public static string AddOrUpdate(this IStorageItemAccessList storageAccessList, IStorageItem storageItem, bool removeOldestIfFull = true, int?maxItemCount = null)
{
if (null == storageAccessList)
{
throw new ArgumentNullException(nameof(storageAccessList));
}
if (null == storageItem)
{
throw new ArgumentNullException(nameof(storageItem));
}
if (maxItemCount <= 0)
{
throw new ArgumentException($"{nameof(maxItemCount)} must be null or >= 1", nameof(maxItemCount));
}
var storageItemMd5Guid = StorageAccessEntryInfo.GetPathMd5Guid(storageItem.Path);
// search in the list
var saeiList = new List <StorageAccessEntryInfo>();
foreach (var sae in storageAccessList.Entries.Reverse())
{
if (false == string.IsNullOrWhiteSpace(sae.Metadata))
{
try
{
var saeInfoFromJson = JsonConvert.DeserializeObject <StorageAccessEntryInfo>(sae.Metadata);
if (saeInfoFromJson.IsManaged &&
null != saeInfoFromJson.LastAccessTimeUtc &&
null != saeInfoFromJson.PathMd5)
{
saeInfoFromJson.Token = sae.Token;
saeInfoFromJson.Metadata = sae.Metadata;
// if found, update the meta and return
if (saeInfoFromJson.PathMd5 == storageItemMd5Guid)
{
saeInfoFromJson.LastAccessTimeUtc = DateTime.UtcNow;
storageAccessList.AddOrReplace(saeInfoFromJson.Token, storageItem, saeInfoFromJson.ToMetadataJson());
return(saeInfoFromJson.Token);
}
saeiList.Add(saeInfoFromJson);
continue;
}
}
catch { }
}
var saeInfo = new StorageAccessEntryInfo
{
IsManaged = false,
Token = sae.Token,
Metadata = sae.Metadata,
};
saeiList.Add(saeInfo);
}
// when allowed, make room if the list is full
var random = new Random(new Random().Next());
maxItemCount = maxItemCount ?? (int)storageAccessList.MaximumItemsAllowed;
while (storageAccessList.Entries.Count() >= maxItemCount && removeOldestIfFull)
{
if (saeiList.Any(saei => false == saei.IsManaged) &&
(
false == saeiList.Any(saei => true == saei.IsManaged) ||
0 == random.Next() % 2
))
{
var lastUnManaged = saeiList.Last(saei => false == saei.IsManaged);
storageAccessList.Remove(lastUnManaged.Token);
saeiList.Remove(lastUnManaged);
continue;
}
var oldestManaged = saeiList.OrderByDescending(saei => saei.LastAccessTimeUtc).First();
storageAccessList.Remove(oldestManaged.Token);
saeiList.Remove(oldestManaged);
}
// add one
var metadataJson = new StorageAccessEntryInfo
{
IsManaged = true,
PathMd5 = storageItemMd5Guid,
LastAccessTimeUtc = DateTime.UtcNow
}.ToMetadataJson();
return(storageAccessList.Add(storageItem, metadataJson));
}
public static async Task <StorageFolder> TryGetFolderFromAccessListAsync(string token, IStorageItemAccessList list)
{
if (list.ContainsItem(token))
{
try { return(await list.GetFolderAsync(token)); }
catch (Exception) { return(null); }
}
else
{
return(null);
}
}
/// <summary>
/// Wraps the specified IStorageItemAccessList in an instance of this class.
/// </summary>
/// <param name="accessList">The list to proxy.</param>
public DatabaseAccessList(IStorageItemAccessList accessList)
{
this.accessList = accessList;
}
