ppapi/host/resource_message_handler.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ppapi/host/resource_message_handler.h"
   6
   7 #include "base/logging.h"
   8 #include "ipc/ipc_message.h"
   9 #include "ppapi/c/pp_errors.h"
  10 #include "ppapi/host/host_message_context.h"
  11
  12 namespace ppapi {
  13 namespace host {
  14
  15 ResourceMessageHandler::ResourceMessageHandler() {
  16 }
  17
  18 ResourceMessageHandler::~ResourceMessageHandler() {
  19 }
  20
  21 void ResourceMessageHandler::RunMessageHandlerAndReply(
  22     const IPC::Message& msg,
  23     HostMessageContext* context) {
  24   ReplyMessageContext reply_context = context->MakeReplyMessageContext();
  25   // CAUTION: Handling the message may cause the destruction of this object.
  26   // The message handler should ensure that if there is a chance that the
  27   // object will be destroyed, PP_OK_COMPLETIONPENDING is returned as the
  28   // result of the message handler. Otherwise the code below will attempt to
  29   // send a reply message on a destroyed object.
  30   reply_context.params.set_result(OnResourceMessageReceived(msg, context));
  31
  32   // Sanity check the resource handler. Note if the result was
  33   // "completion pending" the resource host may have already sent the reply.
  34   if (reply_context.params.result() == PP_OK_COMPLETIONPENDING) {
  35     // Message handler should have only returned a pending result if a
  36     // response will be sent to the plugin.
  37     DCHECK(context->params.has_callback());
  38
  39     // Message handler should not have written a message to be returned if
  40     // completion is pending.
  41     DCHECK(context->reply_msg.type() == 0);
  42   } else if (!context->params.has_callback()) {
  43     // When no response is required, the message handler should not have
  44     // written a message to be returned.
  45     DCHECK(context->reply_msg.type() == 0);
  46
  47     // If there is no callback and the result of running the message handler
  48     // was not PP_OK the client won't find out.
  49     DLOG_IF(WARNING, reply_context.params.result() != PP_OK)
  50         << "'Post' message handler failed to complete successfully.";
  51   }
  52
  53   if (context->params.has_callback() &&
  54       reply_context.params.result() != PP_OK_COMPLETIONPENDING)
  55     SendReply(reply_context, context->reply_msg);
  56 }
  57
  58 int32_t ResourceMessageHandler::OnResourceMessageReceived(
  59     const IPC::Message& msg,
  60     HostMessageContext* context) {
  61   return PP_ERROR_NOTSUPPORTED;
  62 }
  63
  64 }  // namespace host
  65 }  // namespace ppapi