gdata:: Add GDataFileSystem::GetFile().

chrome/browser/chromeos/gdata/gdata_file_system.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_GDATA_FILE_SYSTEM_H_
 #define CHROME_BROWSER_CHROMEOS_GDATA_GDATA_FILE_SYSTEM_H_
 
 #include <map>
 
 #include "base/gtest_prod_util.h"
@@ skipping 19 matching lines @@
 class GDataFileBase {
  public:
   explicit GDataFileBase(GDataDirectory* parent);
   virtual ~GDataFileBase();
   // Converts DocumentEntry into GDataFileBase.
   static GDataFileBase* FromDocumentEntry(GDataDirectory* parent,
                                           DocumentEntry* doc);
   virtual GDataFile* AsGDataFile();
   virtual GDataDirectory* AsGDataDirectory();
   GDataDirectory* parent() { return parent_; }
-  const GURL& content_url() const { return content_url_; }
   const base::PlatformFileInfo& file_info() const { return file_info_; }
   const FilePath::StringType& file_name() const { return file_name_; }
   const FilePath::StringType& original_file_name() const {
     return original_file_name_;
   }
   void set_file_name(const FilePath::StringType& name) { file_name_ = name; }
+
+  // The content URL is used for downloading regular files as is.
+  // TODO(zelidrag): Will give better description when reviewing code.

[zel, 2012/03/02 23:44:04]

i am ok with this descirption

[satorux1, 2012/03/03 00:39:10]

Done.

+  const GURL& content_url() const { return content_url_; }
+
+  // The self URL is used for removing files and hosted documents.
+  // TODO(zelidrag): Will give better description when reviewing code.

[zel, 2012/03/02 23:44:04]

same here

[satorux1, 2012/03/03 00:39:10]

Done.

   const GURL& self_url() const { return self_url_; }
+
   // Returns virtual file path representing this file system entry. This path
   // corresponds to file path expected by public methods of GDataFileSyste
   // class.
   FilePath GetFilePath();
 
  protected:
   base::PlatformFileInfo file_info_;
   FilePath::StringType file_name_;
   FilePath::StringType original_file_name_;
   // Files with the same original name will be uniquely identified with this
@@ skipping 172 matching lines @@
     ~FindFileParams();
 
     const FilePath file_path;
     const bool require_content;
     const FilePath directory_path;
     const GURL feed_url;
     const bool initial_feed;
     const scoped_refptr<FindFileDelegate> delegate;
   };
 
+  // Used for file operations like removing files.
   typedef base::Callback<void(base::PlatformFileError error)>
       FileOperationCallback;
 
+  // Used to get files from the file system.
+  typedef base::Callback<void(base::PlatformFileError error,
+                              const FilePath& file_path)>
+      GetFileCallback;
+
   // ProfileKeyedService override:
   virtual void Shutdown() OVERRIDE;
 
   // Authenticates the user by fetching the auth token as
   // needed. |callback| will be run with the error code and the auth
   // token, on the thread this function is run.
   //
   // Must be called on UI thread.
   void Authenticate(const AuthStatusCallback& callback);
 
@@ skipping 24 matching lines @@
   // an error is raised in case a directory is already present at the
   // |directory_path|. If |is_recursive| is true, the call creates parent
   // directories as needed just like mkdir -p does.
   //
   // Can be called from any thread. |callback| is run on the calling thread.
   void CreateDirectory(const FilePath& directory_path,
                        bool is_exclusive,
                        bool is_recursive,
                        const FileOperationCallback& callback);
 
-  // Initiates directory feed fetching operation and continues previously
+  // Gets |file_path| from the file system. The file entry represented by
+  // |file_path| needs to be present in in-memory representation of the file
+  // system in order to be retrieved. If the file is not cached, the file
+  // will be downloaded through gdata api.
+  //
+  // Can be called from any thread. |callback| is run on the calling thread.
+  void GetFile(const FilePath& file_path, const GetFileCallback& callback);
+
   // initiated FindFileByPath() attempt upon its completion. Safe to be called
   // from any thread. Internally, it will route content refresh request to
   // DocumentsService::GetDocuments() which will initiated content
   // fetching from UI thread as required by gdata library (UrlFetcher).
   //
   // Can be called from any thread.
   void StartDirectoryRefresh(const FindFileParams& params);
 
+  // Finds file object by |file_path| and returns the file info.
+  // Returns NULL if it does not find the file.
+  GDataFileBase* GetGDataFileInfoFromPath(const FilePath& file_path);
+
  private:
   friend class GDataFileSystemFactory;
   friend class GDataFileSystemTest;
   FRIEND_TEST_ALL_PREFIXES(GDataFileSystemTest,
                            FindFirstMissingParentDirectory);
 
   // Defines possible search results of FindFirstMissingParentDirectory().
   enum FindMissingDirectoryResult {
     // Target directory found, it's not a directory.
     FOUND_INVALID,
@@ skipping 22 matching lines @@
     scoped_refptr<base::MessageLoopProxy> proxy;
   };
 
   explicit GDataFileSystem(Profile* profile);
   virtual ~GDataFileSystem();
 
   // Unsafe (unlocked) version of the function above.
   void UnsafeFindFileByPath(const FilePath& file_path,
                             scoped_refptr<FindFileDelegate> delegate);
 
-  // Finds file object by |file_path| and returns its gdata self-url.
-  // Returns empty GURL if it does not find the file.
-  GURL GetDocumentUrlFromPath(const FilePath& file_path);
-
   // Converts document feed from gdata service into DirectoryInfo. On failure,
   // returns NULL and fills in |error| with an appropriate value.
   GDataDirectory* ParseGDataFeed(GDataErrorCode status,
                                  base::Value* data,
                                  base::PlatformFileError *error);
 
   // Callback for handling feed content fetching while searching for file info.
   // This callback is invoked after async feed fetch operation that was
   // invoked by StartDirectoryRefresh() completes. This callback will update
   // the content of the refreshed directory object and continue initially
@@ skipping 10 matching lines @@
       scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
       GDataErrorCode status,
       const GURL& document_url);
 
   // Callback for handling directory create requests.
   void OnCreateDirectoryCompleted(
       const CreateDirectoryParams& params,
       GDataErrorCode status,
       base::Value* created_entry);
 
+  // Callback for handling file downloading requests.
+  void OnFileDownloaded(
+    const GetFileCallback& callback,
+    scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+    GDataErrorCode status,
+    const GURL& content_url,
+    const FilePath& temp_file);
+
   // Removes file under |file_path| from in-memory snapshot of the file system.
   // Return PLATFORM_FILE_OK if successful.
   base::PlatformFileError RemoveFileFromFileSystem(const FilePath& file_path);
 
   // Updates content of the directory identified with |directory_path|. If the
   // feed was not complete, it will return URL for the remaining portion in
   // |next_feed|. On success, returns PLATFORM_FILE_OK.
   base::PlatformFileError UpdateDirectoryWithDocumentFeed(
       const FilePath& directory_path,
       const GURL& feed_url,
@@ skipping 54 matching lines @@
   virtual ~GDataFileSystemFactory();
 
   // ProfileKeyedServiceFactory:
   virtual ProfileKeyedService* BuildServiceInstanceFor(
       Profile* profile) const OVERRIDE;
 };
 
 }  // namespace gdata
 
 #endif  // CHROME_BROWSER_CHROMEOS_GDATA_GDATA_FILE_SYSTEM_H_