Detect removed files and reflect the state in chrome://downloads and the download shelf

chrome/browser/download/download_item.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.
 //
 // Each download is represented by a DownloadItem, and all DownloadItems
 // are owned by the DownloadManager which maintains a global list of all
 // downloads. DownloadItems are created when a user initiates a download,
 // and exist for the duration of the browser life time.
 //
 // Download observers:
@@ skipping 98 matching lines @@
 
   // Constructing for the "Save Page As..." feature:
   DownloadItem(DownloadManager* download_manager,
                const FilePath& path,
                const GURL& url,
                bool is_otr);
 
   ~DownloadItem();
 
   void AddObserver(Observer* observer);
+  bool HasObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   // Notifies our observers periodically.
   void UpdateObservers();
 
   // Whether it is OK to open this download.
   bool CanOpenDownload();
 
   // Tests if a file type should be opened automatically.
   bool ShouldOpenFileBasedOnExtension();
@@ skipping 123 matching lines @@
   int64 received_bytes() const { return received_bytes_; }
   int32 id() const { return id_; }
   base::Time start_time() const { return start_time_; }
   void set_db_handle(int64 handle) { db_handle_ = handle; }
   int64 db_handle() const { return db_handle_; }
   bool is_paused() const { return is_paused_; }
   bool open_when_complete() const { return open_when_complete_; }
   void set_open_when_complete(bool open) { open_when_complete_ = open; }
   int render_process_id() const { return render_process_id_; }
   int request_id() const { return request_id_; }
+  bool file_exists() const { return file_exists_; }
+  void set_file_exists(bool file_exists) {
+    file_exists_ = file_exists;
+  }
   SafetyState safety_state() const { return safety_state_; }
   void set_safety_state(SafetyState safety_state) {
     safety_state_ = safety_state;
   }
   DangerType danger_type() { return danger_type_;}
   bool auto_opened() { return auto_opened_; }
   FilePath target_name() const { return target_name_; }
   bool save_as() const { return save_as_; }
   bool is_otr() const { return is_otr_; }
   bool is_extension_install() const { return is_extension_install_; }
@@ skipping 86 matching lines @@
 
   // Our owning object
   DownloadManager* download_manager_;
 
   // In progress downloads may be paused by the user, we note it here
   bool is_paused_;
 
   // A flag for indicating if the download should be opened at completion.
   bool open_when_complete_;
 
+  // A flag for indicating if the downloaded path exists or not.

[Paweł Hajdan Jr., 2011/05/10 11:37:51]

nit: Please remove "or not", and replace "path" with "file". It's not obvious
what would it mean to download a path.

+  bool file_exists_;
+
   // Whether the download is considered potentially safe or dangerous
   // (executable files are typically considered dangerous).
   SafetyState safety_state_;
 
   // Why |safety_state_| is not SAFE.
   DangerType danger_type_;
 
   // Whether the download was auto-opened. We set this rather than using
   // an observer as it's frequently possible for the download to be auto opened
   // before the observer is added.
@@ skipping 26 matching lines @@
   // Did the user open the item either directly or indirectly (such as by
   // setting always open files of this type)? The shelf also sets this field
   // when the user closes the shelf before the item has been opened but should
   // be treated as though the user opened it.
   bool opened_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItem);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_H_