-// 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 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. The static
+ * methods, fields, and inner classes of JS define the publicly
+ * visible API for the XWT JavaScript engine; code outside this
+ * package should never depend on anything not defined in this file.
+ */
+public abstract class JS {
+
+
+ // Public Helper Methods //////////////////////////////////////////////////////////////////////
+
+ /** parse and compile a function */
+ public static CompiledFunction parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
+ return new CompiledFunction(sourceName, firstLine, sourceCode, null);
+ }
+
+ /** 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 new Long(0);
+ 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);
+ 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 ////////////////////////////////////////////////////////////////////
-/** all objects other than Strings and Numbers which are exposed to JS code must implement this interface */
-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 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 abstract Object get(Object key) throws JS.Exn;
+ public abstract void put(Object key, Object val) throws JS.Exn;
+ public abstract Object[] keys();
+ public Object callMethod(Object method, Array args, boolean checkOnly) throws JS.Exn {
+ if(checkOnly) return Boolean.FALSE;
+ Object o = get(method);
+ if(o instanceof JS.Callable) {
+ return ((JS.Callable)o).call(args);
+ } else if(o == null) {
+ throw new JS.Exn("Attempted to call non-existent method: " + method);
+ } else {
+ throw new JS.Exn("Attempted to call a non-method: " +method);
+ }
+ }
+
+ public Number coerceToNumber() { return new Integer(0); }
+ public String coerceToString() { throw new JS.Exn("tried to coerce a JavaScript object to a String"); }
+ public boolean coerceToBoolean() { return true; }
+
+ public String typeName() { return "object"; }
+
+
+ // Inner Classes /////////////////////////////////////////////////////////////////////////
+
+ /** A sensible implementation of the abstract methods in the JS class */
+ public static class Obj extends JS {
+ private Hash entries = null;
+ private boolean sealed = false;
+ public Obj() { this(false); }
+ public Obj(boolean sealed) { this.sealed = sealed; }
+ public void setSeal(boolean sealed) { this.sealed = sealed; } ///< a sealed object cannot have its properties modified
+ public void put(Object key, Object val) { put(key, null, val); }
+ protected void put(Object key, Object key2, Object val) {
+ if (sealed) return;
+ if (entries == null) entries = new Hash();
+ entries.put(key, key2, val); }
+ public Object[] keys() { return entries == null ? new Object[0] : entries.keys(); }
+ public Object get(Object key) { return get(key, null); }
+ protected Object get(Object key, Object key2) {
+ if (entries == null) return null;
+ if(key2 == null && callMethod((String)key, null, true) == Boolean.TRUE)
+ return new Internal.CallableStub(this, key);
+ return entries.get(key, key2);
+ }
+ }
+
+ /** 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 Object getObject() { return js; }
+ 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; }
}
-
+
+ /** The publicly-visible face of JavaScript Array objects */
+ public static class Array extends ArrayImpl {
+ public Array() { }
+ public Array(int size) { super(size); }
+ public void setSize(int i) { super.setSize(i); }
+ public int length() { return super.length(); }
+ public Object elementAt(int i) { return super.elementAt(i); }
+ public void addElement(Object o) { super.addElement(o); }
+ public void setElementAt(Object o, int i) { super.setElementAt(o, i); }
+ public Object get(Object key) { return super._get(key); }
+ public void put(Object key, Object val) { super._put(key, val); }
+ }
+
/** 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();
+ public static class Scope extends ScopeImpl {
+ public Scope(Scope parentScope) { this(parentScope, false); }
+ public Scope(Scope parentScope, boolean sealed) { super(parentScope, sealed); }
+ /** transparent scopes are not returned by THIS */
+ public boolean isTransparent() { return super.isTransparent(); }
+ public boolean has(Object key) { return super.has(key); }
+ public Object get(Object key) { return super._get(key); }
+ public void put(Object key, Object val) { super._put(key, val); }
+ public void declare(String s) { super.declare(s); }
}
+
+ /** the result of a graft */
+ public static class Graft extends JS {
+ private JS graftee;
+ private Object replaced_key;
+ private Object replaced_val;
+ public Graft(JS graftee, Object key, Object val) {
+ if (graftee instanceof Array) throw new JS.Exn("can't graft onto Arrays (yet)");
+ if (graftee instanceof Callable) throw new JS.Exn("can't graft onto Callables (yet)");
+ if (graftee instanceof Scope) throw new JS.Exn("can't graft onto Scopes (yet)");
+ this.graftee = 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 Object callMethod(Object method, Array args, boolean checkOnly) throws JS.Exn {
+ if (!replaced_key.equals(method)) return graftee.callMethod(method, args, checkOnly);
+ if (replaced_val instanceof Callable) return checkOnly ? Boolean.TRUE : ((Callable)replaced_val).call(args);
+ if (checkOnly) return Boolean.FALSE;
+ throw new JS.Exn("attempt to call non-function");
+ }
+ 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 Object[] keys() {
+ Object[] ret = graftee.keys();
+ for(int i=0; i<ret.length; i++) if (replaced_key.equals(ret[i])) return ret;
+ Object[] ret2 = new Object[ret.length + 1];
+ System.arraycopy(ret, 0, ret2, 0, ret.length);
+ ret2[ret2.length - 1] = replaced_key;
+ return ret2;
+ }
+ }
+
+ /** anything that is callable with the () operator */
+ public static abstract class Callable extends JS.Obj {
+ public abstract Object call(JS.Array args) throws JS.Exn;
+ }
+
+ /** a Callable which was compiled from JavaScript code */
+ public static class CompiledFunction extends CompiledFunctionImpl {
+ public int getNumFormalArgs() { return numFormalArgs; }
+ CompiledFunction(String sourceName, int firstLine, Reader sourceCode, Scope scope) throws IOException {
+ super(sourceName, firstLine, sourceCode, scope);
+ }
+ }
+
+ /** a scope that is populated with js objects and functions normally found in the global scope */
+ public static class GlobalScope extends GlobalScopeImpl {
+ public GlobalScope() { this(null); }
+ public GlobalScope(JS.Scope parent) { super(parent); }
+ }
+
+ public static final JS Math = new org.xwt.js.Math();
- /** 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"); }
-
- }
+ /** encapsulates a single JavaScript thread; the JS.Thread->java.lang.Thread mapping is 1:1 */
+ public static class Thread {
+
+ CompiledFunction currentCompiledFunction = null;
+ Vec stack = new Vec();
+ public Scope scope = null;
+ int pc = 0;
+ boolean paused = false;
+
+ CompiledFunction tailCallFunction = null;
+ JS.Array tailCallArgs = null;
+
+ public Thread(CompiledFunction function) {
+ this(function, new CompiledFunctionImpl.FunctionScope("unknown", function.parentScope));
+ }
+ public Thread(CompiledFunction function, Scope scope) {
+ stack.push(new CompiledFunctionImpl.CallMarker(this));
+ stack.push(new JS.Array());
+ this.currentCompiledFunction = function;
+ this.scope = scope;
+ }
+
+ public void setTailCall(JS.CompiledFunction f, JS.Array args) { tailCallFunction = f; tailCallArgs = args; }
+
+ public static JS.Thread current() { return (JS.Thread)javaThreadToJSThread.get(java.lang.Thread.currentThread()); }
+
+ public Object resume() { bind(); paused = false; Object ret = CompiledFunctionImpl.eval(this); unbind(); return ret; }
+ public void pause() { paused = true; unbind(); }
+ public void bind() { javaThreadToJSThread.put(java.lang.Thread.currentThread(), this); }
+ public void unbind() { if (current() == this) javaThreadToJSThread.remove(java.lang.Thread.currentThread()); }
+ public int getLine() { return currentCompiledFunction == null ? -1 : currentCompiledFunction.getLine(this); }
+ public String getSourceName() { return currentCompiledFunction == null ? null : currentCompiledFunction.getSourceName(); }
+
+ /** fetches the currently-executing javascript function */
+ public JS.CompiledFunction getCurrentCompiledFunction() { return currentCompiledFunction; }
+ private static Hashtable javaThreadToJSThread = new Hashtable();
+ }
}
+
+
+
+