FreeMarker代码分析第六篇

2021SC@SDUSC

• rhino包
• • RhinoFunctionModel.java
  • • 代码分析
  • RhinoscriptableModel.java
  • • 代码分析
  • RhinoWrapper.java
  • • 代码分析

package freemarker.ext.rhino;

import java.util.List;

import org.mozilla.javascript.Context;
import org.mozilla.javascript.Function;
import org.mozilla.javascript.scriptable;
import org.mozilla.javascript.scriptableObject;

import freemarker.ext.beans.BeansWrapper;
import freemarker.template.TemplateMethodModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;


public class RhinoFunctionModel extends RhinoscriptableModel 
implements TemplateMethodModelEx {

    private final scriptable fnThis;
    
    public RhinoFunctionModel(Function function, scriptable fnThis, 
            BeansWrapper wrapper) {
        super(function, wrapper);
        this.fnThis = fnThis;
    }
    
    @Override
    public Object exec(List arguments) throws TemplateModelException {
        Context cx = Context.getCurrentContext();
        Object[] args = arguments.toArray();
        BeansWrapper wrapper = getWrapper();
        for (int i = 0; i < args.length; i++) {
            args[i] = wrapper.unwrap((TemplateModel) args[i]);
        }
        return wrapper.wrap(((Function) getscriptable()).call(cx, 
                scriptableObject.getTopLevelScope(fnThis), fnThis, args));
    }
}

package freemarker.ext.rhino;

import org.mozilla.javascript.Context;
import org.mozilla.javascript.evaluatorException;
import org.mozilla.javascript.Function;
import org.mozilla.javascript.NativeJavaObject;
import org.mozilla.javascript.scriptable;
import org.mozilla.javascript.scriptableObject;

import freemarker.ext.beans.BeansWrapper;
import freemarker.ext.util.ModelFactory;
import freemarker.template.AdapterTemplateModel;
import freemarker.template.ObjectWrapper;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateNumberModel;
import freemarker.template.TemplateScalarModel;
import freemarker.template.TemplateSequenceModel;


public class RhinoscriptableModel implements TemplateHashModelEx, 
TemplateSequenceModel, AdapterTemplateModel, TemplateScalarModel, 
TemplateBooleanModel, TemplateNumberModel {
    static final ModelFactory FACTORY = new ModelFactory() {
        @Override
        public TemplateModel create(Object object, ObjectWrapper wrapper) {
            return new RhinoscriptableModel((scriptable) object, 
                    (BeansWrapper) wrapper);
        }
    };
    
    private final scriptable scriptable;
    private final BeansWrapper wrapper;
    
    public RhinoscriptableModel(scriptable scriptable, BeansWrapper wrapper) {
        this.scriptable = scriptable;
        this.wrapper = wrapper;
    }
    
    @Override
    public TemplateModel get(String key) throws TemplateModelException {
        Object retval = scriptableObject.getProperty(scriptable, key);
        if (retval instanceof Function) {
            return new RhinoFunctionModel((Function) retval, scriptable, wrapper);
        } else {
            return wrapper.wrap(retval);
        }
    }
    
    @Override
    public TemplateModel get(int index) throws TemplateModelException {
        Object retval = scriptableObject.getProperty(scriptable, index);
        if (retval instanceof Function) {
            return new RhinoFunctionModel((Function) retval, scriptable, wrapper);
        } else {
            return wrapper.wrap(retval);
        }
    }
    
    @Override
    public boolean isEmpty() {
        return scriptable.getIds().length == 0;
    }
    
    @Override
    public TemplateCollectionModel keys() throws TemplateModelException {
        return (TemplateCollectionModel) wrapper.wrap(scriptable.getIds());
    }
    
    @Override
    public int size() {
        return scriptable.getIds().length;
    }
    
    @Override
    public TemplateCollectionModel values() throws TemplateModelException {
        Object[] ids = scriptable.getIds();
        Object[] values = new Object[ids.length];
        for (int i = 0; i < values.length; i++) {
            Object id = ids[i];
            if (id instanceof Number) {
                values[i] = scriptableObject.getProperty(scriptable, 
                        ((Number) id).intValue());
            } else {
                values[i] = scriptableObject.getProperty(scriptable, 
                        String.valueOf(id)); 
            }
        }
        return (TemplateCollectionModel) wrapper.wrap(values);
    }
    
    @Override
    public boolean getAsBoolean() {
        return Context.toBoolean(scriptable);
    }
    
    @Override
    public Number getAsNumber() {
        return Double.valueOf(Context.tonumber(scriptable));
    }
    
    @Override
    public String getAsString() {
        return Context.toString(scriptable);
    }
    
    scriptable getscriptable() {
        return scriptable;
    }

    BeansWrapper getWrapper() {
        return wrapper;
    }

    @Override
    public Object getAdaptedObject(Class hint) {
        // FIXME: This does LS3 conversion, which is not very useful for us. Like it won't convert to List, Map, etc.  
        try {
            return NativeJavaObject.coerceType(hint, scriptable);
        } catch (evaluatorException e) {
            return NativeJavaObject.coerceType(Object.class, scriptable);
        }
    }
}

package freemarker.ext.rhino;

import java.security.AccessController;
import java.security.PrivilegedExceptionAction;

import org.mozilla.javascript.scriptable;
import org.mozilla.javascript.Undefined;
import org.mozilla.javascript.UniqueTag;
import org.mozilla.javascript.Wrapper;

import freemarker.ext.beans.BeansWrapper;
import freemarker.ext.util.ModelFactory;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.utility.UndeclaredThrowableException;


public class RhinoWrapper extends BeansWrapper {
    // The type of the "instance" field changed between Rhino versions, so a
    // GETSTATIC with wrong type declaration would cause a NoSuchFieldError;
    // we're avoiding it by acquiring it reflectively.
    private static final Object UNDEFINED_INSTANCE;
    static {
        try {
            UNDEFINED_INSTANCE = AccessController.doPrivileged(new PrivilegedExceptionAction() {
                @Override
                public Object run() throws Exception {
                    return Undefined.class.getField("instance").get(null);
                }
            });
        } catch (RuntimeException e) {
            throw e;
        } catch (Exception e) {
            throw new UndeclaredThrowableException(e);
        }
    }
    
    @Override
    public TemplateModel wrap(Object obj) throws TemplateModelException {
        // So our existence builtins work as expected.
        if (obj == UNDEFINED_INSTANCE || obj == UniqueTag.NOT_FOUND) {
            return null;
        }
        // UniqueTag.NULL_VALUE represents intentionally set null in Rhino, and
        // BeansWrapper#nullModel also represents intentionally returned null.
        // I [A.Sz.] am fairly certain that this value is never passed out of
        // any of the Rhino code back to clients, but is instead always being
        // converted back to null. However, since this object is available to 
        // any 3rd party scriptable implementations as well, they might return
        // it, so we'll just be on the safe side, and handle it.
        if (obj == UniqueTag.NULL_VALUE) {
            return super.wrap(null);
        }
        // So, say, a JavaAdapter for FreeMarker interfaces works
        if (obj instanceof Wrapper) {
            obj = ((Wrapper) obj).unwrap();
        }
        return super.wrap(obj);
    }

    @Override
    protected ModelFactory getModelFactory(Class clazz) {
        if (scriptable.class.isAssignableFrom(clazz)) {
            return RhinoscriptableModel.FACTORY;
        }
        return super.getModelFactory(clazz);
    }
}