Index: src/org/mozilla/javascript/ScriptableObject.java =================================================================== RCS file: /cvsroot/mozilla/js/rhino/src/org/mozilla/javascript/ScriptableObject.java,v retrieving revision 1.137 diff -u -r1.137 ScriptableObject.java --- src/org/mozilla/javascript/ScriptableObject.java 7 Aug 2008 20:59:49 -0000 1.137 +++ src/org/mozilla/javascript/ScriptableObject.java 30 Oct 2008 15:17:31 -0000 @@ -155,6 +155,21 @@ private static final int SLOT_MODIFY_GETTER_SETTER = 4; private static final int SLOT_MODIFY_CONST = 5; + // Used to indicate a failed MOP call. + private static final Object MOP_CALL_FAILED = new Object(); + + private Scriptable metaObject; + + // Guard to protect against infinite recursion with meta object invocation + private ThreadLocal disableMop = new ThreadLocal() { + protected Boolean initialValue() { + return Boolean.FALSE; + } + }; + + // Hack to allow activation of the feature from scripts for testing + public static boolean metaEnable = true; + private static class Slot implements Serializable { private static final long serialVersionUID = -6090581677123995491L; @@ -248,26 +263,97 @@ public abstract String getClassName(); /** + * Gets the meta object for the specified object. + */ + protected Scriptable getMetaObject(Scriptable object) + { + if (!metaEnable) + return null; + if (!disableMop.get()) { + Scriptable meta; + Scriptable obj = this; + do { + meta = ((ScriptableObject) obj).metaObject; + obj = obj.getPrototype(); + } while (meta == null && obj != null && obj instanceof ScriptableObject); + // We want to disable MOP for the meta object itself + if (meta != null) + meta.put("__meta__", meta, null); + return meta; + } else { + } + return null; + } + + /** + * Call the function on the specified meta object, if the function + * is specified by the meta object. + * + * @param meta Meta object which may have the function. + * @param name Function name to call. + * @param start Scope of the meta object, used to disable the meta object. + * @param args Arguments to pass to the function. + * + * @return Result of the call, or MOP_CALL_FAILED. + */ + protected Object callMetaFunction(Scriptable meta, String name, + Scriptable start, Object[] args) + { + Object value = MOP_CALL_FAILED; + Context cx = Context.getCurrentContext(); + if (cx != null) { + Object obj = meta.get(name, meta); + if (obj != Scriptable.NOT_FOUND && obj instanceof Function) { + try { + disableMop.set(true); + value = ((Function) obj).call(cx, start, start, args); + } finally { + disableMop.set(false); + } + } + } + return value; + } + + /** * Returns true if the named property is defined. - * + * + * This looks for a meta object, specified by the __meta__ property. If one + * is found, __meta__.has(thisObj,property) will be called. + * * @param name the name of the property * @param start the object in which the lookup began * @return true if and only if the property was found in the object */ - public boolean has(String name, Scriptable start) - { + public boolean has(String name, Scriptable start) { + if (metaEnable && "__meta__".equals(name)) + return metaObject != null; + Scriptable meta = this.getMetaObject(start); + if (meta != null) { + Object value = this.callMetaFunction(meta, "has", start, + new Object[] { name }); + if (value != MOP_CALL_FAILED) + return ScriptRuntime.toBoolean(value); + } return null != getSlot(name, 0, SLOT_QUERY); } /** * Returns true if the property index is defined. + * Looks for __meta__.has. If not found, works normally. * * @param index the numeric index for the property * @param start the object in which the lookup began * @return true if and only if the property was found in the object */ - public boolean has(int index, Scriptable start) - { + public boolean has(int index, Scriptable start) { + Scriptable meta = this.getMetaObject(start); + if (meta != null) { + Object value = this.callMetaFunction(meta, "has", start, + new Object[] { index }); + if (value != MOP_CALL_FAILED) + return ScriptRuntime.toBoolean(value); + } return null != getSlot(null, index, SLOT_QUERY); } @@ -276,6 +362,8 @@ * * If the property was created using defineProperty, the * appropriate getter method is called. + * This checks for the existence of a __meta__ property with a get method. + * Otherwise, this method will work normally. * * @param name the name of the property * @param start the object in which the lookup began @@ -283,18 +371,36 @@ */ public Object get(String name, Scriptable start) { + if (metaEnable && "__meta__".equals(name)) + return metaObject; + Scriptable meta = this.getMetaObject(start); + if (meta != null) { + Object value = this.callMetaFunction(meta, "get", start, + new Object[] { name }); + if (value != MOP_CALL_FAILED) + return value; + } return getImpl(name, 0, start); } /** * Returns the value of the indexed property or NOT_FOUND. + * This checks for the existence of a __meta__ property with a get method. + * Otherwise, this method will work normally. * * @param index the numeric index for the property * @param start the object in which the lookup began * @return the value of the property (may be null), or NOT_FOUND */ - public Object get(int index, Scriptable start) - { + public Object get(int index, Scriptable start) { + Scriptable meta = this.getMetaObject(start); + if (meta != null) + { + Object value = this.callMetaFunction(meta, "get", start, + new Object[] { index }); + if (value != MOP_CALL_FAILED) + return value; + } return getImpl(null, index, start); } @@ -308,6 +414,8 @@ * taken. * This method will actually set the property in the start * object. + * + * Looks for __meta__.set. Otherwise, works normally. * * @param name the name of the property * @param start the object whose property is being set @@ -315,22 +423,44 @@ */ public void put(String name, Scriptable start, Object value) { - if (putImpl(name, 0, start, value, EMPTY)) - return; + if (metaEnable && "__meta__".equals(name)) { + if (value instanceof Scriptable) + metaObject = (Scriptable) value; + } else { + Scriptable meta = this.getMetaObject(start); + if (meta != null) { + Object result = this.callMetaFunction(meta, "set", start, + new Object[] { name, value }); + if (result != MOP_CALL_FAILED) + return; + } + if (putImpl(name, 0, start, value, EMPTY)) + return; - if (start == this) throw Kit.codeBug(); - start.put(name, start, value); + if (start == this) throw Kit.codeBug(); + start.put(name, start, value); + } } /** * Sets the value of the indexed property, creating it if need be. * + * Looks for __meta__.set. Otherwise, works normally. + * * @param index the numeric index for the property * @param start the object whose property is being set * @param value value to set the property to */ public void put(int index, Scriptable start, Object value) { + Scriptable meta = this.getMetaObject(start); + if (meta != null) + { + Object result = this.callMetaFunction(meta, "set", start, + new Object[] { index, value }); + if (result != MOP_CALL_FAILED) + return; + } if (putImpl(null, index, start, value, EMPTY)) return; @@ -343,13 +473,27 @@ * * If the property is not found, or it has the PERMANENT attribute, * no action is taken. + * + * Looks for __meta__.remove(). If not found, works normally. * * @param name the name of the property */ public void delete(String name) { - checkNotSealed(name, 0); - accessSlot(name, 0, SLOT_REMOVE); + if (metaEnable && "__meta__".equals(name)) { + metaObject = null; + } else { + Scriptable meta = this.getMetaObject(this); + if (meta != null) + { + Object result = this.callMetaFunction(meta, "remove", this, + new Object[] { name }); + if (result != MOP_CALL_FAILED) + return; + } + checkNotSealed(name, 0); + accessSlot(name, 0, SLOT_REMOVE); + } } /** @@ -357,11 +501,21 @@ * * If the property is not found, or it has the PERMANENT attribute, * no action is taken. + * + * Looks for __meta__.remove(). If not found, works normally. * * @param index the numeric index for the property */ public void delete(int index) { + Scriptable start = this; + Scriptable meta = this.getMetaObject(start); + if (meta != null) { + Object result = this.callMetaFunction(meta, "remove", start, + new Object[] { index }); + if (result != MOP_CALL_FAILED) + return; + } checkNotSealed(null, index); accessSlot(null, index, SLOT_REMOVE); } @@ -628,6 +782,7 @@ /** * Sets the prototype of the object. + * @return */ public void setPrototype(Scriptable m) { @@ -651,7 +806,8 @@ } /** - * Returns an array of ids for the properties of the object. + * Returns an array of ids for the properties of the object, deferring to + * __meta__.getIds(thisObj), if that exists. * *

Any properties with the attribute DONTENUM are not listed.

* @@ -661,7 +817,30 @@ * Integer entry in the returned array. Properties accessed by * a String will have a String entry in the returned array. */ - public Object[] getIds() { + public Object[] getIds() + { + Scriptable start = this; + Scriptable meta = this.getMetaObject(start); + + if (meta != null) + { + Object result = this.callMetaFunction(meta, "getIds", start, + new Object[] {}); // TODO: null ok too? + if (result != MOP_CALL_FAILED) { + if (result instanceof NativeArray) { + NativeArray na = (NativeArray) result; + Object[] naIds = na.getIds(); + Object[] ids = new Object[naIds.length]; + for (int i=0; i< naIds.length; i++) + ids[i] = na.get(i, na); + return ids; + } + else { + throw new IllegalArgumentException("Did not receive an array of ids. Got a " + + result.getClass().getName()); + } + } + } return getIds(false); }