xenadmin/XenModel/Actions/PureAsyncAction.cs

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using XenAdmin.Core;
using XenAdmin.Network;
using XenAPI;

namespace XenAdmin.Actions
{
    // A PureAsyncAction is one for which we can determine the set of API calls it will make by doing
    // an initial dummy run through the action using an RbacCollectorProxy.
    // In order to achieve this, it must have the following properties:
    // * No side effects (other than through the API).
    // * It doesn't destroy its own variables as it runs.
    // * No dialogs.
    // * No waits. This generally rules out object creation actions.
    // * No HTTP calls.
    // * No new threads.
    // * No API calls which are allowed to fail.
    public abstract class PureAsyncAction : AsyncAction
    {
        protected PureAsyncAction(IXenConnection connection, string title, string description, bool SuppressHistory)
            : base(connection, title, description, SuppressHistory)
        {
        }

        protected PureAsyncAction(IXenConnection connection, string title, string description)
            : base(connection, title, description)
        {
        }

        protected PureAsyncAction(IXenConnection connection, string title)
            : base(connection, title)
        {
        }

        protected PureAsyncAction(IXenConnection connection, string title, bool suppress_history)
            : base(connection, title, suppress_history)
        {
        }

        public override RbacMethodList GetApiMethodsToRoleCheck
        {
            get
            {
                System.Diagnostics.Trace.Assert(ApiMethodsToRoleCheck.Count == 0);  // shouldn't set ApiMethodsToRoleCheck for PureAsyncAction: it will be ignored
                RbacMethodList rbacMethods = new RbacMethodList();
                var session = Session;
                Session = new Session(RbacCollectorProxy.GetProxy(rbacMethods), Connection);
                var startDescription = Description;
                SuppressProgressReport = true;
                Run();
                Session = session; // reset Session
                Description = startDescription; // reset Description
                //reset SuppressProgressReport after the Description to avoid firing unnecessarily the Changed event
                SuppressProgressReport = false;
                return rbacMethods;
            }
        }
    }
}