2003/11/03 05:28:32

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

diff --git a/src/org/xwt/Trap.java b/src/org/xwt/Trap.java
index f33f75a..ea2ea95 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
@@ -15,6 +16,19 @@ public class Trap {
 
     // Static Data //////////////////////////////////////////////////////////////
 
+    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.Context(cascadeHelper, null, null).resume(null);
+        } catch (Exception e) {
+            Log.log(Trap.class, e);
+        }
+    }
+
     /** List of properties that cannot be trapped */
     private static final Hash PROHIBITED = new Hash(120, 3);
 
@@ -62,12 +76,7 @@ public class Trap {
             if (t.f == f) return;
         
         // actually place the trap
-        Trap t = new Trap();
-        t.next = (Trap)trapee.get(name, Trap.class);
-        trapee.put(name, Trap.class, t);
-        t.trapee = trapee;
-        t.name = name;
-        t.f = f;
+        trapee.put2(name, Trap.class, new Trap(trapee, name.toString(), f, (Trap)trapee.get(name, Trap.class)));
     }
 
 
@@ -79,44 +88,43 @@ public class Trap {
      */
     static void delTrap(Box trapee, Object name, JS.CompiledFunction f) {
         Trap t = (Trap)trapee.get(name, Trap.class);
-        if (t.f == f) {
-            trapee.put(name, Trap.class, t.next);
-            return;
-        }
+        if (t.f == f) { trapee.put2(name, Trap.class, t.next); return; }
         for(; t.next != null; t = t.next)
-            if (t.next.f == f) {
-                t.next = t.next.next;
-                return;
-            }
+            if (t.next.f == f) { t.next = t.next.next; return; }
         Log.logJS("warning: tried to remove a trap that had not been placed");
     }
 
 
     // Instance Methods //////////////////////////////////////////////////////////////////////////
 
-    private Trap() { }
+    private Trap(Box b, String n, JS.CompiledFunction f, Trap nx)
+    { trapee = b; name = n; this.f = f; this.next = nx; }
+
+    // Read Traps //////////////////////////////////////////////////////////////////////
 
-    public Object perform() throws JS.Exn {
+    public Object perform() {
         if (f.getNumFormalArgs() > 0) return cascade();
-        return f.call(new TrapArgs(this));
-    }
-    
-    public void perform(Object val) throws JS.Exn {
-        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 return new JS.TailCall().set(f, new TrapArgs(this));
     }
-    
+
     public Object cascade() {
         if (next != null) return next.perform();
-        return trapee.get(name, true);
+        else return trapee.get(name, true);
     }
 
-    public void cascade(Object val) {
-        if (next != null) next.perform(val);
-        trapee.put(name, val, true);
+    // Write Traps //////////////////////////////////////////////////////////////////////
+
+    public Object perform(Object val) {
+        if (f.getNumFormalArgs() == 0) return cascade(val);
+        else return new JS.TailCall().set(cascadeHelper, new TrapArgs(this, val));
     }
+    
+    public Object cascade(Object val) {
+        if (next != null) return next.perform(val);
+        else return trapee.put(name, val, true);
+    }
+
+    // Args ///////////////////////////////////////////////////////////////////////////
 
     private static class TrapArgs extends JS.Array {
         private Trap t;
@@ -124,17 +132,20 @@ public class Trap {
         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")) { cascadeHappened = true; t.cascade(val); }
-            else super.put(key, val);
+        public Object put(Object key, Object val) {
+            if (key.equals("cascade")) { cascadeHappened = true; return t.cascade(val); }
+            else return super.put(key, val);
         }
 
         public Object get(Object key) {
             // common case
             if(!(key instanceof String)) return super.get(key);
             if (key.equals("trapee")) return t.trapee;
+            if (key.equals("doTrap")) return new JS.TailCall().set(t.f, this);
+            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);
         }
     }