X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Forg%2Fxwt%2Fjs%2FJS.java;h=f2a7c20fd1a5b88129df3f5f8634b963be12ffbe;hb=1503499f4a43295388c7fd0ed1f49942f00b863f;hp=24f133adac144092924c0e5088267b7092e4d5e4;hpb=77f51cd3e157cf6fd2ae85ce774444bb85ea7b81;p=org.ibex.core.git diff --git a/src/org/xwt/js/JS.java b/src/org/xwt/js/JS.java index 24f133a..f2a7c20 100644 --- a/src/org/xwt/js/JS.java +++ b/src/org/xwt/js/JS.java @@ -1,161 +1,227 @@ // 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. 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 { +/** 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 == 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 Helper Methods ////////////////////////////////////////////////////////////////////// + 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 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); + } - /** parse and compile a function */ - public static CompiledFunction parse(String sourceName, int firstLine, Reader sourceCode) throws IOException { - return new CompiledFunction(sourceName, firstLine, sourceCode, null); + 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; if (o instanceof Boolean) return ((Boolean)o).booleanValue(); - if (o instanceof Number) return o.equals(new Integer(0)); + 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 == null) return ZERO; 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); + + // 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"); } - - - // 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; } - /** a sealed object cannot have its properties modified */ - 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 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; } - } - /** 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); } - } - - /** 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 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; - } - - /** a Callable which was compiled from JavaScript code */ - public static class CompiledFunction extends CompiledFunctionImpl { - public Object call(JS.Array args, JS.Scope scope) throws JS.Exn { return super.call(args, scope); } - CompiledFunction(String sourceName, int firstLine, Reader sourceCode, Scope scope) throws IOException { - super(sourceName, firstLine, sourceCode, scope); + public static final Integer ZERO = new Integer(0); + + // 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 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(); - private int line = -1; + // Trap support ////////////////////////////////////////////////////////////////////////////// - /** binds this thread to the current Java Thread */ - public void bindToCurrentJavaThread() { javaThreadToJSThread.put(java.lang.Thread.currentThread(), this); } + /** 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 false; } - /** returns the line of code that is currently executing */ - public int getLine() { return line; } + /** 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); + } - /** returns the name of the source code file which declared the currently executing function */ - public String getSourceName() { return currentCompiledFunction == null ? null : currentCompiledFunction.getSourceName(); } + /** 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); + } - /** fetches the currently-executing javascript function */ - public JS.CompiledFunction getCurrentCompiledFunction() { return currentCompiledFunction; } + /** 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); + } - // Statics /////////////////////////////////////////////////////////////////////// + /** 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))); + } - private static Hashtable javaThreadToJSThread = new Hashtable(); + /** 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; } + } - /** 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; - } - + + // 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"; } + +}