Custom Transformers & Fix OneOf fields (#19)

- add custom (not generated) transformers for sub-messages
- add transformer.custom attribute to mark fields which require custom transformers
- limit oneOfDecl to the specific case it serves
- extend makefile with more commands

Makefile

@@ -1,4 +1,4 @@
-VERSION=1.0.6-dev
+VERSION=1.0.7-dev
 BUILDTIME=$(shell date +"%Y-%m-%dT%T%z")
 LDFLAGS= -ldflags '-X github.com/bold-commerce/protoc-gen-struct-transformer/generator.version=$(VERSION) -X github.com/bold-commerce/protoc-gen-struct-transformer/generator.buildTime=$(BUILDTIME)'
 
@@ -13,6 +13,21 @@ re-generate-example:
 
 generate: version re-generate-example
 
+re-generate-example-debug:
+	protoc \
+		--proto_path=$(GOPATH)/pkg/mod/github.com/gogo:. \
+		--struct-transformer_out=package=transform,debug=true,helper-package=helpers,goimports=true:. \
+		--gogofaster_out=Moptions/annotations.proto=github.com/bold-commerce/protoc-gen-struct-transformer/options:. \
+		./example/message.proto
+
+generate-debug: version re-generate-example-debug
+
+generate-annotations:
+	protoc \
+		--proto_path=$(GOPATH)/pkg/mod/github.com/gogo:. \
+		--gogofaster_out=Moptions/annotations.proto=github.com/bold-commerce/protoc-gen-struct-transformer/options:. \
+		./options/annotations.proto
+
 install: setup
 	go install $(LDFLAGS)
 
@@ -25,4 +40,4 @@ version:
 
 setup:
 	go mod download
-	go mod verify
+	go mod verify

README.md

@@ -215,6 +215,10 @@ message Product {
   // field in model with arbitrary name.
   // Both options "map_as" and "map_to" can be used independently.
   string map_field_1 = 6 [ (transformer.map_as) = "MapField_1", (transformer.map_to) = "MapField1"];
+  // "custom" allows to use custom transformers for fields, which require extended transformation
+  // The plugin won't generate methods for this field,
+  // but rather expect it to be in the same package with the transformer file
+  CustomType custom_field [(transformer.custom) = true]
 }
 ```
 ### Run protoc