javaadapter.java

這是一個javascript 的 interpreter是了解 web browser的好材料

                    } catch (NoSuchMethodException e) {
                        // Not implemented by superclass; fall through
                    }
                }
                // make sure to generate only one instance of a particular
                // method/signature.
                String methodSignature = getMethodSignature(method, argTypes);
                String methodKey = methodName + methodSignature;
                if (! generatedOverrides.has(methodKey)) {
                    generateMethod(cfw, adapterName, methodName,
                                   argTypes, method.getReturnType());
                    generatedOverrides.put(methodKey, 0);
                    generatedMethods.put(methodName, 0);
                }
            }
        }

        // Now, go through the superclass's methods, checking for abstract
        // methods or additional methods to override.

        // generate any additional overrides that the object might contain.
        Method[] methods = getOverridableMethods(superClass);
        for (int j = 0; j < methods.length; j++) {
            Method method = methods[j];
            int mods = method.getModifiers();
            // if a method is marked abstract, must implement it or the
            // resulting class won't be instantiable. otherwise, if the object
            // has a property of the same name, then an override is intended.
            boolean isAbstractMethod = Modifier.isAbstract(mods);
            String methodName = method.getName();
            if (isAbstractMethod || functionNames.has(methodName)) {
                // make sure to generate only one instance of a particular
                // method/signature.
                Class[] argTypes = method.getParameterTypes();
                String methodSignature = getMethodSignature(method, argTypes);
                String methodKey = methodName + methodSignature;
                if (! generatedOverrides.has(methodKey)) {
                    generateMethod(cfw, adapterName, methodName,
                                   argTypes, method.getReturnType());
                    generatedOverrides.put(methodKey, 0);
                    generatedMethods.put(methodName, 0);
                    
                    // if a method was overridden, generate a "super$method"
                    // which lets the delegate call the superclass' version.
                    if (!isAbstractMethod) {
                        generateSuper(cfw, adapterName, superName,
                                      methodName, methodSignature,
                                      argTypes, method.getReturnType());
                    }
                }
            }
        }

        // Generate Java methods for remaining properties that are not
        // overrides.
        ObjToIntMap.Iterator iter = new ObjToIntMap.Iterator(functionNames);
        for (iter.start(); !iter.done(); iter.next()) {
            String functionName = (String)iter.getKey();
            if (generatedMethods.has(functionName))
                continue;
            int length = iter.getValue();
            Class[] parms = new Class[length];
            for (int k=0; k < length; k++)
                parms[k] = ScriptRuntime.ObjectClass;
            generateMethod(cfw, adapterName, functionName, parms,
                           ScriptRuntime.ObjectClass);
        }
        return cfw.toByteArray();
    }

    static Method[] getOverridableMethods(Class c)
    {
        ArrayList<Method> list = new ArrayList<Method>();
        HashSet<String> skip = new HashSet<String>();
        while (c != null) {
            Method[] methods = c.getDeclaredMethods();
            for (int i = 0; i < methods.length; i++) {
                String methodKey = methods[i].getName() + 
                    getMethodSignature(methods[i],
                            methods[i].getParameterTypes());
                if (skip.contains(methodKey))
                    continue; // skip this method
                int mods = methods[i].getModifiers();
                if (Modifier.isStatic(mods))
                    continue;
                if (Modifier.isFinal(mods)) {
                    // Make sure we don't add a final method to the list
                    // of overridable methods.
                    skip.add(methodKey);
                    continue;
                }
                if (Modifier.isPublic(mods) || Modifier.isProtected(mods)) {
                    list.add(methods[i]);
                    skip.add(methodKey);
                }
            }
            c = c.getSuperclass();
        }
        return list.toArray(new Method[list.size()]);
    }

    static Class loadAdapterClass(String className, byte[] classBytes)
    {
        Object staticDomain;
        Class domainClass = SecurityController.getStaticSecurityDomainClass();
        if(domainClass == CodeSource.class || domainClass == ProtectionDomain.class) {
            ProtectionDomain protectionDomain = JavaAdapter.class.getProtectionDomain();
            if(domainClass == CodeSource.class) {
                staticDomain = protectionDomain == null ? null : protectionDomain.getCodeSource();
            }
            else {
                staticDomain = protectionDomain;
            }
        }
        else {
            staticDomain = null;
        }
        GeneratedClassLoader loader = SecurityController.createLoader(null, 
                staticDomain);
        Class result = loader.defineClass(className, classBytes);
        loader.linkClass(result);
        return result;
    }

    public static Function getFunction(Scriptable obj, String functionName)
    {
        Object x = ScriptableObject.getProperty(obj, functionName);
        if (x == Scriptable.NOT_FOUND) {
            // This method used to swallow the exception from calling
            // an undefined method. People have come to depend on this
            // somewhat dubious behavior. It allows people to avoid
            // implementing listener methods that they don't care about,
            // for instance.
            return null;
        }
        if (!(x instanceof Function))
            throw ScriptRuntime.notFunctionError(x, functionName);

        return (Function)x;
    }

    /**
     * Utility method which dynamically binds a Context to the current thread,
     * if none already exists.
     */
    public static Object callMethod(ContextFactory factory,
                                    final Scriptable thisObj,
                                    final Function f, final Object[] args,
                                    final long argsToWrap)
    {
        if (f == null) {
            // See comments in getFunction
            return Undefined.instance;
        }
        if (factory == null) {
            factory = ContextFactory.getGlobal();
        }

        final Scriptable scope = f.getParentScope();
        if (argsToWrap == 0) {
            return Context.call(factory, f, scope, thisObj, args);
        }

        Context cx = Context.getCurrentContext();
        if (cx != null) {
            return doCall(cx, scope, thisObj, f, args, argsToWrap);
        } else {
            return factory.call(new ContextAction() {
                public Object run(Context cx)
                {
                    return doCall(cx, scope, thisObj, f, args, argsToWrap);
                }
            });
        }
    }

    private static Object doCall(Context cx, Scriptable scope,
                                 Scriptable thisObj, Function f,
                                 Object[] args, long argsToWrap)
    {
        // Wrap the rest of objects
        for (int i = 0; i != args.length; ++i) {
            if (0 != (argsToWrap & (1 << i))) {
                Object arg = args[i];
                if (!(arg instanceof Scriptable)) {
                    args[i] = cx.getWrapFactory().wrap(cx, scope, arg,
                                                       null);
                }
            }
        }
        return f.call(cx, scope, thisObj, args);
    }

    public static Scriptable runScript(final Script script)
    {
        return (Scriptable)Context.call(new ContextAction() {
            public Object run(Context cx)
            {
                ScriptableObject global = ScriptRuntime.getGlobal(cx);
                script.exec(cx, global);
                return global;
            }
        });
    }

    private static void generateCtor(ClassFileWriter cfw, String adapterName,
                                     String superName)
    {
        cfw.startMethod("<init>",
                        "(Lorg/mozilla/javascript/ContextFactory;"
                        +"Lorg/mozilla/javascript/Scriptable;)V",
                        ClassFileWriter.ACC_PUBLIC);

        // Invoke base class constructor
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.addInvoke(ByteCode.INVOKESPECIAL, superName, "<init>", "()V");

        // Save parameter in instance variable "factory"
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.add(ByteCode.ALOAD_1);  // first arg: ContextFactory instance
        cfw.add(ByteCode.PUTFIELD, adapterName, "factory",
                "Lorg/mozilla/javascript/ContextFactory;");

        // Save parameter in instance variable "delegee"
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.add(ByteCode.ALOAD_2);  // second arg: Scriptable delegee
        cfw.add(ByteCode.PUTFIELD, adapterName, "delegee",
                "Lorg/mozilla/javascript/Scriptable;");

        cfw.add(ByteCode.ALOAD_0);  // this for the following PUTFIELD for self
        // create a wrapper object to be used as "this" in method calls
        cfw.add(ByteCode.ALOAD_2);  // the Scriptable delegee
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.addInvoke(ByteCode.INVOKESTATIC,
                      "org/mozilla/javascript/JavaAdapter",
                      "createAdapterWrapper",
                      "(Lorg/mozilla/javascript/Scriptable;"
                      +"Ljava/lang/Object;"
                      +")Lorg/mozilla/javascript/Scriptable;");
        cfw.add(ByteCode.PUTFIELD, adapterName, "self",
                "Lorg/mozilla/javascript/Scriptable;");

        cfw.add(ByteCode.RETURN);
        cfw.stopMethod((short)3); // 3: this + factory + delegee
    }

    private static void generateSerialCtor(ClassFileWriter cfw,
                                           String adapterName,
                                           String superName)
    {
        cfw.startMethod("<init>",
                        "(Lorg/mozilla/javascript/ContextFactory;"
                        +"Lorg/mozilla/javascript/Scriptable;"
                        +"Lorg/mozilla/javascript/Scriptable;"
                        +")V",
                        ClassFileWriter.ACC_PUBLIC);

        // Invoke base class constructor
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.addInvoke(ByteCode.INVOKESPECIAL, superName, "<init>", "()V");

        // Save parameter in instance variable "factory"
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.add(ByteCode.ALOAD_1);  // first arg: ContextFactory instance
        cfw.add(ByteCode.PUTFIELD, adapterName, "factory",
                "Lorg/mozilla/javascript/ContextFactory;");

        // Save parameter in instance variable "delegee"
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.add(ByteCode.ALOAD_2);  // second arg: Scriptable delegee
        cfw.add(ByteCode.PUTFIELD, adapterName, "delegee",
                "Lorg/mozilla/javascript/Scriptable;");
        // save self
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.add(ByteCode.ALOAD_3);  // second arg: Scriptable self
        cfw.add(ByteCode.PUTFIELD, adapterName, "self",
                "Lorg/mozilla/javascript/Scriptable;");

        cfw.add(ByteCode.RETURN);
        cfw.stopMethod((short)4); // 4: this + factory + delegee + self
    }

    private static void generateEmptyCtor(ClassFileWriter cfw,
                                          String adapterName,
                                          String superName,
                                          String scriptClassName)
    {
        cfw.startMethod("<init>", "()V", ClassFileWriter.ACC_PUBLIC);

        // Invoke base class constructor
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.addInvoke(ByteCode.INVOKESPECIAL, superName, "<init>", "()V");

        // Set factory to null to use current global when necessary
        cfw.add(ByteCode.ALOAD_0);
        cfw.add(ByteCode.ACONST_NULL);
        cfw.add(ByteCode.PUTFIELD, adapterName, "factory",
                "Lorg/mozilla/javascript/ContextFactory;");

        // Load script class
        cfw.add(ByteCode.NEW, scriptClassName);
        cfw.add(ByteCode.DUP);
        cfw.addInvoke(ByteCode.INVOKESPECIAL, scriptClassName, "<init>", "()V");

        // Run script and save resulting scope
        cfw.addInvoke(ByteCode.INVOKESTATIC,
                      "org/mozilla/javascript/JavaAdapter",
                      "runScript",
                      "(Lorg/mozilla/javascript/Script;"
                      +")Lorg/mozilla/javascript/Scriptable;");
        cfw.add(ByteCode.ASTORE_1);

        // Save the Scriptable in instance variable "delegee"
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.add(ByteCode.ALOAD_1);  // the Scriptable
        cfw.add(ByteCode.PUTFIELD, adapterName, "delegee",
                "Lorg/mozilla/javascript/Scriptable;");

        cfw.add(ByteCode.ALOAD_0);  // this for the following PUTFIELD for self
        // create a wrapper object to be used as "this" in method calls
        cfw.add(ByteCode.ALOAD_1);  // the Scriptable
        cfw.add(ByteCode.ALOAD_0);  // this
        cfw.addInvoke(ByteCode.INVOKESTATIC,
                      "org/mozilla/javascript/JavaAdapter",
                      "createAdapterWrapper",
                      "(Lorg/mozilla/javascript/Scriptable;"
                      +"Ljava/lang/Object;"
                      +")Lorg/mozilla/javascript/Scriptable;");
        cfw.add(ByteCode.PUTFIELD, adapterName, "self",
                "Lorg/mozilla/javascript/Scriptable;");

        cfw.add(ByteCode.RETURN);
        cfw.stopMethod((short)2); // this + delegee
    }

    /**
     * Generates code to wrap Java arguments into Object[].
     * Non-primitive Java types are left as-is pending conversion
     * in the helper method. Leaves the array object on the top of the stack.
     */
    static void generatePushWrappedArgs(ClassFileWriter cfw,
                                        Class[] argTypes,
                                        int arrayLength)
    {
        // push arguments
        cfw.addPush(arrayLength);
        cfw.add(ByteCode.ANEWARRAY, "java/lang/Object");
        int paramOffset = 1;
        for (int i = 0; i != argTypes.length; ++i) {
            cfw.add(ByteCode.DUP); // duplicate array reference
            cfw.addPush(i);
            paramOffset += generateWrapArg(cfw, paramOffset, argTypes[i]);
            cfw.add(ByteCode.AASTORE);
        }
    }

    /**
     * Generates code to wrap Java argument into Object.
     * Non-primitive Java types are left unconverted pending conversion
     * in the helper method. Leaves the wrapper object on the top of the stack.
     */
    private static int generateWrapArg(ClassFileWriter cfw, int paramOffset,
                                       Class argType)
    {
        int size = 1;
        if (!argType.isPrimitive()) {
            cfw.add(ByteCode.ALOAD, paramOffset);

        } else if (argType == Boolean.TYPE) {
            // wrap boolean values with java.lang.Boolean.
            cfw.add(ByteCode.NEW, "java/lang/Boolean");
            cfw.add(ByteCode.DUP);
            cfw.add(ByteCode.ILOAD, paramOffset);
            cfw.addInvoke(ByteCode.INVOKESPECIAL, "java/lang/Boolean",
                          "<init>", "(Z)V");

        } else if (argType == Character.TYPE) {