gdrive: Get JSON feeds parsing off the UI thread.

chrome/browser/chromeos/gdata/operations_base.h

 // Copyright (c) 2012 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_GDATA_OPERATIONS_BASE_H_
 #define CHROME_BROWSER_CHROMEOS_GDATA_OPERATIONS_BASE_H_
 
 #include <string>
 #include <vector>
 
 #include "chrome/browser/chromeos/gdata/gdata_operation_registry.h"
 #include "chrome/browser/chromeos/gdata/gdata_params.h"
 #include "chrome/common/net/gaia/oauth2_access_token_consumer.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_delegate.h"
 
 class Profile;
 class OAuth2AccessTokenFetcher;
 
 namespace gdata {
 
+// Callback type for ProcessURLFetchResults.
+typedef base::Callback<void(bool result)> ProcessURLFetchResultsCallBack;

[hashimoto, 2012/07/20 04:07:37]

nit: s/CallBack/Callback/ We use 'callback' as one word.

BTW, do we need this typedef at all?
Why can't we call OnProcessURLFetchResultsComplete() directly?

[yoshiki, 2012/07/24 16:58:32]

Done
If we call OnProcessURLFetchResultsComplete() directly, we have to change it
public because it is called from OnDataParsed() in operations_base.cc. I think
passing callback is better than it.

[hashimoto, 2012/07/25 06:14:21]

How about making OnDataParsed() a private method of GetDataOperation?

Having two callbacks (|callback| and |result_callback|) as arguments of
OnDataParsed() is confusing.  It's good to avoid it if possible.

+
 //================================ AuthOperation ===============================
 
 // OAuth2 authorization token retrieval operation.
 class AuthOperation : public GDataOperationRegistry::Operation,
                       public OAuth2AccessTokenConsumer {
  public:
   AuthOperation(GDataOperationRegistry* registry,
                 Profile* profile,
                 const AuthStatusCallback& callback,
                 const std::string& refresh_token);
@@ skipping 71 matching lines @@
   // override this method to specify any extra headers needed for the request.
   virtual std::vector<std::string> GetExtraRequestHeaders() const;
   // Used by a derived class to add any content data to the request.
   // Returns true if |upload_content_type| and |upload_content| are updated
   // with the content type and data for the request.
   virtual bool GetContentData(std::string* upload_content_type,
                               std::string* upload_content);
 
   // Invoked by OnURLFetchComplete when the operation completes without an
   // authentication error. Must be implemented by a derived class.
-  virtual bool ProcessURLFetchResults(const net::URLFetcher* source) = 0;
+  virtual void ProcessURLFetchResults(
+      const net::URLFetcher* source,
+      const ProcessURLFetchResultsCallBack& callback) = 0;
 
   // Invoked when it needs to notify the status. Chunked operations that
   // constructs a logically single operation from multiple physical operations
   // should notify resume/suspend instead of start/finish.
   virtual void NotifyStartToOperationRegistry();
   virtual void NotifySuccessToOperationRegistry();
 
   // Invoked by this base class upon an authentication error or cancel by
   // an user operation. Must be implemented by a derived class.
   virtual void RunCallbackOnPrematureFailure(GDataErrorCode code) = 0;
 
   // Implement GDataOperationRegistry::Operation
   virtual void DoCancel() OVERRIDE;
 
   // Overridden from URLFetcherDelegate.
   virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
 
+  // Invoked when ProcessURLFetchResults() is completed.
+  void OnProcessURLFetchResultsComplete(bool result);
+
   // Overridden from GDataOperationInterface.
   virtual void OnAuthFailed(GDataErrorCode code) OVERRIDE;
 
   // Returns an appropriate GDataErrorCode based on the HTTP response code and
   // the status of the URLFetcher.
   GDataErrorCode GetErrorCode(const net::URLFetcher* source) const;
 
   std::string GetResponseHeadersAsString(
       const net::URLFetcher* url_fetcher);
 
   Profile* profile_;
   ReAuthenticateCallback re_authenticate_callback_;
   int re_authenticate_count_;
   bool save_temp_file_;
   FilePath output_file_path_;
   scoped_ptr<net::URLFetcher> url_fetcher_;
   bool started_;
+  base::WeakPtrFactory<UrlFetchOperationBase> weak_ptr_factory_;

[hashimoto, 2012/07/20 04:07:37]

Can't this be private instead of protected?

[yoshiki, 2012/07/24 16:58:32]

Done.

 };
 
 //============================ EntryActionOperation ============================
 
 // This class performs a simple action over a given entry (document/file).
 // It is meant to be used for operations that return no JSON blobs.
 class EntryActionOperation : public UrlFetchOperationBase {
  public:
   EntryActionOperation(GDataOperationRegistry* registry,
                        Profile* profile,
                        const EntryActionCallback& callback,
                        const GURL& document_url);
   virtual ~EntryActionOperation();
 
  protected:
   // Overridden from UrlFetchOperationBase.
-  virtual bool ProcessURLFetchResults(const net::URLFetcher* source) OVERRIDE;
+  virtual void ProcessURLFetchResults(
+      const net::URLFetcher* source,
+      const ProcessURLFetchResultsCallBack& callback) OVERRIDE;
   virtual void RunCallbackOnPrematureFailure(GDataErrorCode code) OVERRIDE;
 
   const GURL& document_url() const { return document_url_; }
 
  private:
   EntryActionCallback callback_;
   GURL document_url_;
 
   DISALLOW_COPY_AND_ASSIGN(EntryActionOperation);
 };
 
 //============================== GetDataOperation ==============================
 
 // This class performs the operation for fetching and parsing JSON data content.
 class GetDataOperation : public UrlFetchOperationBase {
  public:
   GetDataOperation(GDataOperationRegistry* registry,
                    Profile* profile,
                    const GetDataCallback& callback);
   virtual ~GetDataOperation();
 
   // Parse GData JSON response.
-  virtual base::Value* ParseResponse(const std::string& data);
+  virtual void ParseResponse(
+      GDataErrorCode fetch_error_code,
+      const std::string& data,
+      const ProcessURLFetchResultsCallBack& result_callback);
 
  protected:
   // Overridden from UrlFetchOperationBase.
-  virtual bool ProcessURLFetchResults(const net::URLFetcher* source) OVERRIDE;
-  virtual void RunCallbackOnPrematureFailure(GDataErrorCode code) OVERRIDE;
+  virtual void ProcessURLFetchResults(
+      const net::URLFetcher* source,
+      const ProcessURLFetchResultsCallBack& callback) OVERRIDE;
+  virtual void RunCallbackOnPrematureFailure(
+      GDataErrorCode fetch_error_code) OVERRIDE;
+  void RunCallback(GDataErrorCode fetch_error_code,
+                   scoped_ptr<base::Value> value);
 
  private:
   GetDataCallback callback_;
+
   DISALLOW_COPY_AND_ASSIGN(GetDataOperation);
 };
 
 }  // namespace gdata
 
 #endif  // CHROME_BROWSER_CHROMEOS_GDATA_OPERATIONS_BASE_H_