/*
 
* 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.io.InputStream;
import java.io.File;
import java.io.OutputStream;
import java.util.Hashtable;
import sun.net.util.IPAddressUtil;
import sun.net.www.ParseUtil;

/**
 
* 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
     
java.net.URL#URL(java.lang.String, java.lang.String, int, java.lang.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.
     
* @returna {@code URLConnection} object for the {@code URL}.
     
* @exception
  
IOExceptionif 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.
     
* @returna {@code URLConnection} object for the {@code URL}.
     
* @exception
  
IOExceptionif 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
   
startthe 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
   
limitthe 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;

// 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);
            
}
        
}

        
int i = 0;
        
// Parse the authority part if any
        
boolean isUNCName = (start <= limit - 4) &&
                        
(spec.charAt(start) == '/') &&
                        
(spec.charAt(start + 1) == '/') &&
                        
(spec.charAt(start + 2) == '/') &&
                        
(spec.charAt(start + 3) == '/');
        
if (!isUNCName && (start <= limit - 2) && (spec.charAt(start) == '/') &&
            
(spec.charAt(start + 1) == '/')) {
            
start += 2;
            
i = spec.indexOf('/', start);
            
if (i < 0 || i > limit) {
                
i = spec.indexOf('?', start);
                
if (i < 0 || i > limit)
                    
i = limit;
            
}

            
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)) {
                            
port = Integer.parseInt(host.substring(ind + 1));
                        
}
                        
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.
            
if (authority != null && authority.length() > 0)
                
path = "";
        
}

        
if (host == null) {
            
host = "";
        
}

        
// Parse the file path if any
        
if (start < limit) {
            
if (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);
            
}
        
} else if (queryOnly && path != null) {
            
int ind = path.lastIndexOf('/');
            
if (ind < 0)
                
ind = 0;
            
path = path.substring(0, ind) + "/";
        
}
        
if (path == null)
            
path = "";

        
if (isRelPath) {
            
// 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) {
                
/*
                 
* 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
                 
*/

                
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);
        
}

        
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) {
        
String ref1 = u1.getRef();
        
String ref2 = u2.getRef();
        
return (ref1 == ref2 || (ref1 != null && ref1.equals(ref2))) &&
               
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) {
        
int h = 0;

        
// Generate the protocol part.
        
String protocol = u.getProtocol();
        
if (protocol != null)
            
h += protocol.hashCode();

        
// Generate the host part.
        
InetAddress addr = getHostAddress(u);
        
if (addr != null) {
            
h += addr.hashCode();
        
} else {
            
String host = u.getHost();
            
if (host != null)
                
h += host.toLowerCase().hashCode();
        
}

        
// Generate the file part.
        
String file = u.getFile();
        
if (file != null)
            
h += file.hashCode();

        
// Generate the port part.
        
if (u.getPort() == -1)
            
h += getDefaultPort();
        
else
            
h += u.getPort();

        
// Generate the ref part.
        
String ref = u.getRef();
        
if (ref != null)
            
h += ref.hashCode();

        
return h;
    
}

    
/**
     
* 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) {
        
InetAddress a1 = getHostAddress(u1);
        
InetAddress a2 = getHostAddress(u2);
        
// if we have internet address for both, compare them
        
if (a1 != null && a2 != null) {
            
return a1.equals(a2);
        
// else, if both have host names, compare them
        
} else 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
   
uthe 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();

        
StringBuffer result = new StringBuffer(len);
        
result.append(u.getProtocol());
        
result.append(":");
        
if (u.getAuthority() != null && u.getAuthority().length() > 0) {
            
result.append("//");
            
result.append(u.getAuthority());
        
}
        
if (u.getPath() != null) {
            
result.append(u.getPath());
        
}
        
if (u.getQuery() != null) {
            
result.append('?');
            
result.append(u.getQuery());
        
}
        
if (u.getRef() != null) {
            
result.append("#");
            
result.append(u.getRef());
        
}
        
return result.toString();
    
}

    
/**
     
* 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
   
querythe query part for the URL.
     
* @param
   
ref
       
the reference.
     
* @exception
       
SecurityExceptionif the protocol handler of the URL is
     
*
                                  
different from this one
     
* @seejava.net.URL#set(java.lang.String, java.lang.String, int, java.lang.String, java.lang.String)
     
* @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
       
SecurityExceptionif 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);
    
}
}