Improve plugin to handle hierarchical package names (containing dots) and spurious mentions by protoc.

When .proto files import other .proto files, protoc can invoke the plugin multiple times
for the same service, but usually only one of those invocations includes the body of
the service description. The plugin now avoids generating files for empty services.

Author: timburks

Plugin/Sources/protoc-gen-swiftgrpc/main.swift

@@ -37,16 +37,33 @@ import PluginLibrary
 import Stencil
 import PathKit
 
+extension String {
+  var undotted : String {
+    return self.replacingOccurrences(of:".", with:"_")
+  }
+
+  var uppercasedFirst : String {
+    var out = self.characters
+    if let first = out.popFirst() {
+      return String(first).uppercased() + String(out)
+    } else {
+      return self
+    }
+  }
+}
+
 func protoMessageName(_ name :String?) -> String {
   guard let name = name else {
     return ""
   }
-  let parts = name.components(separatedBy:".")
-  if parts.count == 3 {
-    return parts[1].capitalized + "_" + parts[2]
-  } else {
-    return name
+  let parts = name.undotted.components(separatedBy:"_")
+  var capitalizedParts : [String] = []
+  for part in parts {
+    if part != "" {
+      capitalizedParts.append(part.uppercasedFirst)
+    }
   }
+  return capitalizedParts.joined(separator:"_")
 }
 
 func pathName(_ arguments: [Any?]) throws -> String {
@@ -96,7 +113,7 @@ func packageServiceMethodName(_ arguments: [Any?]) throws -> String {
         "Google_Protobuf_MethodDescriptorProto" +
         " argument, received \(arguments[2])")
   }
-  return protoFile.package!.capitalized + "_" + service.name! + method.name!
+  return protoFile.package!.capitalized.undotted + "_" + service.name! + method.name!
 }
 
 func packageServiceName(_ arguments: [Any?]) throws -> String {
@@ -115,7 +132,7 @@ func packageServiceName(_ arguments: [Any?]) throws -> String {
         "Google_Protobuf_ServiceDescriptorProto" +
         " argument, received \(arguments[1])")
   }
-  return protoFile.package!.capitalized + "_" + service.name!
+  return protoFile.package!.capitalized.undotted + "_" + service.name!
 }
 
 // Code templates use "//-" prefixes to comment-out template operators
@@ -161,6 +178,9 @@ func main() throws {
   ext.registerFilter("clienterror") { (value: Any?, arguments: [Any?]) in
     return try packageServiceName(arguments) + "ClientError"
   }
+  ext.registerFilter("serviceclass") { (value: Any?, arguments: [Any?]) in
+    return try packageServiceName(arguments) + "Service"
+  }
   ext.registerFilter("servererror") { (value: Any?, arguments: [Any?]) in
     return try packageServiceName(arguments) + "ServerError"
   }
@@ -193,6 +213,8 @@ func main() throws {
   let rawRequest = try Stdin.readall()
   let request = try Google_Protobuf_Compiler_CodeGeneratorRequest(protobuf: rawRequest)
 
+  var generatedFileNames = Set<String>()
+  
   // process each .proto file separately
   for protoFile in request.protoFile {
 
@@ -216,26 +238,36 @@ func main() throws {
       log += " Options \(service.options)\n"
     }
 
+    if protoFile.service.count > 0 {
     // generate separate implementation files for client and server
     let context = ["protoFile": protoFile]
 
     do {
-      let clientcode = try templateEnvironment.renderTemplate(name:"client.pb.swift",
-                                                              context: context)
-      var clientfile = Google_Protobuf_Compiler_CodeGeneratorResponse.File()
-      clientfile.name = package + ".client.pb.swift"
-      clientfile.content = stripMarkers(clientcode)
-      response.file.append(clientfile)
-
-      let servercode = try templateEnvironment.renderTemplate(name:"server.pb.swift",
-                                                              context: context)
-      var serverfile = Google_Protobuf_Compiler_CodeGeneratorResponse.File()
-      serverfile.name = package + ".server.pb.swift"
-      serverfile.content = stripMarkers(servercode)
-      response.file.append(serverfile)
+      let clientFileName = package + ".client.pb.swift"
+      if !generatedFileNames.contains(clientFileName) {
+        generatedFileNames.insert(clientFileName)
+        let clientcode = try templateEnvironment.renderTemplate(name:"client.pb.swift",
+                                                                context: context)
+        var clientfile = Google_Protobuf_Compiler_CodeGeneratorResponse.File()
+        clientfile.name = clientFileName
+        clientfile.content = stripMarkers(clientcode)
+        response.file.append(clientfile)
+      }
+
+      let serverFileName = package + ".server.pb.swift"
+      if !generatedFileNames.contains(serverFileName) {
+        generatedFileNames.insert(serverFileName)
+        let servercode = try templateEnvironment.renderTemplate(name:"server.pb.swift",
+                                                                context: context)
+        var serverfile = Google_Protobuf_Compiler_CodeGeneratorResponse.File()
+        serverfile.name = serverFileName
+        serverfile.content = stripMarkers(servercode)
+        response.file.append(serverfile)
+      }
     } catch (let error) {
       log += "ERROR: \(error)\n"
     }
+    }
   }
 
   log += "\(request)"
@@ -251,4 +283,8 @@ func main() throws {
   Stdout.write(bytes: serializedResponse)
 }
 
-try main()
+do {
+	try main()	
+} catch (let error) {
+	Log("ERROR: \(error)")	
+}