Parse Drive API responses all at once in the blocking pool.

google_apis/drive/drive_api_requests.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 GOOGLE_APIS_DRIVE_DRIVE_API_REQUESTS_H_
 #define GOOGLE_APIS_DRIVE_DRIVE_API_REQUESTS_H_
 
 #include <string>
 
 #include "base/callback_forward.h"
+#include "base/location.h"
+#include "base/sequenced_task_runner.h"
+#include "base/task_runner_util.h"
 #include "base/time/time.h"
+#include "base/values.h"
 #include "google_apis/drive/base_requests.h"
+#include "google_apis/drive/drive_api_parser.h"
 #include "google_apis/drive/drive_api_url_generator.h"
 #include "google_apis/drive/drive_common_callbacks.h"
 
 namespace google_apis {
 
-class ChangeList;
-class FileResource;
-class FileList;
-
 // Callback used for requests that the server returns FileResource data
 // formatted into JSON value.
 typedef base::Callback<void(GDataErrorCode error,
                             scoped_ptr<FileResource> entry)>
     FileResourceCallback;
 
 // Callback used for requests that the server returns FileList data
 // formatted into JSON value.
 typedef base::Callback<void(GDataErrorCode error,
                             scoped_ptr<FileList> entry)> FileListCallback;
 
 // Callback used for requests that the server returns ChangeList data
 // formatted into JSON value.
 typedef base::Callback<void(GDataErrorCode error,
                             scoped_ptr<ChangeList> entry)> ChangeListCallback;
 
 namespace drive {
 
-//============================ DriveApiDataRequest ===========================
+//============================ DriveApiPartialFieldRequest ====================
 
 // This is base class of the Drive API related requests. All Drive API requests
 // support partial request (to improve the performance). The function can be
 // shared among the Drive API requests.
 // See also https://developers.google.com/drive/performance
-class DriveApiDataRequest : public GetDataRequest {
+class DriveApiPartialFieldRequest : public UrlFetchRequestBase {
  public:
-  DriveApiDataRequest(RequestSender* sender, const GetDataCallback& callback);
-  virtual ~DriveApiDataRequest();
+  explicit DriveApiPartialFieldRequest(RequestSender* sender);
+  virtual ~DriveApiPartialFieldRequest();
 
   // Optional parameter.
   const std::string& fields() const { return fields_; }
   void set_fields(const std::string& fields) { fields_ = fields; }
 
  protected:
-  // Overridden from GetDataRequest.
+  // UrlFetchRequestBase overrides.
   virtual GURL GetURL() const OVERRIDE;
 
   // Derived classes should override GetURLInternal instead of GetURL()
   // directly.
   virtual GURL GetURLInternal() const = 0;
 
  private:
   std::string fields_;
 
+  DISALLOW_COPY_AND_ASSIGN(DriveApiPartialFieldRequest);
+};
+
+//============================ DriveApiDataRequest ===========================
+
+// The base class of Drive API related requests that receive a JSON response
+// representing |DataType|.
+template<class DataType>
+class DriveApiDataRequest : public DriveApiPartialFieldRequest {

[hashimoto, 2014/08/06 09:23:02]

This class is replicating GetDataRequest and, after this change, GetDataRequest
is only inherited by GetResourceEntryRequest.
Could you get rid of GetDataRequest?

[kinaba, 2014/08/07 00:59:34]

sg. done.

+ public:
+  typedef base::Callback<void(GDataErrorCode error,
+                              scoped_ptr<DataType> data)> Callback;
+
+  // |callback| is called when the request finishes either by success or by
+  // failure. On success, a JSON Value object is passed. It must not be null.
+  DriveApiDataRequest(RequestSender* sender, const Callback& callback)
+      : DriveApiPartialFieldRequest(sender),
+        callback_(callback),
+        weak_ptr_factory_(this) {
+    DCHECK(!callback_.is_null());
+  }
+  virtual ~DriveApiDataRequest() {}
+
+ protected:
+  // UrlFetchRequestBase overrides.
+  virtual void ProcessURLFetchResults(const net::URLFetcher* source) OVERRIDE {
+    GDataErrorCode error = GetErrorCode();
+    switch (error) {
+      case HTTP_SUCCESS:
+      case HTTP_CREATED:
+        base::PostTaskAndReplyWithResult(
+            blocking_task_runner(),
+            FROM_HERE,
+            base::Bind(&DriveApiDataRequest::Parse, response_writer()->data()),
+            base::Bind(&DriveApiDataRequest::OnDataParsed,
+                       weak_ptr_factory_.GetWeakPtr(), error));
+        break;
+      default:
+        RunCallbackOnPrematureFailure(error);
+        OnProcessURLFetchResultsComplete();
+        break;
+    }
+  }
+
+  virtual void RunCallbackOnPrematureFailure(GDataErrorCode error) OVERRIDE {
+    callback_.Run(error, scoped_ptr<DataType>());
+  }
+
+ private:
+  // Parses the |json| string by using DataType::CreateFrom.
+  static scoped_ptr<DataType> Parse(const std::string& json) {
+    scoped_ptr<base::Value> value = ParseJson(json);
+    return value ? DataType::CreateFrom(*value) : scoped_ptr<DataType>();
+  }
+
+  // Receives the parsed result and invokes the callback.
+  void OnDataParsed(GDataErrorCode error, scoped_ptr<DataType> value) {
+    callback_.Run(value ? error : GDATA_PARSE_ERROR, value.Pass());
+    OnProcessURLFetchResultsComplete();
+  }
+
+  const Callback callback_;
+
+  // Note: This should remain the last member so it'll be destroyed and
+  // invalidate its weak pointers before any other members are destroyed.
+  base::WeakPtrFactory<DriveApiDataRequest> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(DriveApiDataRequest);
 };
 
 //=============================== FilesGetRequest =============================
 
 // This class performs the request for fetching a file.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/files/get
-class FilesGetRequest : public DriveApiDataRequest {
+class FilesGetRequest : public DriveApiDataRequest<FileResource> {
  public:
   FilesGetRequest(RequestSender* sender,
                   const DriveApiUrlGenerator& url_generator,
                   const FileResourceCallback& callback);
   virtual ~FilesGetRequest();
 
   // Required parameter.
   const std::string& file_id() const { return file_id_; }
   void set_file_id(const std::string& file_id) { file_id_ = file_id; }
 
  protected:
   // Overridden from DriveApiDataRequest.
   virtual GURL GetURLInternal() const OVERRIDE;
 
  private:
   const DriveApiUrlGenerator url_generator_;
   std::string file_id_;
 
   DISALLOW_COPY_AND_ASSIGN(FilesGetRequest);
 };
 
 //============================ FilesAuthorizeRequest ===========================
 
 // This class performs request for authorizing an app to access a file.
 // This request is mapped to /drive/v2internal/file/authorize internal endpoint.
-class FilesAuthorizeRequest : public DriveApiDataRequest {
+class FilesAuthorizeRequest : public DriveApiDataRequest<FileResource> {
  public:
   FilesAuthorizeRequest(RequestSender* sender,
                         const DriveApiUrlGenerator& url_generator,
                         const FileResourceCallback& callback);
   virtual ~FilesAuthorizeRequest();
 
   // Required parameter.
   const std::string& file_id() const { return file_id_; }
   void set_file_id(const std::string& file_id) { file_id_ = file_id; }
   const std::string& app_id() const { return app_id_; }
@@ skipping 14 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(FilesAuthorizeRequest);
 };
 
 //============================ FilesInsertRequest =============================
 
 // This class performs the request for creating a resource.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/files/insert
 // See also https://developers.google.com/drive/manage-uploads and
 // https://developers.google.com/drive/folder
-class FilesInsertRequest : public DriveApiDataRequest {
+class FilesInsertRequest : public DriveApiDataRequest<FileResource> {
  public:
   FilesInsertRequest(RequestSender* sender,
                      const DriveApiUrlGenerator& url_generator,
                      const FileResourceCallback& callback);
   virtual ~FilesInsertRequest();
 
   // Optional request body.
   const base::Time& last_viewed_by_me_date() const {
     return last_viewed_by_me_date_;
   }
@@ skipping 36 matching lines @@
   std::string title_;
 
   DISALLOW_COPY_AND_ASSIGN(FilesInsertRequest);
 };
 
 //============================== FilesPatchRequest ============================
 
 // This class performs the request for patching file metadata.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/files/patch
-class FilesPatchRequest : public DriveApiDataRequest {
+class FilesPatchRequest : public DriveApiDataRequest<FileResource> {
  public:
   FilesPatchRequest(RequestSender* sender,
                     const DriveApiUrlGenerator& url_generator,
                     const FileResourceCallback& callback);
   virtual ~FilesPatchRequest();
 
   // Required parameter.
   const std::string& file_id() const { return file_id_; }
   void set_file_id(const std::string& file_id) { file_id_ = file_id; }
 
@@ skipping 53 matching lines @@
   std::vector<std::string> parents_;
 
   DISALLOW_COPY_AND_ASSIGN(FilesPatchRequest);
 };
 
 //============================= FilesCopyRequest ==============================
 
 // This class performs the request for copying a resource.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/files/copy
-class FilesCopyRequest : public DriveApiDataRequest {
+class FilesCopyRequest : public DriveApiDataRequest<FileResource> {
  public:
   // Upon completion, |callback| will be called. |callback| must not be null.
   FilesCopyRequest(RequestSender* sender,
                    const DriveApiUrlGenerator& url_generator,
                    const FileResourceCallback& callback);
   virtual ~FilesCopyRequest();
 
   // Required parameter.
   const std::string& file_id() const { return file_id_; }
   void set_file_id(const std::string& file_id) { file_id_ = file_id; }
@@ skipping 31 matching lines @@
 };
 
 //============================= FilesListRequest =============================
 
 // This class performs the request for fetching FileList.
 // The result may contain only first part of the result. The remaining result
 // should be able to be fetched by ContinueGetFileListRequest defined below,
 // or by FilesListRequest with setting page token.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/files/list
-class FilesListRequest : public DriveApiDataRequest {
+class FilesListRequest : public DriveApiDataRequest<FileList> {
  public:
   FilesListRequest(RequestSender* sender,
                    const DriveApiUrlGenerator& url_generator,
                    const FileListCallback& callback);
   virtual ~FilesListRequest();
 
   // Optional parameter
   int max_results() const { return max_results_; }
   void set_max_results(int max_results) { max_results_ = max_results; }
 
@@ skipping 17 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(FilesListRequest);
 };
 
 //========================= FilesListNextPageRequest ==========================
 
 // There are two ways to obtain next pages of "Files: list" result (if paged).
 // 1) Set pageToken and all params used for the initial request.
 // 2) Use URL in the nextLink field in the previous response.
 // This class implements 2)'s request.
-class FilesListNextPageRequest : public DriveApiDataRequest {
+class FilesListNextPageRequest : public DriveApiDataRequest<FileList> {
  public:
   FilesListNextPageRequest(RequestSender* sender,
                            const FileListCallback& callback);
   virtual ~FilesListNextPageRequest();
 
   const GURL& next_link() const { return next_link_; }
   void set_next_link(const GURL& next_link) { next_link_ = next_link; }
 
  protected:
   // Overridden from DriveApiDataRequest.
@@ skipping 34 matching lines @@
   std::string etag_;
 
   DISALLOW_COPY_AND_ASSIGN(FilesDeleteRequest);
 };
 
 //============================= FilesTrashRequest ==============================
 
 // This class performs the request for trashing a resource.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/files/trash
-class FilesTrashRequest : public DriveApiDataRequest {
+class FilesTrashRequest : public DriveApiDataRequest<FileResource> {
  public:
   FilesTrashRequest(RequestSender* sender,
                     const DriveApiUrlGenerator& url_generator,
                     const FileResourceCallback& callback);
   virtual ~FilesTrashRequest();
 
   // Required parameter.
   const std::string& file_id() const { return file_id_; }
   void set_file_id(const std::string& file_id) { file_id_ = file_id; }
 
  protected:
   // Overridden from UrlFetchRequestBase.
   virtual net::URLFetcher::RequestType GetRequestType() const OVERRIDE;
 
   // Overridden from DriveApiDataRequest.
   virtual GURL GetURLInternal() const OVERRIDE;
 
  private:
   const DriveApiUrlGenerator url_generator_;
   std::string file_id_;
 
   DISALLOW_COPY_AND_ASSIGN(FilesTrashRequest);
 };
 
 //============================== AboutGetRequest =============================
 
 // This class performs the request for fetching About data.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/about/get
-class AboutGetRequest : public DriveApiDataRequest {
+class AboutGetRequest : public DriveApiDataRequest<AboutResource> {
  public:
   AboutGetRequest(RequestSender* sender,
                   const DriveApiUrlGenerator& url_generator,
                   const AboutResourceCallback& callback);
   virtual ~AboutGetRequest();
 
  protected:
   // Overridden from DriveApiDataRequest.
   virtual GURL GetURLInternal() const OVERRIDE;
 
  private:
   const DriveApiUrlGenerator url_generator_;
 
   DISALLOW_COPY_AND_ASSIGN(AboutGetRequest);
 };
 
 //============================ ChangesListRequest ============================
 
 // This class performs the request for fetching ChangeList.
 // The result may contain only first part of the result. The remaining result
 // should be able to be fetched by ContinueGetFileListRequest defined below.
 // or by ChangesListRequest with setting page token.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/changes/list
-class ChangesListRequest : public DriveApiDataRequest {
+class ChangesListRequest : public DriveApiDataRequest<ChangeList> {
  public:
   ChangesListRequest(RequestSender* sender,
                      const DriveApiUrlGenerator& url_generator,
                      const ChangeListCallback& callback);
   virtual ~ChangesListRequest();
 
   // Optional parameter
   bool include_deleted() const { return include_deleted_; }
   void set_include_deleted(bool include_deleted) {
     include_deleted_ = include_deleted;
@@ skipping 25 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(ChangesListRequest);
 };
 
 //======================== ChangesListNextPageRequest =========================
 
 // There are two ways to obtain next pages of "Changes: list" result (if paged).
 // 1) Set pageToken and all params used for the initial request.
 // 2) Use URL in the nextLink field in the previous response.
 // This class implements 2)'s request.
-class ChangesListNextPageRequest : public DriveApiDataRequest {
+class ChangesListNextPageRequest : public DriveApiDataRequest<ChangeList> {
  public:
   ChangesListNextPageRequest(RequestSender* sender,
                              const ChangeListCallback& callback);
   virtual ~ChangesListNextPageRequest();
 
   const GURL& next_link() const { return next_link_; }
   void set_next_link(const GURL& next_link) { next_link_ = next_link; }
 
  protected:
   // Overridden from DriveApiDataRequest.
   virtual GURL GetURLInternal() const OVERRIDE;
 
  private:
   GURL next_link_;
 
   DISALLOW_COPY_AND_ASSIGN(ChangesListNextPageRequest);
 };
 
 //============================= AppsListRequest ============================
 
 // This class performs the request for fetching AppList.
 // This request is mapped to
 // https://developers.google.com/drive/v2/reference/apps/list
-class AppsListRequest : public DriveApiDataRequest {
+class AppsListRequest : public DriveApiDataRequest<AppList> {
  public:
   AppsListRequest(RequestSender* sender,
                   const DriveApiUrlGenerator& url_generator,
                   bool use_internal_endpoint,
                   const AppListCallback& callback);
   virtual ~AppsListRequest();
 
  protected:
   // Overridden from DriveApiDataRequest.
   virtual GURL GetURLInternal() const OVERRIDE;
@@ skipping 342 matching lines @@
   PermissionRole role_;
   std::string value_;
 
   DISALLOW_COPY_AND_ASSIGN(PermissionsInsertRequest);
 };
 
 }  // namespace drive
 }  // namespace google_apis
 
 #endif  // GOOGLE_APIS_DRIVE_DRIVE_API_REQUESTS_H_