chrome/browser/ui/views/toolbar/browser_actions_container.h

// Copyright 2013 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_UI_VIEWS_TOOLBAR_BROWSER_ACTIONS_CONTAINER_H_
#define CHROME_BROWSER_UI_VIEWS_TOOLBAR_BROWSER_ACTIONS_CONTAINER_H_

#include "base/observer_list.h"
#include "chrome/browser/extensions/extension_keybinding_registry.h"
#include "chrome/browser/extensions/extension_toolbar_model.h"
#include "chrome/browser/ui/views/extensions/extension_keybinding_registry_views.h"
#include "chrome/browser/ui/views/toolbar/browser_action_view.h"
#include "chrome/browser/ui/views/toolbar/chevron_menu_button.h"
#include "ui/gfx/animation/animation_delegate.h"
#include "ui/gfx/animation/tween.h"
#include "ui/views/controls/button/menu_button_listener.h"
#include "ui/views/controls/resize_area_delegate.h"
#include "ui/views/drag_controller.h"
#include "ui/views/view.h"

class BrowserActionsContainerObserver;
class ExtensionPopup;

namespace extensions {
class ActiveTabPermissionGranter;
class Command;
class Extension;
}

namespace gfx {
class SlideAnimation;
}

namespace views {
class ResizeArea;
}

// The BrowserActionsContainer is a container view, responsible for drawing the
// browser action icons (extensions that add icons to the toolbar). It comes in
// two flavors, a main container (when residing on the toolbar) and an overflow
// container (that resides in the main application menu, aka the Chrome menu).
//
// When in 'main' mode, the container supports the full functionality of a
// BrowserActionContainer, but in 'overflow' mode the container is effectively
// just an overflow for the 'main' toolbar (shows only the icons that the main
// toolbar does not) and as such does not have an overflow itself. The overflow
// container also does not support resizing. Since the main container only shows
// icons in the Chrome toolbar, it is limited to a single row of icons. The
// overflow container, however, is allowed to display icons in multiple rows.
//
// The main container is placed flush against the omnibox and hot dog menu,
// whereas the overflow container is placed within the hot dog menu. The
// layout is similar to this:
//   rI_I_IcCs
// Where the letters are as follows:
//   r: An invisible resize area.  This is ToolbarView::kStandardSpacing pixels
//      wide and directly adjacent to the omnibox. Only shown for the main
//      container.
//   I: An icon.  This is as wide as the IDR_BROWSER_ACTION image.
//   _: kItemSpacing pixels of empty space.
//   c: kChevronSpacing pixels of empty space.  Only present if C is present.
//   C: An optional chevron, as wide as the IDR_BROWSER_ACTIONS_OVERFLOW image,
//      and visible only when both of the following statements are true:
//      - The container is set to a width smaller than needed to show all icons.
//      - There is no other container in 'overflow' mode to handle the
//        non-visible icons for this container.
//   s: ToolbarView::kStandardSpacing pixels of empty space (before the wrench
//      menu).
// The reason the container contains the trailing space "s", rather than having
// it be handled by the parent view, is so that when the chevron is invisible
// and the user starts dragging an icon around, we have the space to draw the
// ultimate drop indicator.  (Otherwise, we'd be trying to draw it into the
// padding beyond our right edge, and it wouldn't appear.)
//
// The BrowserActionsContainer in 'main' mode follows a few rules, in terms of
// user experience:
//
// 1) The container can never grow beyond the space needed to show all icons
// (hereby referred to as the max width).
// 2) The container can never shrink below the space needed to show just the
// initial padding and the chevron (ignoring the case where there are no icons
// to show, in which case the container won't be visible anyway).
// 3) The container snaps into place (to the pixel count that fits the visible
// icons) to make sure there is no wasted space at the edges of the container.
// 4) If the user adds or removes icons (read: installs/uninstalls browser
// actions) we grow and shrink the container as needed - but ONLY if the
// container was at max width to begin with.
// 5) If the container is NOT at max width (has an overflow menu), we respect
// that size when adding and removing icons and DON'T grow/shrink the container.
// This means that new icons (which always appear at the far right) will show up
// in the overflow. The install bubble for extensions points to the chevron
// menu in this case.
//
// Resizing the BrowserActionsContainer:
//
// The ResizeArea view sends OnResize messages to the BrowserActionsContainer
// class as the user drags it. This modifies the value for |resize_amount_|.
// That indicates to the container that a resize is in progress and is used to
// calculate the size in GetPreferredSize(), though that function never exceeds
// the defined minimum and maximum size of the container.
//
// When the user releases the mouse (ends the resize), we calculate a target
// size for the container (animation_target_size_), clamp that value to the
// containers min and max and then animate from the *current* position (that the
// user has dragged the view to) to the target size.
//
// Animating the BrowserActionsContainer:
//
// Animations are used when snapping the container to a value that fits all
// visible icons. This can be triggered when the user finishes resizing the
// container or when Browser Actions are added/removed.
//
// We always animate from the current width (container_width_) to the target
// size (animation_target_size_), using |resize_amount| to keep track of the
// animation progress.
//
// NOTE: When adding Browser Actions to a maximum width container (no overflow)
// we make sure to suppress the chevron menu if it wasn't visible. This is
// because we won't have enough space to show the new Browser Action until the
// animation ends and we don't want the chevron to flash into view while we are
// growing the container.
//
////////////////////////////////////////////////////////////////////////////////
class BrowserActionsContainer
    : public views::View,
      public views::ResizeAreaDelegate,
      public gfx::AnimationDelegate,
      public extensions::ExtensionToolbarModel::Observer,
      public BrowserActionView::Delegate,
      public extensions::ExtensionKeybindingRegistry::Delegate {
 public:
  // Horizontal spacing between most items in the container, as well as after
  // the last item or chevron (if visible).
  static const int kItemSpacing;

  // Constructs a BrowserActionContainer for a particular |browser| object. For
  // documentation of |main_container|, see class comments.
  BrowserActionsContainer(Browser* browser,
                          BrowserActionsContainer* main_container);
  virtual ~BrowserActionsContainer();

  void Init();

  // Get the number of browser actions being displayed.
  size_t num_browser_actions() const { return browser_action_views_.size(); }

  // Whether we are performing resize animation on the container.
  bool animating() const { return animation_target_size_ > 0; }

  // Returns the chevron, if any.
  views::View* chevron() { return chevron_; }
  const views::View* chevron() const { return chevron_; }

  // Returns the profile this container is associated with.
  Profile* profile() const { return profile_; }

  // The class that registers for keyboard shortcuts for extension commands.
  extensions::ExtensionKeybindingRegistry* extension_keybinding_registry() {
    return extension_keybinding_registry_.get();
  }

  // Get a particular browser action view.
  BrowserActionView* GetBrowserActionViewAt(int index) {
    return browser_action_views_[index];
  }

  // Returns the ID of the action represented by the view at |index|.
  const std::string& GetIdAt(size_t index);

  // Returns the BrowserActionView* associated with the given |extension|, or
  // NULL if none exists.
  BrowserActionView* GetViewForExtension(
      const extensions::Extension* extension);

  // Update the views to reflect the state of the browser action icons.
  void RefreshBrowserActionViews();

  // Sets up the browser action view vector.
  void CreateBrowserActionViews();

  // Delete all browser action views.
  void DeleteBrowserActionViews();

  // Returns how many browser actions are currently visible. If the intent is
  // to find how many are visible once the container finishes animation, see
  // VisibleBrowserActionsAfterAnimation() below.
  size_t VisibleBrowserActions() const;

  // Returns how many browser actions will be visible once the container
  // finishes animating to a new size, or (if not animating) the currently
  // visible icons.
  size_t VisibleBrowserActionsAfterAnimation() const;

  // Executes |command| registered by |extension|.
  void ExecuteExtensionCommand(const extensions::Extension* extension,
                               const extensions::Command& command);

  // Notify the browser action container that an extension has been moved to
  // the overflow container.
  void NotifyActionMovedToOverflow();

  // Add or remove an observer.
  void AddObserver(BrowserActionsContainerObserver* observer);
  void RemoveObserver(BrowserActionsContainerObserver* observer);

  // Overridden from views::View:
  virtual gfx::Size GetPreferredSize() const override;
  virtual int GetHeightForWidth(int width) const override;
  virtual gfx::Size GetMinimumSize() const override;
  virtual void Layout() override;
  virtual bool GetDropFormats(int* formats,
      std::set<ui::OSExchangeData::CustomFormat>* custom_formats) override;
  virtual bool AreDropTypesRequired() override;
  virtual bool CanDrop(const ui::OSExchangeData& data) override;
  virtual int OnDragUpdated(const ui::DropTargetEvent& event) override;
  virtual void OnDragExited() override;
  virtual int OnPerformDrop(const ui::DropTargetEvent& event) override;
  virtual void GetAccessibleState(ui::AXViewState* state) override;

  // Overridden from views::DragController:
  virtual void WriteDragDataForView(View* sender,
                                    const gfx::Point& press_pt,
                                    ui::OSExchangeData* data) override;
  virtual int GetDragOperationsForView(View* sender,
                                       const gfx::Point& p) override;
  virtual bool CanStartDragForView(View* sender,
                                   const gfx::Point& press_pt,
                                   const gfx::Point& p) override;

  // Overridden from views::ResizeAreaDelegate:
  virtual void OnResize(int resize_amount, bool done_resizing) override;

  // Overridden from gfx::AnimationDelegate:
  virtual void AnimationProgressed(const gfx::Animation* animation) override;
  virtual void AnimationEnded(const gfx::Animation* animation) override;

  // Overridden from BrowserActionView::Delegate:
  virtual content::WebContents* GetCurrentWebContents() override;
  virtual bool ShownInsideMenu() const override;
  virtual void OnBrowserActionViewDragDone() override;
  virtual views::MenuButton* GetOverflowReferenceView() override;
  virtual void SetPopupOwner(BrowserActionView* popup_owner) override;
  virtual void HideActivePopup() override;
  virtual BrowserActionView* GetMainViewForAction(
      BrowserActionView* view) override;

  // Overridden from extension::ExtensionKeybindingRegistry::Delegate:
  virtual extensions::ActiveTabPermissionGranter*
      GetActiveTabPermissionGranter() override;

  // Retrieve the current popup.  This should only be used by unit tests.
  gfx::NativeView TestGetPopup();

  // Returns the width of an icon, optionally with its padding.
  static int IconWidth(bool include_padding);

  // Returns the height of an icon.
  static int IconHeight();

  // During testing we can disable animations by setting this flag to true,
  // so that the bar resizes instantly, instead of having to poll it while it
  // animates to open/closed status.
  static bool disable_animations_during_testing_;

 protected:
  // Overridden from views::View:
  virtual void ViewHierarchyChanged(
      const ViewHierarchyChangedDetails& details) override;
  virtual void OnPaint(gfx::Canvas* canvas) override;
  virtual void OnThemeChanged() override;

 private:
  // A struct representing the position at which an action will be dropped.
  struct DropPosition;

  typedef std::vector<BrowserActionView*> BrowserActionViews;

  // extensions::ExtensionToolbarModel::Observer implementation.
  virtual void ToolbarExtensionAdded(const extensions::Extension* extension,
                                     int index) override;
  virtual void ToolbarExtensionRemoved(
      const extensions::Extension* extension) override;
  virtual void ToolbarExtensionMoved(const extensions::Extension* extension,
                                     int index) override;
  virtual void ToolbarExtensionUpdated(
      const extensions::Extension* extension) override;
  virtual bool ShowExtensionActionPopup(
      const extensions::Extension* extension,
      bool grant_active_tab) override;
  virtual void ToolbarVisibleCountChanged() override;
  virtual void ToolbarHighlightModeChanged(bool is_highlighting) override;
  virtual Browser* GetBrowser() override;

  void LoadImages();

  // Called when a browser action's visibility may have changed.
  void OnBrowserActionVisibilityChanged();

  // Returns the preferred width of the container in order to show all icons
  // that should be visible and, optionally, the chevron.
  int GetPreferredWidth();

  // Sets the chevron to be visible or not based on whether all browser actions
  // are displayed.
  void SetChevronVisibility();

  // Given a number of |icons|, returns the pixels needed to draw the entire
  // container (including the chevron if the number of icons is not all the
  // icons and there's not a separate overflow container). For convenience,
  // callers can set |icons| to -1 to mean "all icons".
  int IconCountToWidth(int icons) const;

  // Given a pixel width, returns the number of icons that fit.  (This
  // automatically determines whether a chevron will be needed and includes it
  // in the calculation.)
  size_t WidthToIconCount(int pixels) const;

  // Returns the absolute minimum size you can shrink the container down to and
  // still show it. If there's no chevron (i.e., there's a separate overflow
  // container), this leaves only enough room for the resize area; otherwise,
  // this assumes a visible chevron because the only way we would not have a
  // chevron when shrinking down this far is if there were no icons, in which
  // case the container wouldn't be shown at all.
  int MinimumNonemptyWidth() const;

  // Animate to the target size (unless testing, in which case we go straight to
  // the target size).
  void Animate(gfx::Tween::Type type, size_t num_visible_icons);

  // Returns the number of icons that this container should draw. This differs
  // from the model's GetVisibleIconCount if this container is for the overflow.
  size_t GetIconCount() const;

  // Whether this container is in overflow mode (as opposed to in 'main'
  // mode). See class comments for details on the difference.
  bool in_overflow_mode() const { return main_container_ != NULL; }

  // Whether or not the container has been initialized.
  bool initialized_;

  // The vector of browser actions (icons/image buttons for each action). Note
  // that not every BrowserAction in the ToolbarModel will necessarily be in
  // this collection. Some extensions may be disabled in incognito windows.
  BrowserActionViews browser_action_views_;

  Profile* profile_;

  // The Browser object the container is associated with.
  Browser* browser_;

  // The main container we are serving as overflow for, or NULL if this
  // class is the the main container. See class comments for details on
  // the difference between main and overflow.
  BrowserActionsContainer* main_container_;

  // The view that triggered the current popup (just a reference to a view
  // from browser_action_views_).
  BrowserActionView* popup_owner_;

  // The model that tracks the order of the toolbar icons.
  extensions::ExtensionToolbarModel* model_;

  // The current width of the container.
  int container_width_;

  // The resize area for the container.
  views::ResizeArea* resize_area_;

  // The chevron for accessing the overflow items. Can be NULL when in overflow
  // mode or if the toolbar is permanently suppressing the chevron menu.
  ChevronMenuButton* chevron_;

  // The painter used when we are highlighting a subset of extensions.
  scoped_ptr<views::Painter> highlight_painter_;

  // The animation that happens when the container snaps to place.
  scoped_ptr<gfx::SlideAnimation> resize_animation_;

  // Don't show the chevron while animating.
  bool suppress_chevron_;

  // This is used while the user is resizing (and when the animations are in
  // progress) to know how wide the delta is between the current state and what
  // we should draw.
  int resize_amount_;

  // Keeps track of the absolute pixel width the container should have when we
  // are done animating.
  int animation_target_size_;

  // The DropPosition for the current drag-and-drop operation, or NULL if there
  // is none.
  scoped_ptr<DropPosition> drop_position_;

  // The class that registers for keyboard shortcuts for extension commands.
  scoped_ptr<ExtensionKeybindingRegistryViews> extension_keybinding_registry_;

  ObserverList<BrowserActionsContainerObserver> observers_;

  // The maximum number of icons to show per row when in overflow mode (showing
  // icons in the application menu).
  static int icons_per_overflow_menu_row_;

  DISALLOW_COPY_AND_ASSIGN(BrowserActionsContainer);
};

#endif  // CHROME_BROWSER_UI_VIEWS_TOOLBAR_BROWSER_ACTIONS_CONTAINER_H_