clang-format: [Proto] Support extending message.

Before:
  extend.foo.Bar {
  }

After:
  extend .foo.Bar {
  }

llvm-svn: 253667

clang/lib/Format/FormatToken.h

@@ -553,6 +553,7 @@ struct AdditionalKeywords {
 
     kw_mark = &IdentTable.get("mark");
 
+    kw_extend = &IdentTable.get("extend");
     kw_option = &IdentTable.get("option");
     kw_optional = &IdentTable.get("optional");
     kw_repeated = &IdentTable.get("repeated");
@@ -597,6 +598,7 @@ struct AdditionalKeywords {
   IdentifierInfo *kw_mark;
 
   // Proto keywords.
+  IdentifierInfo *kw_extend;
   IdentifierInfo *kw_option;
   IdentifierInfo *kw_optional;
   IdentifierInfo *kw_repeated;

clang/lib/Format/TokenAnnotator.cpp

@@ -1949,7 +1949,7 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
   } else if (Style.Language == FormatStyle::LK_Proto) {
     if (Right.is(tok::period) &&
         Left.isOneOf(Keywords.kw_optional, Keywords.kw_required,
-                     Keywords.kw_repeated))
+                     Keywords.kw_repeated, Keywords.kw_extend))
       return true;
     if (Right.is(tok::l_paren) &&
         Left.isOneOf(Keywords.kw_returns, Keywords.kw_option))

clang/unittests/Format/FormatTestProto.cpp

@@ -162,5 +162,10 @@ TEST_F(FormatTestProto, FormatsService) {
                "};");
 }
 
+TEST_F(FormatTestProto, ExtendingMessage) {
+  verifyFormat("extend .foo.Bar {\n"
+               "}");
+}
+
 } // end namespace tooling
 } // end namespace clang