Privileges.cs

using System.Collections.Generic;
using System.Threading.Tasks;
using Waher.Persistence;
using Waher.Persistence.Filters;
using Waher.Runtime.Threading;
 
namespace Waher.Security.Users
{
    public class Privileges
    {
        private static readonly Dictionary<string, Privilege> privileges = new Dictionary<string, Privilege>();
        private static readonly MultiReadSingleWriteObject synchObj = new MultiReadSingleWriteObject(typeof(Privileges));
 
        public static async Task<Privilege> GetPrivilege(string PrivilegeId)
        {
            await synchObj.BeginWrite();
            try
            {
                return await GetPrivilegeLocked(PrivilegeId);
            }
            finally
            {
                await synchObj.EndWrite();
            }
        }
 
        private static async Task<Privilege> GetPrivilegeLocked(string PrivilegeId)
        {
            if (privileges.TryGetValue(PrivilegeId, out Privilege Privilege))
                return Privilege;
 
            Privilege = await Database.FindFirstDeleteRest<Privilege>(new FilterFieldEqualTo("FullId", PrivilegeId));
            if (Privilege is null)
            {
                string ParentId;
                string LocalId;
                int i = PrivilegeId.LastIndexOf('.');
 
                if (i < 0)
                {
                    ParentId = string.Empty;
                    LocalId = PrivilegeId;
                }
                else
                {
                    ParentId = PrivilegeId.Substring(0, i);
                    LocalId = PrivilegeId.Substring(i + 1);
                }
 
                Privilege = new Privilege()
                {
                    ParentFullId = ParentId,
                    LocalId = LocalId,
                    FullId = PrivilegeId,
                    Description = string.Empty
                };
 
                await Database.Insert(Privilege);
            }
 
            if (!string.IsNullOrEmpty(Privilege.ParentFullId))
                Privilege.Parent = await GetPrivilegeLocked(Privilege.ParentFullId);
 
            privileges[PrivilegeId] = Privilege;
 
            return Privilege;
        }
 
        public static async Task LoadAll()
        {
            await synchObj.BeginWrite();
            try
            {
                privileges.Clear();
 
                IEnumerable<Privilege> Privileges = await Database.Find<Privilege>();
 
                foreach (Privilege Privilege in Privileges)
                    privileges[Privilege.FullId] = Privilege;
 
                foreach (Privilege Privilege in Privileges)
                {
                    if (!string.IsNullOrEmpty(Privilege.ParentFullId))
                        Privilege.Parent = await GetPrivilegeLocked(Privilege.ParentFullId);
                }
            }
            finally
            {
                await synchObj.EndWrite();
            }
        }
    }
}