org.mozilla.javascript.NativeFunction Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of rhino Show documentation
The Rhino JavaScript Engine for Java
The newest version!
/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.javascript;

import org.mozilla.javascript.debug.DebuggableScript;

/**
 * This class implements the Function native object.
 * See ECMA 15.3.
 * @author Norris Boyd
 */
public abstract class NativeFunction extends BaseFunction
{

    static final long serialVersionUID = 8713897114082216401L;
    
    public final void initScriptFunction(Context cx, Scriptable scope)
    {
        ScriptRuntime.setFunctionProtoAndParent(this, scope);
    }

    /**
     * @param indent How much to indent the decompiled result
     *
     * @param flags Flags specifying format of decompilation output
     */
    @Override
    final String decompile(int indent, int flags)
    {
        String encodedSource = getEncodedSource();
        if (encodedSource == null) {
            return super.decompile(indent, flags);
        } else {
            UintMap properties = new UintMap(1);
            properties.put(Decompiler.INITIAL_INDENT_PROP, indent);
            return Decompiler.decompile(encodedSource, flags, properties);
        }
    }

    @Override
    public int getLength()
    {
        int paramCount = getParamCount();
        if (getLanguageVersion() != Context.VERSION_1_2) {
            return paramCount;
        }
        Context cx = Context.getContext();
        NativeCall activation = ScriptRuntime.findFunctionActivation(cx, this);
        if (activation == null) {
            return paramCount;
        }
        return activation.originalArgs.length;
    }

    @Override
    public int getArity()
    {
        return getParamCount();
    }

    /**
     * @deprecated Use {@link BaseFunction#getFunctionName()} instead.
     * For backwards compatibility keep an old method name used by
     * Batik and possibly others.
     */
    public String jsGet_name()
    {
        return getFunctionName();
    }

    /**
     * Get encoded source string.
     */
    public String getEncodedSource()
    {
        return null;
    }

    public DebuggableScript getDebuggableView()
    {
        return null;
    }

    /**
     * Resume execution of a suspended generator.
     * @param cx The current context
     * @param scope Scope for the parent generator function
     * @param operation The resumption operation (next, send, etc.. )
     * @param state The generator state (has locals, stack, etc.)
     * @param value The return value of yield (if required).
     * @return The next yielded value (if any)
     */
    public Object resumeGenerator(Context cx, Scriptable scope,
                                  int operation, Object state, Object value)
    {
        throw new EvaluatorException("resumeGenerator() not implemented");
    }


    protected abstract int getLanguageVersion();

    /**
     * Get number of declared parameters. It should be 0 for scripts.
     */
    protected abstract int getParamCount();

    /**
     * Get number of declared parameters and variables defined through var
     * statements.
     */
    protected abstract int getParamAndVarCount();

    /**
     * Get parameter or variable name.
     * If index < {@link #getParamCount()}, then return the name of the
     * corresponding parameter. Otherwise return the name of variable.
     */
    protected abstract String getParamOrVarName(int index);

    /**
     * Get parameter or variable const-ness.
     * If index < {@link #getParamCount()}, then return the const-ness
     * of the corresponding parameter. Otherwise return whether the variable is
     * const.
     */
    protected boolean getParamOrVarConst(int index)
    {
        // By default return false to preserve compatibility with existing
        // classes subclassing this class, which are mostly generated by jsc
        // from earlier Rhino versions. See Bugzilla #396117.
        return false;
    }
}