This CL fixes issue 11480: Support GTK keyboard themes (emacs keybindings)....

chrome/browser/renderer_host/render_widget_host_view_gtk.cc

Index: chrome/browser/renderer_host/render_widget_host_view_gtk.cc
===================================================================
--- chrome/browser/renderer_host/render_widget_host_view_gtk.cc	（版本 21941）
+++ chrome/browser/renderer_host/render_widget_host_view_gtk.cc	（工作副本）
@@ -30,7 +30,352 @@
 
 using WebKit::WebInputEventFactory;
 
-// This class is a conveience wrapper for GtkIMContext.
+// This class is a convenience class for handling editor key bindings defined
+// in gtk keyboard theme.
+// In gtk, only GtkEntry and GtkTextView support customizing editor key bindings
+// through keyboard theme. And in gtk keyboard theme definition file, each key
+// binding must be bound to a specific class or object. So existing keyboard
+// themes only define editor key bindings exactly for GtkEntry and GtkTextView.
+// Then, the only way for us to intercept editor key bindings defined in
+// keyboard theme, is to create a GtkEntry or GtkTextView object and call
+// gtk_bindings_activate_event() against it for the key events. If a key event
+// matches a predefined key binding, corresponding signal will be emitted.
+// GtkTextView is used here because it supports more key bindings than GtkEntry,
+// but in order to minimize the side effect of using a GtkTextView object, a new
+// class derived from GtkTextView is used, which overrides all signals related
+// to key bindings, to make sure GtkTextView won't receive them.
+// Key binding signals will be translated into corresponding webkit editor
+// commands and send to webkit by calling
+// RenderWidgetHost::ForwardEditCommand().
+// See third_party/WebKit/WebCore/editing/EditorCommand.cpp for detailed
+// definition of webkit editor commands.
+// See webkit/glue/editor_client_impl.cc for key bindings predefined in our
+// webkit glue.
+//
+// TODO(james.su@gmail.com): Check if current event flow is appropriate, which
+// sends a key event to renderer(webkit) first, then calls this key bindings
+// handler if the key event is not handled by renderer. So key bindings
+// defined in our webkit glue have higher priority.
+// However, some key bindings defined in our webkit glue may conflict with the
+// key bindings defined in gtk keyboard theme, for example ctrl-a is
+// bound to "SelectAll" in our webkit glue. But in gtk Emacs keyboard theme,
+// it's bound to "MoveToBeginningOfParagraph".
+// In such case, an Emacs user would prefer Emacs key bindings over our
+// built-in key bindings.
+// But it may also cause problem if we call this key bindings handler before
+// sending key events to renderer, because there is no way to prevent webkit
+// from interpreting it as a key binding. Then unexpected behavior may occur,
+// if a key event matches a key binding defined in gtk keyboard theme as well as
+// a (different) key binding defined in webkit glue.
+class RenderWidgetHostViewGtkKeyBindings {

[Evan Stade, 2009/07/30 01:14:56]

ok this file is beginning to get absurdly long. Can we split this out into
another file if it's not too much trouble?

[james.su_gmail.com, 2009/07/30 06:24:10]

I'd like to split this file. Any suggestion to the new file name? Is it
necessary to split RenderWidgetHostViewGtkKeyBindings and
RenderWidgetHostViewGtkIMContext into two separated files?

+ public:
+  explicit RenderWidgetHostViewGtkKeyBindings(
+      RenderWidgetHostViewGtk* host_view)
+      : host_view_(host_view),
+        handler_(CreateNewHandler()),
+        enabled_(false),
+        handled_(false) {
+    GtkWidget* parent_widget = host_view->native_view();
+    DCHECK(GTK_IS_FIXED(parent_widget));
+    // We need add the |handler_| object into gtk widget hierarchy, so that
+    // gtk_bindings_activate_event() can find correct display and keymaps from
+    // the |handler_| object.
+    gtk_fixed_put(GTK_FIXED(parent_widget), handler_.get(), -1, -1);
+  }
+
+  ~RenderWidgetHostViewGtkKeyBindings() {
+    handler_.Destroy();
+  }
+
+  // Key bindings handler will be disabled when IME is disabled by webkit.
+  void set_enabled(bool enabled) {
+    enabled_ = enabled;
+  }
+
+  // Handles a key event, false will be returned if the key event doesn't
+  // correspond to a predefined key binding.
+  bool Handle(const NativeWebKeyboardEvent& wke) {
+    if (!enabled_ || wke.type == WebKit::WebInputEvent::Char ||
+        !wke.os_event || !wke.os_event->keyval)
+      return false;
+
+    DLOG(INFO) << "Unhandled key "
+               << (wke.os_event->type == GDK_KEY_PRESS ? "press" : "release")
+               << ": keyval=" << wke.os_event->keyval
+               << " state=" << wke.os_event->state;
+
+    handled_ = false;
+
+    // If this key event matches a predefined key binding, corresponding signal
+    // will be emitted.
+    gtk_bindings_activate_event(GTK_OBJECT(handler_.get()), wke.os_event);
+    return handled_;
+  }
+
+ private:
+  struct Handler {
+    GtkTextView parent_object;
+    RenderWidgetHostViewGtkKeyBindings *owner;
+  };
+
+  struct HandlerClass {
+    GtkTextViewClass parent_class;
+  };
+
+  GtkWidget* CreateNewHandler() {
+    Handler* handler =
+        static_cast<Handler*>(g_object_new(HandlerGetType(), NULL));
+
+    handler->owner = this;
+
+    // We don't need to show the |handler| object on screen, so set its size to
+    // zero.
+    gtk_widget_set_size_request(GTK_WIDGET(handler), 0, 0);
+
+    // Prevents it from handling any events by itself.
+    gtk_widget_set_sensitive(GTK_WIDGET(handler), FALSE);
+    gtk_widget_set_events(GTK_WIDGET(handler), 0);
+    GTK_WIDGET_UNSET_FLAGS(GTK_WIDGET(handler), GTK_CAN_FOCUS);
+
+#if !GTK_CHECK_VERSION(2, 14, 0)
+    // "move-viewport", "select-all" and "toggle-cursor-visible" have no
+    // corresponding virtual methods. Prior to glib 2.18 (gtk 2.14), there is no
+    // way to override the default class handler of a signal. So we need hook
+    // these signal explicitly, and the default signal handlers of GtkTextView
+    // class will still be called. Hope it won't cause any side effect.
+    g_signal_connect(handler, "move-viewport", G_CALLBACK(MoveViewport), NULL);
+    g_signal_connect(handler, "select-all", G_CALLBACK(SelectAll), NULL);
+    g_signal_connect(handler, "toggle-cursor-visible",
+                     G_CALLBACK(ToggleCursorVisible), NULL);
+#endif
+    return GTK_WIDGET(handler);
+  }
+
+  void ForwardEditCommand(const std::string& name, const std::string& value) {
+    DLOG(INFO) << "ForwardEditCommand:" << name << " value:" << value;
+    host_view_->GetRenderWidgetHost()->ForwardEditCommand(name, value);

[Evan Stade, 2009/07/30 01:14:56]

It looks like ForwardEditCommand does nothing. Is that why you have the
DLOG(INFO) showing you what commands are being forwarded?

[james.su_gmail.com, 2009/07/30 06:24:10]

this DLOG is just for debugging, will be removed afterwards. ForwardEditCommand
is implemented in RenderViewHost.

+
+    // A key event is treated as handled only if an editor command is sent to
+    // webkit.
+    handled_ = true;
+  }
+
+  static void HandlerInit(Handler *self) {
+    self->owner = NULL;
+  }
+
+  static void HandlerClassInit(HandlerClass *klass) {
+    GtkTextViewClass* text_view_class = GTK_TEXT_VIEW_CLASS(klass);
+
+    // Overrides all virtual methods related to editor key bindings.
+    text_view_class->move_cursor = MoveCursor;
+    text_view_class->set_anchor = SetAnchor;
+    text_view_class->insert_at_cursor = InsertAtCursor;
+    text_view_class->delete_from_cursor = DeleteFromCursor;
+    text_view_class->backspace = BackSpace;
+    text_view_class->cut_clipboard = CutClipboard;
+    text_view_class->copy_clipboard = CopyClipboard;
+    text_view_class->paste_clipboard = PasteClipboard;
+    text_view_class->toggle_overwrite = ToggleOverwrite;
+
+#if GTK_CHECK_VERSION(2, 14, 0)
+    // "move-viewport", "select-all" and "toggle-cursor-visible" have no
+    // corresponding virtual methods. Since glib 2.18 (gtk 2.14),
+    // g_signal_override_class_handler() is introduced to override a signal
+    // handler.
+    g_signal_override_class_handler("move-viewport",
+                                    G_TYPE_FROM_CLASS(klass),
+                                    G_CALLBACK(MoveViewport));
+
+    g_signal_override_class_handler("select-all",
+                                    G_TYPE_FROM_CLASS(klass),
+                                    G_CALLBACK(SelectAll));
+
+    g_signal_override_class_handler("toggle-cursor-visible",
+                                    G_TYPE_FROM_CLASS(klass),
+                                    G_CALLBACK(ToggleCursorVisible));
+#endif
+  }
+
+  static GType HandlerGetType() {
+    static volatile gsize type_id_volatile = 0;
+    if (g_once_init_enter(&type_id_volatile)) {
+      GType type_id = g_type_register_static_simple(
+          GTK_TYPE_TEXT_VIEW,
+          g_intern_static_string("RenderWidgetHostViewGtkKeyBindingsHandler"),
+          sizeof(HandlerClass),
+          reinterpret_cast<GClassInitFunc>(HandlerClassInit),
+          sizeof(Handler),
+          reinterpret_cast<GInstanceInitFunc>(HandlerInit),
+          static_cast<GTypeFlags>(0));
+      g_once_init_leave(&type_id_volatile, type_id);
+    }
+    return type_id_volatile;
+  }
+
+  static RenderWidgetHostViewGtkKeyBindings* GetHandlerOwner(
+      GtkTextView* text_view) {
+    Handler* handler = G_TYPE_CHECK_INSTANCE_CAST(
+        text_view, HandlerGetType(), Handler);
+    DCHECK(handler);
+    return handler->owner;
+  }
+
+  static void MoveCursor(GtkTextView* text_view, GtkMovementStep step,
+                         gint count, gboolean extend_selection) {
+    if (!count)
+      return;
+
+    std::string command;
+    switch (step) {
+      case GTK_MOVEMENT_LOGICAL_POSITIONS:
+        command = (count > 0 ? "MoveForward" : "MoveBackward");
+        break;
+      case GTK_MOVEMENT_VISUAL_POSITIONS:
+        command = (count > 0 ? "MoveRight" : "MoveLeft");
+        break;
+      case GTK_MOVEMENT_WORDS:
+        command = (count > 0 ? "MoveWordForward" : "MoveWordBackward");
+        break;
+      case GTK_MOVEMENT_DISPLAY_LINES:
+        command = (count > 0 ? "MoveDown" : "MoveUp");
+        break;
+      case GTK_MOVEMENT_DISPLAY_LINE_ENDS:
+        command = (count > 0 ? "MoveToEndOfLine" : "MoveToBeginningOfLine");
+        break;
+      case GTK_MOVEMENT_PARAGRAPH_ENDS:
+        command = (count > 0 ? "MoveToEndOfParagraph" :
+                   "MoveToBeginningOfParagraph");
+        break;
+      case GTK_MOVEMENT_PAGES:
+        command = (count > 0 ? "MovePageDown" : "MovePageUp");
+        break;
+      case GTK_MOVEMENT_BUFFER_ENDS:
+        command = (count > 0 ? "MoveToEndOfDocument" :
+                   "MoveToBeginningOfDocument");
+        break;
+      default:
+        // GTK_MOVEMENT_PARAGRAPHS and GTK_MOVEMENT_HORIZONTAL_PAGES have
+        // no corresponding editor commands.
+        return;
+    }
+
+    RenderWidgetHostViewGtkKeyBindings* owner = GetHandlerOwner(text_view);
+    if (extend_selection)
+      command.append("AndModifySelection");
+    if (count < 0)
+      count = -count;
+    for (; count > 0; --count)
+      owner->ForwardEditCommand(command, "");
+  }
+
+  static void DeleteFromCursor(GtkTextView* text_view, GtkDeleteType type,
+                               gint count) {
+    if (!count)
+      return;
+
+    const char *commands[3] = { NULL, NULL, NULL };
+    switch (type) {
+      case GTK_DELETE_CHARS:
+        commands[0] = (count > 0 ? "Delete" : "DeleteBackward");
+        break;
+      case GTK_DELETE_WORD_ENDS:
+        commands[0] = (count > 0 ? "DeleteWordForward" : "DeleteWordBackward");
+        break;
+      case GTK_DELETE_WORDS:
+        if (count > 0) {
+          commands[0] = "MoveWordForward";
+          commands[1] = "DeleteWordBackward";
+        } else {
+          commands[0] = "MoveWordBackward";
+          commands[1] = "DeleteWordForward";
+        }
+        break;
+      case GTK_DELETE_DISPLAY_LINES:
+        commands[0] = "MoveToBeginningOfLine";
+        commands[1] = "DeleteToEndOfLine";
+        break;
+      case GTK_DELETE_DISPLAY_LINE_ENDS:
+        commands[0] = (count > 0 ? "DeleteToEndOfLine" :
+                       "DeleteToBeginningOfLine");
+        break;
+      case GTK_DELETE_PARAGRAPH_ENDS:
+        commands[0] = (count > 0 ? "DeleteToEndOfParagraph" :
+                       "DeleteToBeginningOfParagraph");
+        break;
+      case GTK_DELETE_PARAGRAPHS:
+        commands[0] = "MoveToBeginningOfParagraph";
+        commands[1] = "DeleteToEndOfParagraph";
+        break;
+      default:
+        // GTK_DELETE_WHITESPACE has no corresponding editor command.
+        return;
+    }
+
+    RenderWidgetHostViewGtkKeyBindings* owner = GetHandlerOwner(text_view);
+    if (count < 0)
+      count = -count;
+    for (; count > 0; --count) {
+      for (const char* const* p = commands; *p; ++p)
+        owner->ForwardEditCommand(*p, "");
+    }
+  }
+
+  static void InsertAtCursor(GtkTextView* text_view, const gchar* str) {
+    if (str && *str)
+      GetHandlerOwner(text_view)->ForwardEditCommand("InsertText", str);
+  }
+
+  static void BackSpace(GtkTextView* text_view) {
+    GetHandlerOwner(text_view)->ForwardEditCommand("DeleteBackward", "");
+  }
+
+  static void CopyClipboard(GtkTextView* text_view) {
+    GetHandlerOwner(text_view)->ForwardEditCommand("Copy", "");
+  }
+
+  static void CutClipboard(GtkTextView* text_view) {
+    GetHandlerOwner(text_view)->ForwardEditCommand("Cut", "");
+  }
+
+  static void PasteClipboard(GtkTextView* text_view) {
+    GetHandlerOwner(text_view)->ForwardEditCommand("Paste", "");
+  }
+
+  static void SelectAll(GtkTextView* text_view, gboolean select) {
+    if (select)
+      GetHandlerOwner(text_view)->ForwardEditCommand("SelectAll", "");
+    else
+      GetHandlerOwner(text_view)->ForwardEditCommand("Unselect", "");
+  }
+
+  static void SetAnchor(GtkTextView* text_view) {
+    GetHandlerOwner(text_view)->ForwardEditCommand("SetMark", "");
+  }
+
+  static void MoveViewport(GtkTextView* text_view, GtkScrollStep step,
+                           gint count) {
+    // Not supported by webkit.
+  }
+
+  static void ToggleOverwrite(GtkTextView* text_view) {
+    // Not supported by webkit.
+  }
+
+  static void ToggleCursorVisible(GtkTextView* text_view) {
+    // Not supported by webkit.
+  }
+
+  RenderWidgetHostViewGtk* host_view_;
+  OwnedWidgetGtk handler_;
+
+  // Indicates if key bindings handler is enabled or not.
+  // It'll only be enabled if IME is enabled by webkit.
+  bool enabled_;
+  bool handled_;
+};
+
+// This class is a convenience wrapper for GtkIMContext.
 class RenderWidgetHostViewGtkIMContext {
  public:
   explicit RenderWidgetHostViewGtkIMContext(RenderWidgetHostViewGtk* host_view)
@@ -856,6 +1201,7 @@
 
 void RenderWidgetHostViewGtk::InitAsChild() {
   view_.Own(RenderWidgetHostViewGtkWidget::CreateNewWidget(this));
+  key_bindings_handler_.reset(new RenderWidgetHostViewGtkKeyBindings(this));
   plugin_container_manager_.set_host_widget(view_.get());
   gtk_widget_show(view_.get());
 }
@@ -866,6 +1212,7 @@
   parent_ = parent_host_view->GetNativeView();
   GtkWidget* popup = gtk_window_new(GTK_WINDOW_POPUP);
   view_.Own(RenderWidgetHostViewGtkWidget::CreateNewWidget(this));
+  key_bindings_handler_.reset(new RenderWidgetHostViewGtkKeyBindings(this));
   plugin_container_manager_.set_host_widget(view_.get());
   gtk_container_add(GTK_CONTAINER(popup), view_.get());
 
@@ -1016,6 +1363,7 @@
 
 void RenderWidgetHostViewGtk::IMEUpdateStatus(int control,
                                               const gfx::Rect& caret_rect) {
+  key_bindings_handler_->set_enabled(control != IME_DISABLE);
   im_context_->UpdateStatus(control, caret_rect);
 }
 
@@ -1203,3 +1551,9 @@
   }
   plugin_pid_map_.erase(pid);
 }
+
+bool RenderWidgetHostViewGtk::UnhandledKeyboardEvent(
+    const NativeWebKeyboardEvent& event) {
+  DCHECK(key_bindings_handler_.get());
+  return key_bindings_handler_->Handle(event);
+}