Created a DownloadManager interface, for use in unit tests..

content/browser/download/download_manager_impl.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

[jam, 2011/11/10 17:19:09]

nit: this line through 25 should be removed, the comment should only be in the
interface file, and the implementation's header doesn't need to duplicate it

[ahendrickson, 2011/11/18 18:47:39]

Done.

+// updates to the history system and providing the information for displaying
+// the downloads view in the Destinations tab. There is one DownloadManager per
+// active browser context in Chrome.
+//
+// Download observers:
+// Objects that are interested in notifications about new downloads, or progress
+// updates for a given download must implement one of the download observer
+// interfaces:
+//   DownloadManager::Observer:
+//     - allows observers, primarily views, to be notified when changes to the
+//       set of all downloads (such as new downloads, or deletes) occur
+// Use AddObserver() / RemoveObserver() on the appropriate download object to
+// receive state updates.
+//
+// Download state persistence:
+// The DownloadManager uses the history service for storing persistent
+// information about the state of all downloads. The history system maintains a
+// separate table for this called 'downloads'. At the point that the
+// DownloadManager is constructed, we query the history service for the state of
+// all persisted downloads.
+
+#ifndef CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_IMPL_H_
+#define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_IMPL_H_
+#pragma once
+
+#include "content/browser/download/download_manager.h"
+
+#include <map>
+#include <set>
+
+#include "base/hash_tables.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
+#include "base/synchronization/lock.h"
+#include "content/browser/download/download_status_updater_delegate.h"
+#include "content/common/content_export.h"
+
+class DownloadIdFactory;
+class DownloadStatusUpdater;
+
+class CONTENT_EXPORT DownloadManagerImpl
+    : public DownloadManager,
+      public DownloadStatusUpdaterDelegate {
+ public:
+  DownloadManagerImpl(content::DownloadManagerDelegate* delegate,
+                  DownloadIdFactory* id_factory,
+                  DownloadStatusUpdater* status_updater);
+
+  // DownloadManager functions.
+  virtual void Shutdown() OVERRIDE;
+  virtual void GetTemporaryDownloads(const FilePath& dir_path,
+                                     DownloadVector* result) OVERRIDE;
+  virtual void GetAllDownloads(const FilePath& dir_path,
+                               DownloadVector* result) OVERRIDE;
+  virtual void SearchDownloads(const string16& query,
+                               DownloadVector* result) OVERRIDE;
+  virtual bool Init(content::BrowserContext* browser_context) OVERRIDE;
+  virtual void StartDownload(int32 id) OVERRIDE;
+  virtual void UpdateDownload(int32 download_id, int64 size) OVERRIDE;
+  virtual void OnResponseCompleted(int32 download_id, int64 size,
+                                   const std::string& hash) OVERRIDE;
+  virtual void CancelDownload(int32 download_id) OVERRIDE;
+  virtual void OnDownloadInterrupted(int32 download_id, int64 size,
+                                     InterruptReason reason) OVERRIDE;
+  virtual void DownloadCancelledInternal(DownloadItem* download) OVERRIDE;
+  virtual void RemoveDownload(int64 download_handle) OVERRIDE;
+  virtual bool IsDownloadReadyForCompletion(DownloadItem* download) OVERRIDE;
+  virtual void MaybeCompleteDownload(DownloadItem* download) OVERRIDE;
+  virtual void OnDownloadRenamedToFinalName(int download_id,
+                                            const FilePath& full_path,
+                                            int uniquifier) OVERRIDE;
+  virtual int RemoveDownloadsBetween(const base::Time remove_begin,
+                                     const base::Time remove_end) OVERRIDE;
+  virtual int RemoveDownloads(const base::Time remove_begin) OVERRIDE;
+  virtual int RemoveAllDownloads() OVERRIDE;
+  virtual void DownloadCompleted(int32 download_id) OVERRIDE;
+  virtual void DownloadUrl(const GURL& url,
+                           const GURL& referrer,
+                           const std::string& referrer_encoding,
+                           TabContents* tab_contents) OVERRIDE;
+  virtual void DownloadUrlToFile(const GURL& url,
+                                 const GURL& referrer,
+                                 const std::string& referrer_encoding,
+                                 const DownloadSaveInfo& save_info,
+                                 TabContents* tab_contents) OVERRIDE;
+  virtual void AddObserver(Observer* observer) OVERRIDE;
+  virtual void RemoveObserver(Observer* observer) OVERRIDE;
+  virtual void OnPersistentStoreQueryComplete(
+      std::vector<DownloadPersistentStoreInfo>* entries) OVERRIDE;
+  virtual void OnItemAddedToPersistentStore(int32 download_id,
+                                            int64 db_handle) OVERRIDE;
+  virtual void ShowDownloadInBrowser(DownloadItem* download) OVERRIDE;
+  virtual int InProgressCount() const OVERRIDE;
+  virtual content::BrowserContext* BrowserContext() OVERRIDE;
+  virtual FilePath LastDownloadPath() OVERRIDE;
+  virtual void CreateDownloadItem(
+      DownloadCreateInfo* info,
+      const DownloadRequestHandle& request_handle) OVERRIDE;
+  virtual void ClearLastDownloadPath() OVERRIDE;
+
+  // Overridden from DownloadStatusUpdaterDelegate:
+  virtual bool IsDownloadProgressKnown() const OVERRIDE;
+  virtual int64 GetInProgressDownloadCount() const OVERRIDE;
+  virtual int64 GetReceivedDownloadBytes() const OVERRIDE;
+  virtual int64 GetTotalDownloadBytes() const OVERRIDE;
+
+  // More DownloadManager functions.

[jam, 2011/11/10 17:19:09]

nit: all the overridden functions from the same interface should be listed right
after each other

[ahendrickson, 2011/11/18 18:47:39]

Done.

+  virtual void FileSelected(const FilePath& path, void* params) OVERRIDE;
+  virtual void FileSelectionCanceled(void* params) OVERRIDE;
+  virtual void RestartDownload(int32 download_id) OVERRIDE;
+  virtual void MarkDownloadOpened(DownloadItem* download) OVERRIDE;
+  virtual void CheckForHistoryFilesRemoval() OVERRIDE;
+  virtual void CheckForFileRemoval(DownloadItem* download_item) OVERRIDE;
+  virtual void AssertQueueStateConsistent(DownloadItem* download) OVERRIDE;
+  virtual DownloadItem* GetDownloadItem(int id) OVERRIDE;
+  virtual void SavePageDownloadStarted(DownloadItem* download) OVERRIDE;
+  virtual void SavePageDownloadFinished(DownloadItem* download) OVERRIDE;
+  virtual DownloadItem* GetActiveDownloadItem(int id) OVERRIDE;
+  virtual content::DownloadManagerDelegate* delegate() const OVERRIDE;
+  virtual void SetDownloadManagerDelegate(
+      content::DownloadManagerDelegate* delegate) OVERRIDE;
+  virtual DownloadId GetNextId() OVERRIDE;
+
+ private:
+  typedef std::set<DownloadItem*> DownloadSet;
+  typedef base::hash_map<int64, DownloadItem*> DownloadMap;
+
+  // For testing.
+  friend class DownloadManagerTest;
+  friend class DownloadTest;
+  friend class MockDownloadManager;
+
+  friend class base::RefCountedThreadSafe<
+      DownloadManagerImpl, content::BrowserThread::DeleteOnUIThread>;
+  friend struct content::BrowserThread::DeleteOnThread<
+      content::BrowserThread::UI>;
+  friend class DeleteTask<DownloadManagerImpl>;
+
+  virtual ~DownloadManagerImpl();
+
+  // Called on the FILE thread to check the existence of a downloaded file.
+  void CheckForFileRemovalOnFileThread(int64 db_handle, const FilePath& path);
+
+  // Called on the UI thread if the FILE thread detects the removal of
+  // the downloaded file. The UI thread updates the state of the file
+  // and then notifies this update to the file's observer.
+  void OnFileRemovalDetected(int64 db_handle);
+
+  // 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.
+  virtual void ContinueDownloadWithPath(DownloadItem* download,
+                                        const FilePath& chosen_file) OVERRIDE;
+
+  // Retrieves the download from the |download_id|.
+  // Returns NULL if the download is not active.
+  virtual DownloadItem* GetActiveDownload(int32 download_id) OVERRIDE;
+
+  // Removes |download| from the active and in progress maps.
+  // Called when the download is cancelled or has an error.
+  // Does nothing if the download is not in the history DB.
+  void RemoveFromActiveList(DownloadItem* download);
+
+  // Updates the delegate about the overall download progress.
+  void UpdateDownloadProgress();
+
+  // Inform observers that the model has changed.
+  void NotifyModelChanged();
+
+  // Debugging routine to confirm relationship between below
+  // containers; no-op if NDEBUG.
+  void AssertContainersConsistent() const;
+
+  // Add a DownloadItem to history_downloads_.
+  void AddDownloadItemToHistory(DownloadItem* item, int64 db_handle);
+
+  // Remove from internal maps.
+  int RemoveDownloadItems(const DownloadVector& pending_deletes);
+
+  // Called when a download entry is committed to the persistent store.
+  void OnDownloadItemAddedToPersistentStore(int32 download_id, int64 db_handle);
+
+  // Called when Save Page As entry is committed to the persistent store.
+  void OnSavePageItemAddedToPersistentStore(int32 download_id, int64 db_handle);
+
+  // For unit tests only.
+  virtual void SetFileManager(DownloadFileManager* file_manager) OVERRIDE;
+
+  // |downloads_| is the owning set for all downloads known to the
+  // DownloadManager.  This includes downloads started by the user in
+  // this session, downloads initialized from the history system, and
+  // "save page as" downloads.  All other DownloadItem containers in
+  // the DownloadManager are maps; they do not own the DownloadItems.
+  // Note that this is the only place (with any functional implications;
+  // see save_page_downloads_ below) that "save page as" downloads are
+  // kept, as the DownloadManager's only job is to hold onto those
+  // until destruction.
+  //
+  // |history_downloads_| is map of all downloads in this browser context. The
+  // key is the handle returned by the history system, which is unique across
+  // sessions.
+  //
+  // |active_downloads_| is a map of all downloads that are currently being
+  // processed. The key is the ID assigned by the DownloadFileManager,
+  // which is unique for the current session.
+  //
+  // |in_progress_| is a map of all downloads that are in progress and that have
+  // not yet received a valid history handle. The key is the ID assigned by the
+  // DownloadFileManager, which is unique for the current session.
+  //
+  // |save_page_downloads_| (if defined) is a collection of all the
+  // downloads the "save page as" system has given to us to hold onto
+  // until we are destroyed. They key is DownloadFileManager, so it is unique
+  // compared to download item. It is only used for debugging.
+  //
+  // When a download is created through a user action, the corresponding
+  // DownloadItem* is placed in |active_downloads_| and remains there until the
+  // download is in a terminal state (COMPLETE or CANCELLED).  It is also
+  // placed in |in_progress_| and remains there until it has received a
+  // valid handle from the history system. Once it has a valid handle, the
+  // DownloadItem* is placed in the |history_downloads_| map.  When the
+  // download reaches a terminal state, it is removed from |in_progress_|.
+  // Downloads from past sessions read from a persisted state from the
+  // history system are placed directly into |history_downloads_| since
+  // they have valid handles in the history system.
+
+  DownloadSet downloads_;
+  DownloadMap history_downloads_;
+  DownloadMap in_progress_;
+  DownloadMap active_downloads_;
+  DownloadMap save_page_downloads_;
+
+  // True if the download manager has been initialized and requires a shutdown.
+  bool shutdown_needed_;
+
+  // Observers that want to be notified of changes to the set of downloads.
+  ObserverList<Observer> observers_;
+
+  // The current active browser context.
+  content::BrowserContext* browser_context_;
+
+  // Non-owning pointer for handling file writing on the download_thread_.
+  DownloadFileManager* file_manager_;
+
+  // Non-owning pointer for updating the download status.
+  base::WeakPtr<DownloadStatusUpdater> status_updater_;
+
+  // The user's last choice for download directory. This is only used when the
+  // user wants us to prompt for a save location for each download.
+  FilePath last_download_path_;
+
+  // Allows an embedder to control behavior. Guaranteed to outlive this object.
+  content::DownloadManagerDelegate* delegate_;
+
+  DownloadIdFactory* id_factory_;
+
+  // TODO(rdsmith): Remove when http://crbug.com/85408 is fixed.
+  // For debugging only.
+  int64 largest_db_handle_in_history_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadManagerImpl);
+};
+
+#endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_IMPL_H_