components/sync/engine_impl/net/server_connection_manager.cc

// Copyright (c) 2012 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.

#include "components/sync/engine_impl/net/server_connection_manager.h"

#include <errno.h>

#include <ostream>

#include "base/metrics/histogram.h"
#include "build/build_config.h"
#include "components/sync/base/cancelation_signal.h"
#include "components/sync/engine_impl/net/url_translator.h"
#include "components/sync/engine_impl/syncer.h"
#include "components/sync/protocol/sync.pb.h"
#include "components/sync/syncable/directory.h"
#include "net/http/http_status_code.h"
#include "url/gurl.h"

namespace syncer {
namespace {

const char kSyncServerSyncPath[] = "/command/";

#define ENUM_CASE(x)    \
  case HttpResponse::x: \
    return #x;          \
    break

const char* GetServerConnectionCodeString(
    HttpResponse::ServerConnectionCode code) {
  switch (code) {
    ENUM_CASE(NONE);
    ENUM_CASE(CONNECTION_UNAVAILABLE);
    ENUM_CASE(IO_ERROR);
    ENUM_CASE(SYNC_SERVER_ERROR);
    ENUM_CASE(SYNC_AUTH_ERROR);
    ENUM_CASE(SERVER_CONNECTION_OK);
  }
  NOTREACHED();
  return "";
}

#undef ENUM_CASE

}  // namespace

HttpResponse::HttpResponse()
    : server_status(NONE),
      net_error_code(-1),
      http_status_code(-1),
      content_length(-1),
      payload_length(-1) {}

// static
HttpResponse HttpResponse::Uninitialized() {
  return HttpResponse();
}

// static
HttpResponse HttpResponse::ForNetError(int net_error_code) {
  HttpResponse response;
  response.server_status = CONNECTION_UNAVAILABLE;
  response.net_error_code = net_error_code;
  return response;
}

// static
HttpResponse HttpResponse::ForIoError() {
  HttpResponse response;
  response.server_status = IO_ERROR;
  return response;
}

// static
HttpResponse HttpResponse::ForHttpError(int http_status_code) {
  HttpResponse response;
  response.server_status = http_status_code == net::HTTP_UNAUTHORIZED
                               ? SYNC_AUTH_ERROR
                               : SYNC_SERVER_ERROR;
  response.http_status_code = http_status_code;
  return response;
}

// static
HttpResponse HttpResponse::ForSuccess() {
  HttpResponse response;
  response.server_status = SERVER_CONNECTION_OK;
  return response;
}

ServerConnectionManager::ServerConnectionManager()
    : proto_sync_path_(kSyncServerSyncPath),
      server_response_(HttpResponse::Uninitialized()) {}

ServerConnectionManager::~ServerConnectionManager() = default;

bool ServerConnectionManager::SetAccessToken(const std::string& access_token) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);

  if (!access_token.empty()) {
    access_token_.assign(access_token);
    return true;
  }

  access_token_.clear();

  // The access token could be non-empty in cases like server outage/bug. E.g.
  // token returned by first request is considered invalid by sync server and
  // because of token server's caching policy, etc, same token is returned on
  // second request. Need to notify sync frontend again to request new token,
  // otherwise backend will stay in SYNC_AUTH_ERROR state while frontend thinks
  // everything is fine and takes no actions.
  SetServerResponse(HttpResponse::ForHttpError(net::HTTP_UNAUTHORIZED));
  return false;
}

void ServerConnectionManager::ClearAccessToken() {
  access_token_.clear();
}

void ServerConnectionManager::SetServerResponse(
    const HttpResponse& server_response) {
  // Notify only if the server status changed, except for SYNC_AUTH_ERROR: In
  // that case, always notify in order to poke observers to do something about
  // it.
  bool notify =
      (server_response.server_status == HttpResponse::SYNC_AUTH_ERROR ||
       server_response_.server_status != server_response.server_status);
  server_response_ = server_response;
  if (notify) {
    NotifyStatusChanged();
  }
}

void ServerConnectionManager::NotifyStatusChanged() {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  for (auto& observer : listeners_)
    observer.OnServerConnectionEvent(
        ServerConnectionEvent(server_response_.server_status));
}

bool ServerConnectionManager::PostBufferWithCachedAuth(
    const std::string& buffer_in,
    std::string* buffer_out,
    HttpResponse* http_response) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  std::string path =
      MakeSyncServerPath(proto_sync_path(), MakeSyncQueryString(client_id_));
  bool result = PostBufferToPath(buffer_in, path, access_token_, buffer_out,
                                 http_response);
  SetServerResponse(*http_response);
  return result;
}

void ServerConnectionManager::AddListener(
    ServerConnectionEventListener* listener) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  listeners_.AddObserver(listener);
}

void ServerConnectionManager::RemoveListener(
    ServerConnectionEventListener* listener) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  listeners_.RemoveObserver(listener);
}

std::ostream& operator<<(std::ostream& s, const struct HttpResponse& hr) {
  s << " Response Code (bogus on error): " << hr.http_status_code;
  s << " Content-Length (bogus on error): " << hr.content_length;
  s << " Server Status: " << GetServerConnectionCodeString(hr.server_status);
  return s;
}

}  // namespace syncer