Restructure public side of network service.

mojo/services/public/interfaces/network/udp_socket.mojom

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-module mojo;
-
-import "mojo/services/public/interfaces/network/net_address.mojom";
-import "mojo/services/public/interfaces/network/network_error.mojom";
-
-// UDPSocket and UDPSocketClient represent a UDP socket and its client. The
-// typical flow of using the interfaces is:
-// - Acquire a UDPSocket interface pointer and set a UDPSocketClient instance.
-// - (optional) Set options which are allowed prior to Bind().
-// - Bind the socket.
-// - (optional) Set options which are allowed after Bind().
-// - Send / request to receive datagrams. Received datagrams will be delivered
-//   to UDPSocketClient.OnReceived().
-
-[Client=UDPSocketClient]
-interface UDPSocket {
-  // Allows the socket to share the local address to which it will be bound with
-  // other processes. Should be called before Bind().
-  // (This is equivalent to SO_REUSEADDR of the POSIX socket API.)
-  AllowAddressReuse() => (NetworkError result);
-
-  // Binds the socket to the given address.
-  // |bound_addr| is non-NULL on success. It might not be the same as |addr|.
-  // For example, if port 0 is used in |addr|, an available port is picked and
-  // returned in |bound_addr|.
-  Bind(NetAddress addr) => (NetworkError result, NetAddress? bound_addr);
-
-  // Sets the OS send buffer size (in bytes) for the socket. The socket must be
-  // bound.
-  SetSendBufferSize(uint32 size) => (NetworkError result);
-
-  // Sets the OS receive buffer size (in bytes) for the socket. The socket must
-  // be bound.
-  SetReceiveBufferSize(uint32 size) => (NetworkError result);
-
-  // Negotiates the maximum number of pending SendTo() requests. If
-  // |requested_size| is set to 0, this method queries the current settings.
-  //
-  // The service stores SendTo() requests in a queue while they are waiting to
-  // be executed (i.e., while they are waiting to be placed in the OS send
-  // buffer and sent out). This method negotiates how many requests (not bytes)
-  // this queue is able to store. If the queue is full, the service fails new
-  // requests directly with error code ERR_INSUFFICIENT_RESOURCES and discards
-  // those datagrams. If the client wants to avoid such failures, it needs to
-  // keep track of how many SendTo() calls are pending and make sure the number
-  // doesn't exceed the result of this method.
-  NegotiateMaxPendingSendRequests(uint32 requested_size)
-      => (uint32 actual_size);
-
-  // Notifies that the client is ready to accept |number| of datagrams.
-  // Correspondingly, OnReceived() of the UDPSocketClient interface will be
-  // called |number| times (errors also count), unless the connection is closed
-  // before that.
-  //
-  // It is allowed to call this method again before the previous request is
-  // completely satisfied. For example:
-  //   service->ReceiveMore(3);
-  //   ...
-  //   // OnReceived() is called.
-  //   // OnReceived() is called.
-  //   ...
-  //   service->ReceiveMore(3);
-  //   // The client expects 4 more calls to OnReceived().
-  //
-  // Please note that how ReceiveMore() is used will affect performance
-  // significantly. For example:
-  //   // Approach 1:
-  //   service->ReceiveMore(3);
-  //   // OnReceived() is called.
-  //   // OnReceived() is called.
-  //   // OnReceived() is called.
-  //
-  //   // Approach 2:
-  //   service->ReceiveMore(1);
-  //   // OnReceived() is called.
-  //   service->ReceiveMore(1);
-  //   // OnReceived() is called.
-  //   service->ReceiveMore(1);
-  //   // OnReceived() is called.
-  //
-  // It is very likely that approach 1 will perform better than approach 2,
-  // because in approach 2 getting every datagram takes at least the time of a
-  // round trip to the service side.
-  ReceiveMore(uint32 datagram_number);
-
-  // Sends data to the specified destination. The socket must be bound.
-  // On success, |result.code| is a non-negative number indicating how many
-  // bytes have been written. Otherwise, it is a network error code, including
-  // (but not limited to):
-  // - ERR_INSUFFICIENT_RESOURCES (-12): The service doesn't have sufficient
-  //   resource to complete the operation. One possible cause is that the client
-  //   tries to send too many datagrams in a short period of time.
-  // TODO(yzshen): Formalize Mojo networking error codes.
-  SendTo(NetAddress dest_addr, array<uint8> data) => (NetworkError result);
-};
-
-interface UDPSocketClient {
-  // On success, |src_addr| and |data| are non-NULL, and |result.code| is a
-  // non-negative number indicating how many bytes have been received. On
-  // failure, |result.code| is a network error code.
-  OnReceived(NetworkError result, NetAddress? src_addr, array<uint8>? data);
-};