import java.util.*;
import org.xwt.js.*;
import org.xwt.util.*;
+import java.io.*;
/**
* This class encapsulates a single trap placed on a given node. The
private Trap() { }
- public Object perform() throws JS.Exn {
- if (f.getNumFormalArgs() > 0) return cascade();
- return f.call(new TrapArgs(this));
+ public Object perform() {
+ try {
+ if (f.getNumFormalArgs() > 0) return cascade();
+ JS.Thread.current().setTailCall(f, new TrapArgs(this));
+ return null;
+ } catch (Exception e) {
+ Log.log(this, "Exception thrown from within trap: " + e);
+ return null;
+ }
}
-
- public void perform(Object val) throws JS.Exn {
- if (f.getNumFormalArgs()== 0) cascade(val);
- f.call(new TrapArgs(this, val));
+
+ private static JS.CompiledFunction cascadeHelper = null;
+ private static String cascadeHelperText =
+ "return function(q) { var ret = arguments.doTrap;" +
+ "if (ret != false && !arguments.didCascade) arguments.cascade = q; };";
+ static {
+ try {
+ cascadeHelper = JS.parse("cascadeHelper", 1, new StringReader(cascadeHelperText));
+ cascadeHelper = (JS.CompiledFunction)new JS.Thread(cascadeHelper).resume();
+ } catch (Exception e) {
+ Log.log(Trap.class, e);
+ }
+ }
+
+ public void perform(Object val) {
+ try {
+ if (f.getNumFormalArgs() == 0) cascade(val);
+ else JS.Thread.current().setTailCall(cascadeHelper, new TrapArgs(this, val));
+ } catch (Exception e) {
+ Log.log(this, "Exception thrown from within trap: " + e);
+ e.printStackTrace();
+ }
}
public Object cascade() {
- if (next != null) return next.perform();
+ if (next != null) { next.perform(); return null; }
return trapee.get(name, true);
}
private static class TrapArgs extends JS.Array {
private Trap t;
+ public boolean cascadeHappened = false;
public TrapArgs(Trap t) { this.t = t; }
public TrapArgs(Trap t, Object value) { this.t = t; addElement(value); }
public void put(Object key, Object val) {
- if (key.equals("cascade")) t.cascade(val);
+ if (key.equals("cascade")) { cascadeHappened = true; t.cascade(val); }
else super.put(key, val);
}
// common case
if(!(key instanceof String)) return super.get(key);
if (key.equals("trapee")) return t.trapee;
+ if (key.equals("doTrap")) { JS.Thread.current().setTailCall(t.f, this); return null; }
+ if (key.equals("didCascade")) return cascadeHappened ? Boolean.TRUE : Boolean.FALSE;
if (key.equals("trapname")) return t.name;
if (key.equals("cascade")) return t.cascade();
+ if (key.equals("callee")) return t.f;
return super.get(key);
}
}