1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 * Copyright (c) 1995, 2006, Oracle and/or its affiliates. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.  Oracle designates this
9 * particular file as subject to the "Classpath" exception as provided
10 * by Oracle in the LICENSE file that accompanied this code.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
23 * or visit www.oracle.com if you need additional information or have any
24 * questions.
25 */
26
27package java.net;
28
29import java.io.IOException;
30import java.util.Objects;
31
32import sun.net.util.IPAddressUtil;
33
34/**
35 * The abstract class <code>URLStreamHandler</code> is the common
36 * superclass for all stream protocol handlers. A stream protocol
37 * handler knows how to make a connection for a particular protocol
38 * type, such as <code>http</code>, <code>ftp</code>, or
39 * <code>gopher</code>.
40 * <p>
41 * In most cases, an instance of a <code>URLStreamHandler</code>
42 * subclass is not created directly by an application. Rather, the
43 * first time a protocol name is encountered when constructing a
44 * <code>URL</code>, the appropriate stream protocol handler is
45 * automatically loaded.
46 *
47 * @author  James Gosling
48 * @see     java.net.URL#URL(java.lang.String, java.lang.String, int, java.lang.String)
49 * @since   JDK1.0
50 */
51public abstract class URLStreamHandler {
52    /**
53     * Opens a connection to the object referenced by the
54     * <code>URL</code> argument.
55     * This method should be overridden by a subclass.
56     *
57     * <p>If for the handler's protocol (such as HTTP or JAR), there
58     * exists a public, specialized URLConnection subclass belonging
59     * to one of the following packages or one of their subpackages:
60     * java.lang, java.io, java.util, java.net, the connection
61     * returned will be of that subclass. For example, for HTTP an
62     * HttpURLConnection will be returned, and for JAR a
63     * JarURLConnection will be returned.
64     *
65     * @param      u   the URL that this connects to.
66     * @return     a <code>URLConnection</code> object for the <code>URL</code>.
67     * @exception  IOException  if an I/O error occurs while opening the
68     *               connection.
69     */
70    abstract protected URLConnection openConnection(URL u) throws IOException;
71
72    /**
73     * Same as openConnection(URL), except that the connection will be
74     * made through the specified proxy; Protocol handlers that do not
75     * support proxying will ignore the proxy parameter and make a
76     * normal connection.
77     *
78     * Calling this method preempts the system's default ProxySelector
79     * settings.
80     *
81     * @param      u   the URL that this connects to.
82     * @param      p   the proxy through which the connection will be made.
83     *                 If direct connection is desired, Proxy.NO_PROXY
84     *                 should be specified.
85     * @return     a <code>URLConnection</code> object for the <code>URL</code>.
86     * @exception  IOException  if an I/O error occurs while opening the
87     *               connection.
88     * @exception  IllegalArgumentException if either u or p is null,
89     *               or p has the wrong type.
90     * @exception  UnsupportedOperationException if the subclass that
91     *               implements the protocol doesn't support this method.
92     * @since      1.5
93     */
94    protected URLConnection openConnection(URL u, Proxy p) throws IOException {
95        throw new UnsupportedOperationException("Method not implemented.");
96    }
97
98    /**
99     * Parses the string representation of a <code>URL</code> into a
100     * <code>URL</code> object.
101     * <p>
102     * If there is any inherited context, then it has already been
103     * copied into the <code>URL</code> argument.
104     * <p>
105     * The <code>parseURL</code> method of <code>URLStreamHandler</code>
106     * parses the string representation as if it were an
107     * <code>http</code> specification. Most URL protocol families have a
108     * similar parsing. A stream protocol handler for a protocol that has
109     * a different syntax must override this routine.
110     *
111     * @param   u       the <code>URL</code> to receive the result of parsing
112     *                  the spec.
113     * @param   spec    the <code>String</code> representing the URL that
114     *                  must be parsed.
115     * @param   start   the character index at which to begin parsing. This is
116     *                  just past the '<code>:</code>' (if there is one) that
117     *                  specifies the determination of the protocol name.
118     * @param   limit   the character position to stop parsing at. This is the
119     *                  end of the string or the position of the
120     *                  "<code>#</code>" character, if present. All information
121     *                  after the sharp sign indicates an anchor.
122     */
123    protected void parseURL(URL u, String spec, int start, int limit) {
124        // These fields may receive context content if this was relative URL
125        String protocol = u.getProtocol();
126        String authority = u.getAuthority();
127        String userInfo = u.getUserInfo();
128        String host = u.getHost();
129        int port = u.getPort();
130        String path = u.getPath();
131        String query = u.getQuery();
132
133        // This field has already been parsed
134        String ref = u.getRef();
135
136        boolean isRelPath = false;
137        boolean queryOnly = false;
138        // ----- BEGIN android -----
139        boolean querySet = false;
140        // ----- END android -----
141
142        // FIX: should not assume query if opaque
143        // Strip off the query part
144        if (start < limit) {
145            int queryStart = spec.indexOf('?');
146            queryOnly = queryStart == start;
147            if ((queryStart != -1) && (queryStart < limit)) {
148                query = spec.substring(queryStart+1, limit);
149                if (limit > queryStart)
150                    limit = queryStart;
151                spec = spec.substring(0, queryStart);
152                // ----- BEGIN android -----
153                querySet = true;
154                // ----- END android -----
155            }
156        }
157
158        int i = 0;
159        // Parse the authority part if any
160        // ----- BEGIN android -----
161        // boolean isUNCName = (start <= limit - 4) &&
162        //                 (spec.charAt(start) == '/') &&
163        //                 (spec.charAt(start + 1) == '/') &&
164        //                 (spec.charAt(start + 2) == '/') &&
165        //                 (spec.charAt(start + 3) == '/');
166        boolean isUNCName = false;
167        // ----- END android -----
168        if (!isUNCName && (start <= limit - 2) && (spec.charAt(start) == '/') &&
169            (spec.charAt(start + 1) == '/')) {
170            start += 2;
171            i = spec.indexOf('/', start);
172            if (i < 0) {
173                i = spec.indexOf('?', start);
174                if (i < 0)
175                    i = limit;
176            }
177
178            host = authority = spec.substring(start, i);
179
180            int ind = authority.indexOf('@');
181            if (ind != -1) {
182                userInfo = authority.substring(0, ind);
183                host = authority.substring(ind+1);
184            } else {
185                userInfo = null;
186            }
187            if (host != null) {
188                // If the host is surrounded by [ and ] then its an IPv6
189                // literal address as specified in RFC2732
190                if (host.length()>0 && (host.charAt(0) == '[')) {
191                    if ((ind = host.indexOf(']')) > 2) {
192
193                        String nhost = host ;
194                        host = nhost.substring(0,ind+1);
195                        if (!IPAddressUtil.
196                            isIPv6LiteralAddress(host.substring(1, ind))) {
197                            throw new IllegalArgumentException(
198                                "Invalid host: "+ host);
199                        }
200
201                        port = -1 ;
202                        if (nhost.length() > ind+1) {
203                            if (nhost.charAt(ind+1) == ':') {
204                                ++ind ;
205                                // port can be null according to RFC2396
206                                if (nhost.length() > (ind + 1)) {
207                                    port = Integer.parseInt(nhost.substring(ind+1));
208                                }
209                            } else {
210                                throw new IllegalArgumentException(
211                                    "Invalid authority field: " + authority);
212                            }
213                        }
214                    } else {
215                        throw new IllegalArgumentException(
216                            "Invalid authority field: " + authority);
217                    }
218                } else {
219                    ind = host.indexOf(':');
220                    port = -1;
221                    if (ind >= 0) {
222                        // port can be null according to RFC2396
223                        if (host.length() > (ind + 1)) {
224                            // ----- BEGIN android -----
225                            // port = Integer.parseInt(host.substring(ind + 1));
226                            char firstPortChar = host.charAt(ind+1);
227                            if (firstPortChar >= '0' && firstPortChar <= '9') {
228                                port = Integer.parseInt(host.substring(ind + 1));
229                            } else {
230                                throw new IllegalArgumentException("invalid port: " +
231                                                                   host.substring(ind + 1));
232                            }
233                            // ----- END android -----
234                        }
235                        host = host.substring(0, ind);
236                    }
237                }
238            } else {
239                host = "";
240            }
241            if (port < -1)
242                throw new IllegalArgumentException("Invalid port number :" +
243                                                   port);
244            start = i;
245
246            // ----- BEGIN android -----
247            // If the authority is defined then the path is defined by the
248            // spec only; See RFC 2396 Section 5.2.4.
249            // if (authority != null && authority.length() > 0)
250            //   path = "";
251            path = null;
252            if (!querySet) {
253                query = null;
254            }
255            // ----- END android -----
256        }
257
258        if (host == null) {
259            host = "";
260        }
261
262        // Parse the file path if any
263        if (start < limit) {
264            if (spec.charAt(start) == '/') {
265                path = spec.substring(start, limit);
266            } else if (path != null && path.length() > 0) {
267                isRelPath = true;
268                int ind = path.lastIndexOf('/');
269                String seperator = "";
270                if (ind == -1 && authority != null)
271                    seperator = "/";
272                path = path.substring(0, ind + 1) + seperator +
273                         spec.substring(start, limit);
274
275            } else {
276                String seperator = (authority != null) ? "/" : "";
277                path = seperator + spec.substring(start, limit);
278            }
279        }
280        // ----- BEGIN android -----
281        //else if (queryOnly && path != null) {
282        //    int ind = path.lastIndexOf('/');
283        //    if (ind < 0)
284        //        ind = 0;
285        //    path = path.substring(0, ind) + "/";
286        //}
287        // ----- END android -----
288        if (path == null)
289            path = "";
290
291        // ----- BEGIN android -----
292        //if (isRelPath) {
293        if (true) {
294        // ----- END android -----
295            // Remove embedded /./
296            while ((i = path.indexOf("/./")) >= 0) {
297                path = path.substring(0, i) + path.substring(i + 2);
298            }
299            // Remove embedded /../ if possible
300            i = 0;
301            while ((i = path.indexOf("/../", i)) >= 0) {
302                // ----- BEGIN android -----
303                /*
304                 * Trailing /../
305                 */
306                if (i == 0) {
307                    path = path.substring(i + 3);
308                    i = 0;
309                // ----- END android -----
310                /*
311                 * A "/../" will cancel the previous segment and itself,
312                 * unless that segment is a "/../" itself
313                 * i.e. "/a/b/../c" becomes "/a/c"
314                 * but "/../../a" should stay unchanged
315                 */
316                } else if (i > 0 && (limit = path.lastIndexOf('/', i - 1)) >= 0 &&
317                    (path.indexOf("/../", limit) != 0)) {
318                    path = path.substring(0, limit) + path.substring(i + 3);
319                    i = 0;
320                } else {
321                    i = i + 3;
322                }
323            }
324            // Remove trailing .. if possible
325            while (path.endsWith("/..")) {
326                i = path.indexOf("/..");
327                if ((limit = path.lastIndexOf('/', i - 1)) >= 0) {
328                    path = path.substring(0, limit+1);
329                } else {
330                    break;
331                }
332            }
333            // Remove starting .
334            if (path.startsWith("./") && path.length() > 2)
335                path = path.substring(2);
336
337            // Remove trailing .
338            if (path.endsWith("/."))
339                path = path.substring(0, path.length() -1);
340
341            // Remove trailing ?
342            if (path.endsWith("?"))
343                path = path.substring(0, path.length() -1);
344        }
345
346        setURL(u, protocol, host, port, authority, userInfo, path, query, ref);
347    }
348
349    /**
350     * Returns the default port for a URL parsed by this handler. This method
351     * is meant to be overidden by handlers with default port numbers.
352     * @return the default port for a <code>URL</code> parsed by this handler.
353     * @since 1.3
354     */
355    protected int getDefaultPort() {
356        return -1;
357    }
358
359    /**
360     * Provides the default equals calculation. May be overidden by handlers
361     * for other protocols that have different requirements for equals().
362     * This method requires that none of its arguments is null. This is
363     * guaranteed by the fact that it is only called by java.net.URL class.
364     * @param u1 a URL object
365     * @param u2 a URL object
366     * @return <tt>true</tt> if the two urls are
367     * considered equal, ie. they refer to the same
368     * fragment in the same file.
369     * @since 1.3
370     */
371    protected boolean equals(URL u1, URL u2) {
372        return Objects.equals(u1.getRef(), u2.getRef()) &&
373               Objects.equals(u1.getQuery(), u2.getQuery()) &&
374               // sameFile compares the protocol, file, port & host components of
375               // the URLs.
376               sameFile(u1, u2);
377    }
378
379    /**
380     * Provides the default hash calculation. May be overidden by handlers for
381     * other protocols that have different requirements for hashCode
382     * calculation.
383     * @param u a URL object
384     * @return an <tt>int</tt> suitable for hash table indexing
385     * @since 1.3
386     */
387    protected int hashCode(URL u) {
388        // Hash on the same set of fields that we compare in equals().
389        return Objects.hash(
390                u.getRef(),
391                u.getQuery(),
392                u.getProtocol(),
393                u.getFile(),
394                u.getHost(),
395                u.getPort());
396    }
397
398    /**
399     * Compare two urls to see whether they refer to the same file,
400     * i.e., having the same protocol, host, port, and path.
401     * This method requires that none of its arguments is null. This is
402     * guaranteed by the fact that it is only called indirectly
403     * by java.net.URL class.
404     * @param u1 a URL object
405     * @param u2 a URL object
406     * @return true if u1 and u2 refer to the same file
407     * @since 1.3
408     */
409    protected boolean sameFile(URL u1, URL u2) {
410        // Compare the protocols.
411        if (!((u1.getProtocol() == u2.getProtocol()) ||
412              (u1.getProtocol() != null &&
413               u1.getProtocol().equalsIgnoreCase(u2.getProtocol()))))
414            return false;
415
416        // Compare the files.
417        if (!(u1.getFile() == u2.getFile() ||
418              (u1.getFile() != null && u1.getFile().equals(u2.getFile()))))
419            return false;
420
421        // Compare the ports.
422        int port1, port2;
423        port1 = (u1.getPort() != -1) ? u1.getPort() : u1.handler.getDefaultPort();
424        port2 = (u2.getPort() != -1) ? u2.getPort() : u2.handler.getDefaultPort();
425        if (port1 != port2)
426            return false;
427
428        // Compare the hosts.
429        if (!hostsEqual(u1, u2))
430            return false;
431
432        return true;
433    }
434
435    /**
436     * Get the IP address of our host. An empty host field or a DNS failure
437     * will result in a null return.
438     *
439     * @param u a URL object
440     * @return an <code>InetAddress</code> representing the host
441     * IP address.
442     * @since 1.3
443     */
444    protected synchronized InetAddress getHostAddress(URL u) {
445        if (u.hostAddress != null)
446            return u.hostAddress;
447
448        String host = u.getHost();
449        if (host == null || host.equals("")) {
450            return null;
451        } else {
452            try {
453                u.hostAddress = InetAddress.getByName(host);
454            } catch (UnknownHostException ex) {
455                return null;
456            } catch (SecurityException se) {
457                return null;
458            }
459        }
460        return u.hostAddress;
461    }
462
463    /**
464     * Compares the host components of two URLs.
465     * @param u1 the URL of the first host to compare
466     * @param u2 the URL of the second host to compare
467     * @return  <tt>true</tt> if and only if they
468     * are equal, <tt>false</tt> otherwise.
469     * @since 1.3
470     */
471    protected boolean hostsEqual(URL u1, URL u2) {
472        // Android changed: Don't compare the InetAddresses of the hosts.
473        if (u1.getHost() != null && u2.getHost() != null)
474            return u1.getHost().equalsIgnoreCase(u2.getHost());
475         else
476            return u1.getHost() == null && u2.getHost() == null;
477    }
478
479    /**
480     * Converts a <code>URL</code> of a specific protocol to a
481     * <code>String</code>.
482     *
483     * @param   u   the URL.
484     * @return  a string representation of the <code>URL</code> argument.
485     */
486    protected String toExternalForm(URL u) {
487        // pre-compute length of StringBuffer
488        int len = u.getProtocol().length() + 1;
489        if (u.getAuthority() != null && u.getAuthority().length() > 0)
490            len += 2 + u.getAuthority().length();
491        if (u.getPath() != null) {
492            len += u.getPath().length();
493        }
494        if (u.getQuery() != null) {
495            len += 1 + u.getQuery().length();
496        }
497        if (u.getRef() != null)
498            len += 1 + u.getRef().length();
499
500        StringBuilder result = new StringBuilder(len);
501        result.append(u.getProtocol());
502        result.append(":");
503        if (u.getAuthority() != null) {// ANDROID: && u.getAuthority().length() > 0) {
504            result.append("//");
505            result.append(u.getAuthority());
506        }
507        String fileAndQuery = u.getFile();
508        if (fileAndQuery != null) {
509            result.append(fileAndQuery);
510        }
511        if (u.getRef() != null) {
512            result.append("#");
513            result.append(u.getRef());
514        }
515        return result.toString();
516    }
517
518    /**
519     * Sets the fields of the <code>URL</code> argument to the indicated values.
520     * Only classes derived from URLStreamHandler are supposed to be able
521     * to call the set method on a URL.
522     *
523     * @param   u         the URL to modify.
524     * @param   protocol  the protocol name.
525     * @param   host      the remote host value for the URL.
526     * @param   port      the port on the remote machine.
527     * @param   authority the authority part for the URL.
528     * @param   userInfo the userInfo part of the URL.
529     * @param   path      the path component of the URL.
530     * @param   query     the query part for the URL.
531     * @param   ref       the reference.
532     * @exception       SecurityException       if the protocol handler of the URL is
533     *                                  different from this one
534     * @see     java.net.URL#set(java.lang.String, java.lang.String, int, java.lang.String, java.lang.String)
535     * @since 1.3
536     */
537       protected void setURL(URL u, String protocol, String host, int port,
538                             String authority, String userInfo, String path,
539                             String query, String ref) {
540        if (this != u.handler) {
541            throw new SecurityException("handler for url different from " +
542                                        "this handler");
543        }
544        // ensure that no one can reset the protocol on a given URL.
545        u.set(u.getProtocol(), host, port, authority, userInfo, path, query, ref);
546    }
547
548    /**
549     * Sets the fields of the <code>URL</code> argument to the indicated values.
550     * Only classes derived from URLStreamHandler are supposed to be able
551     * to call the set method on a URL.
552     *
553     * @param   u         the URL to modify.
554     * @param   protocol  the protocol name. This value is ignored since 1.2.
555     * @param   host      the remote host value for the URL.
556     * @param   port      the port on the remote machine.
557     * @param   file      the file.
558     * @param   ref       the reference.
559     * @exception       SecurityException       if the protocol handler of the URL is
560     *                                  different from this one
561     * @deprecated Use setURL(URL, String, String, int, String, String, String,
562     *             String);
563     */
564    @Deprecated
565    protected void setURL(URL u, String protocol, String host, int port,
566                          String file, String ref) {
567        /*
568         * Only old URL handlers call this, so assume that the host
569         * field might contain "user:passwd@host". Fix as necessary.
570         */
571        String authority = null;
572        String userInfo = null;
573        if (host != null && host.length() != 0) {
574            authority = (port == -1) ? host : host + ":" + port;
575            int at = host.lastIndexOf('@');
576            if (at != -1) {
577                userInfo = host.substring(0, at);
578                host = host.substring(at+1);
579            }
580        }
581
582        /*
583         * Assume file might contain query part. Fix as necessary.
584         */
585        String path = null;
586        String query = null;
587        if (file != null) {
588            int q = file.lastIndexOf('?');
589            if (q != -1) {
590                query = file.substring(q+1);
591                path = file.substring(0, q);
592            } else
593                path = file;
594        }
595        setURL(u, protocol, host, port, authority, userInfo, path, query, ref);
596    }
597}
598