2003/10/31 10:57:24

[org.ibex.core.git] / src / org / xwt / Trap.java

diff --git a/src/org/xwt/Trap.java b/src/org/xwt/Trap.java
index df51b53..2f436c4 100644 (file)
--- a/src/org/xwt/Trap.java
+++ b/src/org/xwt/Trap.java
@@ -4,6 +4,7 @@ package org.xwt;
 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
@@ -96,29 +97,42 @@ public class Trap {
 
     private Trap() { }
 
-    public Object perform() throws JS.Exn {
+    public Object perform() {
         try {
             if (f.getNumFormalArgs() > 0) return cascade();
-            return f.call(new TrapArgs(this));
+            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 {
+
+    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);
-            TrapArgs ta = new TrapArgs(this, val);
-            Object ret = f.call(ta);
-            if (ret != Boolean.FALSE && !ta.cascadeHappened) 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);
     }
 
@@ -142,6 +156,8 @@ public class Trap {
             // 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;