ui/base/accelerators/accelerator_manager.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_BASE_ACCELERATORS_ACCELERATOR_MANAGER_H_
   6 #define UI_BASE_ACCELERATORS_ACCELERATOR_MANAGER_H_
   7
   8 #include <list>
   9 #include <map>
  10 #include <utility>
  11
  12 #include "base/basictypes.h"
  13 #include "ui/base/accelerators/accelerator.h"
  14 #include "ui/base/ui_base_export.h"
  15 #include "ui/events/event_constants.h"
  16
  17 namespace ui {
  18
  19 // The AcceleratorManger is used to handle keyboard accelerators.
  20 class UI_BASE_EXPORT AcceleratorManager {
  21  public:
  22   enum HandlerPriority {
  23     kNormalPriority,
  24     kHighPriority,
  25   };
  26
  27   AcceleratorManager();
  28   ~AcceleratorManager();
  29
  30   // Register a keyboard accelerator for the specified target. If multiple
  31   // targets are registered for an accelerator, a target registered later has
  32   // higher priority.
  33   // |accelerator| is the accelerator to register.
  34   // |priority| denotes the priority of the handler.
  35   // NOTE: In almost all cases, you should specify kNormalPriority for this
  36   // parameter. Setting it to kHighPriority prevents Chrome from sending the
  37   // shortcut to the webpage if the renderer has focus, which is not desirable
  38   // except for very isolated cases.
  39   // |target| is the AcceleratorTarget that handles the event once the
  40   // accelerator is pressed.
  41   // Note that we are currently limited to accelerators that are either:
  42   // - a key combination including Ctrl or Alt
  43   // - the escape key
  44   // - the enter key
  45   // - any F key (F1, F2, F3 ...)
  46   // - any browser specific keys (as available on special keyboards)
  47   void Register(const Accelerator& accelerator,
  48                 HandlerPriority priority,
  49                 AcceleratorTarget* target);
  50
  51   // Unregister the specified keyboard accelerator for the specified target.
  52   void Unregister(const Accelerator& accelerator, AcceleratorTarget* target);
  53
  54   // Unregister all keyboard accelerator for the specified target.
  55   void UnregisterAll(AcceleratorTarget* target);
  56
  57   // Activate the target associated with the specified accelerator.
  58   // First, AcceleratorPressed handler of the most recently registered target
  59   // is called, and if that handler processes the event (i.e. returns true),
  60   // this method immediately returns. If not, we do the same thing on the next
  61   // target, and so on.
  62   // Returns true if an accelerator was activated.
  63   bool Process(const Accelerator& accelerator);
  64
  65   // Returns the AcceleratorTarget that should be activated for the specified
  66   // keyboard accelerator, or NULL if no view is registered for that keyboard
  67   // accelerator.
  68   AcceleratorTarget* GetCurrentTarget(const Accelerator& accelerator) const;
  69
  70   // Whether the given |accelerator| has a priority handler associated with it.
  71   bool HasPriorityHandler(const Accelerator& accelerator) const;
  72
  73  private:
  74   // The accelerators and associated targets.
  75   typedef std::list<AcceleratorTarget*> AcceleratorTargetList;
  76   // This construct pairs together a |bool| (denoting whether the list contains
  77   // a priority_handler at the front) with the list of AcceleratorTargets.
  78   typedef std::pair<bool, AcceleratorTargetList> AcceleratorTargets;
  79   typedef std::map<Accelerator, AcceleratorTargets> AcceleratorMap;
  80   AcceleratorMap accelerators_;
  81
  82   DISALLOW_COPY_AND_ASSIGN(AcceleratorManager);
  83 };
  84
  85 }  // namespace ui
  86
  87 #endif  // UI_BASE_ACCELERATORS_ACCELERATOR_MANAGER_H_