/**
* 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.
+ * Object which can be manipulated by JavaScript code.
*/
public abstract class JS {
// Public Helper Methods //////////////////////////////////////////////////////////////////////
/** parse and compile a function */
- public static Function parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
- return new Function(sourceName, firstLine, sourceCode, null);
+ public static JSFunction parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
+ return new JSFunction(sourceName, firstLine, sourceCode, null);
}
/** coerce an object to a Boolean */
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";
// Instance Methods ////////////////////////////////////////////////////////////////////
public abstract Object get(Object key) throws JS.Exn;
- public abstract Object put(Object key, Object val) throws JS.Exn;
- public abstract Object[] keys();
+ public void put(Object key, Object val) throws JS.Exn { throw new JS.Exn("you cannot put to this object"); }
+
+ public Enumeration keys() { throw new Error("you cannot apply for..in to a " + this.getClass().getName()); }
- 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() { 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"); }
+
public String typeName() { return "object"; }
// Inner Classes /////////////////////////////////////////////////////////////////////////
- /** A sensible implementation of the abstract methods in the JS class */
- public static class Obj extends JS {
-
- // FIXME: move these to an interface so they're optional
- // 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;
-
- // FIXME: be smart here; perhaps intern
- 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 Boolean B(boolean b) { return b ? Boolean.TRUE : Boolean.FALSE; }
-
- 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 Object put(Object key, Object val) { put2(key, null, val); return null; }
- protected void put2(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 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 Object put(Object key, Object val) { super._put(key, val); return null; }
- }
-
- /** 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); }
- public boolean has(Object key) { return super.has(key); }
- public Object get(Object key) { return super._get(key); }
- public Object put(Object key, Object val) { super._put(key, val); return null; }
- public void declare(String s) { super.declare(s); }
- }
-
/** the result of a graft */
- public static class Graft extends JS {
+ public static class Graft extends JSCallable {
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;
+ 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 Object put(Object key, Object val) { graftee.put(key, val); return null; }
- 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 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 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 and wasn't compiled from JS code */
- public static abstract class Callable extends JS.Obj {
- public abstract Object call(JS.Array args) throws JS.Exn;
- }
-
- /** 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 class TailCall {
- Function func = null;
- JS.Array args = null;
- public TailCall() { }
- public TailCall set(Function func) { this.func = func; this.args = new JS.Array(); return this; }
- public TailCall set(Function func, JS.Array args) { this.func = func; this.args = args; return this; }
- }
-
- /** encapsulates the state of a JavaScript "thread" (ie stack) */
- public static class Context {
-
-
- // Statics //////////////////////////////////////////////////////////////////////
-
- /**
- * Return this from call/get/put in order to make the interpreter pause. The interpreter will expect a value
- * (the return from the call or the get) to be pushed onto the stack when it is resumed.
- */
- public static Object pause = new Object();
-
- private int getLine_() { return current().f == null ? -1 : (pc < 0 || pc >= f.size) ? -1 : f.line[pc]; }
- public static int getLine() { return current().getLine_(); }
- public static String getSourceName() { return current().f == null ? null : current().f.sourceName; }
-
- /** fetches the currently-executing javascript function */
- public static JS.Context current() { return (JS.Context)threadToContext.get(Thread.currentThread()); }
- private static Hashtable threadToContext = new Hashtable();
-
-
- // Instance members and methods //////////////////////////////////////////////////////////////////////
-
- /** the currently-executing Function */
- Function f = null;
-
- /** the currently-executing scope */
- public Scope scope = null; // FIXME: do we really need this? the function should contain this info
-
- /** the object stack */
- Vec stack = new Vec();
-
- /** the program counter */
- int pc = 0;
-
- public Context(Function function, Scope scope) {
- if (scope == null) scope = new Scope(function.parentScope);
- stack.push(new Function.CallMarker(this));
- stack.push(new JS.Array());
- this.f = function;
- this.scope = scope;
- }
-
- public Object resume() { return resume(null); }
- public Object resume(Object o) {
- Thread t = Thread.currentThread();
- Context old = (Context)threadToContext.get(t);
- try {
- threadToContext.put(t, this);
- stack.push(o);
- return Function.eval(this);
- } finally {
- if (old == null) threadToContext.remove(t);
- else threadToContext.put(t, old);
- }
- }
-
- }
-
- public static void recurse(String indent, String name, Object o) {
- if (!name.equals("")) name += " : ";
-
- if (o == null) {
- Log.logJS(indent + name + "<null>");
-
- } else if (o instanceof JS.Array) {
- Log.logJS(indent + name + "<array>");
- JS.Array na = (JS.Array)o;
- for(int i=0; i<na.length(); i++)
- recurse(indent + " ", i + "", na.elementAt(i));
-
- } else if (o instanceof JS) {
- Log.logJS(indent + name + "<object>");
- JS s = (JS)o;
- Object[] keys = s.keys();
- for(int i=0; i<keys.length; i++)
- if (keys[i] != null)
- recurse(indent + " ", keys[i].toString(),
- (keys[i] instanceof Integer) ?
- s.get(((Integer)keys[i])) : s.get(keys[i].toString()));
-
- } else {
- Log.logJS(indent + name + o);
-
+ 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;
+ }
+ }
+ };
}
}
-
}
projects / org.ibex.core.git / blobdiff