[fsp] Refactor handling operations.

chrome/browser/chromeos/file_system_provider/request_manager.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_REQUEST_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_REQUEST_MANAGER_H_
 
 #include <map>
 #include <string>
 
 #include "base/callback.h"
 #include "base/files/file.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_info.h"
-
-namespace base {
-class DictionaryValue;
-}  // namespace base
+#include "chrome/browser/chromeos/file_system_provider/request_value.h"
 
 namespace chromeos {
 namespace file_system_provider {
 
-typedef base::Callback<void(scoped_ptr<base::DictionaryValue> result,
-                            bool has_next)> SuccessCallback;
-typedef base::Callback<void(base::File::Error)> ErrorCallback;
-
 // Manages requests between the service, async utils and the providing
 // extensions.
 class RequestManager {
  public:
+  class HandlerInterface {
+   public:
+    virtual ~HandlerInterface() {}
+
+    // Called when the request is created. Executes the request implementation.
+    // Returns false in case of a execution failure.
+    virtual bool Execute(int request_id) = 0;
+
+    // Success callback invoked by the providing extension in response to
+    // Execute(). It may be called more than once, until |has_next| is set to
+    // false.
+    virtual void OnSuccess(int request_id,
+                           scoped_ptr<RequestValue> result,
+                           bool has_next) = 0;
+
+    // Error callback invoked by the providing extension in response to
+    // Execute(). It can be called at most once. It can be also called if the
+    // request is aborted due to a timeout.
+    virtual void OnError(int request_id, base::File::Error error) = 0;
+  };
+
   RequestManager();
   virtual ~RequestManager();
 
   // Creates a request and returns its request id (greater than 0). Returns 0 in
-  // case of an error (eg. too many requests). The passed callbacks can be NULL.
-  int CreateRequest(const SuccessCallback& success_callback,
-                    const ErrorCallback& error_callback);
+  // case of an error (eg. too many requests).
+  int CreateRequest(scoped_ptr<HandlerInterface> handler);
 
   // Handles successful response for the |request_id|. If |has_next| is false,
   // then the request is disposed, after handling the |response|. On error,
   // returns false, and the request is disposed.
   bool FulfillRequest(int request_id,
-                      scoped_ptr<base::DictionaryValue> response,
+                      scoped_ptr<RequestValue> response,
                       bool has_next);
 
   // Handles error response for the |request_id|. If handling the error fails,
   // returns false. Always disposes the request.
   bool RejectRequest(int request_id, base::File::Error error);
 
   // Sets a custom timeout for tests. The new timeout value will be applied to
   // new requests
   void SetTimeoutForTests(const base::TimeDelta& timeout);
 
  private:
   struct Request {
     Request();
     ~Request();
 
     // Timer for discarding the request during a timeout.
     base::OneShotTimer<RequestManager> timeout_timer;
 
-    // Callback to be called on success.
-    SuccessCallback success_callback;
-
-    // Callback to be called on error.
-    ErrorCallback error_callback;
+    // Handler tied to this request.
+    scoped_ptr<HandlerInterface> handler;
 
    private:
     DISALLOW_COPY_AND_ASSIGN(Request);
   };
 
   typedef std::map<int, Request*> RequestMap;
 
   // Called when a request with |request_id| timeouts.
   void OnRequestTimeout(int request_id);
 
   RequestMap requests_;
   int next_id_;
   base::TimeDelta timeout_;
   base::WeakPtrFactory<RequestManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RequestManager);
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_REQUEST_MANAGER_H_