ash/common/system/chromeos/palette/palette_tool.h

// Copyright 2016 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 ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_TOOL_H_
#define ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_TOOL_H_

#include <map>
#include <memory>
#include <vector>

#include "ash/ash_export.h"
#include "base/callback.h"
#include "base/macros.h"
#include "ui/gfx/vector_icon_types.h"

namespace views {
class View;
}

namespace ash {

class WmWindow;

enum class PaletteGroup;
enum class PaletteToolId;
class PaletteToolManager;

// A PaletteTool is a generalized action inside of the palette menu in the
// shelf. Only one tool per group is active at any given time. When the tool is
// active, it should be showing some specializied UI. The tool is no longer
// active if it completes its action, if the user selects another tool with the
// same group, or if the user just cancels the action from the palette.
class ASH_EXPORT PaletteTool {
 public:
  class Delegate {
   public:
    Delegate() {}
    virtual ~Delegate() {}

    // Enable or disable a specific tool.
    virtual void EnableTool(PaletteToolId tool_id) = 0;
    virtual void DisableTool(PaletteToolId tool_id) = 0;

    // Hide the entire palette. This should not change any tool state.
    virtual void HidePalette() = 0;

    // Returns the root window.
    virtual WmWindow* GetWindow() = 0;

   private:
    DISALLOW_COPY_AND_ASSIGN(Delegate);
  };

  // Adds all available PaletteTool instances to the tool_manager.
  static void RegisterToolInstances(PaletteToolManager* tool_manager);

  // |delegate| must outlive this tool instance.
  explicit PaletteTool(Delegate* delegate);
  virtual ~PaletteTool();

  // The group this tool belongs to. Only one tool per group can be active at
  // any given time.
  virtual PaletteGroup GetGroup() const = 0;

  // The unique identifier for this tool. This should be the only tool that ever
  // has this ID.
  virtual PaletteToolId GetToolId() const = 0;

  // Called when the user activates the tool. Only one tool per group can be
  // active at any given time.
  virtual void OnEnable();

  // Disable the tool, either because this tool called DisableSelf(), the
  // user cancelled the tool, or the user activated another tool within the
  // same group.
  virtual void OnDisable();

  // Create a view that will be used in the palette, or nullptr if this tool
  // should not be displayed. The view is owned by the caller. OnViewDestroyed
  // is called when the view has been deallocated by its owner.
  virtual views::View* CreateView() = 0;
  virtual void OnViewDestroyed() = 0;

  // Returns an icon to use in the tray if this tool is active. Only one tool
  // (per-group) should ever have an active icon at any given time.
  virtual gfx::VectorIconId GetActiveTrayIcon();

 protected:
  // Enables/disables the tool.
  bool enabled() const { return enabled_; }

  Delegate* delegate() { return delegate_; }

 private:
  bool enabled_ = false;

  // Unowned pointer to the delegate. The delegate should outlive this instance.
  Delegate* delegate_;

  DISALLOW_COPY_AND_ASSIGN(PaletteTool);
};

}  // namespace ash

#endif  // ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_PALETTE_TOOL_H_