/// <summary>
/// 异步的，尝试通过表达式获取执行后的结果缓存。
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expression"></param>
/// <param name="context"></param>
/// <param name="creator"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
async Task <T> IExecuteCache.TryGetAsync <T>(Expression expression, ExecuteCacheContext context, Func <CancellationToken, Task <T> > creator, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
var section = ConfigurationUnity.GetSection <TranslatorConfigurationSection>();
var option = section == null ? TranslateOptions.Default : section.Options;
if (context.Enabled == true || (context.Enabled == null && option.CacheExecution))
{
TryExpire(expression);
}
var evaluator = _serviceProvider.TryGetService <IExecuteCacheEvaluator>();
var result = CacheableChecker.Check(evaluator, expression);
//没有开启数据缓存
if ((result.Enabled == null && (context.Enabled == false || (context.Enabled == null && !option.CacheExecution))) ||
result.Enabled == false || _cacheMgr == null)
{
return(await creator(cancellationToken));
}
var generator = _serviceProvider.TryGetService <IExecuteCacheKeyGenerator>(() => ExpressionKeyGenerator.Instance);
var cacheKey = _serviceProvider.GetCacheKey(generator.Generate(expression, CACHE_KEY));
Tracer.Debug($"DefaultExecuteCache access to '{cacheKey}'");
var segment = SegmentFinder.Find(expression);
var pager = segment as DataPager;
using var edps = new EntityDeserializeProcessorScope();
var cacheItem = _cacheMgr.TryGet(cacheKey,
() => HandleCacheItem(cacheKey, expression, creator(cancellationToken).AsSync(), pager),
() => new RelativeTime(GetExpire(result, option, context)));
if (pager != null)
{
pager.RecordCount = cacheItem.Total;
}
TryStartRunner();
return(cacheItem.Data);
}
private TimeSpan GetExpire(CacheableCheckResult checkResult, TranslateOptions option, ExecuteCacheContext cacheOpt)
{
if (checkResult.Expired != null)
{
return(checkResult.Expired.Value);
}
else if (cacheOpt.Times != null)
{
return(cacheOpt.Times.Value);
}
return(option.CacheExecutionTimes);
}