/// <summary>
/// 构造最终执行的表达式。
/// </summary>
/// <param name="expression"></param>
/// <param name="translator">翻译器。</param>
/// <param name="options"></param>
/// <returns></returns>
public static Expression Build(TranslateContext transContext, Expression expression, BuildOptions options)
{
var builder = new ExecutionBuilder()
{
_transContext = transContext,
_executor = Expression.Parameter(typeof(IDatabase), "db"),
_translator = transContext.Translator
};
if (options.IsAsync != null)
{
builder._isAsync = (bool)options.IsAsync;
}
if (options.IsNoTracking == true)
{
builder._isNoTracking = true;
}
var newExpression = builder.Bind(expression);
if (builder._isAsync)
{
var cancelToken = builder._cancelToken ?? Expression.Parameter(typeof(CancellationToken), "token");
return(Expression.Lambda(newExpression, builder._executor, cancelToken));
}
return(Expression.Lambda(newExpression, builder._executor));
}
private Expression BuildInner(Expression expression)
{
var eb = new ExecutionBuilder
{
_executor = _executor,
_scope = _scope,
_receivingMember = _receivingMember,
_readers = _readers,
_lookup = _lookup,
_translator = _translator,
_variableMap = _variableMap
};
return(eb.Visit(expression));
}
/// <summary>
/// 获取表达式的执行计划。
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
public Expression GetExecutionPlan(Expression expression, bool?isAsync = null)
{
try
{
if (expression is LambdaExpression lambda)
{
expression = lambda.Body;
}
var options = GetTranslateOptions();
var transContext = new TranslateContext(ContextService, options);
var transExpression = transContext.TranslateProvider.Translate(transContext, expression);
var buildOptions = new ExecutionBuilder.BuildOptions {
IsAsync = isAsync, IsNoTracking = !options.TraceEntityState
};
return(ExecutionBuilder.Build(transContext, transExpression, buildOptions));
}
catch (Exception ex)
{
throw new TranslateException(expression, ex);
}
}