Added option to flatc to generate dependent header statements.

Bug: 17322776
Change-Id: I3a4d3cb4ccd40bc3200a87653aa0ab8ecb90ce60
Tested: on Linux.

src/flatc.cpp

@@ -101,6 +101,8 @@ static void Error(const char *err, const char *obj, bool usage) {
            "  -I PATH Search for includes in the specified path.\n"
            "  -S      Strict JSON: add quotes to field names.\n"
            "  -P      Don\'t prefix enum values with the enum name in C++.\n"
+           "  -H      Generate include statements for included schemas the\n"
+           "          generated file depends on (C++).\n"
            "FILEs may depend on declarations in earlier files.\n"
            "FILEs after the -- must be binary flatbuffer format files.\n"
            "Output files are named using the base file name of the input,"
@@ -144,6 +146,9 @@ int main(int argc, const char *argv[]) {
         case 'P':
           opts.prefixed_enums = false;
           break;
+        case 'H':
+          opts.include_dependence_headers = true;
+          break;
         case '-':  // Separator between text and binary input files.
           binary_files_from = filenames.size();
           break;
@@ -189,7 +194,8 @@ int main(int argc, const char *argv[]) {
         auto local_include_directory = flatbuffers::StripFileName(*file_it);
         include_directories.push_back(local_include_directory.c_str());
         include_directories.push_back(nullptr);
-        if (!parser.Parse(contents.c_str(), &include_directories[0]))
+        if (!parser.Parse(contents.c_str(), &include_directories[0],
+                          file_it->c_str()))
           Error((*file_it + ": " + parser.error_).c_str());
         include_directories.pop_back();
         include_directories.pop_back();

src/idl_gen_cpp.cpp

@@ -547,6 +547,20 @@ std::string GenerateCPP(const Parser &parser,
 
     code += "#include \"flatbuffers/flatbuffers.h\"\n\n";
 
+    if (opts.include_dependence_headers) {
+      int num_includes = 0;
+      for (auto it = parser.included_files_.begin();
+           it != parser.included_files_.end(); ++it) {
+        auto basename = flatbuffers::StripPath(
+                          flatbuffers::StripExtension(it->first));
+        if (basename != file_name) {
+          code += "#include \"" + basename + "_generated.h\"\n";
+          num_includes++;
+        }
+      }
+      if (num_includes) code += "\n";
+    }
+
     code += forward_decl_code_other_namespace;
     code += "\n";
 

src/idl_parser.cpp

@@ -866,7 +866,9 @@ void Parser::MarkGenerated() {
   }
 }
 
-bool Parser::Parse(const char *source, const char **include_paths) {
+bool Parser::Parse(const char *source, const char **include_paths,
+                   const char *source_filename) {
+  if (source_filename) included_files_[source_filename] = true;
   source_ = cursor_ = source;
   line_ = 1;
   error_.clear();