ServerBuilder interface cleanup

Nothing is added or removed in this PR.

Instead, methods are re-ordered so that important methods are read
first, and less important customization methods are seen later.

The intent here is to simplify the "I just want to bring a server up"
code path.

include/grpc++/server_builder.h

@@ -55,13 +55,18 @@ class ServerBuilder {
   ServerBuilder();
   ~ServerBuilder();
 
-  /// Options for synchronous servers.
-  enum SyncServerOption {
-    NUM_CQS,         ///< Number of completion queues.
-    MIN_POLLERS,     ///< Minimum number of polling threads.
-    MAX_POLLERS,     ///< Maximum number of polling threads.
-    CQ_TIMEOUT_MSEC  ///< Completion queue timeout in milliseconds.
-  };
+  //////////////////////////////////////////////////////////////////////////////
+  // Primary API's
+
+  /// Return a running server which is ready for processing calls.
+  /// Before calling, one typically needs to ensure that:
+  ///  1. a service is registered - so that the server knows what to serve
+  ///     (via RegisterService, or RegisterAsyncGenericService)
+  ///  2. a listening port has been added - so the server knows where to receive
+  ///     traffic (via AddListeningPort)
+  ///  3. [for async api only] completion queues have been added via
+  ///     AddCompletionQueue
+  std::unique_ptr<Server> BuildAndStart();
 
   /// Register a service. This call does not take ownership of the service.
   /// The service must exist for the lifetime of the \a Server instance returned
@@ -69,9 +74,60 @@ class ServerBuilder {
   /// Matches requests with any :authority
   ServerBuilder& RegisterService(Service* service);
 
-  /// Register a generic service.
-  /// Matches requests with any :authority
-  ServerBuilder& RegisterAsyncGenericService(AsyncGenericService* service);
+  /// Enlists an endpoint \a addr (port with an optional IP address) to
+  /// bind the \a grpc::Server object to be created to.
+  ///
+  /// It can be invoked multiple times.
+  ///
+  /// \param addr_uri The address to try to bind to the server in URI form. If
+  /// the scheme name is omitted, "dns:///" is assumed. To bind to any address,
+  /// please use IPv6 any, i.e., [::]:<port>, which also accepts IPv4
+  /// connections.  Valid values include dns:///localhost:1234, /
+  /// 192.168.1.1:31416, dns:///[::1]:27182, etc.).
+  /// \param creds The credentials associated with the server.
+  /// \param selected_port[out] If not `nullptr`, gets populated with the port
+  /// number bound to the \a grpc::Server for the corresponding endpoint after
+  /// it is successfully bound, 0 otherwise.
+  ///
+  ServerBuilder& AddListeningPort(const grpc::string& addr_uri,
+                                  std::shared_ptr<ServerCredentials> creds,
+                                  int* selected_port = nullptr);
+
+  /// Add a completion queue for handling asynchronous services.
+  ///
+  /// Best performance is typically obtained by using one thread per polling
+  /// completion queue.
+  ///
+  /// Caller is required to shutdown the server prior to shutting down the
+  /// returned completion queue. Caller is also required to drain the
+  /// completion queue after shutting it down. A typical usage scenario:
+  ///
+  /// // While building the server:
+  /// ServerBuilder builder;
+  /// ...
+  /// cq_ = builder.AddCompletionQueue();
+  /// server_ = builder.BuildAndStart();
+  ///
+  /// // While shutting down the server;
+  /// server_->Shutdown();
+  /// cq_->Shutdown();  // Always *after* the associated server's Shutdown()!
+  /// // Drain the cq_ that was created
+  /// void* ignored_tag;
+  /// bool ignored_ok;
+  /// while (cq_->Next(&ignored_tag, &ignored_ok)) { }
+  ///
+  /// \param is_frequently_polled This is an optional parameter to inform gRPC
+  /// library about whether this completion queue would be frequently polled
+  /// (i.e. by calling \a Next() or \a AsyncNext()). The default value is
+  /// 'true' and is the recommended setting. Setting this to 'false' (i.e.
+  /// not polling the completion queue frequently) will have a significantly
+  /// negative performance impact and hence should not be used in production
+  /// use cases.
+  std::unique_ptr<ServerCompletionQueue> AddCompletionQueue(
+      bool is_frequently_polled = true);
+
+  //////////////////////////////////////////////////////////////////////////////
+  // RegisterService variants
 
   /// Register a service. This call does not take ownership of the service.
   /// The service must exist for the lifetime of the \a Server instance returned
@@ -79,6 +135,13 @@ class ServerBuilder {
   /// Only matches requests with :authority \a host
   ServerBuilder& RegisterService(const grpc::string& host, Service* service);
 
+  /// Register a generic service.
+  /// Matches requests with any :authority
+  ServerBuilder& RegisterAsyncGenericService(AsyncGenericService* service);
+
+  //////////////////////////////////////////////////////////////////////////////
+  // Fine control knobs
+
   /// Set max receive message size in bytes.
   ServerBuilder& SetMaxReceiveMessageSize(int max_receive_message_size) {
     max_receive_message_size_ = max_receive_message_size;
@@ -119,6 +182,14 @@ class ServerBuilder {
 
   ServerBuilder& SetOption(std::unique_ptr<ServerBuilderOption> option);
 
+  /// Options for synchronous servers.
+  enum SyncServerOption {
+    NUM_CQS,         ///< Number of completion queues.
+    MIN_POLLERS,     ///< Minimum number of polling threads.
+    MAX_POLLERS,     ///< Maximum number of polling threads.
+    CQ_TIMEOUT_MSEC  ///< Completion queue timeout in milliseconds.
+  };
+
   /// Only useful if this is a Synchronous server.
   ServerBuilder& SetSyncServerOption(SyncServerOption option, int value);
 
@@ -129,59 +200,6 @@ class ServerBuilder {
     return SetOption(MakeChannelArgumentOption(arg, value));
   }
 
-  /// Enlists an endpoint \a addr (port with an optional IP address) to
-  /// bind the \a grpc::Server object to be created to.
-  ///
-  /// It can be invoked multiple times.
-  ///
-  /// \param addr_uri The address to try to bind to the server in URI form. If
-  /// the scheme name is omitted, "dns:///" is assumed. To bind to any address,
-  /// please use IPv6 any, i.e., [::]:<port>, which also accepts IPv4
-  /// connections.  Valid values include dns:///localhost:1234, /
-  /// 192.168.1.1:31416, dns:///[::1]:27182, etc.).
-  /// \param creds The credentials associated with the server.
-  /// \param selected_port[out] If not `nullptr`, gets populated with the port
-  /// number bound to the \a grpc::Server for the corresponding endpoint after
-  /// it is successfully bound, 0 otherwise.
-  ///
-  // TODO(dgq): the "port" part seems to be a misnomer.
-  ServerBuilder& AddListeningPort(const grpc::string& addr_uri,
-                                  std::shared_ptr<ServerCredentials> creds,
-                                  int* selected_port = nullptr);
-
-  /// Add a completion queue for handling asynchronous services.
-  ///
-  /// Caller is required to shutdown the server prior to shutting down the
-  /// returned completion queue. Caller is also required to drain the
-  /// completion queue after shutting it down. A typical usage scenario:
-  ///
-  /// // While building the server:
-  /// ServerBuilder builder;
-  /// ...
-  /// cq_ = builder.AddCompletionQueue();
-  /// server_ = builder.BuildAndStart();
-  ///
-  /// // While shutting down the server;
-  /// server_->Shutdown();
-  /// cq_->Shutdown();  // Always *after* the associated server's Shutdown()!
-  /// // Drain the cq_ that was created
-  /// void* ignored_tag;
-  /// bool ignored_ok;
-  /// while (cq_->Next(&ignored_tag, &ignored_ok)) { }
-  ///
-  /// \param is_frequently_polled This is an optional parameter to inform gRPC
-  /// library about whether this completion queue would be frequently polled
-  /// (i.e. by calling \a Next() or \a AsyncNext()). The default value is
-  /// 'true' and is the recommended setting. Setting this to 'false' (i.e.
-  /// not polling the completion queue frequently) will have a significantly
-  /// negative performance impact and hence should not be used in production
-  /// use cases.
-  std::unique_ptr<ServerCompletionQueue> AddCompletionQueue(
-      bool is_frequently_polled = true);
-
-  /// Return a running server which is ready for processing calls.
-  std::unique_ptr<Server> BuildAndStart();
-
   /// For internal use only: Register a ServerBuilderPlugin factory function.
   static void InternalAddPluginFactory(
       std::unique_ptr<ServerBuilderPlugin> (*CreatePlugin)());