1 // Copyright 2004 Adam Megacz, see the COPYING file for licensing [GPL]
9 /** The minimum set of functionality required for objects which are manipulated by JavaScript */
10 public class JS extends org.xwt.util.BalancedTree {
12 public static final Object METHOD = new Object();
13 public final JS unclone() { return _unclone(); }
14 public Enumeration keys() throws JSExn { return entries == null ? emptyEnumeration : entries.keys(); }
15 public Object get(Object key) throws JSExn { return entries == null ? null : entries.get(key, null); }
16 public void put(Object key, Object val) throws JSExn { (entries==null?entries=new Hash():entries).put(key,null,val); }
17 public Object callMethod(Object method, Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
18 throw new JSExn("attempted to call the null value (method "+method+")");
20 public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
21 throw new JSExn("you cannot call this object (class=" + this.getClass().getName() +")");
24 JS _unclone() { return this; }
25 public static class Cloneable extends JS {
26 public Cloneable() { }
27 public Object jsclone() throws JSExn {
28 throw new JSExn("cloning not yet implemented");
32 public static class Clone extends JS.Cloneable {
33 protected JS.Cloneable clonee = null;
34 JS _unclone() { return clonee; }
35 public Clone(JS.Cloneable clonee) { this.clonee = clonee; }
36 public boolean equals(Object o) {
37 if (!(o instanceof JS)) return false;
38 return unclone() == ((JS)o).unclone();
40 public Enumeration keys() throws JSExn { return clonee.keys(); }
41 public Object get(Object key) throws JSExn { return clonee.get(key); }
42 public void put(Object key, Object val) throws JSExn { clonee.put(key, val); }
43 public Object callMethod(Object method, Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
44 return clonee.callMethod(method, a0, a1, a2, rest, nargs);
46 public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
47 return clonee.call(a0, a1, a2, rest, nargs);
51 // Static Interpreter Control Methods ///////////////////////////////////////////////////////////////
53 /** log a message with the current JavaScript sourceName/line */
54 public static void log(Object o, Object message) { log(message); }
55 public static void log(Object message) { Log.echo(Interpreter.getSourceName() + ":" + Interpreter.getLine(), message); }
56 public static void log(JSExn e) { Log.echo(e,"JS Exception: " + e.getObject() + "\n" + e.backtrace()); Log.echo(e,e); }
58 public static class NotPauseableException extends Exception { NotPauseableException() { } }
60 /** returns a callback which will restart the context; expects a value to be pushed onto the stack when unpaused */
61 public static UnpauseCallback pause() throws NotPauseableException {
62 Interpreter i = Interpreter.current();
63 if (i.pausecount == -1) throw new NotPauseableException();
65 return new JS.UnpauseCallback(i);
68 public static class UnpauseCallback implements Scheduler.Task {
70 UnpauseCallback(Interpreter i) { this.i = i; }
71 public void perform() throws JSExn { unpause(null); }
72 public void unpause(Object o) throws JSExn {
73 // FIXME: if o instanceof JSExn, throw it into the JSworld
81 // Static Helper Methods ///////////////////////////////////////////////////////////////////////////////////
83 /** coerce an object to a Boolean */
84 public static boolean toBoolean(Object o) {
85 if (o == null) return false;
86 if (o instanceof Boolean) return ((Boolean)o).booleanValue();
87 if (o instanceof Long) return ((Long)o).longValue() != 0;
88 if (o instanceof Integer) return ((Integer)o).intValue() != 0;
89 if (o instanceof Number) {
90 double d = ((Number) o).doubleValue();
91 // NOTE: d == d is a test for NaN. It should be faster than Double.isNaN()
92 return d != 0.0 && d == d;
94 if (o instanceof String) return ((String)o).length() != 0;
98 /** coerce an object to a Long */
99 public static long toLong(Object o) { return toNumber(o).longValue(); }
101 /** coerce an object to an Int */
102 public static int toInt(Object o) { return toNumber(o).intValue(); }
104 /** coerce an object to a Double */
105 public static double toDouble(Object o) { return toNumber(o).doubleValue(); }
107 /** coerce an object to a Number */
108 public static Number toNumber(Object o) {
109 if (o == null) return ZERO;
110 if (o instanceof Number) return ((Number)o);
112 // NOTE: There are about 3 pages of rules in ecma262 about string to number conversions
113 // We aren't even close to following all those rules. We probably never will be.
114 if (o instanceof String) try { return N((String)o); } catch (NumberFormatException e) { return N(Double.NaN); }
115 if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? N(1) : ZERO;
116 throw new Error("toNumber() got object of type " + o.getClass().getName() + " which we don't know how to handle");
119 /** coerce an object to a String */
120 public static String toString(Object o) {
121 if(o == null) return "null";
122 if(o instanceof String) return (String) o;
123 if(o instanceof Integer || o instanceof Long || o instanceof Boolean) return o.toString();
124 if(o instanceof JSArray) return o.toString();
125 if(o instanceof JSDate) return o.toString();
126 if(o instanceof Double || o instanceof Float) {
127 double d = ((Number)o).doubleValue();
128 if((int)d == d) return Integer.toString((int)d);
131 throw new RuntimeException("can't coerce that!");
134 // Instance Methods ////////////////////////////////////////////////////////////////////
136 public static final Integer ZERO = new Integer(0);
138 // this gets around a wierd fluke in the Java type checking rules for ?..:
139 public static final Object T = Boolean.TRUE;
140 public static final Object F = Boolean.FALSE;
142 public static final Boolean B(boolean b) { return b ? Boolean.TRUE : Boolean.FALSE; }
143 public static final Boolean B(int i) { return i==0 ? Boolean.FALSE : Boolean.TRUE; }
144 public static final Number N(String s) { return s.indexOf('.') == -1 ? N(Integer.parseInt(s)) : new Double(s); }
145 public static final Number N(double d) { return (int)d == d ? N((int)d) : new Double(d); }
146 public static final Number N(long l) { return N((int)l); }
148 private static final Integer[] smallIntCache = new Integer[65535 / 4];
149 private static final Integer[] largeIntCache = new Integer[65535 / 4];
150 public static final Number N(int i) {
152 int idx = i + smallIntCache.length / 2;
153 if (idx < smallIntCache.length && idx > 0) {
154 ret = smallIntCache[idx];
155 if (ret != null) return ret;
157 else ret = largeIntCache[Math.abs(idx % largeIntCache.length)];
158 if (ret == null || ret.intValue() != i) {
159 ret = new Integer(i);
160 if (idx < smallIntCache.length && idx > 0) smallIntCache[idx] = ret;
161 else largeIntCache[Math.abs(idx % largeIntCache.length)] = ret;
166 private static Enumeration emptyEnumeration = new Enumeration() {
167 public boolean hasMoreElements() { return false; }
168 public Object nextElement() { throw new NoSuchElementException(); }
171 private Hash entries = null;
173 public static JS fromReader(String sourceName, int firstLine, Reader sourceCode) throws IOException {
174 return JSFunction._fromReader(sourceName, firstLine, sourceCode);
177 // HACK: caller can't know if the argument is a JSFunction or not...
178 public static JS cloneWithNewParentScope(JS j, JSScope s) {
179 return ((JSFunction)j)._cloneWithNewParentScope(s);
183 // Trap support //////////////////////////////////////////////////////////////////////////////
185 /** override and return true to allow placing traps on this object.
186 * if isRead true, this is a read trap, otherwise write trap
188 protected boolean isTrappable(Object name, boolean isRead) { return true; }
190 /** performs a put, triggering traps if present; traps are run in an unpauseable interpreter */
191 public void putAndTriggerTraps(Object key, Object value) throws JSExn {
192 Trap t = getTrap(key);
193 if (t != null) t.invoke(value);
194 else put(key, value);
197 /** performs a get, triggering traps if present; traps are run in an unpauseable interpreter */
198 public Object getAndTriggerTraps(Object key) throws JSExn {
199 Trap t = getTrap(key);
200 if (t != null) return t.invoke();
201 else return get(key);
204 /** retrieve a trap from the entries hash */
205 protected final Trap getTrap(Object key) {
206 return entries == null ? null : (Trap)entries.get(key, Trap.class);
209 /** retrieve a trap from the entries hash */
210 protected final void putTrap(Object key, Trap value) {
211 if (entries == null) entries = new Hash();
212 entries.put(key, Trap.class, value);
215 /** adds a trap, avoiding duplicates */
216 protected final void addTrap(Object name, JSFunction f) throws JSExn {
217 if (f.numFormalArgs > 1) throw new JSExn("traps must take either one argument (write) or no arguments (read)");
218 boolean isRead = f.numFormalArgs == 0;
219 if (!isTrappable(name, isRead)) throw new JSExn("not allowed "+(isRead?"read":"write")+" trap on property: "+name);
220 for(Trap t = getTrap(name); t != null; t = t.next) if (t.f == f) return;
221 putTrap(name, new Trap(this, name.toString(), f, (Trap)getTrap(name)));
224 /** deletes a trap, if present */
225 protected final void delTrap(Object name, JSFunction f) {
226 Trap t = (Trap)getTrap(name);
227 if (t == null) return;
228 if (t.f == f) { putTrap(t.name, t.next); return; }
229 for(; t.next != null; t = t.next) if (t.next.f == f) { t.next = t.next.next; return; }