Refactoring of SessionService to get componentized.

chrome/browser/sessions/persistent_tab_restore_service.cc

 // 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.
 
 #include "chrome/browser/sessions/persistent_tab_restore_service.h"
 
 #include <cstring>  // memcpy
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
 #include "base/stl_util.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "base/time/time.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/base_session_service.h"
+#include "chrome/browser/sessions/base_session_service_commands.h"
 #include "chrome/browser/sessions/base_session_service_delegate_impl.h"
 #include "chrome/browser/sessions/session_command.h"
 #include "chrome/browser/sessions/session_service.h"
 #include "chrome/browser/sessions/session_service_factory.h"
 #include "chrome/browser/sessions/tab_restore_service_factory.h"
 #include "content/public/browser/session_storage_namespace.h"
 
 namespace {
 
 // Only written if the tab is pinned.
@@ skipping 74 matching lines @@
 // Number of entries (not commands) before we clobber the file and write
 // everything.
 const int kEntriesPerReset = 40;
 
 const size_t kMaxEntries = TabRestoreServiceHelper::kMaxEntries;
 
 }  // namespace
 
 // PersistentTabRestoreService::Delegate ---------------------------------------
 
-// Implements the link between the tab restore service and the session backend.
+// Implements the link between the tab restore service and BaseSessionService.
 class PersistentTabRestoreService::Delegate
-    : public BaseSessionService,
+    : public BaseSessionServiceDelegateImpl,
       public TabRestoreServiceHelper::Observer {
  public:
   explicit Delegate(Profile* profile);
 
   ~Delegate() override;
 
-  // BaseSessionService:
-  void Save() override;
+  // BaseSessionServiceDelegateImpl:
+  void OnWillSaveCommands() override;
+  void OnSavedCommands() override;
 
   // TabRestoreServiceHelper::Observer:
   void OnClearEntries() override;
   void OnRestoreEntryById(SessionID::id_type id,
                           Entries::const_iterator entry_iterator) override;
   void OnAddEntry() override;
 
   void set_tab_restore_service_helper(
       TabRestoreServiceHelper* tab_restore_service_helper) {
     tab_restore_service_helper_ = tab_restore_service_helper;
   }
 
   void LoadTabsFromLastSession();
 
+  void DeleteLastSession();
+
   bool IsLoaded() const;
 
   // Creates and add entries to |entries| for each of the windows in |windows|.
   static void CreateEntriesFromWindows(std::vector<SessionWindow*>* windows,
                                        std::vector<Entry*>* entries);
 
   void Shutdown();
 
   // Schedules the commands for a window close.
   void ScheduleCommandsForWindow(const Window& window);
 
   // Schedules the commands for a tab close. |selected_index| gives the index of
   // the selected navigation.
   void ScheduleCommandsForTab(const Tab& tab, int selected_index);
 
   // Creates a window close command.
-  static SessionCommand* CreateWindowCommand(SessionID::id_type id,
-                                             int selected_tab_index,
-                                             int num_tabs,
-                                             base::Time timestamp);
+  static scoped_ptr<SessionCommand> CreateWindowCommand(SessionID::id_type id,
+                                                        int selected_tab_index,
+                                                        int num_tabs,
+                                                        base::Time timestamp);
 
   // Creates a tab close command.
-  static SessionCommand* CreateSelectedNavigationInTabCommand(
+  static scoped_ptr<SessionCommand> CreateSelectedNavigationInTabCommand(
       SessionID::id_type tab_id,
       int32 index,
       base::Time timestamp);
 
   // Creates a restore command.
-  static SessionCommand* CreateRestoredEntryCommand(
+  static scoped_ptr<SessionCommand> CreateRestoredEntryCommand(
     SessionID::id_type entry_id);
 
   // Returns the index to persist as the selected index. This is the same as
   // |tab.current_navigation_index| unless the entry at
   // |tab.current_navigation_index| shouldn't be persisted. Returns -1 if no
   // valid navigation to persist.
   int GetSelectedNavigationIndexToPersist(const Tab& tab);
 
   // Invoked when we've loaded the session commands that identify the previously
   // closed tabs. This creates entries, adds them to staging_entries_, and
@@ skipping 26 matching lines @@
   void LoadStateChanged();
 
   // If |id_to_entry| contains an entry for |id| the corresponding entry is
   // deleted and removed from both |id_to_entry| and |entries|. This is used
   // when creating entries from the backend file.
   void RemoveEntryByID(SessionID::id_type id,
                        IDToEntry* id_to_entry,
                        std::vector<TabRestoreService::Entry*>* entries);
 
  private:
+  scoped_ptr<BaseSessionService> base_session_service_;
+
   // The associated profile.
   Profile* profile_;
 
   TabRestoreServiceHelper* tab_restore_service_helper_;
 
   // The number of entries to write.
   int entries_to_write_;
 
   // Number of entries we've written.
   int entries_written_;
 
   // Whether we've loaded the last session.
   int load_state_;
 
   // Results from previously closed tabs/sessions is first added here. When the
   // results from both us and the session restore service have finished loading
   // LoadStateChanged is invoked, which adds these entries to entries_.
   ScopedVector<Entry> staging_entries_;
 
   // Used when loading previous tabs/session and open tabs/session.
   base::CancelableTaskTracker cancelable_task_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(Delegate);
 };
 
 PersistentTabRestoreService::Delegate::Delegate(Profile* profile)
-    : BaseSessionService(
-        BaseSessionService::TAB_RESTORE,
-        profile->GetPath(),
-        scoped_ptr<BaseSessionServiceDelegate>(
-          new BaseSessionServiceDelegateImpl(true))),
+    : BaseSessionServiceDelegateImpl(true),
+      base_session_service_(
+          new BaseSessionService(BaseSessionService::TAB_RESTORE,
+                                 profile->GetPath(),
+                                 this)),
       profile_(profile),
       tab_restore_service_helper_(NULL),
       entries_to_write_(0),
       entries_written_(0),
       load_state_(NOT_LOADED) {
   // We should never be created when incognito.
   DCHECK(!profile->IsOffTheRecord());
 }
 
 PersistentTabRestoreService::Delegate::~Delegate() {}
 
-void PersistentTabRestoreService::Delegate::Save() {
+void PersistentTabRestoreService::Delegate::OnWillSaveCommands() {
   const Entries& entries = tab_restore_service_helper_->entries();
   int to_write_count = std::min(entries_to_write_,
                                 static_cast<int>(entries.size()));
   entries_to_write_ = 0;
   if (entries_written_ + to_write_count > kEntriesPerReset) {
     to_write_count = entries.size();
-    set_pending_reset(true);
+    base_session_service_->set_pending_reset(true);
   }
   if (to_write_count) {
     // Write the to_write_count most recently added entries out. The most
     // recently added entry is at the front, so we use a reverse iterator to
     // write in the order the entries were added.
     Entries::const_reverse_iterator i = entries.rbegin();
     DCHECK(static_cast<size_t>(to_write_count) <= entries.size());
     std::advance(i, entries.size() - static_cast<int>(to_write_count));
     for (; i != entries.rend(); ++i) {
       Entry* entry = *i;
       if (entry->type == TAB) {
         Tab* tab = static_cast<Tab*>(entry);
         int selected_index = GetSelectedNavigationIndexToPersist(*tab);
         if (selected_index != -1)
           ScheduleCommandsForTab(*tab, selected_index);
       } else {
         ScheduleCommandsForWindow(*static_cast<Window*>(entry));
       }
       entries_written_++;
     }
   }
-  if (pending_reset())
+  if (base_session_service_->pending_reset())
     entries_written_ = 0;
-  BaseSessionService::Save();
 }
 
+void PersistentTabRestoreService::Delegate::OnSavedCommands() {}
+
 void PersistentTabRestoreService::Delegate::OnClearEntries() {
   // Mark all the tabs as closed so that we don't attempt to restore them.
   const Entries& entries = tab_restore_service_helper_->entries();
   for (Entries::const_iterator i = entries.begin(); i != entries.end(); ++i)
-    ScheduleCommand(CreateRestoredEntryCommand((*i)->id));
+    base_session_service_->ScheduleCommand(
+        CreateRestoredEntryCommand((*i)->id).Pass());
 
   entries_to_write_ = 0;
 
   // Schedule a pending reset so that we nuke the file on next write.
-  set_pending_reset(true);
+  base_session_service_->set_pending_reset(true);
 
   // Schedule a command, otherwise if there are no pending commands Save does
   // nothing.
-  ScheduleCommand(CreateRestoredEntryCommand(1));
+  base_session_service_->ScheduleCommand(CreateRestoredEntryCommand(1).Pass());
 }
 
 void PersistentTabRestoreService::Delegate::OnRestoreEntryById(
     SessionID::id_type id,
     Entries::const_iterator entry_iterator) {
   size_t index = 0;
   const Entries& entries = tab_restore_service_helper_->entries();
   for (Entries::const_iterator j = entries.begin();
        j != entry_iterator && j != entries.end();
        ++j, ++index) {}
   if (static_cast<int>(index) < entries_to_write_)
     entries_to_write_--;
 
-  ScheduleCommand(CreateRestoredEntryCommand(id));
+  base_session_service_->ScheduleCommand(CreateRestoredEntryCommand(id).Pass());
 }
 
 void PersistentTabRestoreService::Delegate::OnAddEntry() {
   // Start the save timer, when it fires we'll generate the commands.
-  StartSaveTimer();
+  base_session_service_->StartSaveTimer();
   entries_to_write_++;
 }
 
 void PersistentTabRestoreService::Delegate::LoadTabsFromLastSession() {
   if (load_state_ != NOT_LOADED)
     return;
 
   if (tab_restore_service_helper_->entries().size() == kMaxEntries) {
     // We already have the max number of entries we can take. There is no point
     // in attempting to load since we'll just drop the results. Skip to loaded.
@@ skipping 23 matching lines @@
         base::Bind(&Delegate::OnGotPreviousSession, base::Unretained(this)),
         &cancelable_task_tracker_);
   } else {
     load_state_ |= LOADED_LAST_SESSION;
   }
 #endif
 
   // Request the tabs closed in the last session. If the last session crashed,
   // this won't contain the tabs/window that were open at the point of the
   // crash (the call to GetLastSession above requests those).
-  ScheduleGetLastSessionCommands(
+  base_session_service_->ScheduleGetLastSessionCommands(
       base::Bind(&Delegate::OnGotLastSessionCommands, base::Unretained(this)),
       &cancelable_task_tracker_);
 }
 
+void PersistentTabRestoreService::Delegate::DeleteLastSession() {
+  base_session_service_->DeleteLastSession();
+}
+
 bool PersistentTabRestoreService::Delegate::IsLoaded() const {
   return !(load_state_ & (NOT_LOADED | LOADING));
 }
 
 // static
 void PersistentTabRestoreService::Delegate::CreateEntriesFromWindows(
     std::vector<SessionWindow*>* windows,
     std::vector<Entry*>* entries) {
   for (size_t i = 0; i < windows->size(); ++i) {
     scoped_ptr<Window> window(new Window());
     if (ConvertSessionWindowToWindow((*windows)[i], window.get()))
       entries->push_back(window.release());
   }
 }
 
 void PersistentTabRestoreService::Delegate::Shutdown() {
-  if (backend())
-    Save();
+  base_session_service_->SaveNow();
 }
 
 void PersistentTabRestoreService::Delegate::ScheduleCommandsForWindow(
     const Window& window) {
   DCHECK(!window.tabs.empty());
   int selected_tab = window.selected_tab_index;
   int valid_tab_count = 0;
   int real_selected_tab = selected_tab;
   for (size_t i = 0; i < window.tabs.size(); ++i) {
     if (GetSelectedNavigationIndexToPersist(window.tabs[i]) != -1) {
       valid_tab_count++;
     } else if (static_cast<int>(i) < selected_tab) {
       real_selected_tab--;
     }
   }
   if (valid_tab_count == 0)
     return;  // No tabs to persist.
 
-  ScheduleCommand(
+  base_session_service_->ScheduleCommand(
       CreateWindowCommand(window.id,
                           std::min(real_selected_tab, valid_tab_count - 1),
                           valid_tab_count,
-                          window.timestamp));
+                          window.timestamp).Pass());
 
   if (!window.app_name.empty()) {
-    ScheduleCommand(
-        CreateSetWindowAppNameCommand(kCommandSetWindowAppName,
-                                      window.id,
-                                      window.app_name));
+    base_session_service_->ScheduleCommand(
+        BaseSessionServiceCommands::CreateSetWindowAppNameCommand(
+            kCommandSetWindowAppName,
+            window.id,
+            window.app_name).Pass());
   }
 
   for (size_t i = 0; i < window.tabs.size(); ++i) {
     int selected_index = GetSelectedNavigationIndexToPersist(window.tabs[i]);
     if (selected_index != -1)
       ScheduleCommandsForTab(window.tabs[i], selected_index);
   }
 }
 
 void PersistentTabRestoreService::Delegate::ScheduleCommandsForTab(
     const Tab& tab,
     int selected_index) {
   const std::vector<sessions::SerializedNavigationEntry>& navigations =
       tab.navigations;
   int max_index = static_cast<int>(navigations.size());
 
   // Determine the first navigation we'll persist.
   int valid_count_before_selected = 0;
   int first_index_to_persist = selected_index;
   for (int i = selected_index - 1; i >= 0 &&
-       valid_count_before_selected < max_persist_navigation_count; --i) {
+       valid_count_before_selected <
+           BaseSessionService::max_persist_navigation_count; --i) {
     if (ShouldTrackEntry(navigations[i].virtual_url())) {
       first_index_to_persist = i;
       valid_count_before_selected++;
     }
   }
 
   // Write the command that identifies the selected tab.
-  ScheduleCommand(
+  base_session_service_->ScheduleCommand(
       CreateSelectedNavigationInTabCommand(tab.id,
                                            valid_count_before_selected,
-                                           tab.timestamp));
+                                           tab.timestamp).Pass());
 
   if (tab.pinned) {
     PinnedStatePayload payload = true;
-    SessionCommand* command =
-        new SessionCommand(kCommandPinnedState, sizeof(payload));
+    scoped_ptr<SessionCommand> command(
+        new SessionCommand(kCommandPinnedState, sizeof(payload)));
     memcpy(command->contents(), &payload, sizeof(payload));
-    ScheduleCommand(command);
+    base_session_service_->ScheduleCommand(command.Pass());
   }
 
   if (!tab.extension_app_id.empty()) {
-    ScheduleCommand(
-        CreateSetTabExtensionAppIDCommand(kCommandSetExtensionAppID, tab.id,
-                                          tab.extension_app_id));
+    base_session_service_->ScheduleCommand(
+        BaseSessionServiceCommands::CreateSetTabExtensionAppIDCommand(
+            kCommandSetExtensionAppID,
+            tab.id,
+            tab.extension_app_id).Pass());
   }
 
   if (!tab.user_agent_override.empty()) {
-    ScheduleCommand(
-        CreateSetTabUserAgentOverrideCommand(kCommandSetTabUserAgentOverride,
-                                             tab.id, tab.user_agent_override));
+    base_session_service_->ScheduleCommand(
+        BaseSessionServiceCommands::CreateSetTabUserAgentOverrideCommand(
+            kCommandSetTabUserAgentOverride,
+            tab.id,
+            tab.user_agent_override).Pass());
   }
 
   // Then write the navigations.
   for (int i = first_index_to_persist, wrote_count = 0;
-       i < max_index && wrote_count < 2 * max_persist_navigation_count; ++i) {
+       wrote_count < 2 * BaseSessionService::max_persist_navigation_count &&
+       i < max_index; ++i) {
     if (ShouldTrackEntry(navigations[i].virtual_url())) {
-      ScheduleCommand(
-          CreateUpdateTabNavigationCommand(kCommandUpdateTabNavigation, tab.id,
-                                           navigations[i]));
+      base_session_service_->ScheduleCommand(
+          BaseSessionServiceCommands::CreateUpdateTabNavigationCommand(
+              kCommandUpdateTabNavigation,
+              tab.id,
+              navigations[i]));
     }
   }
 }
 
 // static
-SessionCommand* PersistentTabRestoreService::Delegate::CreateWindowCommand(
+scoped_ptr<SessionCommand>
+PersistentTabRestoreService::Delegate::CreateWindowCommand(
     SessionID::id_type id,
     int selected_tab_index,
     int num_tabs,
     base::Time timestamp) {
   WindowPayload2 payload;
   // |timestamp| is aligned on a 16 byte boundary, leaving 4 bytes of
   // uninitialized memory in the struct.
   memset(&payload, 0, sizeof(payload));
   payload.window_id = id;
   payload.selected_tab_index = selected_tab_index;
   payload.num_tabs = num_tabs;
   payload.timestamp = timestamp.ToInternalValue();
 
-  SessionCommand* command =
-      new SessionCommand(kCommandWindow, sizeof(payload));
+  scoped_ptr<SessionCommand> command(
+      new SessionCommand(kCommandWindow, sizeof(payload)));
   memcpy(command->contents(), &payload, sizeof(payload));
-  return command;
+  return command.Pass();
 }
 
 // static
-SessionCommand*
+scoped_ptr<SessionCommand>
 PersistentTabRestoreService::Delegate::CreateSelectedNavigationInTabCommand(
     SessionID::id_type tab_id,
     int32 index,
     base::Time timestamp) {
   SelectedNavigationInTabPayload2 payload;
   payload.id = tab_id;
   payload.index = index;
   payload.timestamp = timestamp.ToInternalValue();
-  SessionCommand* command =
-      new SessionCommand(kCommandSelectedNavigationInTab, sizeof(payload));
+  scoped_ptr<SessionCommand> command(
+      new SessionCommand(kCommandSelectedNavigationInTab, sizeof(payload)));
   memcpy(command->contents(), &payload, sizeof(payload));
-  return command;
+  return command.Pass();
 }
 
 // static
-SessionCommand*
+scoped_ptr<SessionCommand>
 PersistentTabRestoreService::Delegate::CreateRestoredEntryCommand(
     SessionID::id_type entry_id) {
   RestoredEntryPayload payload = entry_id;
-  SessionCommand* command =
-      new SessionCommand(kCommandRestoredEntry, sizeof(payload));
+  scoped_ptr<SessionCommand> command(
+      new SessionCommand(kCommandRestoredEntry, sizeof(payload)));
   memcpy(command->contents(), &payload, sizeof(payload));
-  return command;
+  return command.Pass();
 }
 
 int PersistentTabRestoreService::Delegate::GetSelectedNavigationIndexToPersist(
     const Tab& tab) {
   const std::vector<sessions::SerializedNavigationEntry>& navigations =
       tab.navigations;
   int selected_index = tab.current_navigation_index;
   int max_index = static_cast<int>(navigations.size());
 
   // Find the first navigation to persist. We won't persist the selected
@@ skipping 139 matching lines @@
         break;
       }
 
       case kCommandUpdateTabNavigation: {
         if (!current_tab) {
           // Should be in a tab when we get this.
           return;
         }
         current_tab->navigations.resize(current_tab->navigations.size() + 1);
         SessionID::id_type tab_id;
-        if (!RestoreUpdateTabNavigationCommand(
-            command, &current_tab->navigations.back(), &tab_id)) {
+        if (!BaseSessionServiceCommands::RestoreUpdateTabNavigationCommand(
+                 command,
+                 &current_tab->navigations.back(),
+                 &tab_id)) {
           return;
         }
         break;
       }
 
       case kCommandPinnedState: {
         if (!current_tab) {
           // Should be in a tab when we get this.
           return;
         }
         // NOTE: payload doesn't matter. kCommandPinnedState is only written if
         // tab is pinned.
         current_tab->pinned = true;
         break;
       }
 
       case kCommandSetWindowAppName: {
         if (!current_window) {
           // We should have created a window already.
           NOTREACHED();
           return;
         }
 
         SessionID::id_type window_id;
         std::string app_name;
-        if (!RestoreSetWindowAppNameCommand(command, &window_id, &app_name))
+        if (!BaseSessionServiceCommands::RestoreSetWindowAppNameCommand(
+                 command,
+                 &window_id,
+                 &app_name)) {
           return;
+        }
 
         current_window->app_name.swap(app_name);
         break;
       }
 
       case kCommandSetExtensionAppID: {
         if (!current_tab) {
           // Should be in a tab when we get this.
           return;
         }
         SessionID::id_type tab_id;
         std::string extension_app_id;
-        if (!RestoreSetTabExtensionAppIDCommand(command, &tab_id,
-                                                &extension_app_id)) {
+        if (!BaseSessionServiceCommands::RestoreSetTabExtensionAppIDCommand(
+                 command,
+                 &tab_id,
+                 &extension_app_id)) {
           return;
         }
         current_tab->extension_app_id.swap(extension_app_id);
         break;
       }
 
       case kCommandSetTabUserAgentOverride: {
         if (!current_tab) {
           // Should be in a tab when we get this.
           return;
         }
         SessionID::id_type tab_id;
         std::string user_agent_override;
-        if (!RestoreSetTabUserAgentOverrideCommand(command, &tab_id,
-                                                   &user_agent_override)) {
+        if (!BaseSessionServiceCommands::RestoreSetTabUserAgentOverrideCommand(
+                 command,
+                 &tab_id,
+                 &user_agent_override)) {
           return;
         }
         current_tab->user_agent_override.swap(user_agent_override);
         break;
       }
 
       default:
         // Unknown type, usually indicates corruption of file. Ignore it.
         return;
     }
@@ skipping 235 matching lines @@
 }
 
 void PersistentTabRestoreService::PruneEntries() {
   helper_.PruneEntries();
 }
 
 KeyedService* TabRestoreServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* profile) const {
   return new PersistentTabRestoreService(static_cast<Profile*>(profile), NULL);
 }