public async Task <Result <Pointer> > UpdateAsync(string type, MdLocator location)
{
var(pointer, value) = (await _dataTree.GetAllPointerValuesAsync().ConfigureAwait(false))
.Single(c => c.Item1.MdKey == type);
var mdResult = await MdAccess.LocateAsync(pointer.MdLocator).ConfigureAwait(false);
if (!mdResult.HasValue)
{
return(Result.Fail <Pointer>(mdResult.ErrorCode.Value, mdResult.ErrorMsg));
}
value.Payload = location.Json();
return(await mdResult.Value.SetAsync(type, value).ConfigureAwait(false));
}
/// <summary>
/// Instead of traversing through the tree on every add,
/// we keep a reference to current leaf, and add to it directly.
/// </summary>
/// <param name="key">Key under which the value will be stored.</param>
/// <param name="value">The value to store.</param>
/// <returns>A pointer to the value that was added.</returns>
async Task <Result <Pointer> > DirectlyAddToLeaf(string key, StoredValue value)
{
if (_currentLeaf == null)
{
_currentLeaf = _head;
}
else if (_currentLeaf.IsFull)
{
var result = await _head.AddAsync(key, value).ConfigureAwait(false);
var leafResult = await MdAccess.LocateAsync(result.Value.MdLocator);
if (leafResult.HasValue)
{
_currentLeaf = leafResult.Value;
}
return(result);
}
return(await _currentLeaf.AddAsync(key, value));
}
/// <summary>
/// Adds data to a tree structure
/// that grows in an unbalanced way.
/// </summary>
/// <param name="key">Key under which the value will be stored.</param>
/// <param name="value">The value to store.</param>
/// <returns>A pointer to the value that was added, to be used for indexing.</returns>
public async Task <Result <Pointer> > AddAsync(string key, StoredValue value)
{
if (_head.IsFull)
{
// create new head, add pointer to current head in to it.
// the level > 0 indicates its role as pointer holder
var newHead = await MdAccess.CreateAsync(_head.Level + 1).ConfigureAwait(false);
var pointer = new Pointer
{
MdLocator = _head.MdLocator,
ValueType = typeof(Pointer).Name
};
await newHead.AddAsync(pointer).ConfigureAwait(false);
_head = newHead;
await _onHeadAddressChange(newHead.MdLocator).ConfigureAwait(false);
}
return(await DirectlyAddToLeaf(key, value).ConfigureAwait(false));
}