// Copyright 2016 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 network.mojom;

import "url/mojom/url.mojom";

enum WebSocketMessageType {
  CONTINUATION,
  TEXT,
  BINARY,
  LAST = BINARY
};

// TODO(darin): Move to a more general location.
struct HttpHeader {
  string name;
  string value;
};

// TODO(darin): Remove redundancy b/w |headers| and |headers_text|.

struct WebSocketHandshakeRequest {
  url.mojom.Url url;
  array<HttpHeader> headers;
  string headers_text;
};

struct WebSocketHandshakeResponse {
  url.mojom.Url url;
  int32 status_code;
  string status_text;
  array<HttpHeader> headers;
  string headers_text;
};

interface WebSocketClient {
  OnFailChannel(string reason);

  // Notify the renderer that the browser has started an opening handshake.
  // This message is for showing the request in the inspector and
  // can be omitted if the inspector is not active.
  OnStartOpeningHandshake(WebSocketHandshakeRequest request);

  // Notify the renderer that the browser has finished an opening handshake.
  // This message precedes AddChannelResponse.
  // This message is for showing the response in the inspector and
  // can be omitted if the inspector is not active.
  OnFinishOpeningHandshake(WebSocketHandshakeResponse response);

  // Response to an AddChannelRequest. |selected_protocol| is the sub-protocol
  // the server selected, or empty if no sub-protocol was selected.
  // |extensions| is the list of extensions negotiated for the connection.
  OnAddChannelResponse(string selected_protocol, string extensions);

  // Receive a non-control frame from the remote server.
  // - |fin| indicates that this frame is the last in the current message.
  // - |type| is the type of the message. On the first frame of a message, it
  //   must be set to either WebSocketMessageType.TEXT or
  //   WebSocketMessageType.BINARY. On subsequent frames, it must be set to
  //   WebSocketMessageType.CONTINUATION, and the type is the same as that of
  //   the first message. If |type| is WebSocketMessageType.TEXT, then the
  //   concatenation of the |data| from every frame in the message must be valid
  //   UTF-8. If |fin| is not set, |data| must be non-empty.
  OnDataFrame(bool fin, WebSocketMessageType type, array<uint8> data);

  // Add |quota| tokens of send quota for the channel. |quota| must be a
  // positive integer. Both the browser and the renderer set send quota for the
  // other side, and check that quota has not been exceeded when receiving
  // messages.  Both sides start a new channel with a quota of 0, and must wait
  // for a FlowControl message before calling SendFrame. The total available
  // quota on one side must never exceed 0x7FFFFFFFFFFFFFFF tokens.
  OnFlowControl(int64 quota);

  // Drop the channel.
  //
  // When sent by the renderer, this will cause a Close message will be sent and
  // the TCP/IP connection will be closed.
  //
  // When sent by the browser, this indicates that a Close has been received,
  // the connection was closed, or a network or protocol error occurred.
  //
  // - |code| is one of the reason codes specified in RFC6455.
  // - |reason|, if non-empty, is a UTF-8 encoded string which may be useful
  //   for debugging but is not necessarily human-readable, as supplied by the
  //   server in the Close message.
  // - If |was_clean| is false, then the WebSocket connection was not closed
  //   cleanly.
  OnDropChannel(bool was_clean, uint16 code, string reason);

  // Notify the renderer that a closing handshake has been initiated by the
  // server, so that it can set the Javascript readyState to CLOSING.
  OnClosingHandshake();
};

interface WebSocket {
  // The client side may observe the following disconnection reason from the
  // service side:
  const uint32 kInsufficientResources = 1;

  // Open new WebSocket connection to |socket_url|. |requested_protocols| is a
  // list of tokens identifying sub-protocols the renderer would like to use,
  // as described in RFC6455 "Subprotocols Using the WebSocket Protocol".
  AddChannelRequest(url.mojom.Url url,
                    array<string> requested_protocols,
                    url.mojom.Url first_party_for_cookies,
                    string user_agent_override,
                    WebSocketClient client);

  // Send a non-control frame to the remote server.
  // - |fin| indicates that this frame is the last in the current message.
  // - |type| is the type of the message. On the first frame of a message, it
  //   must be set to either WebSocketMessageType.TEXT or
  //   WebSocketMessageType.BINARY. On subsequent frames, it must be set to
  //   WebSocketMessageType.CONTINUATION, and the type is the same as that of
  //   the first message. If |type| is WebSocketMessageType.TEXT, then the
  //   concatenation of the |data| from every frame in the message must be valid
  //   UTF-8. If |fin| is not set, |data| must be non-empty.
  SendFrame(bool fin, WebSocketMessageType type, array<uint8> data);

  // Add |quota| tokens of send quota for the channel. |quota| must be a
  // positive integer. Both the browser and the renderer set send quota for the
  // other side, and check that quota has not been exceeded when receiving
  // messages.  Both sides start a new channel with a quota of 0, and must wait
  // for a FlowControl message before calling SendFrame. The total available
  // quota on one side must never exceed 0x7FFFFFFFFFFFFFFF tokens.
  SendFlowControl(int64 quota);

  // Close the channel gracefully.
  //
  // When sent by the renderer, this will cause a Close message will be sent and
  // the TCP/IP connection will be closed.
  //
  // - |code| is one of the reason codes specified in RFC6455.
  // - |reason|, if non-empty, is a UTF-8 encoded string which may be useful for
  //   debugging but is not necessarily human-readable, as supplied by the
  //   server in the Close message.
  StartClosingHandshake(uint16 code, string reason);
};