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      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 #ifndef CHROME_RENDERER_EXTENSIONS_REQUEST_SENDER_H_
      6 #define CHROME_RENDERER_EXTENSIONS_REQUEST_SENDER_H_
      7 
      8 #include <string>
      9 #include <map>
     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 ChromeV8Context;
     20 class Dispatcher;
     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 ChromeV8Context* 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   explicit RequestSender(Dispatcher* dispatcher);
     46   ~RequestSender();
     47 
     48   // In order to avoid collision, all |request_id|s passed into StartRequest()
     49   // should be generated by this method.
     50   int GetNextRequestId() const;
     51 
     52   // Makes a call to the API function |name| that is to be handled by the
     53   // extension host. The response to this request will be received in
     54   // HandleResponse().
     55   // TODO(koz): Remove |request_id| and generate that internally.
     56   //            There are multiple of these per render view though, so we'll
     57   //            need to vend the IDs centrally.
     58   void StartRequest(Source* source,
     59                     const std::string& name,
     60                     int request_id,
     61                     bool has_callback,
     62                     bool for_io_thread,
     63                     base::ListValue* value_args);
     64 
     65   // Handles responses from the extension host to calls made by StartRequest().
     66   void HandleResponse(int request_id,
     67                       bool success,
     68                       const base::ListValue& response,
     69                       const std::string& error);
     70 
     71   // Notifies this that a request source is no longer valid.
     72   // TODO(kalman): Do this in a generic/safe way.
     73   void InvalidateSource(Source* source);
     74 
     75  private:
     76   typedef std::map<int, linked_ptr<PendingRequest> > PendingRequestMap;
     77 
     78   void InsertRequest(int request_id, PendingRequest* pending_request);
     79   linked_ptr<PendingRequest> RemoveRequest(int request_id);
     80 
     81   Dispatcher* dispatcher_;
     82   PendingRequestMap pending_requests_;
     83 
     84   DISALLOW_COPY_AND_ASSIGN(RequestSender);
     85 };
     86 
     87 }  // namespace extensions
     88 
     89 #endif  // CHROME_RENDERER_EXTENSIONS_REQUEST_SENDER_H_
     90