private object InternalExecuteQuery(Expression expression, Delegate efn, CancellationToken cancellationToken = default)
{
var attrs = GetMethodAttributes(efn.Method);
object result;
if (attrs.Item1)
{
if (attrs.Item2)
{
var segment = SegmentFinder.Find(expression);
result = efn.DynamicInvoke(_database, segment, cancellationToken);
}
else
{
result = efn.DynamicInvoke(_database, cancellationToken);
}
}
else
{
if (attrs.Item2)
{
var segment = SegmentFinder.Find(expression);
result = efn.DynamicInvoke(_database, segment);
}
else
{
result = efn.DynamicInvoke(_database);
}
}
return(result);
}
/// <summary>
/// 执行 <see cref="Expression"/> 的查询，返回查询结果。
/// </summary>
/// <param name="expression">表示 LINQ 查询的表达式树。</param>
/// <returns>单值对象。</returns>
/// <exception cref="TranslateException">对 LINQ 表达式解析失败时抛出此异常。</exception>
public object Execute(Expression expression)
{
var queryCache = ContextService.ServiceProvider.TryGetService(() => DefaultQueryCache.Instance);
var efn = queryCache.TryGetDelegate(expression, GetCacheContext(), () => (LambdaExpression)GetExecutionPlan(expression));
var attrs = GetMethodAttributes(efn.Method);
if (!attrs.Item2)
{
return(efn.DynamicInvoke(_database));
}
var segment = SegmentFinder.Find(expression);
return(efn.DynamicInvoke(_database, segment));
}
/// <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($"DefaultExecuteCache access to '{cacheKey}'");
var segment = SegmentFinder.Find(expression);
var pager = segment as DataPager;
using var edps = new EntityDeserializeProcessorScope();
var cacheItem = _cacheMgr.TryGet(cacheKey,
() => HandleCacheItem(cacheKey, expression, creator(cancellationToken).AsSync(), pager),
() => new RelativeTime(GetExpire(result, option, context)));
if (pager != null)
{
pager.RecordCount = cacheItem.Total;
}
TryStartRunner();
return(cacheItem.Data);
}
/// <summary>
/// 尝试获取指定表达式的缓存。
/// </summary>
/// <param name="expression"></param>
/// <param name="context"></param>
/// <param name="creator">当缓存不存在时，创建缓存数据的函数。</param>
/// <returns></returns>
Delegate IQueryCache.TryGetDelegate(Expression expression, QueryCacheContext context, Func <LambdaExpression> creator)
{
var section = ConfigurationUnity.GetSection <TranslatorConfigurationSection>();
var option = section == null ? TranslateOptions.Default : section.Options;
var result = CacheableChecker.Check(expression);
if (!result.Required ||
(result.Enabled == null && (context.Enabled == false || (context.Enabled == null && !option.CacheParsing))) ||
result.Enabled == false)
{
return(creator().Compile());
}
var generator = _serviceProvider.TryGetService <IQueryCacheKeyGenerator>(() => ExpressionKeyGenerator.Instance);
var cacheKey = _serviceProvider.GetCacheKey(generator.Generate(expression, "Trans"));
Tracer.Debug($"QueryCache access to '{cacheKey}'");
var cacheMgr = _serviceProvider.TryGetService <IMemoryCacheManager>(() => MemoryCacheManager.Instance);
return(cacheMgr.TryGet(cacheKey, () =>
{
var lambdaExp = creator() as LambdaExpression;
var segment = SegmentFinder.Find(expression);
if (segment != null)
{
//将表达式内的 Segment 替换成参数
var segParExp = Expression.Parameter(typeof(IDataSegment), "g");
var newExp = SegmentReplacer.Repalce(lambdaExp.Body, segParExp);
var parameters = new List <ParameterExpression>(lambdaExp.Parameters);
parameters.Insert(1, segParExp);
lambdaExp = Expression.Lambda(newExp, parameters.ToArray());
}
return lambdaExp.Compile();
},
() => new RelativeTime(GetExpire(result, option, context))));
}
