[clang-format] Add option WrapNamespaceBodyWithNewlines (#106145)

It wraps the body of namespace with additional newlines, turning this code:
```
namespace N {
int function();
}
```
into the following:
```
namespace N {

int function();

}
```

---------

Co-authored-by: Owen Pan <owenpiano@gmail.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index a5657f2..e51d7ac 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -839,6 +839,18 @@ template <> struct ScalarEnumerationTraits<FormatStyle::UseTabStyle> {
   }
 };
 
+template <>
+struct ScalarEnumerationTraits<
+    FormatStyle::WrapNamespaceBodyWithEmptyLinesStyle> {
+  static void
+  enumeration(IO &IO,
+              FormatStyle::WrapNamespaceBodyWithEmptyLinesStyle &Value) {
+    IO.enumCase(Value, "Never", FormatStyle::WNBWELS_Never);
+    IO.enumCase(Value, "Always", FormatStyle::WNBWELS_Always);
+    IO.enumCase(Value, "Leave", FormatStyle::WNBWELS_Leave);
+  }
+};
+
 template <> struct MappingTraits<FormatStyle> {
   static void mapping(IO &IO, FormatStyle &Style) {
     // When reading, read the language first, we need it for getPredefinedStyle.
@@ -1171,6 +1183,8 @@ template <> struct MappingTraits<FormatStyle> {
                    Style.VerilogBreakBetweenInstancePorts);
     IO.mapOptional("WhitespaceSensitiveMacros",
                    Style.WhitespaceSensitiveMacros);
+    IO.mapOptional("WrapNamespaceBodyWithEmptyLines",
+                   Style.WrapNamespaceBodyWithEmptyLines);
 
     // If AlwaysBreakAfterDefinitionReturnType was specified but
     // BreakAfterReturnType was not, initialize the latter from the former for
@@ -1639,6 +1653,7 @@ FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
   LLVMStyle.WhitespaceSensitiveMacros.push_back("NS_SWIFT_NAME");
   LLVMStyle.WhitespaceSensitiveMacros.push_back("PP_STRINGIZE");
   LLVMStyle.WhitespaceSensitiveMacros.push_back("STRINGIZE");
+  LLVMStyle.WrapNamespaceBodyWithEmptyLines = FormatStyle::WNBWELS_Leave;
 
   LLVMStyle.PenaltyBreakAssignment = prec::Assignment;
   LLVMStyle.PenaltyBreakBeforeFirstCallParameter = 19;