chrome/browser/ui/gtk/tabs/tab_gtk.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/ui/gtk/tabs/tab_gtk.h"

#include <gdk/gdkkeysyms.h>

#include "base/bind.h"
#include "base/debug/trace_event.h"
#include "base/memory/singleton.h"
#include "base/strings/utf_string_conversions.h"
#include "chrome/app/chrome_command_ids.h"
#include "chrome/browser/ui/gtk/accelerators_gtk.h"
#include "chrome/browser/ui/gtk/gtk_input_event_box.h"
#include "chrome/browser/ui/gtk/menu_gtk.h"
#include "chrome/browser/ui/gtk/tabs/tab_strip_menu_controller.h"
#include "chrome/browser/ui/tabs/tab_menu_model.h"
#include "chrome/browser/ui/tabs/tab_resources.h"
#include "grit/generated_resources.h"
#include "grit/theme_resources.h"
#include "ui/base/dragdrop/gtk_dnd_util.h"
#include "ui/base/gtk/scoped_region.h"
#include "ui/gfx/path.h"

using content::WebContents;

namespace {

// Returns the width of the title for the current font, in pixels.
int GetTitleWidth(gfx::Font* font, base::string16 title) {
  DCHECK(font);
  if (title.empty())
    return 0;

  return font->GetStringWidth(title);
}

}  // namespace

class TabGtk::TabGtkObserverHelper {
 public:
  explicit TabGtkObserverHelper(TabGtk* tab)
      : tab_(tab) {
    base::MessageLoopForUI::current()->AddObserver(tab_);
  }

  ~TabGtkObserverHelper() {
    base::MessageLoopForUI::current()->RemoveObserver(tab_);
  }

 private:
  TabGtk* tab_;

  DISALLOW_COPY_AND_ASSIGN(TabGtkObserverHelper);
};

///////////////////////////////////////////////////////////////////////////////
// TabGtk, public:

TabGtk::TabGtk(TabDelegate* delegate)
    : TabRendererGtk(delegate->GetThemeProvider()),
      delegate_(delegate),
      closing_(false),
      dragging_(false),
      last_mouse_down_(NULL),
      drag_widget_(NULL),
      title_width_(0),
      destroy_factory_(this),
      drag_end_factory_(this) {
  event_box_ = gtk_input_event_box_new();
  g_signal_connect(event_box_, "button-press-event",
                   G_CALLBACK(OnButtonPressEventThunk), this);
  g_signal_connect(event_box_, "button-release-event",
                   G_CALLBACK(OnButtonReleaseEventThunk), this);
  g_signal_connect(event_box_, "enter-notify-event",
                   G_CALLBACK(OnEnterNotifyEventThunk), this);
  g_signal_connect(event_box_, "leave-notify-event",
                   G_CALLBACK(OnLeaveNotifyEventThunk), this);
  gtk_widget_add_events(event_box_,
        GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK |
        GDK_ENTER_NOTIFY_MASK | GDK_LEAVE_NOTIFY_MASK);
  gtk_container_add(GTK_CONTAINER(event_box_), TabRendererGtk::widget());
  gtk_widget_show_all(event_box_);
}

TabGtk::~TabGtk() {
  if (drag_widget_) {
    // Shadow the drag grab so the grab terminates. We could do this using any
    // widget, |drag_widget_| is just convenient.
    gtk_grab_add(drag_widget_);
    gtk_grab_remove(drag_widget_);
    DestroyDragWidget();
  }

  if (menu_controller_.get()) {
    // The menu is showing. Close the menu.
    menu_controller_->Cancel();

    // Invoke this so that we hide the highlight.
    ContextMenuClosed();
  }
}

void TabGtk::Raise() const {
  UNSHIPPED_TRACE_EVENT0("ui::gtk", "TabGtk::Raise");

  GdkWindow* window = gtk_input_event_box_get_window(
      GTK_INPUT_EVENT_BOX(event_box_));
  gdk_window_raise(window);
  TabRendererGtk::Raise();
}

gboolean TabGtk::OnButtonPressEvent(GtkWidget* widget, GdkEventButton* event) {
  // Every button press ensures either a button-release-event or a drag-fail
  // signal for |widget|.
  if (event->button == 1 && event->type == GDK_BUTTON_PRESS) {
    // Store whether or not we were selected just now... we only want to be
    // able to drag foreground tabs, so we don't start dragging the tab if
    // it was in the background.
    if (!IsActive()) {
      if (event->state & GDK_CONTROL_MASK)
        delegate_->ToggleTabSelection(this);
      else if (event->state & GDK_SHIFT_MASK)
        delegate_->ExtendTabSelection(this);
      else
        delegate_->ActivateTab(this);
    }
    // Hook into the message loop to handle dragging.
    observer_.reset(new TabGtkObserverHelper(this));

    // Store the button press event, used to initiate a drag.
    last_mouse_down_ = gdk_event_copy(reinterpret_cast<GdkEvent*>(event));
  } else if (event->button == 3) {
    // Only show the context menu if the left mouse button isn't down (i.e.,
    // the user might want to drag instead).
    if (!last_mouse_down_) {
      menu_controller_.reset(delegate()->GetTabStripMenuControllerForTab(this));
      menu_controller_->RunMenu(gfx::Point(event->x_root, event->y_root),
                                event->time);
    }
  }

  return TRUE;
}

gboolean TabGtk::OnButtonReleaseEvent(GtkWidget* widget,
                                      GdkEventButton* event) {
  if (event->button == 1) {
    if (IsActive() && !(event->state & (GDK_SHIFT_MASK | GDK_CONTROL_MASK))) {
      delegate_->ActivateTab(this);
    }
    observer_.reset();

    if (last_mouse_down_) {
      gdk_event_free(last_mouse_down_);
      last_mouse_down_ = NULL;
    }
  }

  GtkAllocation allocation;
  gtk_widget_get_allocation(widget, &allocation);

  // Middle mouse up means close the tab, but only if the mouse is over it
  // (like a button).
  if (event->button == 2 &&
      event->x >= 0 && event->y >= 0 &&
      event->x < allocation.width &&
      event->y < allocation.height) {
    // If the user is currently holding the left mouse button down but hasn't
    // moved the mouse yet, a drag hasn't started yet.  In that case, clean up
    // some state before closing the tab to avoid a crash.  Once the drag has
    // started, we don't get the middle mouse click here.
    if (last_mouse_down_) {
      DCHECK(!drag_widget_);
      observer_.reset();
      gdk_event_free(last_mouse_down_);
      last_mouse_down_ = NULL;
    }
    delegate_->CloseTab(this);
  }

  return TRUE;
}

gboolean TabGtk::OnDragFailed(GtkWidget* widget, GdkDragContext* context,
                              GtkDragResult result) {
  bool canceled = (result == GTK_DRAG_RESULT_USER_CANCELLED);
  EndDrag(canceled);
  return TRUE;
}

gboolean TabGtk::OnDragButtonReleased(GtkWidget* widget,
                                      GdkEventButton* button) {
  // We always get this event when gtk is releasing the grab and ending the
  // drag.  However, if the user ended the drag with space or enter, we don't
  // get a follow up event to tell us the drag has finished (either a
  // drag-failed or a drag-end).  So we post a task to manually end the drag.
  // If GTK+ does send the drag-failed or drag-end event, we cancel the task.
  base::MessageLoop::current()->PostTask(
      FROM_HERE,
      base::Bind(&TabGtk::EndDrag, drag_end_factory_.GetWeakPtr(), false));
  return TRUE;
}

void TabGtk::OnDragBegin(GtkWidget* widget, GdkDragContext* context) {
  GdkPixbuf* pixbuf = gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8, 1, 1);
  gdk_pixbuf_fill(pixbuf, 0);
  gtk_drag_set_icon_pixbuf(context, pixbuf, 0, 0);
  g_object_unref(pixbuf);
}

///////////////////////////////////////////////////////////////////////////////
// TabGtk, MessageLoop::Observer implementation:

void TabGtk::WillProcessEvent(GdkEvent* event) {
  // Nothing to do.
}

void TabGtk::DidProcessEvent(GdkEvent* event) {
  if (!(event->type == GDK_MOTION_NOTIFY || event->type == GDK_LEAVE_NOTIFY ||
        event->type == GDK_ENTER_NOTIFY)) {
    return;
  }

  if (drag_widget_) {
    delegate_->ContinueDrag(NULL);
    return;
  }

  gint old_x = static_cast<gint>(last_mouse_down_->button.x_root);
  gint old_y = static_cast<gint>(last_mouse_down_->button.y_root);
  gdouble new_x;
  gdouble new_y;
  gdk_event_get_root_coords(event, &new_x, &new_y);

  if (gtk_drag_check_threshold(widget(), old_x, old_y,
      static_cast<gint>(new_x), static_cast<gint>(new_y))) {
    StartDragging(gfx::Point(
        static_cast<int>(last_mouse_down_->button.x),
        static_cast<int>(last_mouse_down_->button.y)));
  }
}

///////////////////////////////////////////////////////////////////////////////
// TabGtk, TabRendererGtk overrides:

bool TabGtk::IsActive() const {
  return delegate_->IsTabActive(this);
}

bool TabGtk::IsSelected() const {
  return delegate_->IsTabSelected(this);
}

bool TabGtk::IsVisible() const {
  return gtk_widget_get_visible(event_box_);
}

void TabGtk::SetVisible(bool visible) const {
  gtk_widget_set_visible(event_box_, visible);
}

void TabGtk::CloseButtonClicked() {
  delegate_->CloseTab(this);
}

void TabGtk::UpdateData(WebContents* contents, bool app, bool loading_only) {
  TabRendererGtk::UpdateData(contents, app, loading_only);
  // Cache the title width so we don't recalculate it every time the tab is
  // resized.
  title_width_ = GetTitleWidth(title_font(), GetTitle());
  UpdateTooltipState();
}

void TabGtk::SetBounds(const gfx::Rect& bounds) {
  TabRendererGtk::SetBounds(bounds);

  if (gtk_input_event_box_get_window(GTK_INPUT_EVENT_BOX(event_box_))) {
    gfx::Path mask;
    TabResources::GetHitTestMask(bounds.width(), bounds.height(), false, &mask);
    ui::ScopedRegion region(mask.CreateNativeRegion());
    gdk_window_input_shape_combine_region(
        gtk_input_event_box_get_window(GTK_INPUT_EVENT_BOX(event_box_)),
        region.Get(),
        0, 0);
  }

  UpdateTooltipState();
}

///////////////////////////////////////////////////////////////////////////////
// TabGtk, private:

void TabGtk::ContextMenuClosed() {
  delegate()->StopAllHighlighting();
  menu_controller_.reset();
}

void TabGtk::UpdateTooltipState() {
  // Only show the tooltip if the title is truncated.
  if (title_width_ > title_bounds().width()) {
    gtk_widget_set_tooltip_text(widget(), UTF16ToUTF8(GetTitle()).c_str());
  } else {
    gtk_widget_set_has_tooltip(widget(), FALSE);
  }
}

void TabGtk::CreateDragWidget() {
  DCHECK(!drag_widget_);
  drag_widget_ = gtk_invisible_new();
  g_signal_connect(drag_widget_, "drag-failed",
                   G_CALLBACK(OnDragFailedThunk), this);
  g_signal_connect(drag_widget_, "button-release-event",
                   G_CALLBACK(OnDragButtonReleasedThunk), this);
  g_signal_connect_after(drag_widget_, "drag-begin",
                         G_CALLBACK(OnDragBeginThunk), this);
}

void TabGtk::DestroyDragWidget() {
  if (drag_widget_) {
    gtk_widget_destroy(drag_widget_);
    drag_widget_ = NULL;
  }
}

void TabGtk::StartDragging(gfx::Point drag_offset) {
  // If the drag is processed after the selection change it's possible
  // that the tab has been deselected, in which case we don't want to drag.
  if (!IsSelected())
    return;

  CreateDragWidget();

  GtkTargetList* list = ui::GetTargetListFromCodeMask(ui::CHROME_TAB);
  gtk_drag_begin(drag_widget_, list, GDK_ACTION_MOVE,
                 1,  // Drags are always initiated by the left button.
                 last_mouse_down_);
  // gtk_drag_begin adds a reference to list, so unref it here.
  gtk_target_list_unref(list);
  delegate_->MaybeStartDrag(this, drag_offset);
}

void TabGtk::EndDrag(bool canceled) {
  // Make sure we only run EndDrag once by canceling any tasks that want
  // to call EndDrag.
  drag_end_factory_.InvalidateWeakPtrs();

  // We must let gtk clean up after we handle the drag operation, otherwise
  // there will be outstanding references to the drag widget when we try to
  // destroy it.
  base::MessageLoop::current()->PostTask(
      FROM_HERE,
      base::Bind(&TabGtk::DestroyDragWidget, destroy_factory_.GetWeakPtr()));

  if (last_mouse_down_) {
    gdk_event_free(last_mouse_down_);
    last_mouse_down_ = NULL;
  }

  // Notify the drag helper that we're done with any potential drag operations.
  // Clean up the drag helper, which is re-created on the next mouse press.
  delegate_->EndDrag(canceled);

  observer_.reset();
}