1 // Copyright (c) 2013 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.
5 #ifndef MEDIA_MIDI_MIDI_MANAGER_H_
6 #define MEDIA_MIDI_MIDI_MANAGER_H_
11 #include "base/basictypes.h"
12 #include "base/synchronization/lock.h"
13 #include "media/base/media_export.h"
14 #include "media/midi/midi_port_info.h"
18 // A MidiManagerClient registers with the MidiManager to receive MIDI data.
19 // See MidiManager::RequestAccess() and MidiManager::ReleaseAccess()
21 class MEDIA_EXPORT MidiManagerClient {
23 virtual ~MidiManagerClient() {}
25 // ReceiveMidiData() is called when MIDI data has been received from the
27 // |port_index| represents the specific input port from input_ports().
28 // |data| represents a series of bytes encoding one or more MIDI messages.
29 // |length| is the number of bytes in |data|.
30 // |timestamp| is the time the data was received, in seconds.
31 virtual void ReceiveMidiData(uint32 port_index,
34 double timestamp) = 0;
36 // AccumulateMidiBytesSent() is called to acknowledge when bytes have
37 // successfully been sent to the hardware.
38 // This happens as a result of the client having previously called
39 // MidiManager::DispatchSendMidiData().
40 virtual void AccumulateMidiBytesSent(size_t n) = 0;
43 // Manages access to all MIDI hardware.
44 class MEDIA_EXPORT MidiManager {
46 static MidiManager* Create();
49 virtual ~MidiManager();
51 // A client calls StartSession() to receive and send MIDI data.
52 // If the session is ready to start, the MIDI system is lazily initialized
53 // and the client is registered to receive MIDI data.
54 // Returns |true| if the session succeeds to start.
55 bool StartSession(MidiManagerClient* client);
57 // A client calls ReleaseSession() to stop receiving MIDI data.
58 void EndSession(MidiManagerClient* client);
60 // DispatchSendMidiData() is called when MIDI data should be sent to the MIDI
62 // This method is supposed to return immediately and should not block.
63 // |port_index| represents the specific output port from output_ports().
64 // |data| represents a series of bytes encoding one or more MIDI messages.
65 // |length| is the number of bytes in |data|.
66 // |timestamp| is the time to send the data, in seconds. A value of 0
67 // means send "now" or as soon as possible.
68 // The default implementation is for unsupported platforms.
69 virtual void DispatchSendMidiData(MidiManagerClient* client,
71 const std::vector<uint8>& data,
74 // input_ports() is a list of MIDI ports for receiving MIDI data.
75 // Each individual port in this list can be identified by its
76 // integer index into this list.
77 const MidiPortInfoList& input_ports() { return input_ports_; }
79 // output_ports() is a list of MIDI ports for sending MIDI data.
80 // Each individual port in this list can be identified by its
81 // integer index into this list.
82 const MidiPortInfoList& output_ports() { return output_ports_; }
85 // Initializes the MIDI system, returning |true| on success.
86 // The default implementation is for unsupported platforms.
87 virtual bool Initialize();
89 void AddInputPort(const MidiPortInfo& info);
90 void AddOutputPort(const MidiPortInfo& info);
92 // Dispatches to all clients.
93 void ReceiveMidiData(uint32 port_index,
100 // Keeps track of all clients who wish to receive MIDI data.
101 typedef std::set<MidiManagerClient*> ClientList;
104 // Protects access to our clients.
105 base::Lock clients_lock_;
107 MidiPortInfoList input_ports_;
108 MidiPortInfoList output_ports_;
110 DISALLOW_COPY_AND_ASSIGN(MidiManager);
115 #endif // MEDIA_MIDI_MIDI_MANAGER_H_