ppapi/shared_impl/host_resource.h

   1 // Copyright (c) 2011 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 #ifndef PPAPI_SHARED_IMPL_HOST_RESOURCE_H_
   6 #define PPAPI_SHARED_IMPL_HOST_RESOURCE_H_
   7
   8 #include "ppapi/c/pp_instance.h"
   9 #include "ppapi/c/pp_resource.h"
  10 #include "ppapi/shared_impl/ppapi_shared_export.h"
  11
  12 namespace ppapi {
  13
  14 // For "old" style resources, PP_Resource values differ on the host and plugin
  15 // side. Implementations of those should be careful to use HostResource to
  16 // prevent confusion. "New" style resources use the same PP_Resource value on
  17 // the host and plugin sides, and should not use HostResource.
  18 //
  19 // Old style resources match these file specs:
  20 //   Proxy: ppapi/proxy/ppb_*_proxy.*
  21 //   Host: content/ppapi_plugin/*
  22 // New style resources match these file specs:
  23 //   Proxy: ppapi/proxy/*_resource.*
  24 //   Browser: (content|chrome)/browser/renderer_host/pepper/pepper_*_host.*
  25 //   Renderer: (content|chrome)/renderer/pepper/pepper_*_host.*
  26 //
  27 //
  28 // Represents a PP_Resource sent over the wire. This just wraps a PP_Resource.
  29 // The point is to prevent mistakes where the wrong resource value is sent.
  30 // Resource values are remapped in the plugin so that it can talk to multiple
  31 // hosts. If all values were PP_Resource, it would be easy to forget to do
  32 // this transformation.
  33 //
  34 // To get the corresponding plugin PP_Resource for a HostResource, use
  35 // PluginResourceTracker::PluginResourceForHostResource().
  36 //
  37 // All HostResources respresent IDs valid in the host.
  38 class PPAPI_SHARED_EXPORT HostResource {
  39  public:
  40   HostResource();
  41
  42   bool is_null() const { return !host_resource_; }
  43
  44   // Some resources are plugin-side only and don't have a corresponding
  45   // resource in the host. Yet these resources still need an instance to be
  46   // associated with. This function creates a HostResource with the given
  47   // instances and a 0 host resource ID for these cases.
  48   static HostResource MakeInstanceOnly(PP_Instance instance);
  49
  50   // Sets and retrieves the internal PP_Resource which is valid for the host
  51   // (a.k.a. renderer, as opposed to the plugin) process.
  52   //
  53   // DO NOT CALL THESE FUNCTIONS IN THE PLUGIN SIDE OF THE PROXY. The values
  54   // will be invalid. See the class comment above.
  55   void SetHostResource(PP_Instance instance, PP_Resource resource);
  56   PP_Resource host_resource() const { return host_resource_; }
  57
  58   PP_Instance instance() const { return instance_; }
  59
  60   // This object is used in maps so we need to provide this sorting operator.
  61   bool operator<(const HostResource& other) const {
  62     if (instance_ != other.instance_)
  63       return instance_ < other.instance_;
  64     return host_resource_ < other.host_resource_;
  65   }
  66
  67   bool operator!=(const HostResource& other) const {
  68     return instance_ != other.instance_ ||
  69            host_resource_ != other.host_resource_;
  70   }
  71
  72  private:
  73   PP_Instance instance_;
  74   PP_Resource host_resource_;
  75 };
  76
  77 }  // namespace ppapi
  78
  79 #endif  // PPAPI_SHARED_IMPL_HOST_RESOURCE_H_