NativeInterfaceManager.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_PLATFORM_ANDROID_NATIVE_INTERFACE_MANAGER_H
#define META_OCEAN_PLATFORM_ANDROID_NATIVE_INTERFACE_MANAGER_H
 
#include "ocean/platform/android/Android.h"
#include "ocean/platform/android/ScopedJNIObject.h"
 
#include "ocean/base/Lock.h"
#include "ocean/base/Singleton.h"
 
namespace Ocean
{
 
namespace Platform
{
 
namespace Android
{
 
/**
 * This class implements the manager of the java native interface as singleton.
 * @ingroup platformandroid
 */
class OCEAN_PLATFORM_ANDROID_EXPORT NativeInterfaceManager : public Singleton<NativeInterfaceManager>
{
    friend class Singleton<NativeInterfaceManager>;
 
    private:
 
        /**
         * Definition of a map mapping thread ids to Java native interface environments.
         */
        using ThreadEnvironmentMap = std::unordered_map<pid_t, JNIEnv*>;
 
    public:
 
        /**
         * Returns the JNI virtual machine object.
         * @return The JNI virtual machine object
         */
        JavaVM* virtualMachine();
 
        /**
         * Returns the java native interface environment object for the current calling thread.
         * @return JNI environment object.
         */
        JNIEnv* environment();
 
        /**
         * Returns the current activity.
         * @return The current activity, may be nullptr if no activity is set
         */
        jobject currentActivity();
 
        /**
         * Sets the virtual machine object of this manager.
         * @param virtualMachine Virtual machine to be set
         * @return True, if succeeded
         */
        bool setVirtualMachine(JavaVM* virtualMachine);
 
        /**
         * Sets or changes the current activity.
         * @param activity The current activity to be set or updated, can be nullptr to remove the previously set activity
         */
        void setCurrentActivity(jobject activity);
 
    protected:
 
        /**
         * Creates a new manger object.
         * This object will be created indirectly by the singleton object.
         * @see Singleton::get().
         */
        NativeInterfaceManager();
 
        /**
         * Destructs a manger object.
         */
        virtual ~NativeInterfaceManager();
 
    protected:
 
        /// Manager lock.
        Lock lock_;
 
        /// JNI virtual machine object.
        JavaVM* virtualMachine_ = nullptr;
 
        /// The JNI object of the current activity with global reference, nullptr if not set.
        ScopedJObject currentActivity_;
 
        /// Map holding Java native environments individually for each thread.
        ThreadEnvironmentMap threadEnvironmentMap_;
};
 
}
 
}
 
}
 
#endif // META_OCEAN_PLATFORM_ANDROID_NATIVE_INTERFACE_MANAGER_H