Made .proto parsing understand nested declarations.

Bug: 24401812
Change-Id: I196a03b8c5ef0bcd3c26178239c764e40ca1950d
Tested: on Linux.

docs/html/md__compiler.html

@@ -84,7 +84,7 @@ $(document).ready(function(){initNavTree('md__compiler.html','');});
 <li><code>--gen-mutable</code> : Generate additional non-const accessors for mutating FlatBuffers in-place.</li>
 <li><code>--gen-onefile</code> : Generate single output file (useful for C#)</li>
 <li><code>--raw-binary</code> : Allow binaries without a file_indentifier to be read. This may crash flatc given a mismatched schema.</li>
-<li><code>--proto</code>: Expect input files to be .proto files (protocol buffers). Output the corresponding .fbs file. Currently supports: <code>package</code>, <code>message</code>, <code>enum</code>. Does not support, but will skip without error: <code>import</code>, <code>option</code>. Does not support, will generate error: <code>service</code>, <code>extend</code>, <code>extensions</code>, <code>oneof</code>, <code>group</code>, custom options, nested declarations.</li>
+<li><code>--proto</code>: Expect input files to be .proto files (protocol buffers). Output the corresponding .fbs file. Currently supports: <code>package</code>, <code>message</code>, <code>enum</code>, nested declarations. Does not support, but will skip without error: <code>import</code>, <code>option</code>. Does not support, will generate error: <code>service</code>, <code>extend</code>, <code>extensions</code>, <code>oneof</code>, <code>group</code>, custom options.</li>
 <li><code>--schema</code>: Serialize schemas instead of JSON (use with -b). This will output a binary version of the specified schema that itself corresponds to the reflection/reflection.fbs schema. Loading this binary file is the basis for reflection functionality. </li>
 </ul>
 </div></div><!-- contents -->

docs/source/Compiler.md

@@ -71,10 +71,10 @@ be generated for each file processed:
 
 -   `--proto`: Expect input files to be .proto files (protocol buffers).
     Output the corresponding .fbs file.
-    Currently supports: `package`, `message`, `enum`.
+    Currently supports: `package`, `message`, `enum`, nested declarations.
     Does not support, but will skip without error: `import`, `option`.
     Does not support, will generate error: `service`, `extend`, `extensions`,
-    `oneof`, `group`, custom options, nested declarations.
+    `oneof`, `group`, custom options.
 
 -   `--schema`: Serialize schemas instead of JSON (use with -b). This will
     output a binary version of the specified schema that itself corresponds

src/idl_parser.cpp

@@ -1052,6 +1052,10 @@ void Parser::ParseProtoDecl() {
     struct_def.doc_comment = struct_comment;
     Expect('{');
     while (token_ != '}') {
+      if (attribute_ == "message" || attribute_ == "enum") {
+        // Nested declarations.
+        ParseProtoDecl();
+      } else {
         std::vector<std::string> field_comment = doc_comment_;
         // Parse the qualifier.
         bool required = false;
@@ -1092,6 +1096,7 @@ void Parser::ParseProtoDecl() {
         }
         Expect(';');
       }
+    }
     Next();
   } else if (attribute_ == "enum") {
     // These are almost the same, just with different terminator:

tests/prototest/test.golden

@@ -9,12 +9,6 @@ enum ProtoEnum : short {
   BAR = 5,
 }
 
-table OtherMessage {
-  a:double;
-  /// doc comment for b.
-  b:float = 3.14149;
-}
-
 /// 2nd table doc comment with
 /// many lines.
 table ProtoMessage {
@@ -39,3 +33,9 @@ table ProtoMessage {
   o:[string];
 }
 
+table OtherMessage {
+  a:double;
+  /// doc comment for b.
+  b:float = 3.14149;
+}
+

tests/prototest/test.proto

@@ -12,16 +12,16 @@ enum ProtoEnum {
   BAR = 5;
 }
 
+/// 2nd table doc comment with
+/// many lines.
+message ProtoMessage {
   // Ignored non-doc comment.
+  // A nested message declaration, will be moved to top level in .fbs
   message OtherMessage {
     optional double a = 26;
     /// doc comment for b.
     optional float b = 32 [default = 3.14149];
   }
-
-/// 2nd table doc comment with
-/// many lines.
-message ProtoMessage {
   optional int32 c = 12 [default = 16];
   optional int64 d = 1 [default = 0];
   optional uint32 p = 1;