content: /*
   * Copyright (C) 2014 The Android Open Source Project
   * Copyright (c) 1995, 2013, 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 java.net;
  
  import java.io.IOException;
  import java.util.Objects;
  
  import sun.net.util.IPAddressUtil;
  
  /**
   * The abstract class {@code URLStreamHandler} is the common
   * superclass for all stream protocol handlers. A stream protocol
   * handler knows how to make a connection for a particular protocol
   * type, such as {@code http} or {@code https}.
   * <p>
   * In most cases, an instance of a {@code URLStreamHandler}
   * subclass is not created directly by an application. Rather, the
   * first time a protocol name is encountered when constructing a
   * {@code URL}, the appropriate stream protocol handler is
   * automatically loaded.
   *
   * @author  James Gosling
   * @see     URL#URL(String, String, int, String)
   * @since   JDK1.0
   */
  public abstract class URLStreamHandler {
      /**
       * Opens a connection to the object referenced by the
       * {@code URL} argument.
       * This method should be overridden by a subclass.
       *
       * <p>If for the handler's protocol (such as HTTP or JAR), there
       * exists a public, specialized URLConnection subclass belonging
       * to one of the following packages or one of their subpackages:
       * java.lang, java.io, java.util, java.net, the connection
       * returned will be of that subclass. For example, for HTTP an
       * HttpURLConnection will be returned, and for JAR a
       * JarURLConnection will be returned.
       *
       * @param      u   the URL that this connects to.
       * @return     a {@code URLConnection} object for the {@code URL}.
       * @exception  IOException  if an I/O error occurs while opening the
       *               connection.
       */
      abstract protected URLConnection openConnection(URL u) throws IOException;
  
      /**
       * Same as openConnection(URL), except that the connection will be
       * made through the specified proxy; Protocol handlers that do not
       * support proxying will ignore the proxy parameter and make a
       * normal connection.
       *
       * Calling this method preempts the system's default ProxySelector
       * settings.
       *
       * @param      u   the URL that this connects to.
       * @param      p   the proxy through which the connection will be made.
       *                 If direct connection is desired, Proxy.NO_PROXY
       *                 should be specified.
       * @return     a {@code URLConnection} object for the {@code URL}.
       * @exception  IOException  if an I/O error occurs while opening the
       *               connection.
       * @exception  IllegalArgumentException if either u or p is null,
       *               or p has the wrong type.
       * @exception  UnsupportedOperationException if the subclass that
       *               implements the protocol doesn't support this method.
       * @since      1.5
       */
      protected URLConnection openConnection(URL u, Proxy p) throws IOException {
          throw new UnsupportedOperationException("Method not implemented.");
      }
  
      /**
       * Parses the string representation of a {@code URL} into a
       * {@code URL} object.
       * <p>
       * If there is any inherited context, then it has already been
       * copied into the {@code URL} argument.
       * <p>
       * The {@code parseURL} method of {@code URLStreamHandler}
       * parses the string representation as if it were an
       * {@code http} specification. Most URL protocol families have a
       * similar parsing. A stream protocol handler for a protocol that has
       * a different syntax must override this routine.
       *
       * @param   u       the {@code URL} to receive the result of parsing
       *                  the spec.
       * @param   spec    the {@code String} representing the URL that
       *                  must be parsed.
       * @param   start   the character index at which to begin parsing. This is
       *                  just past the '{@code :}' (if there is one) that
       *                  specifies the determination of the protocol name.
       * @param   limit   the character position to stop parsing at. This is the
       *                  end of the string or the position of the
       *                  "{@code #}" character, if present. All information
       *                  after the sharp sign indicates an anchor.
       */
      protected void parseURL(URL u, String spec, int start, int limit) {
          // These fields may receive context content if this was relative URL
          String protocol = u.getProtocol();
          String authority = u.getAuthority();
          String userInfo = u.getUserInfo();
          String host = u.getHost();
          int port = u.getPort();
          String path = u.getPath();
          String query = u.getQuery();
  
          // This field has already been parsed
          String ref = u.getRef();
  
          boolean isRelPath = false;
          boolean queryOnly = false;
          // BEGIN Android-changed: App compat
          boolean querySet = false;
          // END Android-changed: App compat
  
  // FIX: should not assume query if opaque
          // Strip off the query part
          if (start < limit) {
              int queryStart = spec.indexOf('?');
              queryOnly = queryStart == start;
              if ((queryStart != -1) && (queryStart < limit)) {
                  query = spec.substring(queryStart+1, limit);
                  if (limit > queryStart)
                      limit = queryStart;
                  spec = spec.substring(0, queryStart);
                  // BEGIN Android-changed: App compat
                  querySet = true;
                  // END Android-changed: App compat
              }
          }
  
          int i = 0;
          // Parse the authority part if any
          // BEGIN Android-changed: App compat
          // boolean isUNCName = (start <= limit - 4) &&
          //                 (spec.charAt(start) == '/') &&
          //                 (spec.charAt(start + 1) == '/') &&
          //                 (spec.charAt(start + 2) == '/') &&
          //                 (spec.charAt(start + 3) == '/');
          boolean isUNCName = false;
          // END Android-changed: App compat
          if (!isUNCName && (start <= limit - 2) && (spec.charAt(start) == '/') &&
              (spec.charAt(start + 1) == '/')) {
              start += 2;
              // BEGIN Android-changed: Check for all hostname termination chars. http://b/110955991
              /*
              i = spec.indexOf('/', start);
              if (i < 0 || i > limit) {
                  i = spec.indexOf('?', start);
                  if (i < 0 || i > limit)
                      i = limit;
              }
              */
              LOOP: for (i = start; i < limit; i++) {
                  switch (spec.charAt(i)) {
                      case '/':  // Start of path
                      case '\\': // Start of path - see https://url.spec.whatwg.org/#host-state
                      case '?':  // Start of query
                      case '#':  // Start of fragment
                          break LOOP;
                  }
              }
              // END Android-changed: Check for all hostname termination chars. http://b/110955991
  
              host = authority = spec.substring(start, i);
  
              int ind = authority.indexOf('@');
              if (ind != -1) {
                  if (ind != authority.lastIndexOf('@')) {
                      // more than one '@' in authority. This is not server based
                      userInfo = null;
                      host = null;
                  } else {
                      userInfo = authority.substring(0, ind);
                      host = authority.substring(ind+1);
                  }
              } else {
                  userInfo = null;
              }
              if (host != null) {
                  // If the host is surrounded by [ and ] then its an IPv6
                  // literal address as specified in RFC2732
                  if (host.length()>0 && (host.charAt(0) == '[')) {
                      if ((ind = host.indexOf(']')) > 2) {
  
                          String nhost = host ;
                          host = nhost.substring(0,ind+1);
                          if (!IPAddressUtil.
                              isIPv6LiteralAddress(host.substring(1, ind))) {
                              throw new IllegalArgumentException(
                                  "Invalid host: "+ host);
                          }
  
                          port = -1 ;
                          if (nhost.length() > ind+1) {
                              if (nhost.charAt(ind+1) == ':') {
                                  ++ind ;
                                  // port can be null according to RFC2396
                                  if (nhost.length() > (ind + 1)) {
                                      port = Integer.parseInt(nhost.substring(ind+1));
                                  }
                              } else {
                                  throw new IllegalArgumentException(
                                      "Invalid authority field: " + authority);
                              }
                          }
                      } else {
                          throw new IllegalArgumentException(
                              "Invalid authority field: " + authority);
                      }
                  } else {
                      ind = host.indexOf(':');
                      port = -1;
                      if (ind >= 0) {
                          // port can be null according to RFC2396
                          if (host.length() > (ind + 1)) {
                              // BEGIN Android-changed: App compat
                              // port = Integer.parseInt(host.substring(ind + 1));
                              char firstPortChar = host.charAt(ind+1);
                              if (firstPortChar >= '0' && firstPortChar <= '9') {
                                  port = Integer.parseInt(host.substring(ind + 1));
                              } else {
                                  throw new IllegalArgumentException("invalid port: " +
                                                                     host.substring(ind + 1));
                              }
                              // END Android-changed: App compat
                          }
                          host = host.substring(0, ind);
                      }
                  }
              } else {
                  host = "";
              }
              if (port < -1)
                  throw new IllegalArgumentException("Invalid port number :" +
                                                     port);
              start = i;
  
              // If the authority is defined then the path is defined by the
              // spec only; See RFC 2396 Section 5.2.4.
              // BEGIN Android-changed: App compat
              // if (authority != null && authority.length() > 0)
              //   path = "";
              path = null;
              if (!querySet) {
                  query = null;
              }
              // END Android-changed: App compat
          }
  
          if (host == null) {
              host = "";
          }
  
          // Parse the file path if any
          if (start < limit) {
              // Android-changed: Check for all hostname termination chars. http://b/110955991
              // if (spec.charAt(start) == '/') {
              if (spec.charAt(start) == '/' || spec.charAt(start) == '\\') {
                  path = spec.substring(start, limit);
              } else if (path != null && path.length() > 0) {
                  isRelPath = true;
                  int ind = path.lastIndexOf('/');
                  String seperator = "";
                  if (ind == -1 && authority != null)
                      seperator = "/";
                  path = path.substring(0, ind + 1) + seperator +
                           spec.substring(start, limit);
  
              } else {
                  String seperator = (authority != null) ? "/" : "";
                  path = seperator + spec.substring(start, limit);
              }
          }
          // BEGIN Android-changed: App compat
          //else if (queryOnly && path != null) {
          //    int ind = path.lastIndexOf('/');
          //    if (ind < 0)
          //        ind = 0;
          //    path = path.substring(0, ind) + "/";
          //}
          // END Android-changed: App compat
          if (path == null)
              path = "";
  
          // BEGIN Android-changed
          //if (isRelPath) {
          if (true) {
          // END Android-changed
              // Remove embedded /./
              while ((i = path.indexOf("/./")) >= 0) {
                  path = path.substring(0, i) + path.substring(i + 2);
              }
              // Remove embedded /../ if possible
              i = 0;
              while ((i = path.indexOf("/../", i)) >= 0) {
                  // BEGIN Android-changed: App compat
                  /*
                   * Trailing /../
                   */
                  if (i == 0) {
                      path = path.substring(i + 3);
                      i = 0;
                  // END Android-changed: App compat
                  /*
                   * A "/../" will cancel the previous segment and itself,
                   * unless that segment is a "/../" itself
                   * i.e. "/a/b/../c" becomes "/a/c"
                   * but "/../../a" should stay unchanged
                   */
                  // Android-changed: App compat
                  // if (i > 0 && (limit = path.lastIndexOf('/', i - 1)) >= 0 &&
                  } else if (i > 0 && (limit = path.lastIndexOf('/', i - 1)) >= 0 &&
                      (path.indexOf("/../", limit) != 0)) {
                      path = path.substring(0, limit) + path.substring(i + 3);
                      i = 0;
                  } else {
                      i = i + 3;
                  }
              }
              // Remove trailing .. if possible
              while (path.endsWith("/..")) {
                  i = path.indexOf("/..");
                  if ((limit = path.lastIndexOf('/', i - 1)) >= 0) {
                      path = path.substring(0, limit+1);
                  } else {
                      break;
                  }
              }
              // Remove starting .
              if (path.startsWith("./") && path.length() > 2)
                  path = path.substring(2);
  
              // Remove trailing .
              if (path.endsWith("/."))
                  path = path.substring(0, path.length() -1);
  
              // Android-changed: App compat: Remove trailing ?
              if (path.endsWith("?"))
                  path = path.substring(0, path.length() -1);
          }
  
          setURL(u, protocol, host, port, authority, userInfo, path, query, ref);
      }
  
      /**
       * Returns the default port for a URL parsed by this handler. This method
       * is meant to be overidden by handlers with default port numbers.
       * @return the default port for a {@code URL} parsed by this handler.
       * @since 1.3
       */
      protected int getDefaultPort() {
          return -1;
      }
  
      /**
       * Provides the default equals calculation. May be overidden by handlers
       * for other protocols that have different requirements for equals().
       * This method requires that none of its arguments is null. This is
       * guaranteed by the fact that it is only called by java.net.URL class.
       * @param u1 a URL object
       * @param u2 a URL object
       * @return {@code true} if the two urls are
       * considered equal, ie. they refer to the same
       * fragment in the same file.
       * @since 1.3
       */
      protected boolean equals(URL u1, URL u2) {
          // Android-changed: Avoid network I/O
          return Objects.equals(u1.getRef(), u2.getRef()) &&
                 Objects.equals(u1.getQuery(), u2.getQuery()) &&
                 // sameFile compares the protocol, file, port & host components of
                 // the URLs.
                 sameFile(u1, u2);
      }
  
      /**
       * Provides the default hash calculation. May be overidden by handlers for
       * other protocols that have different requirements for hashCode
       * calculation.
       * @param u a URL object
       * @return an {@code int} suitable for hash table indexing
       * @since 1.3
       */
      protected int hashCode(URL u) {
          // Android-changed: Avoid network I/O
          // Hash on the same set of fields that we compare in equals().
          return Objects.hash(
                  u.getRef(),
                  u.getQuery(),
                  u.getProtocol(),
                  u.getFile(),
                  u.getHost(),
                  u.getPort());
      }
  
      /**
       * Compare two urls to see whether they refer to the same file,
       * i.e., having the same protocol, host, port, and path.
       * This method requires that none of its arguments is null. This is
       * guaranteed by the fact that it is only called indirectly
       * by java.net.URL class.
       * @param u1 a URL object
       * @param u2 a URL object
       * @return true if u1 and u2 refer to the same file
       * @since 1.3
       */
      protected boolean sameFile(URL u1, URL u2) {
          // Compare the protocols.
          if (!((u1.getProtocol() == u2.getProtocol()) ||
                (u1.getProtocol() != null &&
                 u1.getProtocol().equalsIgnoreCase(u2.getProtocol()))))
              return false;
  
          // Compare the files.
          if (!(u1.getFile() == u2.getFile() ||
                (u1.getFile() != null && u1.getFile().equals(u2.getFile()))))
              return false;
  
          // Compare the ports.
          int port1, port2;
          port1 = (u1.getPort() != -1) ? u1.getPort() : u1.handler.getDefaultPort();
          port2 = (u2.getPort() != -1) ? u2.getPort() : u2.handler.getDefaultPort();
          if (port1 != port2)
              return false;
  
          // Compare the hosts.
          if (!hostsEqual(u1, u2))
              return false;
  
          return true;
      }
  
      /**
       * Get the IP address of our host. An empty host field or a DNS failure
       * will result in a null return.
       *
       * @param u a URL object
       * @return an {@code InetAddress} representing the host
       * IP address.
       * @since 1.3
       */
      protected synchronized InetAddress getHostAddress(URL u) {
          if (u.hostAddress != null)
              return u.hostAddress;
  
          String host = u.getHost();
          if (host == null || host.equals("")) {
              return null;
          } else {
              try {
                  u.hostAddress = InetAddress.getByName(host);
              } catch (UnknownHostException ex) {
                  return null;
              } catch (SecurityException se) {
                  return null;
              }
          }
          return u.hostAddress;
      }
  
      /**
       * Compares the host components of two URLs.
       * @param u1 the URL of the first host to compare
       * @param u2 the URL of the second host to compare
       * @return  {@code true} if and only if they
       * are equal, {@code false} otherwise.
       * @since 1.3
       */
      protected boolean hostsEqual(URL u1, URL u2) {
          // Android-changed: Don't compare the InetAddresses of the hosts.
          if (u1.getHost() != null && u2.getHost() != null)
              return u1.getHost().equalsIgnoreCase(u2.getHost());
           else
              return u1.getHost() == null && u2.getHost() == null;
      }
  
      /**
       * Converts a {@code URL} of a specific protocol to a
       * {@code String}.
       *
       * @param   u   the URL.
       * @return  a string representation of the {@code URL} argument.
       */
      protected String toExternalForm(URL u) {
  
          // pre-compute length of StringBuffer
          int len = u.getProtocol().length() + 1;
          if (u.getAuthority() != null && u.getAuthority().length() > 0)
              len += 2 + u.getAuthority().length();
          if (u.getPath() != null) {
              len += u.getPath().length();
          }
          if (u.getQuery() != null) {
              len += 1 + u.getQuery().length();
          }
          if (u.getRef() != null)
              len += 1 + u.getRef().length();
  
          // BEGIN Android-changed: Add a toExternalForm variant that optionally escapes illegal chars
          // TODO: The variant has been removed. We can potentially revert the change
          StringBuilder result = new StringBuilder(len);
          result.append(u.getProtocol());
          result.append(":");
          if (u.getAuthority() != null) {// ANDROID: && u.getAuthority().length() > 0) {
              result.append("//");
              result.append(u.getAuthority());
          }
          String fileAndQuery = u.getFile();
          if (fileAndQuery != null) {
              result.append(fileAndQuery);
          }
          // END Android-changed: Add a toExternalForm variant that optionally escapes illegal chars
          if (u.getRef() != null) {
              result.append("#");
              result.append(u.getRef());
          }
          return result.toString();
      }
  
      // Android-changed: Removed @see tag (target is package-private):
      // @see     java.net.URL#set(java.lang.String, java.lang.String, int, java.lang.String, java.lang.String)
      /**
       * Sets the fields of the {@code URL} argument to the indicated values.
       * Only classes derived from URLStreamHandler are able
       * to use this method to set the values of the URL fields.
       *
       * @param   u         the URL to modify.
       * @param   protocol  the protocol name.
       * @param   host      the remote host value for the URL.
       * @param   port      the port on the remote machine.
       * @param   authority the authority part for the URL.
       * @param   userInfo the userInfo part of the URL.
       * @param   path      the path component of the URL.
       * @param   query     the query part for the URL.
       * @param   ref       the reference.
       * @exception       SecurityException       if the protocol handler of the URL is
       *                                  different from this one
       * @since 1.3
       */
         protected void setURL(URL u, String protocol, String host, int port,
                               String authority, String userInfo, String path,
                               String query, String ref) {
          if (this != u.handler) {
              throw new SecurityException("handler for url different from " +
                                          "this handler");
          }
          // ensure that no one can reset the protocol on a given URL.
          u.set(u.getProtocol(), host, port, authority, userInfo, path, query, ref);
      }
  
      /**
       * Sets the fields of the {@code URL} argument to the indicated values.
       * Only classes derived from URLStreamHandler are able
       * to use this method to set the values of the URL fields.
       *
       * @param   u         the URL to modify.
       * @param   protocol  the protocol name. This value is ignored since 1.2.
       * @param   host      the remote host value for the URL.
       * @param   port      the port on the remote machine.
       * @param   file      the file.
       * @param   ref       the reference.
       * @exception       SecurityException       if the protocol handler of the URL is
       *                                  different from this one
       * @deprecated Use setURL(URL, String, String, int, String, String, String,
       *             String);
       */
      @Deprecated
      protected void setURL(URL u, String protocol, String host, int port,
                            String file, String ref) {
          /*
           * Only old URL handlers call this, so assume that the host
           * field might contain "user:passwd@host". Fix as necessary.
           */
          String authority = null;
          String userInfo = null;
          if (host != null && host.length() != 0) {
              authority = (port == -1) ? host : host + ":" + port;
              int at = host.lastIndexOf('@');
              if (at != -1) {
                  userInfo = host.substring(0, at);
                  host = host.substring(at+1);
              }
          }
  
          /*
           * Assume file might contain query part. Fix as necessary.
           */
          String path = null;
          String query = null;
          if (file != null) {
              int q = file.lastIndexOf('?');
              if (q != -1) {
                  query = file.substring(q+1);
                  path = file.substring(0, q);
              } else
                  path = file;
          }
          setURL(u, protocol, host, port, authority, userInfo, path, query, ref);
      }
  }
  