public IExecutionPlan <T> Compile <T>(Expression expression)
{
// Define execution context as parameter
ParameterExpression parameter =
Expression.Parameter(typeof(IExecutionContext), "executionContext");
// Create new transformation context
ITransformationContext context = new TransformationContext(parameter);
TransformationStepRecorder recorder = new TransformationStepRecorder();
// Execute optimization
expression = this.TransformExpression(expression, context, recorder);
// Compile query
Func <IExecutionContext, T> executable =
this.CompileCore(expression, parameter) as Func <IExecutionContext, T>;
// Compose result
IExecutionPlanInfo info = new ExecutionPlanInfo(recorder.Steps);
IExecutionPlan <T> plan = new ExecutionPlan <T>(executable, info);
return(plan);
}
private Expression TransformExpression(
Expression expression,
ITransformationContext context,
TransformationStepRecorder recorder)
{
expression = this.PreprocessExpression(expression, context);
if (context.IsFinished)
{
return(expression);
}
// Set up the rewriter chain
IList <IExpressionRewriter> allRewriters =
new IExpressionRewriter[]
{
new DatabaseParameterRewriter(context),
new StoredProcedureParameterRewriter(context),
}
.Concat(
this.GetRewriters(expression, context))
.Concat(new IExpressionRewriter[]
{
new TableScanRewriter(),
new QueryableRewriter()
})
.ToList();
// Initialize rewriters
foreach (IDatabaseComponent databaseComponent in allRewriters)
{
databaseComponent.Initialize(this.database);
}
// Last chance to alter rewriters
allRewriters = this.ReviewRewriters(allRewriters);
// Record the initial state
recorder.Record(new TransformationStep(expression));
// Execute rewriters
foreach (IExpressionRewriter rewriter in allRewriters)
{
if (rewriter == null)
{
continue;
}
expression = rewriter.Rewrite(expression);
recorder.Record(new TransformationStep(expression));
}
expression = this.PostprocessExpression(expression, context);
recorder.Record(new TransformationStep(expression));
// Reduce the expression
while (expression.CanReduce)
{
expression = expression.Reduce();
recorder.Record(new TransformationStep(expression));
}
return(expression);
}
