-// Copyright 2003 Adam Megacz, see the COPYING file for licensing [GPL]
-
+// Copyright 2004 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 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 ///////////////////////////////////////////////////////////////
- // Static Methods //////////////////////////////////////////////////////////////////////
+ /** log a message with the current JavaScript sourceName/line */
+ public static void log(Object o, Object message) { log(message); }
+ public static void log(Object message) { Log.echo(JS.getSourceName() + ":" + JS.getLine(), message); }
+ public static void log(JSExn e) {
+ Log.echo(e,"JS Exception: " + e.getObject() + "\n" + e.backtrace());
+ Log.echo(e,e);
+ }
- private static Hashtable currentFunction = new Hashtable();
- public static Function getCurrentFunction() { return (Function)currentFunction.get(Thread.currentThread()); }
- public static String getCurrentFunctionSourceName() { return getCurrentFunctionSourceName(Thread.currentThread()); }
- public static String getFileAndLine() { return getCurrentFunctionSourceName() + ":" + getCurrentFunction().getLine(); }
- public static String getCurrentFunctionSourceName(Thread t) {
- Function f = (Function)currentFunction.get(t);
- if (f == null) return "null";
- return f.getSourceName();
+ 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];
}
+ 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 Number) return o.equals(new Integer(0));
- return true;
+ 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 new Long(0);
- if (o instanceof Number) return ((Number)o);
- if (o instanceof String) try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(0); }
- if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? new Long(1) : new Long(0);
- 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");
+ 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 abstract Object get(Object key) throws JS.Exn;
- public abstract void put(Object key, Object val) throws JS.Exn;
- public abstract Object[] keys();
-
- public Number coerceToNumber() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a Number"); }
- public String coerceToString() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a String"); }
- public boolean coerceToBoolean() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a Boolean"); }
-
-
- // Subclasses /////////////////////////////////////////////////////////////////////////
-
- /** A slightly more featureful version of JS */
- public static class Obj extends JS {
- private Hash entries = new Hash();
- private boolean sealed = false;
- public Obj() { this(false); }
- public Obj(boolean sealed) { this.sealed = sealed; }
- public void setSeal(boolean sealed) { this.sealed = sealed; }
- public Object get(Object key) { return entries.get(key); }
- public void put(Object key, Object val) { if (!sealed) entries.put(key, val); }
- public Object[] keys() { return(entries.keys()); }
- }
-
- /** An exception which can be thrown and caught by JavaScripts */
- 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; }
- }
- /** A JavaScript Array */
- public static class Array extends Obj {
- private Vec vec = new Vec();
- public Array() { }
- public Array(int size) { vec.setSize(size); }
- 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) throws JS.Exn {
- // FIXME: HACK!
- if (key.equals("cascade")) return org.xwt.Trap.cascadeFunction;
- if (key.equals("trapee")) return org.xwt.Trap.currentTrapee();
- if (key.equals("length")) return new Long(vec.size());
- int i = intVal(key);
- if (i == Integer.MIN_VALUE) return super.get(key);
- try {
- return vec.elementAt(i);
- } catch (ArrayIndexOutOfBoundsException e) {
- return null;
- }
- }
- public void put(Object key, Object val) {
- if (key.equals("length")) vec.setSize(toNumber(val).intValue());
- int i = intVal(key);
- if (i == Integer.MIN_VALUE) super.put(key, val);
- else {
- if (i >= vec.size()) vec.setSize(i+1);
- vec.setElementAt(val, i);
- }
- }
- public Object[] keys() {
- Object[] sup = super.keys();
- Object[] ret = new Object[vec.size() + 1 + sup.length];
- System.arraycopy(sup, 0, ret, vec.size(), sup.length);
- for(int i=0; i<vec.size(); i++) ret[i] = new Integer(i);
- ret[vec.size()] = "length";
- return ret;
- }
- public void setSize(int i) { vec.setSize(i); }
- public int length() { return vec.size(); }
- public Object elementAt(int i) { return vec.elementAt(i); }
- public void addElement(Object o) { vec.addElement(o); }
- public void setElementAt(Object o, int i) { vec.setElementAt(o, i); }
- }
-
- /** Anything that is callable */
- public static class Function extends Obj {
- ByteCodeBlock bytecodes;
- int line;
- String sourceName;
- Scope parentScope;
- public Function(int line, String sourceName, ByteCodeBlock bytecodes, Scope parentScope) {
- this.sourceName = sourceName;
- this.line = line;
- this.bytecodes = bytecodes;
- this.parentScope = parentScope;
- }
- public Function cloneWithNewParentScope(Scope s) {
- if (this.getClass() != Function.class)
- throw new Error("org.xwt.js.JS.Function.cloneWithNewParentScope() is not valid for subclasses");
- return new Function(line, sourceName, bytecodes, s);
- }
- public String getSourceName() throws JS.Exn { return sourceName; }
- public int getLine() throws JS.Exn { return line; }
- public Object _call(JS.Array args) throws JS.Exn, ByteCodeBlock.ControlTransferException {
- if (bytecodes == null) throw new Error("tried to call() a JS.Function with bytecodes == null");
- Context cx = Context.getContextForCurrentThread();
- int size = cx.stack.size();
- cx.stack.push(new Context.CallMarker());
- cx.stack.push(args);
- bytecodes.eval(args == null ? parentScope : new FunctionScope(sourceName, parentScope));
- Object ret = cx.stack.pop();
- if (cx.stack.size() > size) {
- Log.log(this, "warning, stack grew by " + (cx.stack.size() - size) +
- " elements during call to " + getSourceName() + ":" + getLine());
- Log.log(this, "top element is " + cx.stack.peek());
- }
- return ret;
- }
- public final Object call(JS.Array args) throws JS.Exn {
- Function saved = (Function)currentFunction.get(Thread.currentThread());
- if (!getSourceName().equals("java")) currentFunction.put(Thread.currentThread(), this);
- try {
- return _call(args);
- } catch (ByteCodeBlock.ReturnException e) { // ignore
- return e.retval;
- } catch (ByteCodeBlock.ControlTransferException e) {
- throw new RuntimeException(getSourceName() + ":" + getLine() +
- " error, ControlTransferException tried to leave a function");
- } finally {
- if (saved == null) currentFunction.remove(Thread.currentThread());
- else currentFunction.put(Thread.currentThread(), saved);
- }
- }
- }
-
- public static Function parse(Reader r, String sourceName, int line) throws IOException {
- ByteCodeBlock b = new ByteCodeBlock(line, sourceName);
- Parser p = new Parser(r, sourceName, line);
- try {
- while(true) {
- int size = b.size();
- p.parseStatement(false, b);
- if (size == b.size()) break;
- }
- b.add(Tokens.RETURN);
- return new Function(line, sourceName, b, null);
- } catch (Exception e) {
- if (Log.on) Log.log(Parser.class, e);
- return null;
- }
- }
-
- /** 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, false); }
- public Scope(Scope parentScope, boolean sealed) { super(sealed); this.parentScope = parentScope; }
- public Scope getParentScope() { return parentScope; }
-
- // transparent scopes are not returned by THIS
- public boolean isTransparent() { return false; }
-
- public boolean has(Object key) { return super.get(key) != null; }
- public Object get(Object key) {
- if (!has(key)) return parentScope == null ? null : getParentScope().get(key);
- Object ret = super.get(key); return ret == NULL ? null : ret;
- }
- public void put(Object key, Object val) {
- if (!has(key) && parentScope != null) getParentScope().put(key, val);
- else super.put(key, val == null ? NULL : val);
- }
- public Object[] keys() { throw new Error("you can't enumerate the properties of a Scope"); }
- public void declare(String s) {
- if (isTransparent()) getParentScope().declare(s);
- else super.put(s, NULL);
- }
- }
+ public static final Integer ZERO = new Integer(0);
- private class FunctionScope extends JS.Scope {
- String sourceName;
- public FunctionScope(String sourceName, Scope parentScope) { super(parentScope); this.sourceName = sourceName; }
- public String getSourceName() { return sourceName; }
- public Object get(Object key) throws JS.Exn {
- if (key.equals("trapee")) return org.xwt.Trap.currentTrapee();
- else if (key.equals("cascade")) return org.xwt.Trap.cascadeFunction;
- return super.get(key);
- }
+ // 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 true; }
+
+ /** 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 of type " +
+ getClass().getName() + " to a Number"); }
+ public String coerceToString() { throw new JSRuntimeExn("tried to coerce a JavaScript object of type " +
+ getClass().getName() + " to a String"); }
+ public boolean coerceToBoolean() { throw new JSRuntimeExn("tried to coerce a JavaScript object of type " +
+ getClass().getName() + " to a Boolean"); }
+
+ public String typeName() { return "object"; }
+
+}