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. 4 5 #ifndef MEDIA_MIDI_MIDI_MANAGER_H_ 6 #define MEDIA_MIDI_MIDI_MANAGER_H_ 7 8 #include <set> 9 #include <vector> 10 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" 15 16 namespace media { 17 18 // A MIDIManagerClient registers with the MIDIManager to receive MIDI data. 19 // See MIDIManager::RequestAccess() and MIDIManager::ReleaseAccess() 20 // for details. 21 class MEDIA_EXPORT MIDIManagerClient { 22 public: 23 virtual ~MIDIManagerClient() {} 24 25 // ReceiveMIDIData() is called when MIDI data has been received from the 26 // MIDI system. 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, 32 const uint8* data, 33 size_t length, 34 double timestamp) = 0; 35 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; 41 }; 42 43 // Manages access to all MIDI hardware. 44 class MEDIA_EXPORT MIDIManager { 45 public: 46 static MIDIManager* Create(); 47 48 MIDIManager(); 49 virtual ~MIDIManager(); 50 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); 56 57 // A client calls ReleaseSession() to stop receiving MIDI data. 58 void EndSession(MIDIManagerClient* client); 59 60 // DispatchSendMIDIData() is called when MIDI data should be sent to the MIDI 61 // system. 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 virtual void DispatchSendMIDIData(MIDIManagerClient* client, 69 uint32 port_index, 70 const std::vector<uint8>& data, 71 double timestamp) = 0; 72 73 // input_ports() is a list of MIDI ports for receiving MIDI data. 74 // Each individual port in this list can be identified by its 75 // integer index into this list. 76 const MIDIPortInfoList& input_ports() { return input_ports_; } 77 78 // output_ports() is a list of MIDI ports for sending MIDI data. 79 // Each individual port in this list can be identified by its 80 // integer index into this list. 81 const MIDIPortInfoList& output_ports() { return output_ports_; } 82 83 protected: 84 // Initializes the MIDI system, returning |true| on success. 85 virtual bool Initialize() = 0; 86 87 void AddInputPort(const MIDIPortInfo& info); 88 void AddOutputPort(const MIDIPortInfo& info); 89 90 // Dispatches to all clients. 91 void ReceiveMIDIData(uint32 port_index, 92 const uint8* data, 93 size_t length, 94 double timestamp); 95 96 bool initialized_; 97 98 // Keeps track of all clients who wish to receive MIDI data. 99 typedef std::set<MIDIManagerClient*> ClientList; 100 ClientList clients_; 101 102 // Protects access to our clients. 103 base::Lock clients_lock_; 104 105 MIDIPortInfoList input_ports_; 106 MIDIPortInfoList output_ports_; 107 108 DISALLOW_COPY_AND_ASSIGN(MIDIManager); 109 }; 110 111 } // namespace media 112 113 #endif // MEDIA_MIDI_MIDI_MANAGER_H_ 114
