using System;
using System.Runtime.CompilerServices;
using System.Runtime.ConstrainedExecution;

namespace Foodsoft.Alpm
{
    internal class SafeFilePackageHandle : SafePackageHandle
    {
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        [PrePrepareMethod]
        internal SafeFilePackageHandle(IntPtr ptr, SafeAlpmHandle parentHandle) : base(parentHandle)
        {
            var success = false;

            RuntimeHelpers.PrepareConstrainedRegions();
            try { }
            finally
            {
                parentHandle.DangerousAddRef(ref success);
                if (success) handle = ptr;
            }

            if (!success) throw new ObjectDisposedException(GetType().FullName);
        }

        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        [PrePrepareMethod]
        protected override bool ReleaseHandle()
        {
            var err = alpm.alpm_pkg_free(handle);
            SafeAlpmHandle.DangerousRelease();
            return err == 0;
        }
    }
}