Makes the tab restore service persist closed tabs/windows to disk and

reload them when asked.

Sorry for largish looking change. It's made big by refactoring common
code between TabRestoreService and SessionService into a common
superclass. At the same time I removed some dead code and shuffled the
session related classes into a single directory for easier perusal.

BUG=384
TEST=close the browser, start the browser and make sure the new tab
     page shows closed windows/tabs from the previous session.

Review URL: http://codereview.chromium.org/13152

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6490 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 349 insertions, 0 deletions

diff --git a/chrome/browser/sessions/session_service.h b/chrome/browser/sessions/session_service.h
new file mode 100644
index 0000000..1c3402d3
--- /dev/null
+++ b/chrome/browser/sessions/session_service.h
@@ -0,0 +1,349 @@
+// Copyright (c) 2006-2008 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_SESSIONS_SESSION_SERVICE_H_
+#define CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "chrome/browser/browser.h"
+#include "chrome/browser/sessions/base_session_service.h"
+#include "chrome/browser/sessions/session_id.h"
+#include "chrome/common/notification_service.h"
+
+class Browser;
+class NavigationController;
+class NavigationEntry;
+class Profile;
+class SessionCommand;
+struct SessionTab;
+struct SessionWindow;
+
+// SessionService ------------------------------------------------------------
+
+// SessionService is responsible for maintaining the state of open windows
+// and tabs so that they can be restored at a later date. The state of the
+// currently open browsers is referred to as the current session.
+//
+// SessionService supports restoring from the previous or last session. The
+// previous session typically corresponds to the last run of the browser, but
+// not always. For example, if the user has a tabbed browser and app window
+// running, closes the tabbed browser, then creates a new tabbed browser the
+// current session is made the last session and the current session reset. This
+// is done to provide the illusion that app windows run in separate processes.
+//
+// SessionService itself maintains a set of SessionCommands that allow
+// SessionService to rebuild the open state of the browser (as
+// SessionWindow, SessionTab and TabNavigation). The commands are periodically
+// flushed to SessionBackend and written to a file. Every so often
+// SessionService rebuilds the contents of the file from the open state
+// of the browser.
+class SessionService : public BaseSessionService,
+                       public NotificationObserver {
+  friend class SessionServiceTestHelper;
+ public:
+  // Creates a SessionService for the specified profile.
+  explicit SessionService(Profile* profile);
+  // For testing.
+  explicit SessionService(const std::wstring& save_path);
+
+  virtual ~SessionService();
+
+  // Resets the contents of the file from the current state of all open
+  // browsers whose profile matches our profile.
+  void ResetFromCurrentBrowsers();
+
+  // Moves the current session to the last session. This is useful when a
+  // checkpoint occurs, such as when the user launches the app and no tabbed
+  // browsers are running.
+  void MoveCurrentSessionToLastSession();
+
+  // Associates a tab with a window.
+  void SetTabWindow(const SessionID& window_id,
+                    const SessionID& tab_id);
+
+  // Sets the bounds of a window.
+  void SetWindowBounds(const SessionID& window_id,
+                       const gfx::Rect& bounds,
+                       bool is_maximized);
+
+  // Sets the visual index of the tab in its parent window.
+  void SetTabIndexInWindow(const SessionID& window_id,
+                           const SessionID& tab_id,
+                           int new_index);
+
+  // Notification that a tab has been closed.
+  //
+  // Note: this is invoked from the NavigationController's destructor, which is
+  // after the actual tab has been removed.
+  void TabClosed(const SessionID& window_id, const SessionID& tab_id);
+
+  // Notification the window is about to close.
+  void WindowClosing(const SessionID& window_id);
+
+  // Notification a window has finished closing.
+  void WindowClosed(const SessionID& window_id);
+
+  // Sets the type of window. In order for the contents of a window to be
+  // tracked SetWindowType must be invoked with a type we track
+  // (should_track_changes_for_browser_type returns true).
+  void SetWindowType(const SessionID& window_id, Browser::Type type);
+
+  // Invoked when the NavigationController has removed entries from the back of
+  // the list. |count| gives the number of entries in the navigation controller.
+  void TabNavigationPathPrunedFromBack(const SessionID& window_id,
+                                       const SessionID& tab_id,
+                                       int count);
+
+  // Invoked when the NavigationController has removed entries from the front of
+  // the list. |count| gives the number of entries that were removed.
+  void TabNavigationPathPrunedFromFront(const SessionID& window_id,
+                                        const SessionID& tab_id,
+                                        int count);
+
+  // Updates the navigation entry for the specified tab.
+  void UpdateTabNavigation(const SessionID& window_id,
+                           const SessionID& tab_id,
+                           int index,
+                           const NavigationEntry& entry);
+
+  // Notification that a tab has restored its entries or a closed tab is being
+  // reused.
+  void TabRestored(NavigationController* controller);
+
+  // Sets the index of the selected entry in the navigation controller for the
+  // specified tab.
+  void SetSelectedNavigationIndex(const SessionID& window_id,
+                                  const SessionID& tab_id,
+                                  int index);
+
+  // Sets the index of the selected tab in the specified window.
+  void SetSelectedTabInWindow(const SessionID& window_id, int index);
+
+  // Callback from GetSavedSession of GetLastSession.
+  //
+  // The contents of the supplied vector are deleted after the callback is
+  // notified. To take ownership of the vector clear it before returning.
+  //
+  // The time gives the time the session was closed.
+  typedef Callback2<Handle, std::vector<SessionWindow*>*>::Type
+      LastSessionCallback;
+
+  // Fetches the contents of the last session, notifying the callback when
+  // done. If the callback is supplied an empty vector of SessionWindows
+  // it means the session could not be restored.
+  //
+  // The created request does NOT directly invoke the callback, rather the
+  // callback invokes OnGotSessionCommands from which we map the
+  // SessionCommands to browser state, then notify the callback.
+  Handle GetLastSession(CancelableRequestConsumerBase* consumer,
+                        LastSessionCallback* callback);
+
+ private:
+  typedef std::map<SessionID::id_type,std::pair<int,int> > IdToRange;
+  typedef std::map<SessionID::id_type,SessionTab*> IdToSessionTab;
+  typedef std::map<SessionID::id_type,SessionWindow*> IdToSessionWindow;
+
+  void Init();
+
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+  // Methods to create the various commands. It is up to the caller to delete
+  // the returned the SessionCommand* object.
+  SessionCommand* CreateSetSelectedTabInWindow(const SessionID& window_id,
+                                               int index);
+
+  SessionCommand* CreateSetTabWindowCommand(const SessionID& window_id,
+                                            const SessionID& tab_id);
+
+  SessionCommand* CreateSetWindowBoundsCommand(const SessionID& window_id,
+                                               const gfx::Rect& bounds,
+                                               bool is_maximized);
+
+  SessionCommand* CreateSetTabIndexInWindowCommand(const SessionID& tab_id,
+                                                   int new_index);
+
+  SessionCommand* CreateTabClosedCommand(SessionID::id_type tab_id);
+
+  SessionCommand* CreateWindowClosedCommand(SessionID::id_type tab_id);
+
+  SessionCommand* CreateSetSelectedNavigationIndexCommand(
+      const SessionID& tab_id,
+      int index);
+
+  SessionCommand* CreateSetWindowTypeCommand(const SessionID& window_id,
+                                             Browser::Type type);
+
+  // Callback form the backend for getting the commands from the previous
+  // or save file. Converts the commands in SessionWindows and notifies
+  // the real callback.
+  void OnGotLastSessionCommands(
+      Handle handle,
+      scoped_refptr<InternalGetCommandsRequest> request);
+
+  // Converts the commands into SessionWindows. On return any valid
+  // windows are added to valid_windows. It is up to the caller to delete
+  // the windows added to valid_windows.
+  //
+  // If ignore_recent_closes is true, any window/tab closes within in a certain
+  // time frame are ignored.
+  void RestoreSessionFromCommands(const std::vector<SessionCommand*>& commands,
+                                  std::vector<SessionWindow*>* valid_windows);
+
+  // Iterates through the vector updating the selected_tab_index of each
+  // SessionWindow based on the actual tabs that were restored.
+  void UpdateSelectedTabIndex(std::vector<SessionWindow*>* windows);
+
+  // Returns the window in windows with the specified id. If a window does
+  // not exist, one is created.
+  SessionWindow* GetWindow(SessionID::id_type window_id,
+                           IdToSessionWindow* windows);
+
+  // Returns the tab with the specified id in tabs. If a tab does not exist,
+  // it is created.
+  SessionTab* GetTab(SessionID::id_type tab_id,
+                     IdToSessionTab* tabs);
+
+  // Returns an iterator into navigations pointing to the navigation whose
+  // index matches |index|. If no navigation index matches |index|, the first
+  // navigation with an index > |index| is returned.
+  //
+  // This assumes the navigations are ordered by index in ascending order.
+  std::vector<TabNavigation>::iterator FindClosestNavigationWithIndex(
+      std::vector<TabNavigation>* navigations,
+      int index);
+
+  // Does the following:
+  // . Deletes and removes any windows with no tabs or windows with types other
+  //   than tabbed_browser or browser. NOTE: constrained windows that have
+  //   been dragged out are of type browser. As such, this preserves any dragged
+  //   out constrained windows (aka popups that have been dragged out).
+  // . Sorts the tabs in windows with valid tabs based on the tabs
+  //   visual order, and adds the valid windows to windows.
+  void SortTabsBasedOnVisualOrderAndPrune(
+      std::map<int,SessionWindow*>* windows,
+      std::vector<SessionWindow*>* valid_windows);
+
+  // Adds tabs to their parent window based on the tab's window_id. This
+  // ignores tabs with no navigations.
+  void AddTabsToWindows(std::map<int,SessionTab*>* tabs,
+                        std::map<int,SessionWindow*>* windows);
+
+  // Creates tabs and windows from the specified commands. The created tabs
+  // and windows are added to |tabs| and |windows| respectively. It is up to
+  // the caller to delete the tabs and windows added to |tabs| and |windows|.
+  //
+  // This does NOT add any created SessionTabs to SessionWindow.tabs, that is
+  // done by AddTabsToWindows.
+  bool CreateTabsAndWindows(const std::vector<SessionCommand*>& data,
+                            std::map<int,SessionTab*>* tabs,
+                            std::map<int,SessionWindow*>* windows);
+
+  // Adds commands to commands that will recreate the state of the specified
+  // NavigationController. This adds at most kMaxNavigationCountToPersist
+  // navigations (in each direction from the current navigation index).
+  // A pair is added to tab_to_available_range indicating the range of
+  // indices that were written.
+  void BuildCommandsForTab(
+      const SessionID& window_id,
+      NavigationController* controller,
+      int index_in_window,
+      std::vector<SessionCommand*>* commands,
+      IdToRange* tab_to_available_range);
+
+  // Adds commands to create the specified browser, and invokes
+  // BuildCommandsForTab for each of the tabs in the browser. This ignores
+  // any tabs not in the profile we were created with.
+  void BuildCommandsForBrowser(
+      Browser* browser,
+      std::vector<SessionCommand*>* commands,
+      IdToRange* tab_to_available_range,
+      std::set<SessionID::id_type>* windows_to_track);
+
+  // Iterates over all the known browsers invoking BuildCommandsForBrowser.
+  // This only adds browsers that should be tracked
+  // (should_track_changes_for_browser_type returns true). All browsers that
+  // are tracked are added to windows_to_track (as long as it is non-null).
+  void BuildCommandsFromBrowsers(
+      std::vector<SessionCommand*>* commands,
+      IdToRange* tab_to_available_range,
+      std::set<SessionID::id_type>* windows_to_track);
+
+  // Schedules a reset. A reset means the contents of the file are recreated
+  // from the state of the browser.
+  void ScheduleReset();
+
+  // Searches for a pending command that can be replaced with command.
+  // If one is found, pending command is removed, command is added to
+  // the pending commands and true is returned.
+  bool ReplacePendingCommand(SessionCommand* command);
+
+  // Schedules the specified command. This method takes ownership of the
+  // command.
+  void ScheduleCommand(SessionCommand* command);
+
+  // Converts all pending tab/window closes to commands and schedules them.
+  void CommitPendingCloses();
+
+  // Returns true if there is only one window open with a single tab that shares
+  // our profile.
+  bool IsOnlyOneTabLeft();
+
+  // Returns true if there are no open tabbed browser windows with our profile,
+  // or the only tabbed browser open has a session id of window_id.
+  bool HasOpenTabbedBrowsers(const SessionID& window_id);
+
+  // Returns true if changes to tabs in the specified window should be tracked.
+  bool ShouldTrackChangesToWindow(const SessionID& window_id);
+
+  // Returns true if we track changes to the specified browser type.
+  static bool should_track_changes_for_browser_type(Browser::Type type) {
+    return type == Browser::TYPE_NORMAL;
+  }
+
+  // Maps from session tab id to the range of navigation entries that has
+  // been written to disk.
+  //
+  // This is only used if not all the navigation entries have been
+  // written.
+  IdToRange tab_to_available_range_;
+
+  // When the user closes the last window, where the last window is the
+  // last tabbed browser and no more tabbed browsers are open with the same
+  // profile, the window ID is added here. These IDs are only committed (which
+  // marks them as closed) if the user creates a new tabbed browser.
+  typedef std::set<SessionID::id_type> PendingWindowCloseIDs;
+  PendingWindowCloseIDs pending_window_close_ids_;
+
+  // Set of tabs that have been closed by way of the last window or last tab
+  // closing, but not yet committed.
+  typedef std::set<SessionID::id_type> PendingTabCloseIDs;
+  PendingTabCloseIDs pending_tab_close_ids_;
+
+  // When a window other than the last window (see description of
+  // pending_window_close_ids) is closed, the id is added to this set.
+  typedef std::set<SessionID::id_type> WindowClosingIDs;
+  WindowClosingIDs window_closing_ids_;
+
+  // Set of windows we're tracking changes to. This is only browsers that
+  // return true from should_track_changes_for_browser_type.
+  typedef std::set<SessionID::id_type> WindowsTracking;
+  WindowsTracking windows_tracking_;
+
+  // Are there any open open tabbed browsers?
+  bool has_open_tabbed_browsers_;
+
+  // If true and a new tabbed browser is created and there are no opened tabbed
+  // browser (has_open_tabbed_browsers_ is false), then the current session
+  // is made the previous session. See description above class for details on
+  // current/previou session.
+  bool move_on_new_browser_;
+
+  DISALLOW_COPY_AND_ASSIGN(SessionService);
+};
+
+#endif  // CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_