/// <summary>
/// Method to unlock a DCRGraph in the database. This is a helper method which is used by all methods which change data in the database.
/// </summary>
/// <param name="guid"></param>
/// <param name="graphId"></param>
/// <param name="db"></param>
/// <returns></returns>
public async Task <Tuple <bool, string> > Unlock(Guid guid, int graphId, DBO.Database db)
{
var graph = await db.DCRGraphs.FindAsync(graphId);
if (graph == null)
{
return(new Tuple <bool, string>(false, "The graph did not exist"));
}
if (graph.Lock == false)
{
return(new Tuple <bool, string>(false, "The graph was not locked when reaching the unlock phase"));
}
if (graph.Guid != guid)
{
return(new Tuple <bool, string>(false, "someone else has locked the graph. Should not be possible."));
}
//unlock and save to db.
graph.Lock = false;
db.Entry(graph).State = EntityState.Modified;
await db.SaveChangesAsync();
return(new Tuple <bool, string>(true, ""));
}
/// <summary>
/// Method to lock a DCRGraph in the database. This is a helper method which is used by all methods which change data in the database.
/// </summary>
/// <param name="guid"></param>
/// <param name="graphId"></param>
/// <param name="db"></param>
/// <returns></returns>
public async Task <Tuple <bool, string> > LockGraph(Guid guid, int graphId, DBO.Database db)
{
var graph = await db.DCRGraphs.FindAsync(graphId);
//check if the graph exist
if (graph == null)
{
return(new Tuple <bool, string>(false, "The graph did not exist"));
}
//Check that the graph is not locked, and if it is, check whether it's an old lock. Locks older than 1minute we do no care about.
if (graph.Lock && DateTime.Now.Subtract(graph.LockTime).Minutes < 1)
{
return(new Tuple <bool, string>(false, "The graph is already locked"));
}
//lock this
graph.Lock = true;
graph.LockTime = DateTime.Now;
graph.Guid = guid;
db.Entry(graph).State = EntityState.Modified;
await db.SaveChangesAsync();
return(new Tuple <bool, string>(true, ""));
}
/// <summary>
/// Method to check if a DCRGraph in the database is locked. This is a helper method which is used by all methods which change data in the database.
/// </summary>
/// <param name="guid"></param>
/// <param name="graphId"></param>
/// <param name="db"></param>
/// <returns></returns>
public async Task <Tuple <bool, string> > CheckLock(Guid guid, int graphId, DBO.Database db)
{
var graph = await db.DCRGraphs.FindAsync(graphId);
if (graph == null)
{
return(new Tuple <bool, string>(false, "The graph did not exist"));
}
if (graph.Lock == false)
{
return(new Tuple <bool, string>(false, "The graph was not locked when reaching the check lock phase"));
}
if (graph.Guid != guid)
{
return(new Tuple <bool, string>(false, "someone else has locked the graph."));
}
return(new Tuple <bool, string>(true, ""));
}