Merge pull request #22871 from jagobagascon/feature/add-autogenerated-header-to-objc-files

objc: add autogenerated header to generated files

src/compiler/objective_c_plugin.cc

@@ -127,6 +127,12 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
       }
     }
 
+    // Write out a file header.
+    ::grpc::string file_header =
+        "// Code generated by gRPC proto compiler.  DO NOT EDIT!\n"
+        "// source: " +
+        file->name() + "\n\n";
+
     {
       // Generate .pbrpc.h
 
@@ -187,7 +193,7 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
       }
 
       Write(context, file_name + ".pbrpc.h",
-            PreprocIfNot(kForwardDeclare, imports) + "\n" +
+            file_header + PreprocIfNot(kForwardDeclare, imports) + "\n" +
                 PreprocIfNot(kProtocolOnly, system_imports) + "\n" +
                 class_declarations + "\n" +
                 PreprocIfNot(kForwardDeclare, class_imports) + "\n" +
@@ -228,8 +234,9 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
       }
 
       Write(context, file_name + ".pbrpc.m",
-            PreprocIfNot(kProtocolOnly,
-                         imports + "\n" + class_imports + "\n" + definitions));
+            file_header +
+                PreprocIfNot(kProtocolOnly, imports + "\n" + class_imports +
+                                                "\n" + definitions));
     }
 
     return true;