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

[Owen Pan via cfe-commits]

================
@@ -1493,6 +1513,28 @@ static auto computeNewlines(const AnnotatedLine &Line,
     Newlines = 1;
   }
 
+  // Modify empty lines after "{" that opens namespace scope.
+  if (Style.WrapNamespaceBodyWithEmptyLines != FormatStyle::WNBWELS_Leave &&
+      LineStartsNamespaceScope(&Line, PreviousLine, PrevPrevLine)) {
+    if (Style.WrapNamespaceBodyWithEmptyLines == FormatStyle::WNBWELS_Never)
+      Newlines = std::min(Newlines, 1u);
+    else if (!Line.startsWithNamespace())
+      Newlines = std::max(Newlines, 2u);
+    else
+      Newlines = std::min(Newlines, 1u);
+  }
+
+  // Modify empty lines before "}" that closes namespace scope.
+  if (Style.WrapNamespaceBodyWithEmptyLines != FormatStyle::WNBWELS_Leave &&
+      LineEndsNamespaceScope(&Line, Lines)) {
+    if (Style.WrapNamespaceBodyWithEmptyLines == FormatStyle::WNBWELS_Never)
+      Newlines = std::min(Newlines, 1u);
+    else if (!LineEndsNamespaceScope(PreviousLine, Lines))
+      Newlines = std::max(Newlines, 2u);
+    else
+      Newlines = std::min(Newlines, 1u);
----------------
owenca wrote:

Refactor and simplify:
```suggestion
  if (Style.WrapNamespaceBodyWithEmptyLines != FormatStyle::WNBWELS_Leave) {
    // Modify empty lines after TT_NamespaceLBrace.
    if (PreviousLine && PreviousLine->endsWith(TT_NamespaceLBrace)) {
      if (Style.WrapNamespaceBodyWithEmptyLines == FormatStyle::WNBWELS_Never)
        Newlines = 1;
      else if (!Line.startsWithNamespace())
        Newlines = std::max(Newlines, 2u);
      else
        Newlines = 1;
    }

    // Modify empty lines before TT_NamespaceRBrace.
    if (Line.startsWith(TT_NamespaceRBrace)) {
      if (Style.WrapNamespaceBodyWithEmptyLines == FormatStyle::WNBWELS_Never)
        Newlines = 1;
      else if (!PreviousLine->startsWith(TT_NamespaceRBrace))
        Newlines = std::max(Newlines, 2u);
      else
        Newlines = 1;
    }
```

https://github.com/llvm/llvm-project/pull/106145