Protobufs: Added '--oneof-union' option. (#4647)

* Added '--oneof-union' option.

Used with the .proto -> .fbs converter, will translate protobuff oneofs to flatbuffer unions.
Updated proto test to check both methods of converting oneofs.

* Added '--oneof-union' option.

Used with the .proto -> .fbs converter, will translate protobuff oneofs to flatbuffer unions.
Updated proto test to check both methods of converting oneofs.

* FlatBuffers: Moved MakeCamel() into idl_parser.cpp

Removes library dependency on Java/C# generator code.

tests/prototest/test.golden

@@ -36,6 +36,8 @@ table ProtoMessage {
   n:proto.test.ProtoMessage_.OtherMessage;
   o:[string];
   z:proto.test.ImportedMessage;
+  /// doc comment for r.
+  r:proto.test.ProtoMessage_.Anonymous0;
 }
 
 namespace proto.test.ProtoMessage_;
@@ -46,3 +48,11 @@ table OtherMessage {
   b:float = 3.14149;
 }
 
+table Anonymous0 {
+  /// doc comment for s.
+  s:proto.test.ImportedMessage;
+  /// doc comment for t on 2
+  /// lines.
+  t:proto.test.ProtoMessage_.OtherMessage;
+}
+

tests/prototest/test.proto

@@ -42,4 +42,12 @@ message ProtoMessage {
   optional OtherMessage n = 12;
   repeated string o = 14;
   optional ImportedMessage z = 16;
+  /// doc comment for r.
+  oneof r {
+    /// doc comment for s.
+    ImportedMessage s = 17;
+    /// doc comment for t on 2
+    /// lines.
+    OtherMessage t = 18;
+  }
 }

tests/prototest/test_union.golden

@@ -0,0 +1,62 @@
+// Generated from test.proto
+
+namespace proto.test;
+
+/// Enum doc comment.
+enum ProtoEnum : int {
+  FOO = 1,
+  /// Enum 2nd value doc comment misaligned.
+  BAR = 5,
+}
+
+namespace proto.test.ProtoMessage_;
+
+union RUnion {
+  /// doc comment for s.
+  proto.test.ImportedMessage,
+  /// doc comment for t on 2
+  /// lines.
+  proto.test.ProtoMessage_.OtherMessage,
+}
+
+namespace proto.test;
+
+table ImportedMessage {
+  a:int;
+}
+
+/// 2nd table doc comment with
+/// many lines.
+table ProtoMessage {
+  c:int = 16;
+  d:long;
+  p:uint;
+  e:ulong;
+  /// doc comment for f.
+  f:int = -1;
+  g:long;
+  h:uint;
+  q:ulong;
+  i:int;
+  j:long;
+  /// doc comment for k.
+  k:bool;
+  /// doc comment for l on 2
+  /// lines
+  l:string (required);
+  m:[ubyte];
+  n:proto.test.ProtoMessage_.OtherMessage;
+  o:[string];
+  z:proto.test.ImportedMessage;
+  /// doc comment for r.
+  r:proto.test.ProtoMessage_.RUnion;
+}
+
+namespace proto.test.ProtoMessage_;
+
+table OtherMessage {
+  a:double;
+  /// doc comment for b.
+  b:float = 3.14149;
+}
+

tests/test.cpp

@@ -863,6 +863,7 @@ void ParseProtoTest() {
   // load the .proto and the golden file from disk
   std::string protofile;
   std::string goldenfile;
+  std::string goldenunionfile;
   TEST_EQ(
       flatbuffers::LoadFile((test_data_path + "prototest/test.proto").c_str(),
                             false, &protofile),
@@ -871,6 +872,11 @@ void ParseProtoTest() {
       flatbuffers::LoadFile((test_data_path + "prototest/test.golden").c_str(),
                             false, &goldenfile),
       true);
+  TEST_EQ(
+      flatbuffers::LoadFile((test_data_path +
+                            "prototest/test_union.golden").c_str(),
+                            false, &goldenunionfile),
+      true);
 
   flatbuffers::IDLOptions opts;
   opts.include_dependence_headers = false;
@@ -889,6 +895,19 @@ void ParseProtoTest() {
   flatbuffers::Parser parser2;
   TEST_EQ(parser2.Parse(fbs.c_str(), nullptr), true);
   TEST_EQ_STR(fbs.c_str(), goldenfile.c_str());
+
+  // Parse proto with --oneof-union option.
+  opts.proto_oneof_union = true;
+  flatbuffers::Parser parser3(opts);
+  TEST_EQ(parser3.Parse(protofile.c_str(), include_directories), true);
+
+  // Generate fbs.
+  auto fbs_union = flatbuffers::GenerateFBS(parser3, "test");
+
+  // Ensure generated file is parsable.
+  flatbuffers::Parser parser4;
+  TEST_EQ(parser4.Parse(fbs_union.c_str(), nullptr), true);
+  TEST_EQ_STR(fbs_union.c_str(), goldenunionfile.c_str());
 }
 
 template<typename T>