content/child/resource_loader_bridge.h

   1 // Copyright 2014 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 // The intent of this file is to provide a type-neutral abstraction between
   6 // Chrome and WebKit for resource loading. This pure-virtual interface is
   7 // implemented by the embedder.
   8 //
   9 // One of these objects will be created by WebKit for each request. WebKit
  10 // will own the pointer to the bridge, and will delete it when the request is
  11 // no longer needed.
  12 //
  13 // In turn, the bridge's owner on the WebKit end will implement the
  14 // RequestPeer interface, which we will use to communicate notifications
  15 // back.
  16
  17 #ifndef CONTENT_CHILD_RESOURCE_LOADER_BRIDGE_H_
  18 #define CONTENT_CHILD_RESOURCE_LOADER_BRIDGE_H_
  19
  20 #include "base/macros.h"
  21 #include "content/common/content_export.h"
  22 #include "net/base/request_priority.h"
  23
  24 namespace blink {
  25 class WebThreadedDataReceiver;
  26 }
  27
  28 namespace content {
  29
  30 class RequestPeer;
  31 class ResourceRequestBody;
  32 struct SyncLoadResponse;
  33
  34 // TODO(tfarina): Refactor code that uses this class. This shouldn't be needed
  35 // now that it lives in content/.
  36 class CONTENT_EXPORT ResourceLoaderBridge {
  37  public:
  38   // use BlinkPlatformImpl::CreateResourceLoader() for construction, but
  39   // anybody can delete at any time, INCLUDING during processing of callbacks.
  40   virtual ~ResourceLoaderBridge();
  41
  42   // Call this method before calling Start() to set the request body.
  43   // May only be used with HTTP(S) POST requests.
  44   virtual void SetRequestBody(ResourceRequestBody* request_body) = 0;
  45
  46   // Call this method to initiate the request.  If this method succeeds, then
  47   // the peer's methods will be called asynchronously to report various events.
  48   virtual bool Start(RequestPeer* peer) = 0;
  49
  50   // Call this method to cancel a request that is in progress.  This method
  51   // causes the request to immediately transition into the 'done' state. The
  52   // OnCompletedRequest method will be called asynchronously; this assumes
  53   // the peer is still valid.
  54   virtual void Cancel() = 0;
  55
  56   // Call this method to suspend or resume a load that is in progress.  This
  57   // method may only be called after a successful call to the Start method.
  58   virtual void SetDefersLoading(bool value) = 0;
  59
  60   // Call this method when the priority of the requested resource changes after
  61   // Start() has been called.  This method may only be called after a successful
  62   // call to the Start method.
  63   virtual void DidChangePriority(net::RequestPriority new_priority,
  64                                  int intra_priority_value) = 0;
  65
  66   // Call this method to attach a data receiver which will receive resource data
  67   // on its own thread.
  68   virtual bool AttachThreadedDataReceiver(
  69       blink::WebThreadedDataReceiver* threaded_data_receiver) = 0;
  70
  71   // Call this method to load the resource synchronously (i.e., in one shot).
  72   // This is an alternative to the Start method.  Be warned that this method
  73   // will block the calling thread until the resource is fully downloaded or an
  74   // error occurs.  It could block the calling thread for a long time, so only
  75   // use this if you really need it!  There is also no way for the caller to
  76   // interrupt this method.  Errors are reported via the status field of the
  77   // response parameter.
  78   virtual void SyncLoad(SyncLoadResponse* response) = 0;
  79
  80  protected:
  81   // Construction must go through BlinkPlatformImpl::CreateResourceLoader().
  82   // For HTTP(S) POST requests, the AppendDataToUpload and AppendFileToUpload
  83   // methods may be called to construct the body of the request.
  84   ResourceLoaderBridge();
  85
  86  private:
  87   DISALLOW_COPY_AND_ASSIGN(ResourceLoaderBridge);
  88 };
  89
  90 }  // namespace content
  91
  92 #endif  // CONTENT_CHILD_RESOURCE_LOADER_BRIDGE_H_