-// 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 */
-// FEATURE: try using mutable, recycled 'Num' objects
+/**
+ * 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 {
- // Static Methods //////////////////////////////////////////////////////////////////////
- public static Function getCurrentFunction() {
- return (Function)currentFunction.get(Thread.currentThread());
- }
- public static String getCurrentFunctionSourceName() {
- return getCurrentFunctionSourceName(Thread.currentThread());
- }
- public static String getCurrentFunctionSourceName(Thread t) {
- Function f = (Function)currentFunction.get(t);
- if (f == null) return "null";
- return f.getSourceName();
- }
- public static String getFileAndLine() {
- return "unknown:??";
+ // 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 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();
- // FIXME
- throw new Error("toNumber() got object of type " + o.getClass().getName());
+ if (o == null) return new Long(0);
+ if (o instanceof Number) return ((Number)o);
+ // FIXME: There are about 3 pages of rules in ecma262 about string to number conversions
+ // We aren't even close to following all those rules
+ 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 ////////////////////////////////////////////////////////////////////
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 abstract Object callMethod(Object method, JS.Array args, boolean justChecking);
- 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"); }
+ 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"; }
- // Subclasses /////////////////////////////////////////////////////////////////////////
+ // Inner Classes /////////////////////////////////////////////////////////////////////////
+ /** A sensible implementation of the abstract methods in the JS class */
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()); }
+ private Hash entries = new Hash();
+ private boolean sealed = false;
+ public Obj() { this(false); }
+ public Obj(boolean sealed) { this.sealed = sealed; }
+ /** a sealed object cannot have its properties modified */
+ public void setSeal(boolean sealed) { this.sealed = sealed; }
+ public void put(Object key, Object val) { if (!sealed) entries.put(key, val); }
+ public Object[] keys() { return(entries.keys()); }
+ public Object get(Object key) {
+ if(callMethod((String)key,null,true) == Boolean.TRUE)
+ return new Internal.CallableStub(this,key);
+ return entries.get(key);
+ }
+ public Object callMethod(Object method, JS.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);
+ }
+ }
}
+ /** 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.toString(); }
- public String getMessage() { return toString(); }
- 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; }
}
- 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) {
- throw new JS.Exn(e.getMessage());
- }
- }
- 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); }
+ /** 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); }
}
- public static Hashtable currentFunction = new Hashtable();
- public static abstract class Function extends Obj {
- public abstract Object _call(JS.Array args) throws JS.Exn;
- public String getSourceName() throws JS.Exn { return "unknown"; }
- public final Object call(JS.Array args) throws JS.Exn { return _call(args); }
+ /** Any object which becomes part of the scope chain must support this interface */
+ 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); }
+ }
+
+ /** 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;
}
- public static class Script extends Function {
- Vector e = null;
- private Script(Vector e) { this.e = e; }
- public String getSourceName() throws JS.Exn { return ((ForthBlock)e.elementAt(0)).sourceName; }
- public Object _call(JS.Array args) throws JS.Exn {
- Scope rootScope = (Scope)args.elementAt(0);
- Function saved = (Function)currentFunction.get(Thread.currentThread());
- currentFunction.put(Thread.currentThread(), this);
- try {
- for(int i=0; i<e.size(); i++)
- ((ForthBlock)e.elementAt(i)).eval(rootScope);
- } catch (ForthBlock.ReturnException e) {
- // ignore
- } catch (ForthBlock.ControlTransferException e) {
- throw new JS.Exn("block threw a ControlTransferException: " + e);
- } finally {
- if (saved == null) currentFunction.remove(Thread.currentThread());
- else currentFunction.put(Thread.currentThread(), saved);
- }
- return null;
- }
- public static Script parse(Reader r, String sourceName, int line) throws IOException {
- Parser p = new Parser(r, sourceName, line);
- try {
- Vector exprs = new Vector();
- while(true) {
- ForthBlock ret = p.parseStatement(false);
- if (ret == null) break;
- exprs.addElement(ret);
- }
- return new Script(exprs);
- } catch (Exception e) {
- if (Log.on) Log.log(Parser.class, e);
- return null;
- }
- }
+ /** a Callable which was compiled from JavaScript code */
+ public static class CompiledFunction extends CompiledFunctionImpl {
+ 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); }
}
- /** 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 JS Math = new org.xwt.js.Math();
+ /** 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();
+ int pc;
+
+ /** binds this thread to the current Java Thread */
+ public void bindToCurrentJavaThread() { javaThreadToJSThread.put(java.lang.Thread.currentThread(), this); }
+
+ /** returns the line of code that is currently executing */
+ public int getLine() { return currentCompiledFunction == null ? -1 : currentCompiledFunction.getLine(pc); }
+ /** returns the name of the source code file which declared the currently executing function */
+ public String getSourceName() { return currentCompiledFunction == null ? null : currentCompiledFunction.getSourceName(); }
+
+ /** fetches the currently-executing javascript function */
+ public JS.CompiledFunction getCurrentCompiledFunction() { return currentCompiledFunction; }
+
+
+ // Statics ///////////////////////////////////////////////////////////////////////
+
+ private static Hashtable javaThreadToJSThread = new Hashtable();
+
+ /** returns the JS thread for a given Java thread, creating one if necessary */
+ public static JS.Thread fromJavaThread(java.lang.Thread t) {
+ JS.Thread ret = (JS.Thread)javaThreadToJSThread.get(t);
+ if (ret == null) {
+ ret = new JS.Thread();
+ ret.bindToCurrentJavaThread();
+ }
+ return ret;
+ }
+
+ public static JS.Thread currentJSThread() {
+ return fromJavaThread(java.lang.Thread.currentThread());
+ }
+ }
}
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