Change SpellChecker language without restarting the browser.

Review URL: http://codereview.chromium.org/7056

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@3407 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 150 insertions, 25 deletions

diff --git a/chrome/browser/profile.cc b/chrome/browser/profile.cc
index ad2ddb1..bf40016 100644
--- a/chrome/browser/profile.cc
+++ b/chrome/browser/profile.cc
@@ -479,6 +479,10 @@ class OffTheRecordProfileImpl : public Profile,
     return NULL;
   }
 
+  virtual void InitializeSpellChecker() {
+    profile_->InitializeSpellChecker();
+  }
+
   virtual void ResetTabRestoreService() {
   }
 
@@ -837,24 +841,79 @@ void ProfileImpl::ResetTabRestoreService() {
   tab_restore_service_.reset(NULL);
 }
 
+// To be run in the IO thread to notify all resource message filters that the 
+// spellchecker has changed.
+class NotifySpellcheckerChangeTask : public Task {
+ public:
+  NotifySpellcheckerChangeTask(
+      Profile* profile, const SpellcheckerReinitializedDetails& spellchecker)
+      : profile_(profile),
+        spellchecker_(spellchecker) {
+  }
+
+ private:
+  void Run(void) {
+    NotificationService::current()->Notify(
+        NOTIFY_SPELLCHECKER_REINITIALIZED,
+        Source<Profile>(profile_),
+        Details<SpellcheckerReinitializedDetails>(&spellchecker_));
+  }
+
+  Profile* profile_;
+  SpellcheckerReinitializedDetails spellchecker_;
+};
+
+void ProfileImpl::InitializeSpellChecker() {
+  bool need_to_broadcast = false;
+
+  // The I/O thread may be NULL during testing.
+  base::Thread* io_thread = g_browser_process->io_thread();
+  if (spellchecker_) {
+    // The spellchecker must be deleted on the I/O thread.
+    // A dummy variable to aid in logical clarity.
+    SpellChecker* last_spellchecker = spellchecker_;
+
+    if (io_thread)
+      io_thread->message_loop()->ReleaseSoon(FROM_HERE, last_spellchecker);
+    else  //  during testing, we don't have an I/O thread
+      last_spellchecker->Release();
+
+    need_to_broadcast = true;
+  }
+
+  std::wstring dict_dir;
+  PathService::Get(chrome::DIR_APP_DICTIONARIES, &dict_dir);
+
+  // Retrieve the (perhaps updated recently) dictionary name from preferences.
+  PrefService* prefs = GetPrefs();
+  std::wstring language = prefs->GetString(prefs::kSpellCheckDictionary);
+
+  // Note that, as the object pointed to by previously by spellchecker_ 
+  // is being deleted in the io thread, the spellchecker_ can be made to point
+  // to a new object (RE-initialized) in parallel in this UI thread.
+  spellchecker_ = new SpellChecker(dict_dir, language, GetRequestContext(), 
+                                   L"");
+  spellchecker_->AddRef();  // Manual refcounting.
+
+  if (need_to_broadcast && io_thread) {  // Notify resource message filters.
+    SpellcheckerReinitializedDetails scoped_spellchecker;
+    scoped_spellchecker.spellchecker = spellchecker_;
+    io_thread->message_loop()->PostTask(
+        FROM_HERE, 
+        new NotifySpellcheckerChangeTask(this, scoped_spellchecker));
+  }
+}
+
 SpellChecker* ProfileImpl::GetSpellChecker() {
   if (!spellchecker_) {
-    // Don't check for an error here. In the extremely unlikely case that this
-    // fails, the spellchecker just won't find the file. This prevents callers
-    // from having to check for NULL return values from this function.
-    std::wstring dict_dir;
-    PathService::Get(chrome::DIR_APP_DICTIONARIES, &dict_dir);
-
-    // Retrieve the dictionary name from preferences or the language DLL.
-    // When we retrieve it from the language DLL.
-    PrefService* prefs = GetPrefs();
-    std::wstring dictionary_name = prefs->GetString(
-        prefs::kSpellCheckDictionary);
-
-    spellchecker_ = new SpellChecker(dict_dir, dictionary_name,
-                                     GetRequestContext(), L"");
-    spellchecker_->AddRef();  // Manual refcounting.
+    // This is where spellchecker gets initialized. Note that this is being
+    // initialized in the ui_thread. However, this is not a problem as long as
+    // it is *used* in the io thread.
+    // TODO (sidchat) One day, change everything so that spellchecker gets
+    // initialized in the IO thread itself.
+    InitializeSpellChecker();
   }
+
   return spellchecker_;
 }
 
diff --git a/chrome/browser/profile.h b/chrome/browser/profile.h
index 09b0baf..2edc40c 100644
--- a/chrome/browser/profile.h
+++ b/chrome/browser/profile.h
@@ -194,6 +194,13 @@ class Profile {
 
   virtual void ResetTabRestoreService() = 0;
 
+  // Initializes the spellchecker. If the spellchecker already exsts, then
+  // it is released, and initialized again. This model makes sure that 
+  // spellchecker language can be changed without restarting the browser.
+  // NOTE: This is being currently called in the UI thread, which is OK as long
+  // as the spellchecker object is USED in the IO thread.
+  virtual void InitializeSpellChecker() = 0;
+
   // Returns the spell checker object for this profile. THIS OBJECT MUST ONLY
   // BE USED ON THE I/O THREAD! This pointer is retrieved from the profile and
   // sent to the I/O thread where it is actually used.
@@ -203,8 +210,7 @@ class Profile {
   //
   // NOTE: this is invoked internally on a normal shutdown, but is public so
   // that it can be invoked when the user logs out/powers down (WM_ENDSESSION).
-  virtual void MarkAsCleanShutdown() = 0;
-
+  virtual void MarkAsCleanShutdown() = 0;  
 #ifdef UNIT_TEST
   // Use with caution.  GetDefaultRequestContext may be called on any thread!
   static void set_default_request_context(URLRequestContext* c) {
@@ -250,6 +256,7 @@ class ProfileImpl : public Profile {
   virtual Time GetStartTime() const;
   virtual TabRestoreService* GetTabRestoreService();
   virtual void ResetTabRestoreService();
+  virtual void InitializeSpellChecker();
   virtual SpellChecker* GetSpellChecker();
   virtual void MarkAsCleanShutdown();
 #ifdef CHROME_PERSONALIZATION
@@ -316,5 +323,12 @@ class ProfileImpl : public Profile {
   DISALLOW_EVIL_CONSTRUCTORS(ProfileImpl);
 };
 
+// This struct is used to pass the spellchecker object through the notification
+// NOTIFY_SPELLCHECKER_REINITIALIZED. This is used as the details for the
+// notification service.
+struct SpellcheckerReinitializedDetails {
+  scoped_refptr<SpellChecker> spellchecker;
+};
+
 #endif  // CHROME_BROWSER_PROFILE_H__
 
diff --git a/chrome/browser/resource_message_filter.cc b/chrome/browser/resource_message_filter.cc
index 4821cfd..5afe628 100644
--- a/chrome/browser/resource_message_filter.cc
+++ b/chrome/browser/resource_message_filter.cc
@@ -91,6 +91,7 @@ ResourceMessageFilter::ResourceMessageFilter(
       render_process_host_id_(render_process_host_id),
       render_handle_(NULL),
       request_context_(profile->GetRequestContext()),
+      profile_(profile),
       render_widget_helper_(render_widget_helper),
       spellchecker_(spellchecker) {
 
@@ -101,11 +102,23 @@ ResourceMessageFilter::ResourceMessageFilter(
 ResourceMessageFilter::~ResourceMessageFilter() {
   if (render_handle_)
     CloseHandle(render_handle_);
+
+  // This function should be called on the IO thread.
+  DCHECK(MessageLoop::current() ==
+         ChromeThread::GetMessageLoop(ChromeThread::IO));
+  NotificationService::current()->RemoveObserver(
+      this, NOTIFY_SPELLCHECKER_REINITIALIZED,
+      Source<Profile>(profile_));
 }
 
 // Called on the IPC thread:
 void ResourceMessageFilter::OnFilterAdded(IPC::Channel* channel) {
   channel_ = channel;
+
+  // Add the observers to intercept 
+  NotificationService::current()->AddObserver(
+      this, NOTIFY_SPELLCHECKER_REINITIALIZED,
+      Source<Profile>(profile_));
 }
 
 // Called on the IPC thread:
@@ -738,6 +751,15 @@ void ResourceMessageFilter::OnSpellCheck(const std::wstring& word,
   }
 }
 
+void ResourceMessageFilter::Observe(NotificationType type, 
+                                    const NotificationSource &source,
+                                    const NotificationDetails &details) {
+    if (type == NOTIFY_SPELLCHECKER_REINITIALIZED) {
+      spellchecker_ = Details<SpellcheckerReinitializedDetails>
+          (details).ptr()->spellchecker;
+    }
+}
+
 void ResourceMessageFilter::OnDnsPrefetch(
          const std::vector<std::string>& hostnames) {
   chrome_browser_net::DnsPrefetchList(hostnames);
diff --git a/chrome/browser/resource_message_filter.h b/chrome/browser/resource_message_filter.h
index a83a0e9..aee07c1 100644
--- a/chrome/browser/resource_message_filter.h
+++ b/chrome/browser/resource_message_filter.h
@@ -9,6 +9,7 @@
 #include "base/ref_counted.h"
 #include "chrome/browser/resource_dispatcher_host.h"
 #include "chrome/common/ipc_channel_proxy.h"
+#include "chrome/common/notification_service.h"
 #include "webkit/glue/cache_manager.h"
 
 class ClipboardService;
@@ -29,12 +30,13 @@ class PrintJobManager;
 // will not interfere with browser UI.
 
 class ResourceMessageFilter : public IPC::ChannelProxy::MessageFilter,
-                              public ResourceDispatcherHost::Receiver {
+                              public ResourceDispatcherHost::Receiver,
+                              public NotificationObserver {
  public:
   // Create the filter.
   // Note:  because the lifecycle of the ResourceMessageFilter is not
   //        tied to the lifecycle of the object which created it, the
-  //        ResourceMessageFilter is 'given' ownership of the spellcker
+  //        ResourceMessageFilter is 'given' ownership of the spellchecker
   //        object and must clean it up on exit.
   ResourceMessageFilter(ResourceDispatcherHost* resource_dispatcher_host,
                         PluginService* plugin_service,
@@ -60,6 +62,11 @@ class ResourceMessageFilter : public IPC::ChannelProxy::MessageFilter,
   int render_process_host_id() const { return render_process_host_id_;}
 
   HANDLE renderer_handle() const { return render_handle_;}
+  
+  // NotificationObserver implementation.
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
 
  private:
   void OnMsgCreateView(int opener_id, bool user_gesture, int* route_id,
@@ -176,6 +183,9 @@ class ResourceMessageFilter : public IPC::ChannelProxy::MessageFilter,
   // Contextual information to be used for requests created here.
   scoped_refptr<URLRequestContext> request_context_;
 
+  // Save the profile pointer so that notification observer can be added.
+  Profile* profile_;
+
   scoped_refptr<RenderWidgetHelper> render_widget_helper_;
 };
 
diff --git a/chrome/browser/views/options/languages_page_view.cc b/chrome/browser/views/options/languages_page_view.cc
index 465a2fa..9a22c74 100644
--- a/chrome/browser/views/options/languages_page_view.cc
+++ b/chrome/browser/views/options/languages_page_view.cc
@@ -681,6 +681,7 @@ void LanguagesPageView::NotifyPrefChanged(const std::wstring* pref_name) {
     int index = dictionary_language_model_->GetSelectedLanguageIndex(
         prefs::kSpellCheckDictionary);
     change_dictionary_language_combobox_->SetSelectedItem(index);
+    spellcheck_language_index_selected_ = -1;
   }
 }
 
@@ -693,11 +694,8 @@ void LanguagesPageView::ItemChanged(ChromeViews::ComboBox* sender,
     app_locale_.SetValue(ui_language_model_->GetLocaleFromIndex(new_index));
     RestartMessageBox::ShowMessageBox(GetRootWindow());
   } else if (sender == change_dictionary_language_combobox_) {
-    UserMetricsRecordAction(L"Options_DictionaryLanguage",
-                            profile()->GetPrefs());
-    dictionary_language_.SetValue(dictionary_language_model_->
-        GetLocaleFromIndex(new_index));
-    RestartMessageBox::ShowMessageBox(GetRootWindow());
+    if (new_index != prev_index)
+      spellcheck_language_index_selected_ = new_index;
   }
 }
 
@@ -750,5 +748,16 @@ void LanguagesPageView::OnMoveUpLanguage() {
 void LanguagesPageView::SaveChanges() {
   if (language_order_table_model_.get() && language_table_edited_)
     accept_languages_.SetValue(language_order_table_model_->GetLanguageList());
-}
 
+  if (spellcheck_language_index_selected_ != -1) {
+    UserMetricsRecordAction(L"Options_DictionaryLanguage",
+                            profile()->GetPrefs());
+    dictionary_language_.SetValue(dictionary_language_model_->
+        GetLocaleFromIndex(spellcheck_language_index_selected_));
+
+    // Initialize spellchecker. Keeping with the tradition, spellchecker is
+    // being initialized in this UI thread. However, it must be USED in the IO
+    // thread.
+    profile()->InitializeSpellChecker();
+  }
+}
diff --git a/chrome/browser/views/options/languages_page_view.h b/chrome/browser/views/options/languages_page_view.h
index 41c362f..fc7d0b0 100644
--- a/chrome/browser/views/options/languages_page_view.h
+++ b/chrome/browser/views/options/languages_page_view.h
@@ -89,6 +89,10 @@ class LanguagesPageView : public OptionsPageView,
   // The contents of the "dictionary language" combobox.
   scoped_ptr<LanguageComboboxModel> dictionary_language_model_;
   StringPrefMember dictionary_language_;
+  
+  // This is assigned the new index of spellcheck language if the language
+  // is changed. Otherwise, it remains -1, and pref members are not updated.
+  int spellcheck_language_index_selected_;
 
   bool language_table_edited_;
 
diff --git a/chrome/common/notification_types.h b/chrome/common/notification_types.h
index 4340c9b..29ba6e1 100644
--- a/chrome/common/notification_types.h
+++ b/chrome/common/notification_types.h
@@ -397,6 +397,11 @@ enum NotificationType {
   // Profile, and the details aren't used.
   NOTIFY_BOOKMARK_MODEL_LOADED,
 
+  // Sent when the spellchecker object changes. Note that this is not sent the
+  // first time the spellchecker gets initialized. The source is the profile, 
+  // the details is SpellcheckerReinitializedDetails defined in profile.
+  NOTIFY_SPELLCHECKER_REINITIALIZED,
+
   // Sent when the bookmark bubble is shown for a particular URL. The source
   // is the profile, the details the URL.
   NOTIFY_BOOKMARK_BUBBLE_SHOWN,
diff --git a/chrome/test/testing_profile.h b/chrome/test/testing_profile.h
index c68e9fcb..892d357 100644
--- a/chrome/test/testing_profile.h
+++ b/chrome/test/testing_profile.h
@@ -140,6 +140,8 @@ class TestingProfile : public Profile {
   }
   virtual void ResetTabRestoreService() {
   }
+  virtual void InitializeSpellChecker() {
+  }
   virtual SpellChecker* GetSpellChecker() {
     return NULL;
   }