Mercurial > jdk8-mips64-public > langtools / file revision

 /*

  * Copyright 2006-2008 Sun Microsystems, Inc.  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.  Sun designates this

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

  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  */

 package com.sun.tools.javac.processing;

 import java.io.BufferedReader;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.net.MalformedURLException;

 import java.net.URL;

 /**

  * Utility class to determine if a service can be found on the

  * path that might be used to create a class loader.

  *

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

  * 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>

  *

  */

 // based on sun.misc.Service

 class ServiceProxy {

     static class ServiceConfigurationError extends Error {

         static final long serialVersionUID = 7732091036771098303L;

         ServiceConfigurationError(String msg) {

             super(msg);

         }

     }

     private static final String prefix = "META-INF/services/";

     private static void fail(Class<?> service, String msg)

             throws ServiceConfigurationError {

         throw new ServiceConfigurationError(service.getName() + ": " + msg);

     }

     private static void fail(Class<?> service, URL u, int line, String msg)

             throws ServiceConfigurationError {

         fail(service, u + ":" + line + ": " + msg);

     }

     /**

      * Parse the content of the given URL as a provider-configuration file.

      *

      * @param  service

      *         The service class for which providers are being sought;

      *         used to construct error detail strings

      *

      * @param  url

      *         The URL naming the configuration file to be parsed

      *

      * @return true if the name of a service is found

      *

      * @throws ServiceConfigurationError

      *         If an I/O error occurs while reading from the given URL, or

      *         if a configuration-file format error is detected

      */

     private static boolean parse(Class<?> service, URL u) throws ServiceConfigurationError {

         InputStream in = null;

         BufferedReader r = null;

         try {

             in = u.openStream();

             r = new BufferedReader(new InputStreamReader(in, "utf-8"));

             int lc = 1;

             String ln;

             while ((ln = r.readLine()) != null) {

                 int ci = ln.indexOf('#');

                 if (ci >= 0) ln = ln.substring(0, ci);

                 ln = ln.trim();

                 int n = ln.length();

                 if (n != 0) {

                     if ((ln.indexOf(' ') >= 0) || (ln.indexOf('\t') >= 0))

                         fail(service, u, lc, "Illegal configuration-file syntax");

                     int cp = ln.codePointAt(0);

                     if (!Character.isJavaIdentifierStart(cp))

                         fail(service, u, lc, "Illegal provider-class name: " + ln);

                     for (int i = Character.charCount(cp); i < n; i += Character.charCount(cp)) {

                         cp = ln.codePointAt(i);

                         if (!Character.isJavaIdentifierPart(cp) && (cp != '.'))

                             fail(service, u, lc, "Illegal provider-class name: " + ln);

                     }

                     return true;

                 }

             }

         } catch (FileNotFoundException x) {

             return false;

         } catch (IOException x) {

             fail(service, ": " + x);

         } finally {

             try {

                 if (r != null) r.close();

             } catch (IOException y) {

                 fail(service, ": " + y);

             }

             try {

                 if (in != null) in.close();

             } catch (IOException y) {

                 fail(service, ": " + y);

             }

         }

         return false;

     }

     /**

      * Return true if a description for at least one service is found in the

      * service configuration files in the given URLs.

      */

     public static boolean hasService(Class<?> service, URL[] urls)

             throws ServiceConfigurationError {

         for (URL url: urls) {

             try {

                 String fullName = prefix + service.getName();

                 URL u = new URL(url, fullName);

                 boolean found = parse(service, u);

                 if (found)

                     return true;

             } catch (MalformedURLException e) {

                 // should not happen; ignore it if it does

             }

         }

         return false;

     }

 }