private async Task ApplyChangeAsync(
object key,
object entity,
EntityState entityState)
{
var targetPath = Path.AppendFile(key.ToString());
switch (entityState)
{
case EntityState.Deleted:
await AsyncFileSystem.DeleteAsync(targetPath);
break;
case EntityState.Added:
var metadata = EntityMetadata(key, entity, EntityState.Added, null);
using (var stream = await AsyncFileSystem.CreateFileAsync(targetPath))
Serialize(stream, metadata);
break;
case EntityState.Updated:
var updatedMetadata = EntityMetadata(key, entity, EntityState.Updated,
await FindByIdInternalAsync(key));
using (var stream = await AsyncFileSystem.CreateFileAsync(targetPath))
Serialize(stream, updatedMetadata);
break;
}
}
private async Task EnsureInitializedAsync()
{
if (!await AsyncFileSystem.ExistsAsync(Path))
{
await AsyncFileSystem.CreateDirectoryAsync(Path);
}
}
public async Task EnsureInitializedAsync()
{
if (_initialized)
{
return;
}
using (_lock.WriteLock())
{
if (!await AsyncFileSystem.ExistsAsync(Path))
{
_initialized = true;
return;
}
using (var stream = await AsyncFileSystem.OpenFileAsync(Path, DesiredFileAccess.Read))
using (var instream = new StreamReader(stream))
{
var json = "[" + instream.ReadToEnd().Replace(Environment.NewLine, ",") + "]";
var entities = JsonConvert.DeserializeObject(
json,
typeof(List <>).MakeGenericType(typeof(MetadataEntity))
) as IEnumerable <MetadataEntity>;
_entities = entities.ToDictionary(
key => key.Identity,
value => new Tuple <object, MetadataEntity>(value.EntityOfType(EntityType), value)
);
_initialized = true;
}
}
}
private async Task <MetadataEntity> FindByIdInternalAsync(object key)
{
await EnsureInitializedAsync();
var targetPath = Path.AppendFile(key.ToString());
using (var stream = await AsyncFileSystem.OpenFileAsync(targetPath, DesiredFileAccess.Read))
return(Deserialize(stream));
}
public override async Task <int> CountAsync()
{
using (_lock.ReadLock())
{
await EnsureInitializedAsync();
return((await AsyncFileSystem.GetEntitiesAsync(Path)).Count());
}
}
private async Task FlushAsync(List <MetadataEntity> raw)
{
using (var stream = await AsyncFileSystem.CreateFileAsync(Path))
using (var outstream = new StreamWriter(stream))
{
var writer = new JsonTextWriter(outstream);
_listSerializer.WriteJson(writer, raw, _serializer);
}
}
