/// <summary>
/// 检查表达式是否能够被缓存。
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
public static CacheableCheckResult Check(Expression expression)
{
var checker = new CacheableChecker();
checker.Visit(expression);
return(checker.result);
}
/// <summary>
/// 尝试获取指定表达式的缓存。
/// </summary>
/// <param name="expression"></param>
/// <param name="func">当缓存不存在时，创建缓存数据的函数。</param>
/// <returns></returns>
internal static Delegate TryGetDelegate(Expression expression, Func <LambdaExpression> func)
{
var section = ConfigurationUnity.GetSection <TranslatorConfigurationSection>();
var option = section == null ? TranslateOptions.Default : section.Options;
var result = CacheableChecker.Check(expression);
if (!result.Required || (result.Enabled == null && !option.CacheParsing) || result.Enabled == false)
{
return(func().Compile());
}
var cacheKey = ExpressionKeyGenerator.GetKey(expression, "Trans");
cacheKey = NativeCacheKeyContext.GetKey(cacheKey);
return(MemoryCacheManager.Instance.TryGet(cacheKey, () =>
{
var lambdaExp = func() 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(result.Expired ?? TimeSpan.FromSeconds(option.CacheParsingTimes))));
}
/// <summary>
/// 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="func"></param>
/// <returns></returns>
internal static T TryGet <T>(Expression expression, Func <T> func)
{
var section = ConfigurationUnity.GetSection <TranslatorConfigurationSection>();
var option = section == null ? TranslateOptions.Default : section.Options;
var result = CacheableChecker.Check(expression);
//没有开启数据缓存
if ((result.Enabled == null && !option.CacheExecution) || result.Enabled == false)
{
return(func());
}
var cacheMgr = CacheManagerFactory.CreateManager();
if (cacheMgr == null)
{
return(func());
}
var cacheKey = ExpressionKeyGenerator.GetKey(expression, "Exec");
cacheKey = NativeCacheKeyContext.GetKey(cacheKey);
Reference(cacheKey, expression);
var segment = SegmentFinder.Find(expression);
var pager = segment as DataPager;
var cacheFunc = new Func <CacheItem <T> >(() =>
{
var data = EnumerateData(func());
var isEnumerable = typeof(T).IsGenericType && typeof(T).GetGenericTypeDefinition() == typeof(IEnumerable <>);
if (isEnumerable)
{
var elementType = typeof(T).GetEnumerableElementType();
var method = typeof(Enumerable).GetMethod(nameof(Enumerable.ToList)).MakeGenericMethod(elementType);
data = (T)method.Invoke(null, new object[] { data });
}
var total = 0;
if (pager != null)
{
total = pager.RecordCount;
}
return(new CacheItem <T> {
Data = data, Total = total
});
});
var cacheItem = cacheMgr.TryGet(cacheKey, cacheFunc, () => new RelativeTime(result.Expired ?? TimeSpan.FromSeconds(option.CacheExecutionTimes)));
if (pager != null)
{
pager.RecordCount = cacheItem.Total;
}
return(cacheItem.Data);
}
/// <summary>
/// 判断是否被缓存。
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
internal static bool CanCache(Expression expression)
{
var section = ConfigurationUnity.GetSection <TranslatorConfigurationSection>();
var option = section == null ? TranslateOptions.Default : section.Options;
var result = CacheableChecker.Check(expression);
return(typeof(IQueryable).IsAssignableFrom(expression.Type) && (result.Enabled == true || (result.Enabled == null && option.CacheExecution)));
}
/// <summary>
/// 检查表达式是否能够被缓存。
/// </summary>
/// <param name="evaluator"></param>
/// <param name="expression"></param>
/// <returns></returns>
public static CacheableCheckResult Check(IExecuteCacheEvaluator evaluator, Expression expression)
{
var checker = new CacheableChecker {
_evaluator = evaluator
};
checker.Visit(expression);
return(checker._result);
}
/// <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))));
}
