dom/midi/MIDIAccess.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_MIDIAccess_h
   8 #define mozilla_dom_MIDIAccess_h
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/DOMEventTargetHelper.h"
  12 #include "mozilla/Observer.h"
  13 #include "nsCycleCollectionParticipant.h"
  14 #include "nsWrapperCache.h"
  15
  16 struct JSContext;
  17
  18 namespace mozilla {
  19 class ErrorResult;
  20
  21 // Predeclare void_t here, as including IPCMessageUtils brings in windows.h and
  22 // causes binding compilation problems.
  23 struct void_t;
  24
  25 namespace dom {
  26
  27 class MIDIAccessManager;
  28 class MIDIInputMap;
  29 struct MIDIOptions;
  30 class MIDIOutputMap;
  31 class MIDIPermissionRequest;
  32 class MIDIPort;
  33 class MIDIPortChangeEvent;
  34 class MIDIPortInfo;
  35 class MIDIPortList;
  36 class Promise;
  37
  38 using MIDIAccessDestructionObserver = Observer<void_t>;
  39
  40 /**
  41  * MIDIAccess is the DOM object that is handed to the user upon MIDI permissions
  42  * being successfully granted. It manages access to MIDI ports, and fires events
  43  * for device connection and disconnection.
  44  *
  45  * New MIDIAccess objects are created every time RequestMIDIAccess is called.
  46  * MIDIAccess objects are managed via MIDIAccessManager.
  47  */
  48 class MIDIAccess final : public DOMEventTargetHelper,
  49                          public Observer<MIDIPortList> {
  50   // Use the Permission Request class in MIDIAccessManager for creating
  51   // MIDIAccess objects.
  52   friend class MIDIPermissionRequest;
  53   friend class MIDIAccessManager;
  54
  55  public:
  56   NS_DECL_ISUPPORTS_INHERITED
  57   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(MIDIAccess,
  58                                                          DOMEventTargetHelper)
  59  public:
  60   virtual JSObject* WrapObject(JSContext* aCx,
  61                                JS::Handle<JSObject*> aGivenProto) override;
  62
  63   // Return map of MIDI Input Ports
  64   MIDIInputMap* Inputs() const { return mInputMap; }
  65
  66   // Return map of MIDI Output Ports
  67   MIDIOutputMap* Outputs() const { return mOutputMap; }
  68
  69   // Returns true if sysex permissions were given
  70   bool SysexEnabled() const { return mSysexEnabled; }
  71
  72   // Observer implementation for receiving port connection updates
  73   void Notify(const MIDIPortList& aEvent) override;
  74
  75   // All MIDIPort objects observe destruction of the MIDIAccess object that
  76   // created them, as the port object receives disconnection events which then
  77   // must be passed up to the MIDIAccess object. If the Port object dies before
  78   // the MIDIAccess object, it needs to be removed from the observer list.
  79   void RemovePortListener(MIDIAccessDestructionObserver* aObs);
  80
  81   // Fires DOM event on port connection/disconnection
  82   void FireConnectionEvent(MIDIPort* aPort);
  83
  84   // Notify all MIDIPorts that were created by this MIDIAccess and are still
  85   // alive, and detach from the MIDIAccessManager.
  86   void Shutdown();
  87   IMPL_EVENT_HANDLER(statechange);
  88
  89   void DisconnectFromOwner() override;
  90
  91  private:
  92   MIDIAccess(nsPIDOMWindowInner* aWindow, bool aSysexEnabled,
  93              Promise* aAccessPromise);
  94   ~MIDIAccess();
  95
  96   // On receiving a connection event from MIDIAccessManager, create a
  97   // corresponding MIDIPort object if we don't already have one.
  98   void MaybeCreateMIDIPort(const MIDIPortInfo& aInfo, ErrorResult& aRv);
  99
 100   // Stores all known MIDIInput Ports
 101   RefPtr<MIDIInputMap> mInputMap;
 102   // Stores all known MIDIOutput Ports
 103   RefPtr<MIDIOutputMap> mOutputMap;
 104   // List of MIDIPort observers that need to be updated on destruction.
 105   ObserverList<void_t> mDestructionObservers;
 106   // True if user gave permissions for sysex usage to this object.
 107   bool mSysexEnabled;
 108   // Promise created by RequestMIDIAccess call, to be resolved after port
 109   // populating is finished.
 110   RefPtr<Promise> mAccessPromise;
 111   // True if shutdown process has started, so we don't try to add more ports.
 112   bool mHasShutdown;
 113 };
 114
 115 }  // namespace dom
 116 }  // namespace mozilla
 117
 118 #endif  // mozilla_dom_MIDIAccess_h