AndroidSharedGlContextUsageGuard.h

#pragma once

#include <pthread.h>

namespace Eegeo
{
    namespace Android
    {
        class IAndroidSharedGlContextUsageGuard
        {
        public:

            virtual ~IAndroidSharedGlContextUsageGuard() {}

            virtual void AcquireContextReadLock() = 0;
            virtual void ReleaseContextReadLock() = 0;
            virtual void AcquireContextWriteLock() = 0;
            virtual void ReleaseContextWriteLock() = 0;
        };

        class AndroidSharedGlContextUsageGuard : public IAndroidSharedGlContextUsageGuard
        {
        public:

            AndroidSharedGlContextUsageGuard()
            {
                pthread_rwlock_init(&m_contextReaderWriterLock, nullptr);
            }

            ~AndroidSharedGlContextUsageGuard()
            {
                pthread_rwlock_destroy(&m_contextReaderWriterLock);
            }

            void AcquireContextReadLock() override
            {
                pthread_rwlock_rdlock(&m_contextReaderWriterLock);
            }

            void ReleaseContextReadLock() override
            {
                pthread_rwlock_unlock(&m_contextReaderWriterLock);
            }

            void AcquireContextWriteLock() override
            {
                pthread_rwlock_wrlock(&m_contextReaderWriterLock);
            }

            void ReleaseContextWriteLock() override
            {
                pthread_rwlock_unlock(&m_contextReaderWriterLock);
            }

        private:

            pthread_rwlock_t m_contextReaderWriterLock;
        };

        class ScopedAndroidGlContextWriteLock
        {
        public:

            ScopedAndroidGlContextWriteLock(IAndroidSharedGlContextUsageGuard& guard)
                : m_guard(guard)
            {
                m_guard.AcquireContextWriteLock();
            }

            ~ScopedAndroidGlContextWriteLock()
            {
                m_guard.ReleaseContextWriteLock();
            }

        private:

            IAndroidSharedGlContextUsageGuard& m_guard;
        };
    }
}