-// Copyright 2002 Adam Megacz, see the COPYING file for licensing [GPL]
-
+// Copyright 2003 Adam Megacz, see the COPYING file for licensing [GPL]
package org.xwt.js;
+
import org.xwt.util.*;
+import org.xwt.*;
+import java.io.*;
+import java.util.*;
-/** The public API for the JS engine */
-// FEATURE: try using mutable, recycled 'Num' objects
-public interface JS {
-
- public abstract Object get(Object key) throws JS.Exn;
- public abstract void put(Object key, Object val) throws JS.Exn;
- public abstract Object[] enumerateProperties();
-
- public abstract Number coerceToNumber() throws JS.Exn;
- public abstract boolean coerceToBoolean() throws JS.Exn;
- public abstract String coerceToString() throws JS.Exn;
-
- public static class Obj implements JS {
- private Hash entries;
- public Obj() { }
- public Object get(Object key) { return entries.get(key); }
- public void put(Object key, Object val) { entries.put(key, val); }
- public Object[] enumerateProperties() { return(entries.keys()); }
- public Number coerceToNumber() { throw new Error("tried to turn a Object into a Number"); }
- public String coerceToString() { throw new Error("tried to turn a Object into a String"); }
- public boolean coerceToBoolean() { throw new Error("tried to turn a Object into a Boolean"); }
- }
-
- public static class Array extends Obj {
- private Vec vec = new Vec();
- private static int intVal(Object o) {
- if (o instanceof Number) {
- int intVal = ((Number)o).intValue();
- if (intVal == ((Number)o).doubleValue()) return intVal;
- return Integer.MIN_VALUE;
- }
- if (!(o instanceof String)) return Integer.MIN_VALUE;
- String s = (String)o;
- for(int i=0; i<s.length(); i++) if (s.charAt(i) < '0' || s.charAt(i) > '9') return Integer.MIN_VALUE;
- return Integer.parseInt(s);
- }
- public Object get(Object key) {
- if (key.equals("length")) return new Long(vec.size());
- int i = intVal(key);
- if (i == Integer.MIN_VALUE) return super.get(key);
- return vec.elementAt(i);
- }
- public void put(Object key, Object val) {
- if (key.equals("length")) vec.setSize(Expr.toNumber(val).intValue());
- int i = intVal(key);
- if (i == Integer.MIN_VALUE) super.put(key, val);
- else vec.setElementAt(val, i);
- }
- public Object[] enumerateProperties() { return null; } // FIXME
- void addElement(Object o) { vec.addElement(o); }
- }
-
- public static interface Function extends JS {
- public abstract Object call(JS.Array args) throws JS.Exn; // FEATURE: try to recycle these arrays?
- public abstract Scope getParentScopeOfDeclaration();
- }
-
- public static abstract class ObjFunction extends Obj implements Function { }
-
- /** if JS calls a Java method, and the Java method throws an exception, it can only be caught by JS if it is a subclass of Exn. */
- public static class Exn extends RuntimeException {
- private Object js = null;
- public Exn(Object js) { this.js = js; }
- public Object getObject() { return js; }
- }
+/** The minimum set of functionality required for objects which are manipulated by JavaScript */
+public class JS extends org.xwt.util.BalancedTree {
+
+ // Static Interpreter Control Methods ///////////////////////////////////////////////////////////////
+
+ /** log a message with the current JavaScript sourceName/line */
+ public static void log(Object o, Object message) { logJS(message); }
+ public static void log(Object message) { Log.echo(JS.getSourceName() + ":" + JS.getLine(), message); }
+
+ public static int getLine() {
+ Interpreter c = Interpreter.current();
+ return c == null || c.f == null || c.pc < 0 || c.pc >= c.f.size ? -1 : c.f.line[c.pc];
+ }
- /** Any object which becomes part of the scope chain must support this interface */
- public static class Scope extends Obj {
- private Scope parentScope;
- private static Object NULL = new Object();
- public Scope(Scope parentScope) { this.parentScope = parentScope; }
- public JS getParentScope() { return parentScope; }
- public boolean has(Object key) { return super.get(key) != null; }
- public Object get(Object key) {
- if (!has(key)) return getParentScope().get(key);
- Object ret = super.get(key); return ret == NULL ? null : ret;
- }
- public void put(Object key, Object val) {
- if (!has(key)) getParentScope().put(key, val);
- else super.put(key, val == null ? NULL : val);
- }
- public Object[] enumerateProperties() { throw new Error("you can't enumerate the properties of a Scope"); }
- public void declare(String s) { super.put(s, NULL); }
+ public static String getSourceName() {
+ Interpreter c = Interpreter.current();
+ return c == null || c.f == null ? null : c.f.sourceName;
}
+
+ public static class NotPauseableException extends Exception { NotPauseableException() { } }
+
+ /** returns a callback which will restart the context; expects a value to be pushed onto the stack when unpaused */
+ public static UnpauseCallback pause() throws NotPauseableException {
+ Interpreter i = Interpreter.current();
+ if (i.pausecount == -1) throw new NotPauseableException();
+ i.pausecount++;
+ return new JS.UnpauseCallback(i);
+ }
+
+ public static class UnpauseCallback implements Scheduler.Task {
+ Interpreter i;
+ UnpauseCallback(Interpreter i) { this.i = i; }
+ public void perform() throws JSExn { unpause(null); }
+ public void unpause(Object o) throws JSExn {
+ // FIXME: if o instanceof JSExn, throw it into the JSworld
+ i.stack.push(o);
+ i.resume();
+ }
+ }
+
+
+
+ // Static Helper Methods ///////////////////////////////////////////////////////////////////////////////////
+
+ /** coerce an object to a Boolean */
+ public static boolean toBoolean(Object o) {
+ if (o == null) return false;
+ if (o instanceof Boolean) return ((Boolean)o).booleanValue();
+ if (o instanceof Long) return ((Long)o).longValue() != 0;
+ if (o instanceof Integer) return ((Integer)o).intValue() != 0;
+ if (o instanceof Number) {
+ double d = ((Number) o).doubleValue();
+ // NOTE: d == d is a test for NaN. It should be faster than Double.isNaN()
+ return d != 0.0 && d == d;
+ }
+ if (o instanceof String) return ((String)o).length() != 0;
+ return true;
+ }
+
+ /** coerce an object to a Long */
+ public static long toLong(Object o) { return toNumber(o).longValue(); }
+
+ /** coerce an object to an Int */
+ public static int toInt(Object o) { return toNumber(o).intValue(); }
+
+ /** coerce an object to a Double */
+ public static double toDouble(Object o) { return toNumber(o).doubleValue(); }
+
+ /** coerce an object to a Number */
+ public static Number toNumber(Object o) {
+ if (o == null) return ZERO;
+ if (o instanceof Number) return ((Number)o);
+
+ // NOTE: There are about 3 pages of rules in ecma262 about string to number conversions
+ // We aren't even close to following all those rules. We probably never will be.
+ if (o instanceof String)
+ try { return N((String)o); } catch (NumberFormatException e) { return N(Double.NaN); }
+ if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? N(1) : ZERO;
+ if (o instanceof JS) return ((JS)o).coerceToNumber();
+ throw new Error("toNumber() got object of type " + o.getClass().getName() + " which we don't know how to handle");
+ }
+
+ /** coerce an object to a String */
+ public static String toString(Object o) {
+ if(o == null) return "null";
+ if(o instanceof String) return (String) o;
+ if(o instanceof Integer || o instanceof Long || o instanceof Boolean) return o.toString();
+ if(o instanceof JS) return ((JS)o).coerceToString();
+ if(o instanceof Double || o instanceof Float) {
+ double d = ((Number)o).doubleValue();
+ if((int)d == d) return Integer.toString((int)d);
+ return o.toString();
+ }
+ return o.toString();
+ }
+
+
+ // Instance Methods ////////////////////////////////////////////////////////////////////
+
+ public static final Integer ZERO = new Integer(0);
-}
+ // this gets around a wierd fluke in the Java type checking rules for ?..:
+ public static final Object T = Boolean.TRUE;
+ public static final Object F = Boolean.FALSE;
+
+ public static final Boolean B(boolean b) { return b ? Boolean.TRUE : Boolean.FALSE; }
+ public static final Boolean B(int i) { return i==0 ? Boolean.FALSE : Boolean.TRUE; }
+ public static final Number N(String s) { return s.indexOf('.') == -1 ? N(Integer.parseInt(s)) : new Double(s); }
+ public static final Number N(double d) { return (int)d == d ? N((int)d) : new Double(d); }
+ public static final Number N(long l) { return N((int)l); }
+
+ private static final Integer[] smallIntCache = new Integer[65535 / 4];
+ private static final Integer[] largeIntCache = new Integer[65535 / 4];
+ public static final Number N(int i) {
+ Integer ret = null;
+ int idx = i + smallIntCache.length / 2;
+ if (idx < smallIntCache.length && idx > 0) {
+ ret = smallIntCache[idx];
+ if (ret != null) return ret;
+ }
+ else ret = largeIntCache[Math.abs(idx % largeIntCache.length)];
+ if (ret == null || ret.intValue() != i) {
+ ret = new Integer(i);
+ if (idx < smallIntCache.length && idx > 0) smallIntCache[idx] = ret;
+ else largeIntCache[Math.abs(idx % largeIntCache.length)] = ret;
+ }
+ return ret;
+ }
+
+ private static Enumeration emptyEnumeration = new Enumeration() {
+ public boolean hasMoreElements() { return false; }
+ public Object nextElement() { throw new NoSuchElementException(); }
+ };
+
+ private Hash entries = null;
+ public Enumeration keys() throws JSExn {
+ return entries == null ? emptyEnumeration : entries.keys();
+ }
+ public Object get(Object key) throws JSExn { return entries == null ? null : entries.get(key, null); }
+ public void put(Object key, Object val) throws JSExn {
+ if (entries == null) entries = new Hash();
+ entries.put(key, null, val);
+ }
+
+ // Trap support //////////////////////////////////////////////////////////////////////////////
+ /** override and return true to allow placing traps on this object.
+ * if isRead true, this is a read trap, otherwise write trap
+ **/
+ protected boolean isTrappable(Object name, boolean isRead) { return false; }
+ /** performs a put, triggering traps if present; traps are run in an unpauseable interpreter */
+ public void putAndTriggerTraps(Object key, Object value) throws JSExn {
+ Trap t = getTrap(key);
+ if (t != null) t.invoke(value);
+ else put(key, value);
+ }
+
+ /** performs a get, triggering traps if present; traps are run in an unpauseable interpreter */
+ public Object getAndTriggerTraps(Object key) throws JSExn {
+ Trap t = getTrap(key);
+ if (t != null) return t.invoke();
+ else return get(key);
+ }
+
+ /** retrieve a trap from the entries hash */
+ protected final Trap getTrap(Object key) {
+ return entries == null ? null : (Trap)entries.get(key, Trap.class);
+ }
+
+ /** retrieve a trap from the entries hash */
+ protected final void putTrap(Object key, Trap value) {
+ if (entries == null) entries = new Hash();
+ entries.put(key, Trap.class, value);
+ }
+ /** adds a trap, avoiding duplicates */
+ protected final void addTrap(Object name, JSFunction f) throws JSExn {
+ if (f.numFormalArgs > 1) throw new JSExn("traps must take either one argument (write) or no arguments (read)");
+ boolean isRead = f.numFormalArgs == 0;
+ if (!isTrappable(name, isRead)) throw new JSExn("not allowed "+(isRead?"read":"write")+" trap on property: "+name);
+ for(Trap t = getTrap(name); t != null; t = t.next) if (t.f == f) return;
+ putTrap(name, new Trap(this, name.toString(), f, (Trap)getTrap(name)));
+ }
+
+ /** deletes a trap, if present */
+ protected final void delTrap(Object name, JSFunction f) {
+ Trap t = (Trap)getTrap(name);
+ if (t == null) return;
+ if (t.f == f) { putTrap(t.name, t.next); return; }
+ for(; t.next != null; t = t.next) if (t.next.f == f) { t.next = t.next.next; return; }
+ }
+
+
+ // Call Support //////////////////////////////////////////////////////////////////////////////
+
+ // return this from get() if the key was actually a method.
+ public static final Object METHOD = new Object();
+ public Object callMethod(Object method, Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
+ throw new JSExn("attempted to call the null value (method "+method+")");
+ }
+ public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
+ throw new JSExn("you cannot call this object (class=" + this.getClass().getName() +")");
+ }
+
+
+ // Typing Support //////////////////////////////////////////////////////////////////////////////
+
+ public Number coerceToNumber() { throw new JSRuntimeExn("tried to coerce a JavaScript object to a Number"); }
+ public String coerceToString() { throw new JSRuntimeExn("tried to coerce a JavaScript object to a String"); }
+ public boolean coerceToBoolean() { throw new JSRuntimeExn("tried to coerce a JavaScript object to a Boolean"); }
+
+ public String typeName() { return "object"; }
+
+}
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