Updates Objective-C Generation to allow for ommission of the generated @interface and @implementation

3 files changed, 165 insertions, 120 deletions

diff --git a/src/compiler/objective_c_generator.cc b/src/compiler/objective_c_generator.cc
index ab7d869758..7c1c8d4f26 100644
--- a/src/compiler/objective_c_generator.cc
+++ b/src/compiler/objective_c_generator.cc
@@ -212,37 +212,48 @@ void PrintMethodImplementations(Printer* printer,
   return output;
 }
 
-::grpc::string GetHeader(const ServiceDescriptor* service) {
+::grpc::string GetProtocol(const ServiceDescriptor* service) {
   ::grpc::string output;
-  {
-    // Scope the output stream so it closes and finalizes output to the string.
-    grpc::protobuf::io::StringOutputStream output_stream(&output);
-    Printer printer(&output_stream, '$');
 
-    map< ::grpc::string, ::grpc::string> vars = {
-        {"service_class", ServiceClassName(service)}};
+  // Scope the output stream so it closes and finalizes output to the string.
+  grpc::protobuf::io::StringOutputStream output_stream(&output);
+  Printer printer(&output_stream, '$');
 
-    printer.Print(vars, "@protocol $service_class$ <NSObject>\n\n");
+  map< ::grpc::string, ::grpc::string> vars = {
+      {"service_class", ServiceClassName(service)}};
 
-    for (int i = 0; i < service->method_count(); i++) {
-      PrintMethodDeclarations(&printer, service->method(i));
-    }
-    printer.Print("@end\n\n");
-
-    printer.Print(
-        "/**\n"
-        " * Basic service implementation, over gRPC, that only does\n"
-        " * marshalling and parsing.\n"
-        " */\n");
-    printer.Print(vars,
-                  "@interface $service_class$ :"
-                  " GRPCProtoService<$service_class$>\n");
-    printer.Print(
-        "- (instancetype)initWithHost:(NSString *)host"
-        " NS_DESIGNATED_INITIALIZER;\n");
-    printer.Print("+ (instancetype)serviceWithHost:(NSString *)host;\n");
-    printer.Print("@end\n");
+  printer.Print(vars, "@protocol $service_class$ <NSObject>\n\n");
+  for (int i = 0; i < service->method_count(); i++) {
+    PrintMethodDeclarations(&printer, service->method(i));
   }
+  printer.Print("@end\n\n");
+
+  return output;
+}
+
+::grpc::string GetInterface(const ServiceDescriptor* service) {
+  ::grpc::string output;
+
+  // Scope the output stream so it closes and finalizes output to the string.
+  grpc::protobuf::io::StringOutputStream output_stream(&output);
+  Printer printer(&output_stream, '$');
+
+  map< ::grpc::string, ::grpc::string> vars = {
+      {"service_class", ServiceClassName(service)}};
+
+  printer.Print(vars,
+                "/**\n"
+                " * Basic service implementation, over gRPC, that only does\n"
+                " * marshalling and parsing.\n"
+                " */\n");
+  printer.Print(vars,
+                "@interface $service_class$ :"
+                " GRPCProtoService<$service_class$>\n");
+  printer.Print("- (instancetype)initWithHost:(NSString *)host"
+                " NS_DESIGNATED_INITIALIZER;\n");
+  printer.Print("+ (instancetype)serviceWithHost:(NSString *)host;\n");
+  printer.Print("@end\n");
+
   return output;
 }
 
@@ -258,26 +269,30 @@ void PrintMethodImplementations(Printer* printer,
         {"service_class", ServiceClassName(service)},
         {"package", service->file()->package()}};
 
-    printer.Print(vars, "@implementation $service_class$\n\n");
-
-    printer.Print("// Designated initializer\n");
-    printer.Print("- (instancetype)initWithHost:(NSString *)host {\n");
-    printer.Print(
-        vars,
-        "  return (self = [super initWithHost:host"
-        " packageName:@\"$package$\" serviceName:@\"$service_name$\"]);\n");
-    printer.Print("}\n\n");
-    printer.Print(
-        "// Override superclass initializer to disallow different"
-        " package and service names.\n");
-    printer.Print("- (instancetype)initWithHost:(NSString *)host\n");
-    printer.Print("                 packageName:(NSString *)packageName\n");
-    printer.Print("                 serviceName:(NSString *)serviceName {\n");
-    printer.Print("  return [self initWithHost:host];\n");
-    printer.Print("}\n\n");
-    printer.Print("+ (instancetype)serviceWithHost:(NSString *)host {\n");
-    printer.Print("  return [[self alloc] initWithHost:host];\n");
-    printer.Print("}\n\n\n");
+    printer.Print(vars,
+                  "@implementation $service_class$\n\n"
+                  "// Designated initializer\n"
+                  "- (instancetype)initWithHost:(NSString *)host {\n"
+                  "  self = [super initWithHost:host\n"
+                  "                 packageName:@\"$package$\"\n"
+                  "                 serviceName:@\"$service_name$\"];\n"
+                  "  return self;\n"
+                  "}\n\n");
+
+    printer.Print("// Override superclass initializer to disallow different"
+                  " package and service names.\n"
+                  "- (instancetype)initWithHost:(NSString *)host\n"
+                  "                 packageName:(NSString *)packageName\n"
+                  "                 serviceName:(NSString *)serviceName {\n"
+                  "  return [self initWithHost:host];\n"
+                  "}\n\n");
+
+    printer.Print("#pragma mark - Class Methods\n\n"
+                  "+ (instancetype)serviceWithHost:(NSString *)host {\n"
+                  "  return [[self alloc] initWithHost:host];\n"
+                  "}\n\n");
+
+    printer.Print("#pragma mark - Method Implementations\n\n");
 
     for (int i = 0; i < service->method_count(); i++) {
       PrintMethodImplementations(&printer, service->method(i));
diff --git a/src/compiler/objective_c_generator.h b/src/compiler/objective_c_generator.h
index d3aed76c4f..eb1c7ff005 100644
--- a/src/compiler/objective_c_generator.h
+++ b/src/compiler/objective_c_generator.h
@@ -31,9 +31,13 @@ using ::grpc::string;
 // Returns forward declaration of classes in the generated header file.
 string GetAllMessageClasses(const FileDescriptor* file);
 
-// Returns the content to be included in the "global_scope" insertion point of
-// the generated header file.
-string GetHeader(const ServiceDescriptor* service);
+// Returns the content to be included defining the @protocol segment at the
+// insertion point of the generated implementation file.
+string GetProtocol(const ServiceDescriptor* service);
+
+// Returns the content to be included defining the @interface segment at the
+// insertion point of the generated implementation file.
+string GetInterface(const ServiceDescriptor* service);
 
 // Returns the content to be included in the "global_scope" insertion point of
 // the generated implementation file.
diff --git a/src/compiler/objective_c_plugin.cc b/src/compiler/objective_c_plugin.cc
index d5d488e84d..398bbc25a7 100644
--- a/src/compiler/objective_c_plugin.cc
+++ b/src/compiler/objective_c_plugin.cc
@@ -30,11 +30,58 @@ using ::google::protobuf::compiler::objectivec::
     IsProtobufLibraryBundledProtoFile;
 using ::google::protobuf::compiler::objectivec::ProtobufLibraryFrameworkName;
 
+namespace {
+
+inline ::grpc::string LocalImport(const ::grpc::string &import) {
+  return ::grpc::string("#import \"" + import + "\"\n");
+}
+
+inline ::grpc::string SystemImport(const ::grpc::string &import) {
+  return ::grpc::string("#import <" + import + ">\n");
+}
+
+inline ::grpc::string PreprocIf(const ::grpc::string& condition,
+                                const ::grpc::string& if_true) {
+  return ::grpc::string("#if " + condition + "\n" + if_true + "#endif\n");
+}
+
+inline ::grpc::string PreprocIfElse(const ::grpc::string& condition,
+                                    const ::grpc::string& if_true,
+                                    const ::grpc::string& if_false) {
+  return ::grpc::string("#if " + condition + "\n" +
+                        if_true + "#else\n" + if_false + "#endif\n");
+}
+
+inline ::grpc::string ImportProtoHeaders(
+    const grpc::protobuf::FileDescriptor* dep,
+    const char *indent) {
+  ::grpc::string header = grpc_objective_c_generator::MessageHeaderName(dep);
+
+  if (!IsProtobufLibraryBundledProtoFile(dep)) {
+    return indent + LocalImport(header);
+  }
+
+  ::grpc::string base_name = header;
+  grpc_generator::StripPrefix(&base_name, "google/protobuf/");
+  // create the import code snippet
+  ::grpc::string framework_header =
+      ::grpc::string(ProtobufLibraryFrameworkName) + "/" + base_name;
+
+  static const ::grpc::string kFrameworkImportsCondition =
+      "GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS";
+  return PreprocIfElse(kFrameworkImportsCondition,
+                       indent + SystemImport(framework_header),
+                       indent + LocalImport(header));
+}
+
+}  // namespace
+
 class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
  public:
   ObjectiveCGrpcGenerator() {}
   virtual ~ObjectiveCGrpcGenerator() {}
 
+ public:
   virtual bool Generate(const grpc::protobuf::FileDescriptor* file,
                         const ::grpc::string& parameter,
                         grpc::protobuf::compiler::GeneratorContext* context,
@@ -46,95 +93,70 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
 
     ::grpc::string file_name =
         google::protobuf::compiler::objectivec::FilePath(file);
-    ::grpc::string prefix = file->options().objc_class_prefix();
 
+    static const ::grpc::string kNonNullBegin = "NS_ASSUME_NONNULL_BEGIN\n";
+    static const ::grpc::string kNonNullEnd = "NS_ASSUME_NONNULL_END\n";
+    static const ::grpc::string kForwardDeclareCondition =
+        "GPB_GRPC_FORWARD_DECLARE_MESSAGE_PROTO";
+    static const ::grpc::string kOmitInterfaceCondition =
+        "GPB_GRPC_OMIT_INTERFACE";
     {
       // Generate .pbrpc.h
 
-      ::grpc::string imports =
-          ::grpc::string("#if !GPB_GRPC_FORWARD_DECLARE_MESSAGE_PROTO\n") +
-          "#import \"" + file_name +
-          ".pbobjc.h\"\n"
-          "#endif\n\n"
-          "#import <ProtoRPC/ProtoService.h>\n"
-          "#import <ProtoRPC/ProtoRPC.h>\n"
-          "#import <RxLibrary/GRXWriteable.h>\n"
-          "#import <RxLibrary/GRXWriter.h>\n";
-
-      ::grpc::string proto_imports;
-      proto_imports += "#if GPB_GRPC_FORWARD_DECLARE_MESSAGE_PROTO\n" +
-                       grpc_objective_c_generator::GetAllMessageClasses(file) +
-                       "#else\n";
+      ::grpc::string imports = LocalImport(file_name + ".pbobjc.h");
+
+      ::grpc::string system_imports =
+                    SystemImport("ProtoRPC/ProtoService.h") +
+                    SystemImport("ProtoRPC/ProtoRPC.h") +
+                    SystemImport("RxLibrary/GRXWriteable.h") +
+                    SystemImport("RxLibrary/GRXWriter.h");
+
+      ::grpc::string forward_declarations = "@class GRPCProtoCall;\n\n";
+
+      ::grpc::string class_declarations =
+          grpc_objective_c_generator::GetAllMessageClasses(file);
+
+      ::grpc::string class_imports;
       for (int i = 0; i < file->dependency_count(); i++) {
-        ::grpc::string header =
-            grpc_objective_c_generator::MessageHeaderName(file->dependency(i));
-        const grpc::protobuf::FileDescriptor* dependency = file->dependency(i);
-        if (IsProtobufLibraryBundledProtoFile(dependency)) {
-          ::grpc::string base_name = header;
-          grpc_generator::StripPrefix(&base_name, "google/protobuf/");
-          // create the import code snippet
-          proto_imports +=
-              "  #if GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS\n"
-              "    #import <" +
-              ::grpc::string(ProtobufLibraryFrameworkName) + "/" + base_name +
-              ">\n"
-              "  #else\n"
-              "    #import \"" +
-              header +
-              "\"\n"
-              "  #endif\n";
-        } else {
-          proto_imports += ::grpc::string("  #import \"") + header + "\"\n";
-        }
+        class_imports += ImportProtoHeaders(file->dependency(i), "  ");
       }
-      proto_imports += "#endif\n";
 
-      ::grpc::string declarations;
+      ::grpc::string protocols;
       for (int i = 0; i < file->service_count(); i++) {
         const grpc::protobuf::ServiceDescriptor* service = file->service(i);
-        declarations += grpc_objective_c_generator::GetHeader(service);
+        protocols += grpc_objective_c_generator::GetProtocol(service);
       }
 
-      static const ::grpc::string kNonNullBegin =
-          "\nNS_ASSUME_NONNULL_BEGIN\n\n";
-      static const ::grpc::string kNonNullEnd = "\nNS_ASSUME_NONNULL_END\n";
+      ::grpc::string interfaces;
+      for (int i = 0; i < file->service_count(); i++) {
+        const grpc::protobuf::ServiceDescriptor* service = file->service(i);
+        interfaces += grpc_objective_c_generator::GetInterface(service);
+      }
 
       Write(context, file_name + ".pbrpc.h",
-            imports + '\n' + proto_imports + '\n' + kNonNullBegin +
-                declarations + kNonNullEnd);
+            PreprocIf("!" + kForwardDeclareCondition, imports) + "\n" +
+            PreprocIf("!" + kOmitInterfaceCondition, system_imports) + "\n" +
+            PreprocIfElse(kForwardDeclareCondition,
+                          class_declarations, class_imports) + "\n" +
+            forward_declarations + "\n" +
+            kNonNullBegin + "\n" +
+            protocols + "\n" +
+            PreprocIf("!" + kOmitInterfaceCondition, interfaces) + "\n" +
+            kNonNullEnd + "\n");
     }
 
     {
       // Generate .pbrpc.m
 
-      ::grpc::string imports = ::grpc::string("#import \"") + file_name +
-                               ".pbrpc.h\"\n"
-                               "#import \"" +
-                               file_name +
-                               ".pbobjc.h\"\n\n"
-                               "#import <ProtoRPC/ProtoRPC.h>\n"
-                               "#import <RxLibrary/GRXWriter+Immediate.h>\n";
+      ::grpc::string imports =
+          LocalImport(file_name + ".pbrpc.h") +
+          LocalImport(file_name + ".pbobjc.h") +
+          SystemImport("ProtoRPC/ProtoRPC.h") +
+          SystemImport("RxLibrary/GRXWriter+Immediate.h");
+
+      ::grpc::string class_imports;
       for (int i = 0; i < file->dependency_count(); i++) {
-        ::grpc::string header =
-            grpc_objective_c_generator::MessageHeaderName(file->dependency(i));
-        const grpc::protobuf::FileDescriptor* dependency = file->dependency(i);
-        if (IsProtobufLibraryBundledProtoFile(dependency)) {
-          ::grpc::string base_name = header;
-          grpc_generator::StripPrefix(&base_name, "google/protobuf/");
-          // create the import code snippet
-          imports +=
-              "#if GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS\n"
-              "  #import <" +
-              ::grpc::string(ProtobufLibraryFrameworkName) + "/" + base_name +
-              ">\n"
-              "#else\n"
-              "  #import \"" +
-              header +
-              "\"\n"
-              "#endif\n";
-        } else {
-          imports += ::grpc::string("#import \"") + header + "\"\n";
-        }
+        class_imports += ImportProtoHeaders(file->dependency(i), "");
       }
 
       ::grpc::string definitions;
@@ -143,7 +165,11 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
         definitions += grpc_objective_c_generator::GetSource(service);
       }
 
-      Write(context, file_name + ".pbrpc.m", imports + '\n' + definitions);
+      Write(context, file_name + ".pbrpc.m",
+            PreprocIf("!" + kOmitInterfaceCondition,
+                      imports + "\n" +
+                      class_imports + "\n" +
+                      definitions));
     }
 
     return true;