private Expression RewriteFaultHandler(TryExpression node)
{
//
// 0. Recurse into the children.
//
var body = Visit(node.Body);
var fault = Visit(node.Fault);
//
// 1. Initialize rewriter.
//
var rewriter = new HandlerRewriter();
//
// 2. Rewrite body and handler.
//
var rewrittenTry = rewriter.Rewrite(body)();
var rewrittenTryHandler = Expression.Lambda <Func <LeaveHandlerData> >(rewrittenTry);
var rewrittenFaultHandler = Expression.Lambda <Action>(fault);
//
// 3. Emit call to TryFault helper.
//
var tryFault = Expression.Call(s_tryFault, rewrittenTryHandler, rewrittenFaultHandler);
//
// 4. Create resulting expression.
//
return(CreateRewrittenTry(node, rewriter, tryFault));
}
private static Expression CreateRewrittenTry(TryExpression node, HandlerRewriter rewriter, Expression call)
{
var assignLeaveResult = Expression.Assign(rewriter.LeaveResult, call);
var leaveResultValue = Expression.PropertyOrField(rewriter.LeaveResult, "Value");
//
// 1. Create jump table.
//
var dispatch = rewriter.GetDispatchTable();
//
// 2. Count number of expressions needed in resulting block.
//
var n = (node.Type == typeof(void) ? 0 : 1) + (dispatch != null ? 1 : 0) + 1;
var statements = new Expression[n];
//
// 3. Store result of call in temporary.
//
var i = 0;
statements[i++] = assignLeaveResult;
//
// 4. For non-emptyu dispatch tables, emit the dispatch.
//
if (dispatch != null)
{
statements[i++] = dispatch;
}
//
// 5. For non-null nodes, extract the result.
//
if (node.Type != typeof(void))
{
statements[i++] = Expression.Convert(leaveResultValue, node.Type);
}
//
// 6. Put everything together in a block.
//
var res = Expression.Block(node.Type, new[] { rewriter.LeaveResult }, statements);
return(res);
}
private Expression RewriteFilterHandler(TryExpression node)
{
if (node.Handlers.Count == 1 && node.Finally == null)
{
//
// 0. Recurse into the children.
//
var body = Visit(node.Body);
var handler = VisitCatchBlock(node.Handlers[0]);
//
// 1. Initialize rewriter.
//
var rewriter = new HandlerRewriter();
//
// 2. Obtain rewriters for the body and the handler.
//
var bodyRewriter = rewriter.Rewrite(body);
var catchRewriter = rewriter.Rewrite(handler.Body); // TODO: verify we can't jump out of the filter
//
// 3. Rewrite body, handler, and filter.
//
var rewrittenTry = bodyRewriter();
var rewrittenTryHandler = Expression.Lambda <Func <LeaveHandlerData> >(rewrittenTry);
var rewrittenCatch = catchRewriter();
var rewrittenCatchHandler = Expression.Lambda(rewrittenCatch, handler.Variable);
var rewrittenFilterHandler = Expression.Lambda(handler.Filter, handler.Variable);
//
// 4. Emit call to TryFilter helper.
//
var tryFilter = Expression.Call(s_tryFilter.MakeGenericMethod(handler.Test), rewrittenTryHandler, rewrittenFilterHandler, rewrittenCatchHandler);
//
// 4. Create resulting expression.
//
return(CreateRewrittenTry(node, rewriter, tryFilter));
}
else
{
return(Visit(Expand(node)));
}
}
private Expression RewriteFilterHandler(TryExpression node)
{
if (node.Handlers.Count == 1 && node.Finally == null)
{
//
// 0. Recurse into the children.
//
var body = Visit(node.Body);
var handler = VisitCatchBlock(node.Handlers[0]);
//
// 1. Initialize rewriter.
//
var rewriter = new HandlerRewriter();
//
// 2. Obtain rewriters for the body and the handler.
//
var bodyRewriter = rewriter.Rewrite(body);
var catchRewriter = rewriter.Rewrite(handler.Body); // TODO: verify we can't jump out of the filter
//
// 3. Rewrite body, handler, and filter.
//
var rewrittenTry = bodyRewriter();
var rewrittenTryHandler = Expression.Lambda<Func<LeaveHandlerData>>(rewrittenTry);
var rewrittenCatch = catchRewriter();
var rewrittenCatchHandler = Expression.Lambda(rewrittenCatch, handler.Variable);
var rewrittenFilterHandler = Expression.Lambda(handler.Filter, handler.Variable);
//
// 4. Emit call to TryFilter helper.
//
var tryFilter = Expression.Call(s_tryFilter.MakeGenericMethod(handler.Test), rewrittenTryHandler, rewrittenFilterHandler, rewrittenCatchHandler);
//
// 4. Create resulting expression.
//
return CreateRewrittenTry(node, rewriter, tryFilter);
}
else
{
return Visit(Expand(node));
}
}
private Expression RewriteFaultHandler(TryExpression node)
{
//
// 0. Recurse into the children.
//
var body = Visit(node.Body);
var fault = Visit(node.Fault);
//
// 1. Initialize rewriter.
//
var rewriter = new HandlerRewriter();
//
// 2. Rewrite body and handler.
//
var rewrittenTry = rewriter.Rewrite(body)();
var rewrittenTryHandler = Expression.Lambda<Func<LeaveHandlerData>>(rewrittenTry);
var rewrittenFaultHandler = Expression.Lambda<Action>(fault);
//
// 3. Emit call to TryFault helper.
//
var tryFault = Expression.Call(s_tryFault, rewrittenTryHandler, rewrittenFaultHandler);
//
// 4. Create resulting expression.
//
return CreateRewrittenTry(node, rewriter, tryFault);
}
private static Expression CreateRewrittenTry(TryExpression node, HandlerRewriter rewriter, Expression call)
{
var assignLeaveResult = Expression.Assign(rewriter.LeaveResult, call);
var leaveResultValue = Expression.PropertyOrField(rewriter.LeaveResult, "Value");
//
// 1. Create jump table.
//
var dispatch = rewriter.GetDispatchTable();
//
// 2. Count number of expressions needed in resulting block.
//
var n = (node.Type == typeof(void) ? 0 : 1) + (dispatch != null ? 1 : 0) + 1;
var statements = new Expression[n];
//
// 3. Store result of call in temporary.
//
var i = 0;
statements[i++] = assignLeaveResult;
//
// 4. For non-emptyu dispatch tables, emit the dispatch.
//
if (dispatch != null)
{
statements[i++] = dispatch;
}
//
// 5. For non-null nodes, extract the result.
//
if (node.Type != typeof(void))
{
statements[i++] = Expression.Convert(leaveResultValue, node.Type);
}
//
// 6. Put everything together in a block.
//
var res = Expression.Block(node.Type, new[] { rewriter.LeaveResult }, statements);
return res;
}
