feat: support protoc options

vertx-grpc-docs/src/main/asciidoc/plugin.adoc

@@ -161,6 +161,51 @@ protobuf {
 }
 ----
 
+Gradle protobuf plugin cannot set args, You can use standard `option` to control the generation of code, eg:
+
+[source,groovy]
+----
+...
+apply plugin: 'com.google.protobuf'
+...
+buildscript {
+  ...
+  dependencies {
+    // ASSUMES GRADLE 2.12 OR HIGHER. Use plugin version 0.7.5 with earlier gradle versions
+    classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.0'
+  }
+}
+...
+protobuf {
+  protoc {
+    artifact = 'com.google.protobuf:protoc:3.2.0'
+  }
+  plugins {
+    grpc {
+      artifact = "io.grpc:protoc-gen-grpc-java:1.25.0"
+    }
+    vertx {
+      artifact = "io.vertx:vertx-grpc-protoc-plugin2:${vertx.grpc.version}"
+    }
+  }
+  generateProtoTasks {
+    all()*.plugins {
+      grpc
+      vertx {
+        option("grpc-io")
+      }
+    }
+  }
+}
+----
+
+The plugin accepts the following option:
+
+- _grpc-client_: `bool` generate the client files, default `true`.set `option("grpc-client=false")` client side code will not be generated.
+- _grpc-service_: `bool` generate the service files, default `true`. set `option("grpc-service=false")` service side will not be generated.
+- _grpc-io_: `bool` whether to generate stub files compatible with `io.grpc:grpc-stub`, not generated by default. set `option("grpc-io")` or `option("grpc-io=true")` to generate it.
+- _grpc-transcoding_: `bool` whether to generate transcoding options for methods with HTTP annotations.
+
 This plugin will compile your proto files under `build/generated/source/proto/main` and make them available to your project.
 
 NOTE: the generator plugin is tech preview and can be subject to changes

vertx-grpc-protoc-plugin2/src/main/java/io/vertx/grpc/plugin/VertxGrpcGeneratorImpl.java

@@ -12,6 +12,7 @@
 
 import com.google.api.AnnotationsProto;
 import com.google.api.HttpRule;
+import com.google.common.base.Splitter;
 import com.google.common.base.Strings;
 import com.google.common.html.HtmlEscapers;
 import com.google.protobuf.DescriptorProtos;
@@ -20,11 +21,7 @@
 import com.salesforce.jprotoc.GeneratorException;
 import com.salesforce.jprotoc.ProtoTypeMap;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 import java.util.stream.Collectors;
 
 public class VertxGrpcGeneratorImpl extends Generator {
@@ -58,6 +55,8 @@ protected List<PluginProtos.CodeGeneratorResponse.Feature> supportedFeatures() {
 
   @Override
   public List<PluginProtos.CodeGeneratorResponse.File> generateFiles(PluginProtos.CodeGeneratorRequest request) throws GeneratorException {
+    this.parseParameter(request);
+
     ProtoTypeMap typeMap = ProtoTypeMap.of(request.getProtoFileList());
 
     List<DescriptorProtos.FileDescriptorProto> protosToGenerate = request.getProtoFileList().stream()
@@ -68,6 +67,54 @@ public List<PluginProtos.CodeGeneratorResponse.File> generateFiles(PluginProtos.
     return generateFiles(services);
   }
 
+  private void parseParameter(PluginProtos.CodeGeneratorRequest request) {
+    Splitter.on(',')
+      .trimResults()
+      .omitEmptyStrings()
+      .split(request.getParameter())
+      .forEach(parameter -> {
+        Iterator<String> it = Splitter.on('=').trimResults().omitEmptyStrings().limit(2).split(parameter).iterator();
+        switch (it.next()) {
+          case "grpc-client":
+            if (it.hasNext()) {
+              options.generateClient = Boolean.parseBoolean(it.next());
+            } else {
+              options.generateClient = true;
+            }
+            break;
+          case "grpc-service":
+            if (it.hasNext()) {
+              options.generateService = Boolean.parseBoolean(it.next());
+            } else {
+              options.generateService = true;
+            }
+            break;
+          case "grpc-io":
+            if (it.hasNext()) {
+              options.generateIo = Boolean.parseBoolean(it.next());
+            } else {
+              options.generateIo = true;
+            }
+            break;
+          case "grpc-transcoding":
+            if (it.hasNext()) {
+              options.generateTranscoding = Boolean.parseBoolean(it.next());
+            } else {
+              options.generateTranscoding = true;
+            }
+            break;
+          case "service-prefix":
+            if (it.hasNext()) {
+              options.servicePrefix = it.next();
+            }
+        }
+      });
+    if (options.generateIo) {
+      options.generateClient = true;
+      options.generateService = true;
+    }
+  }
+
   private List<ServiceContext> findServices(List<DescriptorProtos.FileDescriptorProto> protos, ProtoTypeMap typeMap) {
     List<ServiceContext> contexts = new ArrayList<>();
 
@@ -104,7 +151,7 @@ private String extractPackageFqn(DescriptorProtos.FileDescriptorProto proto) {
   }
 
   private ServiceContext buildServiceContext(DescriptorProtos.ServiceDescriptorProto serviceProto, ProtoTypeMap typeMap, List<DescriptorProtos.SourceCodeInfo.Location> locations,
-    int serviceNumber) {
+                                             int serviceNumber) {
     ServiceContext serviceContext = new ServiceContext(serviceProto, options.servicePrefix);
     // Set Later
     //serviceContext.fileName = CLASS_PREFIX + serviceProto.getName() + "Grpc.java";
@@ -138,7 +185,7 @@ private ServiceContext buildServiceContext(DescriptorProtos.ServiceDescriptorPro
   }
 
   private MethodContext buildMethodContext(DescriptorProtos.MethodDescriptorProto methodProto, ProtoTypeMap typeMap, List<DescriptorProtos.SourceCodeInfo.Location> locations,
-    int methodNumber) {
+                                           int methodNumber) {
     MethodContext methodContext = new MethodContext();
     methodContext.transcodingContext = new TranscodingContext();