/*

 * Copyright (c) 1998, 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.javadoc;

import java.io.File;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.net.URL;

import java.net.URLClassLoader;

import javax.tools.DocumentationTool;

import javax.tools.JavaFileManager;

import com.sun.javadoc.*;

import com.sun.tools.javac.file.Locations;

import com.sun.tools.javac.util.ClientCodeException;

import com.sun.tools.javac.util.List;

import static com.sun.javadoc.LanguageVersion.*;

/**

 * Class creates, controls and invokes doclets.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 *

 * @author Neal Gafter (rewrite)

 */

public class DocletInvoker {

    private final Class<?> docletClass;

    private final String docletClassName;

    private final ClassLoader appClassLoader;

    private final Messager messager;

    /**

     * In API mode, exceptions thrown while calling the doclet are

     * propagated using ClientCodeException.

     */

    private final boolean apiMode;

    private static class DocletInvokeException extends Exception {

        private static final long serialVersionUID = 0;

    }

    private String appendPath(String path1, String path2) {

        if (path1 == null || path1.length() == 0) {

            return path2 == null ? "." : path2;

        } else if (path2 == null || path2.length() == 0) {

            return path1;

        } else {

            return path1  + File.pathSeparator + path2;

        }

    }

    public DocletInvoker(Messager messager, Class<?> docletClass, boolean apiMode) {

        this.messager = messager;

        this.docletClass = docletClass;

        docletClassName = docletClass.getName();

        appClassLoader = null;

        this.apiMode = apiMode;

    }

    public DocletInvoker(Messager messager, JavaFileManager fileManager,

                         String docletClassName, String docletPath,

                         ClassLoader docletParentClassLoader,

                         boolean apiMode) {

        this.messager = messager;

        this.docletClassName = docletClassName;

        this.apiMode = apiMode;

        if (fileManager != null && fileManager.hasLocation(DocumentationTool.Location.DOCLET_PATH)) {

            appClassLoader = fileManager.getClassLoader(DocumentationTool.Location.DOCLET_PATH);

        } else {

            // construct class loader

            String cpString = null;   // make sure env.class.path defaults to dot

            // do prepends to get correct ordering

            cpString = appendPath(System.getProperty("env.class.path"), cpString);

            cpString = appendPath(System.getProperty("java.class.path"), cpString);

            cpString = appendPath(docletPath, cpString);

            URL[] urls = Locations.pathToURLs(cpString);

            if (docletParentClassLoader == null)

                appClassLoader = new URLClassLoader(urls, getDelegationClassLoader(docletClassName));

            else

                appClassLoader = new URLClassLoader(urls, docletParentClassLoader);

        }

        // attempt to find doclet

        Class<?> dc = null;

        try {

            dc = appClassLoader.loadClass(docletClassName);

        } catch (ClassNotFoundException exc) {

            messager.error(Messager.NOPOS, "main.doclet_class_not_found", docletClassName);

            messager.exit();

        }

        docletClass = dc;

    }

    /*

     * Returns the delegation class loader to use when creating

     * appClassLoader (used to load the doclet).  The context class

     * loader is the best choice, but legacy behavior was to use the

     * default delegation class loader (aka system class loader).

     *

     * Here we favor using the context class loader.  To ensure

     * compatibility with existing apps, we revert to legacy

     * behavior if either or both of the following conditions hold:

     *

     * 1) the doclet is loadable from the system class loader but not

     *    from the context class loader,

     *

     * 2) this.getClass() is loadable from the system class loader but not

     *    from the context class loader.

     */

    private ClassLoader getDelegationClassLoader(String docletClassName) {

        ClassLoader ctxCL = Thread.currentThread().getContextClassLoader();

        ClassLoader sysCL = ClassLoader.getSystemClassLoader();

        if (sysCL == null)

            return ctxCL;

        if (ctxCL == null)

            return sysCL;

        // Condition 1.

        try {

            sysCL.loadClass(docletClassName);

            try {

                ctxCL.loadClass(docletClassName);

            } catch (ClassNotFoundException e) {

                return sysCL;

            }

        } catch (ClassNotFoundException e) {

        }

        // Condition 2.

        try {

            if (getClass() == sysCL.loadClass(getClass().getName())) {

                try {

                    if (getClass() != ctxCL.loadClass(getClass().getName()))

                        return sysCL;

                } catch (ClassNotFoundException e) {

                    return sysCL;

                }

            }

        } catch (ClassNotFoundException e) {

        }

        return ctxCL;

    }

    /**

     * Generate documentation here.  Return true on success.

     */

    public boolean start(RootDoc root) {

        Object retVal;

        String methodName = "start";

        Class<?>[] paramTypes = { RootDoc.class };

        Object[] params = { root };

        try {

            retVal = invoke(methodName, null, paramTypes, params);

        } catch (DocletInvokeException exc) {

            return false;

        }

        if (retVal instanceof Boolean) {

            return ((Boolean)retVal).booleanValue();

        } else {

            messager.error(Messager.NOPOS, "main.must_return_boolean",

                           docletClassName, methodName);

            return false;

        }

    }

    /**

     * Check for doclet added options here. Zero return means

     * option not known.  Positive value indicates number of

     * arguments to option.  Negative value means error occurred.

     */

    public int optionLength(String option) {

        Object retVal;

        String methodName = "optionLength";

        Class<?>[] paramTypes = { String.class };

        Object[] params = { option };

        try {

            retVal = invoke(methodName, 0, paramTypes, params);

        } catch (DocletInvokeException exc) {

            return -1;

        }

        if (retVal instanceof Integer) {

            return ((Integer)retVal).intValue();

        } else {

            messager.error(Messager.NOPOS, "main.must_return_int",

                           docletClassName, methodName);

            return -1;

        }

    }

    /**

     * Let doclet check that all options are OK. Returning true means

     * options are OK.  If method does not exist, assume true.

     */

    public boolean validOptions(List<String[]> optlist) {

        Object retVal;

        String options[][] = optlist.toArray(new String[optlist.length()][]);

        String methodName = "validOptions";

        DocErrorReporter reporter = messager;

        Class<?>[] paramTypes = { String[][].class, DocErrorReporter.class };

        Object[] params = { options, reporter };

        try {

            retVal = invoke(methodName, Boolean.TRUE, paramTypes, params);

        } catch (DocletInvokeException exc) {

            return false;

        }

        if (retVal instanceof Boolean) {

            return ((Boolean)retVal).booleanValue();

        } else {

            messager.error(Messager.NOPOS, "main.must_return_boolean",

                           docletClassName, methodName);

            return false;

        }

    }

    /**

     * Return the language version supported by this doclet.

     * If the method does not exist in the doclet, assume version 1.1.

     */

    public LanguageVersion languageVersion() {

        try {

            Object retVal;

            String methodName = "languageVersion";

            Class<?>[] paramTypes = new Class<?>[0];

            Object[] params = new Object[0];

            try {

                retVal = invoke(methodName, JAVA_1_1, paramTypes, params);

            } catch (DocletInvokeException exc) {

                return JAVA_1_1;

            }

            if (retVal instanceof LanguageVersion) {

                return (LanguageVersion)retVal;

            } else {

                messager.error(Messager.NOPOS, "main.must_return_languageversion",

                               docletClassName, methodName);

                return JAVA_1_1;

            }

        } catch (NoClassDefFoundError ex) { // for boostrapping, no Enum class.

            return null;

        }

    }

    /**

     * Utility method for calling doclet functionality

     */

    private Object invoke(String methodName, Object returnValueIfNonExistent,

                          Class<?>[] paramTypes, Object[] params)

        throws DocletInvokeException {

            Method meth;

            try {

                meth = docletClass.getMethod(methodName, paramTypes);

            } catch (NoSuchMethodException exc) {

                if (returnValueIfNonExistent == null) {

                    messager.error(Messager.NOPOS, "main.doclet_method_not_found",

                                   docletClassName, methodName);

                    throw new DocletInvokeException();

                } else {

                    return returnValueIfNonExistent;

                }

            } catch (SecurityException exc) {

                messager.error(Messager.NOPOS, "main.doclet_method_not_accessible",

                               docletClassName, methodName);

                throw new DocletInvokeException();

            }

            if (!Modifier.isStatic(meth.getModifiers())) {

                messager.error(Messager.NOPOS, "main.doclet_method_must_be_static",

                               docletClassName, methodName);

                throw new DocletInvokeException();

            }

            ClassLoader savedCCL =

                Thread.currentThread().getContextClassLoader();

            try {

                if (appClassLoader != null) // will be null if doclet class provided via API

                    Thread.currentThread().setContextClassLoader(appClassLoader);

                return meth.invoke(null , params);

            } catch (IllegalArgumentException | NullPointerException exc) {

                messager.error(Messager.NOPOS, "main.internal_error_exception_thrown",

                               docletClassName, methodName, exc.toString());

                throw new DocletInvokeException();

            } catch (IllegalAccessException exc) {

                messager.error(Messager.NOPOS, "main.doclet_method_not_accessible",

                               docletClassName, methodName);

                throw new DocletInvokeException();

            }

            catch (InvocationTargetException exc) {

                Throwable err = exc.getTargetException();

                if (apiMode)

                    throw new ClientCodeException(err);

                if (err instanceof java.lang.OutOfMemoryError) {

                    messager.error(Messager.NOPOS, "main.out.of.memory");

                } else {

                    messager.error(Messager.NOPOS, "main.exception_thrown",

                               docletClassName, methodName, exc.toString());

                    exc.getTargetException().printStackTrace();

                }

                throw new DocletInvokeException();

            } finally {

                Thread.currentThread().setContextClassLoader(savedCCL);

            }

    }

}