public async Task <string> CatchUp()
{
var result = await Client.ReadFrom(Ref);
Ref = result.Next;
return(result.Value);
}
public async Task <ReadResult <string> > ReadFrom(LogRef @ref)
{
long offset = @ref.Offset.GetValueOrDefault(0);
var value = (string)await Redis.StringGetRangeAsync(@ref.Key, offset, -1);
return(AppendResult.Ok(value, next: @ref.WithOffset(offset + value.Length)));
}
public async Task <AppendResult> AppendTo(LogRef @ref, string val)
{
if (@ref.Offset == null)
{
throw new LogException("Can't append using a handle without an offset!");
}
await _luaAppend.EnsureLoaded(_redisMultiplexer);
var newOffset = (long)await Redis.ScriptEvaluateAsync(
script : _luaAppend.LoadedLuaScript,
parameters : new { key = (RedisKey)@ref.Key, offset = @ref.Offset, val }
);
if (newOffset < 0)
{
return(AppendResult.Fail);
}
return(AppendResult.Ok(next: @ref.WithOffset(newOffset)));
}
public static LogCursor CreateCursor(this LogClient client, LogRef @ref) => new LogCursor(client, @ref);
public async Task Write(string value)
{
var result = await Client.AppendTo(Ref, value);
Ref = result.Next;
}
internal LogCursor(LogClient client, LogRef @ref)
{
Client = client;
Ref = @ref;
}