Adds --ignore_service nano proto compiler flag

Nano proto compiler normally throws an error if any service is
defined. If --ignore-services=true is set, no error is thrown and the
service is simply skipped.

Change-Id: Id82583555085cc55550d03a485d3f0189885240b

java/README.txt

@@ -475,6 +475,7 @@ java_multiple_files    -> true or false
 java_nano_generate_has -> true or false [DEPRECATED]
 optional_field_style   -> default or accessors
 enum_style             -> c or java
+ignore_services        -> true or false
 
 java_package:
 java_outer_classname:
@@ -580,6 +581,13 @@ enum_style={c,java} (default: c)
   compiler inlines all referenced enum constants into the call sites,
   the interface remains unused and can be removed by ProGuard.
 
+ignore_services={true,false} (default: false)
+  Skips services definitions.
+
+  Nano doesn't support services. By default, if a service is defined
+  it will generate a compilation error. If this flag is set to true,
+  services will be silently ignored, instead.
+
 
 To use nano protobufs within the Android repo:
 

src/google/protobuf/compiler/javanano/javanano_file.cc

@@ -105,7 +105,7 @@ bool FileGenerator::Validate(string* error) {
     return false;
   }
 
-  if (file_->service_count() != 0) {
+  if (file_->service_count() != 0 && !params_.ignore_services()) {
     error->assign(file_->name());
     error->append(
       ": Java NANO_RUNTIME does not support services\"");

src/google/protobuf/compiler/javanano/javanano_generator.cc

@@ -142,6 +142,8 @@ bool JavaNanoGenerator::Generate(const FileDescriptor* file,
       params.set_use_reference_types_for_primitives(option_value == "reftypes");
     } else if (option_name == "generate_equals") {
       params.set_generate_equals(option_value == "true");
+    } else if (option_name == "ignore_services") {
+      params.set_ignore_services(option_value == "true");
     } else {
       *error = "Ignore unknown javanano generator option: " + option_name;
     }

src/google/protobuf/compiler/javanano/javanano_params.h

@@ -62,6 +62,7 @@ class Params {
   bool optional_field_accessors_;
   bool use_reference_types_for_primitives_;
   bool generate_equals_;
+  bool ignore_services_;
 
  public:
   Params(const string & base_name) :
@@ -73,7 +74,8 @@ class Params {
     java_enum_style_(false),
     optional_field_accessors_(false),
     use_reference_types_for_primitives_(false),
-    generate_equals_(false) {
+    generate_equals_(false),
+    ignore_services_(false) {
   }
 
   const string& base_name() const {
@@ -195,6 +197,13 @@ class Params {
   bool generate_equals() const {
     return generate_equals_;
   }
+
+  void set_ignore_services(bool value) {
+    ignore_services_ = value;
+  }
+  bool ignore_services() const {
+    return ignore_services_;
+  }
 };
 
 }  // namespace javanano