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      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: webkit/plugins/ppapi/*
     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 {
     43     return !host_resource_;
     44   }
     45 
     46   // Some resources are plugin-side only and don't have a corresponding
     47   // resource in the host. Yet these resources still need an instance to be
     48   // associated with. This function creates a HostResource with the given
     49   // instances and a 0 host resource ID for these cases.
     50   static HostResource MakeInstanceOnly(PP_Instance instance);
     51 
     52   // Sets and retrieves the internal PP_Resource which is valid for the host
     53   // (a.k.a. renderer, as opposed to the plugin) process.
     54   //
     55   // DO NOT CALL THESE FUNCTIONS IN THE PLUGIN SIDE OF THE PROXY. The values
     56   // will be invalid. See the class comment above.
     57   void SetHostResource(PP_Instance instance, PP_Resource resource);
     58   PP_Resource host_resource() const {
     59     return host_resource_;
     60   }
     61 
     62   PP_Instance instance() const { return instance_; }
     63 
     64   // This object is used in maps so we need to provide this sorting operator.
     65   bool operator<(const HostResource& other) const {
     66     if (instance_ != other.instance_)
     67       return instance_ < other.instance_;
     68     return host_resource_ < other.host_resource_;
     69   }
     70 
     71  private:
     72   PP_Instance instance_;
     73   PP_Resource host_resource_;
     74 };
     75 
     76 }  // namespace ppapi
     77 
     78 #endif  // PPAPI_SHARED_IMPL_HOST_RESOURCE_H_
     79