clang-format: Add option for the offset of constructor initializers.

Some coding styles use a different indent for constructor initializers.

Patch by Klemens Baum. Thank you.
Review: http://llvm-reviews.chandlerc.com/D1360

Post review changes: Changed data type to unsigned as a negative indent
width does not make sense and added test for configuration parsing.

llvm-svn: 188260

clang/include/clang/Format/Format.h

@@ -141,6 +141,10 @@ struct FormatStyle {
   /// \brief The number of characters to use for indentation.
   unsigned IndentWidth;
 
+  /// \brief The number of characters to use for indentation of constructor
+  /// initializer lists.
+  unsigned ConstructorInitializerIndentWidth;
+
   /// \brief If \c true, always break after the \c template<...> of a template
   /// declaration.
   bool AlwaysBreakTemplateDeclarations;
@@ -192,6 +196,8 @@ struct FormatStyle {
 
   bool operator==(const FormatStyle &R) const {
     return AccessModifierOffset == R.AccessModifierOffset &&
+           ConstructorInitializerIndentWidth ==
+               R.ConstructorInitializerIndentWidth &&
            AlignEscapedNewlinesLeft == R.AlignEscapedNewlinesLeft &&
            AlignTrailingComments == R.AlignTrailingComments &&
            AllowAllParametersOfDeclarationOnNextLine ==

clang/lib/Format/Format.cpp

@@ -91,6 +91,8 @@ template <> struct MappingTraits<clang::format::FormatStyle> {
     }
 
     IO.mapOptional("AccessModifierOffset", Style.AccessModifierOffset);
+    IO.mapOptional("ConstructorInitializerIndentWidth",
+                   Style.ConstructorInitializerIndentWidth);
     IO.mapOptional("AlignEscapedNewlinesLeft", Style.AlignEscapedNewlinesLeft);
     IO.mapOptional("AlignTrailingComments", Style.AlignTrailingComments);
     IO.mapOptional("AllowAllParametersOfDeclarationOnNextLine",
@@ -167,6 +169,7 @@ FormatStyle getLLVMStyle() {
   LLVMStyle.BreakConstructorInitializersBeforeComma = false;
   LLVMStyle.ColumnLimit = 80;
   LLVMStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = false;
+  LLVMStyle.ConstructorInitializerIndentWidth = 4;
   LLVMStyle.Cpp11BracedListStyle = false;
   LLVMStyle.DerivePointerBinding = false;
   LLVMStyle.ExperimentalAutoDetectBinPacking = false;
@@ -203,6 +206,7 @@ FormatStyle getGoogleStyle() {
   GoogleStyle.BreakConstructorInitializersBeforeComma = false;
   GoogleStyle.ColumnLimit = 80;
   GoogleStyle.ConstructorInitializerAllOnOneLineOrOnePerLine = true;
+  GoogleStyle.ConstructorInitializerIndentWidth = 4;
   GoogleStyle.Cpp11BracedListStyle = true;
   GoogleStyle.DerivePointerBinding = true;
   GoogleStyle.ExperimentalAutoDetectBinPacking = false;
@@ -651,6 +655,10 @@ private:
                  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
@@ -821,8 +829,9 @@ private:
       //     : First(...), ...
       //       Next(...)
       //       ^ line up here.
-      if (!Style.BreakConstructorInitializersBeforeComma)
+      State.Stack.back().Indent =
-        State.Stack.back().Indent = State.Column + 2;
+          State.Column +
+          (Style.BreakConstructorInitializersBeforeComma ? 0 : 2);
       if (Style.ConstructorInitializerAllOnOneLineOrOnePerLine)
         State.Stack.back().AvoidBinPacking = true;
       State.Stack.back().BreakBeforeParameter = false;

clang/unittests/Format/FormatTest.cpp

@@ -4186,7 +4186,7 @@ TEST_F(FormatTest, UnderstandContextOfRecordTypeKeywords) {
                "  f();\n");
 
   // This is simply incomplete. Formatting is not important, but must not crash.
-  verifyFormat("class A:"); 
+  verifyFormat("class A:");
 }
 
 TEST_F(FormatTest, DoNotInterfereWithErrorAndWarning) {
@@ -5660,6 +5660,8 @@ TEST_F(FormatTest, ParsesConfiguration) {
   CHECK_PARSE_BOOL(IndentFunctionDeclarationAfterType);
 
   CHECK_PARSE("AccessModifierOffset: -1234", AccessModifierOffset, -1234);
+  CHECK_PARSE("ConstructorInitializerIndentWidth: 1234",
+              ConstructorInitializerIndentWidth, 1234u);
   CHECK_PARSE("ColumnLimit: 1234", ColumnLimit, 1234u);
   CHECK_PARSE("MaxEmptyLinesToKeep: 1234", MaxEmptyLinesToKeep, 1234u);
   CHECK_PARSE("PenaltyExcessCharacter: 1234", PenaltyExcessCharacter, 1234u);
@@ -5789,6 +5791,53 @@ TEST_F(FormatTest, SplitsUTF8BlockComments) {
             format("/* 𝓣𝓮𝓼𝓽 𝔣𝔬𝔲𝔯 𝕓𝕪𝕥𝕖 𝖀𝕿𝕱-𝟠 */", getLLVMStyleWithColumns(12)));
 }
 
+TEST_F(FormatTest, ConstructorInitializerIndentWidth) {
+  FormatStyle Style = getLLVMStyle();
+
+  Style.ConstructorInitializerIndentWidth = 4;
+  verifyFormat(
+      "SomeClass::Constructor()\n"
+      "    : aaaaaaaaaaaaa(aaaaaaaaaaaaaa), aaaaaaaaaaaaa(aaaaaaaaaaaaaa),\n"
+      "      aaaaaaaaaaaaa(aaaaaaaaaaaaaa) {}",
+      Style);
+
+  Style.ConstructorInitializerIndentWidth = 2;
+  verifyFormat(
+      "SomeClass::Constructor()\n"
+      "  : aaaaaaaaaaaaa(aaaaaaaaaaaaaa), aaaaaaaaaaaaa(aaaaaaaaaaaaaa),\n"
+      "    aaaaaaaaaaaaa(aaaaaaaaaaaaaa) {}",
+      Style);
+
+  Style.ConstructorInitializerIndentWidth = 0;
+  verifyFormat(
+      "SomeClass::Constructor()\n"
+      ": aaaaaaaaaaaaa(aaaaaaaaaaaaaa), aaaaaaaaaaaaa(aaaaaaaaaaaaaa),\n"
+      "  aaaaaaaaaaaaa(aaaaaaaaaaaaaa) {}",
+      Style);
+
+  Style.BreakConstructorInitializersBeforeComma = true;
+  Style.ConstructorInitializerIndentWidth = 4;
+  verifyFormat("SomeClass::Constructor()\n"
+               "    : a(a)\n"
+               "    , b(b)\n"
+               "    , c(c) {}",
+               Style);
+
+  Style.ConstructorInitializerIndentWidth = 2;
+  verifyFormat("SomeClass::Constructor()\n"
+               "  : a(a)\n"
+               "  , b(b)\n"
+               "  , c(c) {}",
+               Style);
+
+  Style.ConstructorInitializerIndentWidth = 0;
+  verifyFormat("SomeClass::Constructor()\n"
+               ": a(a)\n"
+               ", b(b)\n"
+               ", c(c) {}",
+               Style);
+}
+
 #endif
 
 TEST_F(FormatTest, FormatsWithWebKitStyle) {