When the download folder does not exist, change the download folder to a user's "Downloads"

chrome/browser/download/download_manager.h

 // Copyright (c) 2011 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.
 //
 // The DownloadManager object manages the process of downloading, including
 // updates to the history system and providing the information for displaying
 // the downloads view in the Destinations tab. There is one DownloadManager per
 // active profile in Chrome.
 //
 // Download observers:
@@ skipping 68 matching lines @@
     // of downloads.
     virtual void ModelChanged() = 0;
 
     // Called when the DownloadManager is being destroyed to prevent Observers
     // from calling back to a stale pointer.
     virtual void ManagerGoingDown() {}
 
     // Called immediately after the DownloadManager puts up a select file
     // dialog.
     // |id| indicates which download opened the dialog.
-    virtual void SelectFileDialogDisplayed(int32 id) {}
+    // |suggested_path| indicates the path suggested in the dialog.
+    virtual void SelectFileDialogDisplayed(
+        int32 id, const FilePath& suggested_path) {}
 
    protected:
     virtual ~Observer() {}
   };
 
   // Return all temporary downloads that reside in the specified directory.
   void GetTemporaryDownloads(const FilePath& dir_path,
                              std::vector<DownloadItem*>* result);
 
   // Return all non-temporary downloads in the specified directory that are
@@ skipping 144 matching lines @@
                                       bool visited_referrer_before);
 
   // Callback function after download file hash is checked with safebrowsing
   // service.
   void CheckDownloadHashDone(int32 download_id, bool is_dangerous_hash);
 
   // Assert the named download item is in no queues in the DownloadManager.
   // For debugging.
   void AssertNotInQueues(DownloadItem* download);
 
+  // Chooses a writable directory from |website_save_dir|, |download_save_dir|
+  // and |default_download_dir| in this order of priority.
+  // If none of them is writable, creates |download_save_dir| and
+  // chooses |download_save_dir|. The choosed directory is stored to |save_dir|.
+  // Returns true if neither |website_save_dir| nor |download_save_dir|
+  // is writable, which indicates the select file dialog should be displayed.
+  static bool ChooseSavableDirectory(const FilePath& website_save_dir,

[Paweł Hajdan Jr., 2011/06/15 09:31:33]

Let's avoid having static methods in DownloadManager. Could you move this to
download_util, or, if Randy doesn't like it, find a different place for it?

[haraken1, 2011/06/15 10:39:45]

Actually, I also prefer download_util.cc to download_manager.cc, although I am
not sure if download_util.cc is the best place. I would like to wait for Randy's
opinion. (No change for now.)

[Randy Smith (Not in Mondays), 2011/06/15 19:48:59]

Pawel: Why do you prefer not to have static methods on DownloadManager?  The
argument I know of against static methods is that they can't be mocked by
inheriting the class--I think that's a valid argument, but if we're comparing
download_util.cc to putting it on DownloadManager, it doesn't apply.  So I
presume there's some argument against static methods I'm missing?  I feel like
DownloadManager is the right place for this functionality...?

[Paweł Hajdan Jr., 2011/06/16 17:41:31]

No, actually I'm fine with static methods per se. However, I'd like to keep any
code that doesn't _have_ to be in DownloadManager out of DownloadManager. The
class is unfortunately named ("Manager"), and there is a tendency to put
anything related to downloads inside it.

[haraken1, 2011/06/22 18:01:58]

Randy:
In conclusion, I placed ChooseSavableDirectory() in download_util.cc.

+                                     const FilePath& download_save_dir,
+                                     const FilePath& default_download_dir,
+                                     FilePath* save_dir);
+
  private:
   // For testing.
   friend class DownloadManagerTest;
   friend class MockDownloadManager;
 
   // This class is used to let an incognito DownloadManager observe changes to
   // a normal DownloadManager, to propagate ModelChanged() calls from the parent
   // DownloadManager to the observers of the incognito DownloadManager.
   class OtherDownloadManagerObserver : public Observer {
    public:
@@ skipping 17 matching lines @@
   friend class DeleteTask<DownloadManager>;
   friend class OtherDownloadManagerObserver;
 
   virtual ~DownloadManager();
 
   // Called on the download thread to check whether the suggested file path
   // exists.  We don't check if the file exists on the UI thread to avoid UI
   // stalls from interacting with the file system.
   void CheckIfSuggestedPathExists(int32 download_id,
                                   DownloadStateInfo state,
-                                  const FilePath& default_path);
+                                  const FilePath& download_save_dir,
+                                  const FilePath& default_download_dir);
 
   // Called on the UI thread once the DownloadManager has determined whether the
   // suggested file path exists.
   void OnPathExistenceAvailable(int32 download_id,
                                 DownloadStateInfo new_state);
 
   // Called back after a target path for the file to be downloaded to has been
   // determined, either automatically based on the suggested file name, or by
   // the user in a Save As dialog box.
   void ContinueDownloadWithPath(DownloadItem* download,
@@ skipping 104 matching lines @@
   // The "Save As" dialog box used to ask the user where a file should be
   // saved.
   scoped_refptr<SelectFileDialog> select_file_dialog_;
 
   scoped_ptr<OtherDownloadManagerObserver> other_download_manager_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadManager);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_H_