USBLibrary.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_MEDIA_USB_USB_LIBRARY_H
#define META_OCEAN_MEDIA_USB_USB_LIBRARY_H
 
#include "ocean/media/usb/USB.h"
 
#include "ocean/media/Library.h"
#include "ocean/media/Manager.h"
 
#ifdef OCEAN_PLATFORM_BUILD_ANDROID
    #include "ocean/system/usb/android/OceanUSBManager.h"
#endif
 
namespace Ocean
{
 
namespace Media
{
 
namespace USB
{
 
/**
 * This class implements the USB library.
 * @ingroup mediausb
 */
class OCEAN_MEDIA_USB_EXPORT USBLibrary : public Library
{
    friend class USBLiveVideo;
    friend class Media::Manager;
 
    public:
 
        /**
         * Creates a new medium by a given url.
         * @see Library::newMedium().
         */
        MediumRef newMedium(const std::string& url, bool useExclusive = false) override;
 
        /**
         * Creates a new medium by a given url and an expected type.
         * @see Library::newMedium().
         */
        MediumRef newMedium(const std::string& url, const Medium::Type type, bool useExclusive = false) override;
 
        /**
         * Creates a new recorder specified by the recorder type.
         * @see Library::newRecorder().
         */
        RecorderRef newRecorder(const Recorder::Type type) override;
 
        /**
         * Returns a list of selectable mediums.
         * @see Library::selectableMedia().
         */
        Definitions selectableMedia() const override;
 
        /**
         * Returns a list of specific selectable mediums.
         * @see Library::selectableMedia().
         */
        Definitions selectableMedia(const Medium::Type type) const override;
 
        /**
         * Returns the supported medium types.
         * @see Library::supportedTypes().
         */
        Medium::Type supportedTypes() const override;
 
        /**
         * Registers this library at the global media manager.
         * With each register call, the reference counter for a specific library will be incremented.
         * Each call to registerLibrary() needs to be balanced with a corresponding call of unregisterLibrary() before shutting down.
         * @return True, if the library has not been registered before
         * @see Manager, unregisterLibrary()
         */
        static bool registerLibrary();
 
        /**
         * Unregisters this library at the global media manager.
         * With each unregister call, the reference counter for a specific library will be decremented and removed from the system if the counter reaches zero.
         * Each call to registerLibrary() needs to be balanced with a corresponding call of unregisterLibrary() before shutting down.
         * @return True, if the library was actually removed from the system (as the reference counter reached zero); False, if the library is still used by someone else
         * @see registerLibrary().
         */
        static bool unregisterLibrary();
 
        /**
         * Returns the definitions of all available USB camera devices.
         * @return The definitions of the available USB cameras, empty if no camera is connected or an error occurred
         */
        static Definitions enumerateCameraDefinitions();
 
#ifdef OCEAN_PLATFORM_BUILD_ANDROID
 
        /**
         * Returns device descriptors for all available USB camera devices on Android platforms.
         * On Android, we cannot enumerate all USB devices through libusb, instead we need to enumerate devices through Java.
         * @return The device descriptors for all available USB camera devices, empty if no camera is connected or an error occurred
         */
        static System::USB::Android::OceanUSBManager::DeviceDescriptors androidEnumerateCameraDevices();
 
#endif // OCEAN_PLATFORM_BUILD_ANDROID
 
    protected:
 
        /**
         * Creates a new USBLibrary object.
         */
        USBLibrary();
 
        /**
         * Destructs an USBLibrary object.
         */
        ~USBLibrary() override;
 
        /**
         * Ensures that the available devices are up-to-date.
         */
        void updateAvailableDevices() const;
 
        /**
         * Resolves a medium url to a device name.
         * @param url The URL of the medium, must be valid
         * @param deviceName The resulting device name
         * @return True, if succeeded
         */
        std::string resolveUrl(const std::string& url, std::string& deviceName) const;
 
        /**
         * Creates a new live video medium.
         * @param url The URL of the live video medium to create
         * @param useExclusive Determines whether the caller would like to use this medium exclusively
         * @return Reference of the new medium
         */
        MediumRef newLiveVideo(const std::string& url, bool useExclusive);
 
        /**
         * Creates this library and returns it an object reference.
         * @return The new library object
         */
        static LibraryRef create();
 
    protected:
 
        /// The definitions of available USB devices.
        mutable Definitions availableDevices_;
 
        /// The timestamp when the available devices have been queried the last time.
        mutable Timestamp lastAvailableDevicesTimestamp_;
};
 
}
 
}
 
}
 
#endif // META_OCEAN_MEDIA_USB_USB_LIBRARY_H