extensions/renderer/request_sender.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 #ifndef EXTENSIONS_RENDERER_REQUEST_SENDER_H_
   6 #define EXTENSIONS_RENDERER_REQUEST_SENDER_H_
   7
   8 #include <map>
   9 #include <string>
  10
  11 #include "base/memory/linked_ptr.h"
  12 #include "v8/include/v8.h"
  13
  14 namespace base {
  15 class ListValue;
  16 }
  17
  18 namespace extensions {
  19 class Dispatcher;
  20 class ScriptContext;
  21
  22 struct PendingRequest;
  23
  24 // Responsible for sending requests for named extension API functions to the
  25 // extension host and routing the responses back to the caller.
  26 class RequestSender {
  27  public:
  28   // Source represents a user of RequestSender. Every request is associated with
  29   // a Source object, which will be notified when the corresponding response
  30   // arrives. When a Source object is going away and there are pending requests,
  31   // it should call InvalidateSource() to make sure no notifications are sent to
  32   // it later.
  33   class Source {
  34    public:
  35     virtual ~Source() {}
  36
  37     virtual ScriptContext* GetContext() = 0;
  38     virtual void OnResponseReceived(const std::string& name,
  39                                     int request_id,
  40                                     bool success,
  41                                     const base::ListValue& response,
  42                                     const std::string& error) = 0;
  43   };
  44
  45   // Helper class to (re)set the |source_tab_id_| below.
  46   class ScopedTabID {
  47    public:
  48     ScopedTabID(RequestSender* request_sender, int tab_id);
  49     ~ScopedTabID();
  50
  51    private:
  52     RequestSender* const request_sender_;
  53     const int tab_id_;
  54     const int previous_tab_id_;
  55
  56     DISALLOW_COPY_AND_ASSIGN(ScopedTabID);
  57   };
  58
  59   explicit RequestSender(Dispatcher* dispatcher);
  60   ~RequestSender();
  61
  62   // In order to avoid collision, all |request_id|s passed into StartRequest()
  63   // should be generated by this method.
  64   int GetNextRequestId() const;
  65
  66   // Makes a call to the API function |name| that is to be handled by the
  67   // extension host. The response to this request will be received in
  68   // HandleResponse().
  69   // TODO(koz): Remove |request_id| and generate that internally.
  70   //            There are multiple of these per render view though, so we'll
  71   //            need to vend the IDs centrally.
  72   void StartRequest(Source* source,
  73                     const std::string& name,
  74                     int request_id,
  75                     bool has_callback,
  76                     bool for_io_thread,
  77                     base::ListValue* value_args);
  78
  79   // Handles responses from the extension host to calls made by StartRequest().
  80   void HandleResponse(int request_id,
  81                       bool success,
  82                       const base::ListValue& response,
  83                       const std::string& error);
  84
  85   // Notifies this that a request source is no longer valid.
  86   // TODO(kalman): Do this in a generic/safe way.
  87   void InvalidateSource(Source* source);
  88
  89  private:
  90   friend class ScopedTabID;
  91   typedef std::map<int, linked_ptr<PendingRequest> > PendingRequestMap;
  92
  93   void InsertRequest(int request_id, PendingRequest* pending_request);
  94   linked_ptr<PendingRequest> RemoveRequest(int request_id);
  95
  96   Dispatcher* dispatcher_;
  97   PendingRequestMap pending_requests_;
  98
  99   int source_tab_id_;  // Id of the tab sending the request, or -1 if no tab.
 100
 101   DISALLOW_COPY_AND_ASSIGN(RequestSender);
 102 };
 103
 104 }  // namespace extensions
 105
 106 #endif  // EXTENSIONS_RENDERER_REQUEST_SENDER_H_