System.Security.CodeAccessSecurityEngine.CheckSetHelper C# (CSharp) Method

        internal static bool CheckSetHelper(PermissionSet grants,
                                           PermissionSet refused,
                                           PermissionSet demands,
                                           RuntimeMethodHandle rmh,
                                           Object assemblyOrString,
                                           SecurityAction action,
                                           bool throwException)
        {

            BCLDebug.Assert(demands != null, "Should not reach here with a null demand set");
    #if _DEBUG
            if (debug)
            {
                DEBUG_OUT("Granted: ");
                DEBUG_OUT(grants.ToXml().ToString());
                DEBUG_OUT("Refused: ");
                DEBUG_OUT(refused != null ? refused.ToXml().ToString() : "<null>");
                DEBUG_OUT("Demanded: ");
                DEBUG_OUT(demands!=null ? demands.ToXml().ToString() : "<null>");
            }
    #endif

            IPermission permThatFailed = null;
            if (grants != null)
                grants.CheckDecoded(demands);
            if (refused != null)
                refused.CheckDecoded(demands);

            bool bThreadSecurity = SecurityManager._SetThreadSecurity(false);

            try
            {

                // Check grant set
                if (!demands.CheckDemand(grants, out permThatFailed))
                {
                    if (throwException)
                        ThrowSecurityException(assemblyOrString, grants, refused, rmh, action, demands, permThatFailed);
                    else
                        return false;
                }

                // Check refused set
                if (!demands.CheckDeny(refused, out permThatFailed))
                {
                    if (throwException)
                        ThrowSecurityException(assemblyOrString, grants, refused, rmh, action, demands, permThatFailed);
                    else
                        return false;
                }
            }
            catch (SecurityException)
            {
                throw;
            }
            catch (Exception)
            {
                // Any exception besides a security exception in this code means that
                // a permission was unable to properly handle what we asked of it.
                // We will define this to mean that the demand failed.
                if (throwException)
                    ThrowSecurityException(assemblyOrString, grants, refused, rmh, action, demands, permThatFailed);
                else
                    return false;
            }
            catch
            {
                return false;
            }
            finally
            {
                if (bThreadSecurity)
                    SecurityManager._SetThreadSecurity(true);
            }
            return true;
        }

 internal static void CheckSetHelper(CompressedStack cs, PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandleInternal rmh, RuntimeAssembly asm, SecurityAction action)
 {
     if (cs != null)
     {
         cs.CheckSetDemand(demands, rmh);
         return;
     }
     CodeAccessSecurityEngine.CheckSetHelper(grants, refused, demands, rmh, asm, action, true);
 }