verifyFormat("enum ShortEnum { A, B, C };");
 }
 
 TEST_F(FormatTest, FormatsEnumsWithErrors) {
   verifyFormat("enum Type {\n"
-               "  One = 0;\n" // These semicolons should be commas.
+               "  One = 0; // These semicolons should be commas.\n"
                "  Two = 1;\n"
                "};");
   verifyFormat("namespace n {\n"
                "enum Type {\n"
                "  One,\n"
-               "  Two,\n" // missing };
+               "  Two, // missing };\n"
                "  int i;\n"
                "}\n"
                "void g() {}");
@@ -1703,13 +1706,11 @@ TEST_F(FormatTest, FormatsEnumClass) {
 
 TEST_F(FormatTest, FormatsEnumTypes) {
   verifyFormat("enum X : int {\n"
-               "  A,\n"
-               "  B\n"
-               "};");
-  verifyFormat("enum X : std::uint32_t {\n"
-               "  A,\n"
+               "  A, // Force multiple lines.\n"
                "  B\n"
                "};");
+  verifyFormat("enum X : int { A, B };");
+  verifyFormat("enum X : std::uint32_t { A, B };");
 }
 
 TEST_F(FormatTest, FormatsBitfields) {
@@ -6605,7 +6606,7 @@ TEST_F(FormatTest, ConfigurableUseOfTab) {
                "};",
                Tab);
   verifyFormat("enum A {\n"
-               "\ta1,\n"
+               "\ta1, // Force multiple lines\n"
                "\ta2,\n"
                "\ta3\n"
                "};",