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- // Copyright (c) 2013 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 MEDIA_MIDI_MIDI_MANAGER_H_
- #define MEDIA_MIDI_MIDI_MANAGER_H_
- #include <stddef.h>
- #include <stdint.h>
- #include <set>
- #include <vector>
- #include "base/memory/raw_ptr.h"
- #include "base/memory/ref_counted.h"
- #include "base/synchronization/lock.h"
- #include "base/thread_annotations.h"
- #include "base/time/time.h"
- #include "media/midi/midi_export.h"
- #include "media/midi/midi_service.mojom.h"
- namespace base {
- class SingleThreadTaskRunner;
- } // namespace base
- namespace midi {
- class MidiService;
- // A MidiManagerClient registers with the MidiManager to receive MIDI data.
- // See MidiManager::RequestAccess() and MidiManager::ReleaseAccess()
- // for details.
- // TODO(toyoshim): Consider to have a MidiServiceClient interface.
- class MIDI_EXPORT MidiManagerClient {
- public:
- virtual ~MidiManagerClient() {}
- // AddInputPort() and AddOutputPort() are called before CompleteStartSession()
- // is called to notify existing MIDI ports, and also called after that to
- // notify new MIDI ports are added.
- virtual void AddInputPort(const mojom::PortInfo& info) = 0;
- virtual void AddOutputPort(const mojom::PortInfo& info) = 0;
- // SetInputPortState() and SetOutputPortState() are called to notify a known
- // device gets disconnected, or connected again.
- virtual void SetInputPortState(uint32_t port_index,
- mojom::PortState state) = 0;
- virtual void SetOutputPortState(uint32_t port_index,
- mojom::PortState state) = 0;
- // CompleteStartSession() is called when platform dependent preparation is
- // finished.
- virtual void CompleteStartSession(mojom::Result result) = 0;
- // ReceiveMidiData() is called when MIDI data has been received from the
- // MIDI system.
- // |port_index| represents the specific input port from input_ports().
- // |data| represents a series of bytes encoding one or more MIDI messages.
- // |length| is the number of bytes in |data|.
- // |timestamp| is the time the data was received, in seconds.
- virtual void ReceiveMidiData(uint32_t port_index,
- const uint8_t* data,
- size_t length,
- base::TimeTicks timestamp) = 0;
- // AccumulateMidiBytesSent() is called to acknowledge when bytes have
- // successfully been sent to the hardware.
- // This happens as a result of the client having previously called
- // MidiManager::DispatchSendMidiData().
- virtual void AccumulateMidiBytesSent(size_t n) = 0;
- // Detach() is called when MidiManager is going to shutdown immediately.
- // Client should not touch MidiManager instance after Detach() is called.
- virtual void Detach() = 0;
- };
- // Manages access to all MIDI hardware. MidiManager runs on the I/O thread.
- //
- // Note: We will eventually remove utility functions that are shared among
- // platform dependent MidiManager inheritances such as MidiManagerClient
- // management. MidiService should provide such shareable utility functions as
- // it does TaskService.
- class MIDI_EXPORT MidiManager {
- public:
- static const size_t kMaxPendingClientCount = 128;
- explicit MidiManager(MidiService* service);
- MidiManager(const MidiManager&) = delete;
- MidiManager& operator=(const MidiManager&) = delete;
- virtual ~MidiManager();
- static MidiManager* Create(MidiService* service);
- // A client calls StartSession() to receive and send MIDI data.
- // If the session is ready to start, the MIDI system is lazily initialized
- // and the client is registered to receive MIDI data.
- // CompleteStartSession() is called with mojom::Result::OK if the session is
- // started. Otherwise CompleteStartSession() is called with a proper
- // mojom::Result code.
- void StartSession(MidiManagerClient* client);
- // A client calls EndSession() to stop receiving MIDI data.
- // Returns false if |client| did not start a session.
- bool EndSession(MidiManagerClient* client);
- // Returns true if there is at least one client that keep a session open.
- bool HasOpenSession();
- // DispatchSendMidiData() is called when MIDI data should be sent to the MIDI
- // system.
- // This method is supposed to return immediately and should not block.
- // |port_index| represents the specific output port from output_ports().
- // |data| represents a series of bytes encoding one or more MIDI messages.
- // |length| is the number of bytes in |data|.
- // |timestamp| is the time to send the data. A value of 0 means send "now" or
- // as soon as possible. The default implementation is for unsupported
- // platforms.
- virtual void DispatchSendMidiData(MidiManagerClient* client,
- uint32_t port_index,
- const std::vector<uint8_t>& data,
- base::TimeTicks timestamp);
- // This method ends all sessions by detaching and removing all registered
- // clients. This method can be called from any thread.
- void EndAllSessions();
- protected:
- friend class MidiManagerUsb;
- // Initializes the platform dependent MIDI system. MidiManager class has a
- // default implementation that synchronously calls CompleteInitialization()
- // with mojom::Result::NOT_SUPPORTED. A derived class for a specific platform
- // should override this method correctly.
- // Platform dependent initialization can be processed synchronously or
- // asynchronously. When the initialization is completed,
- // CompleteInitialization() should be called with |result|.
- // |result| should be mojom::Result::OK on success, otherwise a proper
- // mojom::Result.
- virtual void StartInitialization();
- // Called from a platform dependent implementation of StartInitialization().
- // The method distributes |result| to MIDIManagerClient objects in
- // |pending_clients_|.
- void CompleteInitialization(mojom::Result result);
- // The following five methods can be called on any thread to notify clients of
- // status changes on ports, or to obtain port status.
- void AddInputPort(const mojom::PortInfo& info);
- void AddOutputPort(const mojom::PortInfo& info);
- void SetInputPortState(uint32_t port_index, mojom::PortState state);
- void SetOutputPortState(uint32_t port_index, mojom::PortState state);
- mojom::PortState GetOutputPortState(uint32_t port_index);
- // Invoke AccumulateMidiBytesSent() for |client| safely. If the session was
- // already closed, do nothing. Can be called on any thread.
- void AccumulateMidiBytesSent(MidiManagerClient* client, size_t n);
- // Dispatches to all clients. Can be called on any thread.
- void ReceiveMidiData(uint32_t port_index,
- const uint8_t* data,
- size_t length,
- base::TimeTicks time);
- // Only for testing.
- size_t GetClientCountForTesting();
- size_t GetPendingClientCountForTesting();
- MidiService* service() { return service_; }
- private:
- enum class InitializationState {
- NOT_STARTED,
- STARTED,
- COMPLETED,
- };
- // Note: Members that are not protected by any lock should be accessed only on
- // the I/O thread.
- // Tracks platform dependent initialization state.
- InitializationState initialization_state_ = InitializationState::NOT_STARTED;
- // Keeps the platform dependent initialization result if initialization is
- // completed. Otherwise keeps mojom::Result::NOT_INITIALIZED.
- mojom::Result result_ = mojom::Result::NOT_INITIALIZED;
- // Keeps track of all clients who are waiting for CompleteStartSession().
- std::set<MidiManagerClient*> pending_clients_ GUARDED_BY(lock_);
- // Keeps track of all clients who wish to receive MIDI data.
- std::set<MidiManagerClient*> clients_ GUARDED_BY(lock_);
- // Keeps a SingleThreadTaskRunner of the thread that calls StartSession in
- // order to invoke CompleteStartSession() on the thread. This is touched only
- // on the IO thread usually, but to be guarded by |lock_| for thread checks.
- scoped_refptr<base::SingleThreadTaskRunner> session_thread_runner_
- GUARDED_BY(lock_);
- // Keeps all PortInfo.
- std::vector<mojom::PortInfo> input_ports_ GUARDED_BY(lock_);
- std::vector<mojom::PortInfo> output_ports_ GUARDED_BY(lock_);
- // Tracks if actual data transmission happens.
- bool data_sent_ GUARDED_BY(lock_) = false;
- bool data_received_ GUARDED_BY(lock_) = false;
- // Protects members above.
- base::Lock lock_;
- // MidiService outlives MidiManager.
- const raw_ptr<MidiService> service_;
- };
- } // namespace midi
- #endif // MEDIA_MIDI_MIDI_MANAGER_H_
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