-// 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.*;
-
-/** The public API for the JS engine */
-public interface JS {
-
- public Object get(Object key) throws JS.Exn;
- public Object put(Object key, Object val) throws JS.Exn;
- public Object[] enumerateProperties();
- public String coerceToString() throws JS.Exn;
- /*
- public Num coerceToNumber() throws JS.Exn;
- public boolean coerceToBoolean() throws JS.Exn;
- public Object call(Object[] args) throws JS.Exn;
- */
- /** 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; }
+import org.xwt.*;
+import java.io.*;
+import java.util.*;
+
+/** The minimum set of functionality required for objects which are manipulated by JavaScript */
+public class JS {
+
+ // Static Interpreter Control Methods ///////////////////////////////////////////////////////////////
+
+ public static int getLine() {
+ Interpreter c = Interpreter.current();
+ return c.f == null || c.pc < 0 || c.pc >= c.f.size ? -1 : c.f.line[c.pc];
+ }
+
+ public static String getSourceName() {
+ Interpreter c = Interpreter.current();
+ return c == null || c.f == null ? null : c.f.sourceName;
}
+
+ public static class PausedException extends Exception { PausedException() { } }
+
+ public static void invokePauseable(JSFunction function) throws JS.PausedException {
+ Interpreter i = new Interpreter(function, true, new JSArray());
+ int oldpausecount = i.pausecount;
+ i.resume();
+ if (i.pausecount > oldpausecount) throw new PausedException();
+ }
+
+ 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 {
+ Interpreter i;
+ UnpauseCallback(Interpreter i) { this.i = i; }
+ public void unpause(Object o) throws PausedException {
+ 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);
- /** Any object which becomes part of the scope chain must support this interface */
- public static interface Scope extends JS {
- public boolean has(Object key);
- public void declare(String s);
- public JS getParentScope();
- }
-
- /** A mutable, boxed numeric value. These are recycled -- never duplicate references -- use duplicate() instead. */
- /*
- public static class Num implements Cloneable, JS {
-
- private Num() { }
- public boolean isDouble = false;
- public long longVal = -1;
- public double doubleVal = -1;
-
- private static Vec pool = new Vec();
- public static synchronized void recycle(Num n) { pool.push(n); }
- public static synchronized Num getOne() { return (pool.size() > 0) ? (Num)pool.pop() : new Num(); }
-
- public Num duplicate() { try { return (Num)clone(); } catch (CloneNotSupportedException c) { throw new Error(c); } }
-
- public Object get(Object key) throws JS.Exn { return null; }
- public Object put(Object key, Object val) throws JS.Exn { throw new JS.Exn("attempt to set a property on a Number"); }
- public Object[] enumerateProperties() { return new Object[] { }; }
- public String coerceToString() throws JS.Exn { return isDouble ? String.valueOf(doubleVal) : String.valueOf(longVal); }
- public Num coerceToNumber() throws JS.Exn { return duplicate(); }
- public Object call(Object[] args) throws JS.Exn { throw new JS.Exn("attempt to apply the () operator to a Number"); }
- }
- */
+ // 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 Number N(int i) { return new Integer(i); }
+ public static final Number N(long l) { return new Long(l); }
+ public static final Number N(double d) { return new Double(d); }
+ public static final Number N(String s) { return new Double(s); }
+ 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; }
+
+ private static Enumeration emptyEnumeration = new Enumeration() {
+ public boolean hasMoreElements() { return false; }
+ public Object nextElement() { throw new NoSuchElementException(); }
+ };
+
+ private Hash entries = null;
+ public Enumeration keys() { return entries == null ? emptyEnumeration : entries.keys(); }
+ public Object get(Object key) { return entries == null ? null : entries.get(key, null); }
+ public void put(Object key, Object val) { if (entries == null) entries = new Hash(); entries.put(key, null, val); }
+
+
+ // Trap support //////////////////////////////////////////////////////////////////////////////
+
+ /** override and return true to allow placing traps on this object */
+ protected boolean isTrappable() { return false; }
+
+ /** performs a put, triggering traps if present; traps are run in an unpauseable interpreter */
+ public final void putAndTriggerTraps(Object key, Object value) {
+ Trap t = getTrap(key);
+ if (t != null) t.invoke(key, value);
+ else put(key, value);
+ }
+
+ /** performs a get, triggering traps if present; traps are run in an unpauseable interpreter */
+ public final Object getAndTriggerTraps(Object key) {
+ Trap t = getTrap(key);
+ if (t != null) return t.invoke(key);
+ else return get(key);
+ }
+
+ /** retrieve a trap from the entries hash */
+ protected final Trap getTrap(Object key) {
+ return !isTrappable() || 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 (!isTrappable()) return;
+ 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) {
+ 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) {
+ throw new JSExn("attempted to call the null value (method "+method+")");
+ }
+ public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) {
+ throw new JSExn("you cannot call this object (class=" + this.getClass().getName() +")");
+ }
+
+
+ // Typing Support //////////////////////////////////////////////////////////////////////////////
+
+ public Number coerceToNumber() { throw new JSExn("tried to coerce a JavaScript object to a Number"); }
+ public String coerceToString() { throw new JSExn("tried to coerce a JavaScript object to a String"); }
+ public boolean coerceToBoolean() { throw new JSExn("tried to coerce a JavaScript object to a Boolean"); }
+
+ public String typeName() { return "object"; }
+
}
projects / org.ibex.core.git / blobdiff