// 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. JS itself is actually a class
- * implementing the absolute minimal amount of functionality for an
- * Object which can be manipulated by JavaScript code.
- */
-public abstract class 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 ///////////////////////////////////////////////////////////////
+
+ 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, JSExn {
+ Interpreter i = new Interpreter(function, true, new JSArray());
+ int oldpausecount = i.pausecount;
+ i.resume();
+ if (i.pausecount > oldpausecount) throw new PausedException();
+ }
- // Public Helper Methods //////////////////////////////////////////////////////////////////////
+ public static class NotPauseableException extends Exception { NotPauseableException() { } }
- /** parse and compile a function */
- public static JSFunction parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
- return new JSFunction(sourceName, firstLine, sourceCode, null);
+ /** 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, JSExn {
+ 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;
/** coerce an object to a Number */
public static Number toNumber(Object o) {
- if (o == null) return new Long(0);
+ 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 new Double((String)o); } catch (NumberFormatException e) { return new Double(Double.NaN); }
- if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? new Long(1) : new Long(0);
+ 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");
}
}
return o.toString();
}
+
// Instance Methods ////////////////////////////////////////////////////////////////////
+
+ public static final Integer ZERO = new Integer(0);
- public abstract Object get(Object key) throws JS.Exn;
- public void put(Object key, Object val) throws JS.Exn { throw new JS.Exn("you cannot put to this object"); }
+ // 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);
+ }
- public Enumeration keys() { throw new Error("you cannot apply for..in to a " + this.getClass().getName()); }
- public Number coerceToNumber() { throw new JS.Exn("tried to coerce a JavaScript object to a Number"); }
- public String coerceToString() { throw new JS.Exn("tried to coerce a JavaScript object to a String"); }
- public boolean coerceToBoolean() { throw new JS.Exn("tried to coerce a JavaScript object to a Boolean"); }
+ // Trap support //////////////////////////////////////////////////////////////////////////////
- public String typeName() { return "object"; }
+ /** 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 void putAndTriggerTraps(Object key, Object value) throws JSExn {
+ Trap t = getTrap(key);
+ if (t != null) t.invoke(key, value);
+ else put(key, value);
+ }
- // Inner Classes /////////////////////////////////////////////////////////////////////////
+ /** 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(key);
+ else return get(key);
+ }
- /** An exception which can be thrown and caught by JavaScript code */
- public static class Exn extends RuntimeException {
- private Object js = null;
- public Exn(Object js) { this.js = js; }
- public String toString() { return "JS.Exn: " + js; }
- public String getMessage() { return toString(); }
- public Object getObject() { return js; }
- }
+ /** retrieve a trap from the entries hash */
+ protected final Trap getTrap(Object key) {
+ return !isTrappable() || entries == null ? null : (Trap)entries.get(key, Trap.class);
+ }
- /** the result of a graft */
- public static class Graft extends JSCallable {
- private JS graftee;
- private Object replaced_key;
- private Object replaced_val;
- public Graft(Object graftee, Object key, Object val) {
- if (graftee instanceof JSArray) throw new JS.Exn("can't graft onto JSArrays (yet)");
- if (graftee instanceof JSCallable) throw new JS.Exn("can't graft onto JSCallables (yet)");
- if (graftee instanceof JSScope) throw new JS.Exn("can't graft onto JSScopes (yet)");
- this.graftee = (JS)graftee;
- replaced_key = key;
- replaced_val = val;
- }
- public boolean equals(Object o) { return (this == o || graftee.equals(o)); }
- public int hashCode() { return graftee.hashCode(); }
- public Object get(Object key) { return replaced_key.equals(key) ? replaced_val : graftee.get(key); }
- public void put(Object key, Object val) { graftee.put(key, val); }
- public void call(Object method, JSArray args) {
- if (replaced_key.equals(method)) return ((JSCallable)replaced_val).call(null, args);
- else if (graftee instanceof JSCallable) return graftee.call(method, args);
- else throw new JS.Exn("cannot call this value");
- }
- public Number coerceToNumber() { return graftee.coerceToNumber(); }
- public String coerceToString() { return graftee.coerceToString(); }
- public boolean coerceToBoolean() { return graftee.coerceToBoolean(); }
- public String typeName() { return graftee.typeName(); }
- public Enumeration keys() {
- return new Enumeration() {
- Enumeration graftee_enumeration = graftee.keys();
- boolean returned_replaced = false;
- public boolean hasMoreElements() {
- if (graftee_enumeration.hasMoreElements()) return true;
- return !returned_replaced;
- }
- public Object nextElement() {
- if (!graftee_enumeration.hasMoreElements()) {
- if (returned_replaced) throw new NoSuchElementException();
- returned_replaced = true;
- return replaced_key;
- } else {
- Object ret = graftee_enumeration.nextElement();
- if (!returned_replaced && ret.equals(replaced_key)) returned_replaced = true;
- return ret;
- }
- }
- };
- }
+ /** 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) 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"; }
+
+}
projects / org.ibex.core.git / blobdiff