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Diffstat (limited to 'libjava/classpath/java/net/URLStreamHandler.java')
| -rw-r--r-- | libjava/classpath/java/net/URLStreamHandler.java | 532 |
1 files changed, 532 insertions, 0 deletions
diff --git a/libjava/classpath/java/net/URLStreamHandler.java b/libjava/classpath/java/net/URLStreamHandler.java new file mode 100644 index 00000000000..57ce2dfa290 --- /dev/null +++ b/libjava/classpath/java/net/URLStreamHandler.java @@ -0,0 +1,532 @@ +/* URLStreamHandler.java -- Abstract superclass for all protocol handlers + Copyright (C) 1998, 1999, 2002, 2003, 2004 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package java.net; + +import java.io.File; +import java.io.IOException; + + +/* + * Written using on-line Java Platform 1.2 API Specification, as well + * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998). + * Status: Believed complete and correct. + */ + +/** + * This class is the superclass of all URL protocol handlers. The URL + * class loads the appropriate protocol handler to establish a connection + * to a (possibly) remote service (eg, "http", "ftp") and to do protocol + * specific parsing of URL's. Refer to the URL class documentation for + * details on how that class locates and loads protocol handlers. + * <p> + * A protocol handler implementation should override the openConnection() + * method, and optionally override the parseURL() and toExternalForm() + * methods if necessary. (The default implementations will parse/write all + * URL's in the same form as http URL's). A protocol specific subclass + * of URLConnection will most likely need to be created as well. + * <p> + * Note that the instance methods in this class are called as if they + * were static methods. That is, a URL object to act on is passed with + * every call rather than the caller assuming the URL is stored in an + * instance variable of the "this" object. + * <p> + * The methods in this class are protected and accessible only to subclasses. + * URLStreamConnection objects are intended for use by the URL class only, + * not by other classes (unless those classes are implementing protocols). + * + * @author Aaron M. Renn (arenn@urbanophile.com) + * @author Warren Levy (warrenl@cygnus.com) + * + * @see URL + */ +public abstract class URLStreamHandler +{ + /** + * Creates a URLStreamHander + */ + public URLStreamHandler() + { + } + + /** + * Returns a URLConnection for the passed in URL. Note that this should + * not actually create the connection to the (possibly) remote host, but + * rather simply return a URLConnection object. The connect() method of + * URL connection is used to establish the actual connection, possibly + * after the caller sets up various connection options. + * + * @param url The URL to get a connection object for + * + * @return A URLConnection object for the given URL + * + * @exception IOException If an error occurs + */ + protected abstract URLConnection openConnection(URL url) + throws IOException; + + /** + * This method parses the string passed in as a URL and set's the + * instance data fields in the URL object passed in to the various values + * parsed out of the string. The start parameter is the position to start + * scanning the string. This is usually the position after the ":" which + * terminates the protocol name. The end parameter is the position to + * stop scanning. This will be either the end of the String, or the + * position of the "#" character, which separates the "file" portion of + * the URL from the "anchor" portion. + * <p> + * This method assumes URL's are formatted like http protocol URL's, so + * subclasses that implement protocols with URL's the follow a different + * syntax should override this method. The lone exception is that if + * the protocol name set in the URL is "file", this method will accept + * an empty hostname (i.e., "file:///"), which is legal for that protocol + * + * @param url The URL object in which to store the results + * @param spec The String-ized URL to parse + * @param start The position in the string to start scanning from + * @param end The position in the string to stop scanning + */ + protected void parseURL(URL url, String spec, int start, int end) + { + String host = url.getHost(); + int port = url.getPort(); + String file = url.getFile(); + String ref = url.getRef(); + String userInfo = url.getUserInfo(); + String authority = url.getAuthority(); + String query = null; + + // On Windows we need to change \ to / for file URLs + char separator = File.separatorChar; + if (url.getProtocol().equals("file") && separator != '/') + { + file = file.replace(separator, '/'); + spec = spec.replace(separator, '/'); + } + + if (spec.regionMatches(start, "//", 0, 2)) + { + String genuineHost; + int hostEnd; + int colon; + int at_host; + + start += 2; + int slash = spec.indexOf('/', start); + if (slash >= 0) + hostEnd = slash; + else + hostEnd = end; + + authority = host = spec.substring(start, hostEnd); + + // We first need a genuine host name (with userinfo). + // So we check for '@': if it's present check the port in the + // section after '@' in the other case check it in the full string. + // P.S.: We don't care having '@' at the beginning of the string. + if ((at_host = host.indexOf('@')) >= 0) + { + genuineHost = host.substring(at_host); + userInfo = host.substring(0, at_host); + } + else + genuineHost = host; + + // Look for optional port number. It is valid for the non-port + // part of the host name to be null (e.g. a URL "http://:80"). + // TBD: JDK 1.2 in this case sets host to null rather than ""; + // this is undocumented and likely an unintended side effect in 1.2 + // so we'll be simple here and stick with "". Note that + // "http://" or "http:///" produce a "" host in JDK 1.2. + if ((colon = genuineHost.indexOf(':')) >= 0) + { + try + { + port = Integer.parseInt(genuineHost.substring(colon + 1)); + } + catch (NumberFormatException e) + { + // Ignore invalid port values; port is already set to u's + // port. + } + + // Now we must cut the port number in the original string. + if (at_host >= 0) + host = host.substring(0, at_host + colon); + else + host = host.substring(0, colon); + } + file = null; + start = hostEnd; + } + else if (host == null) + host = ""; + + if (file == null || file.length() == 0 + || (start < end && spec.charAt(start) == '/')) + { + // No file context available; just spec for file. + // Or this is an absolute path name; ignore any file context. + file = spec.substring(start, end); + ref = null; + } + else if (start < end) + { + // Context is available, but only override it if there is a new file. + int lastSlash = file.lastIndexOf('/'); + if (lastSlash < 0) + file = spec.substring(start, end); + else + file = (file.substring(0, lastSlash) + + '/' + spec.substring(start, end)); + + // For URLs constructed relative to a context, we + // need to canonicalise the file path. + file = canonicalizeFilename(file); + + ref = null; + } + + if (ref == null) + { + // Normally there should be no '#' in the file part, + // but we are nice. + int hash = file.indexOf('#'); + if (hash != -1) + { + ref = file.substring(hash + 1, file.length()); + file = file.substring(0, hash); + } + } + + // We care about the query tag only if there is no reference at all. + if (ref == null) + { + int queryTag = file.indexOf('?'); + if (queryTag != -1) + { + query = file.substring(queryTag + 1); + file = file.substring(0, queryTag); + } + } + + // XXX - Classpath used to call PlatformHelper.toCanonicalForm() on + // the file part. It seems like overhead, but supposedly there is some + // benefit in windows based systems (it also lowercased the string). + setURL(url, url.getProtocol(), host, port, authority, userInfo, file, query, ref); + } + + /* + * Canonicalize a filename. + */ + private static String canonicalizeFilename(String file) + { + // XXX - GNU Classpath has an implementation that might be more appropriate + // for Windows based systems (gnu.java.io.PlatformHelper.toCanonicalForm) + int index; + + // Replace "/./" with "/". This probably isn't very efficient in + // the general case, but it's probably not bad most of the time. + while ((index = file.indexOf("/./")) >= 0) + file = file.substring(0, index) + file.substring(index + 2); + + // Process "/../" correctly. This probably isn't very efficient in + // the general case, but it's probably not bad most of the time. + while ((index = file.indexOf("/../")) >= 0) + { + // Strip of the previous directory - if it exists. + int previous = file.lastIndexOf('/', index - 1); + if (previous >= 0) + file = file.substring(0, previous) + file.substring(index + 3); + else + break; + } + return file; + } + + /** + * Compares two URLs, excluding the fragment component + * + * @param url1 The first url + * @param url2 The second url to compare with the first + * + * @return True if both URLs point to the same file, false otherwise. + * + * @specnote Now protected + */ + protected boolean sameFile(URL url1, URL url2) + { + if (url1 == url2) + return true; + + // This comparison is very conservative. It assumes that any + // field can be null. + if (url1 == null || url2 == null) + return false; + int p1 = url1.getPort(); + if (p1 == -1) + p1 = url1.ph.getDefaultPort(); + int p2 = url2.getPort(); + if (p2 == -1) + p2 = url2.ph.getDefaultPort(); + if (p1 != p2) + return false; + String s1; + String s2; + s1 = url1.getProtocol(); + s2 = url2.getProtocol(); + if (s1 != s2 && (s1 == null || ! s1.equals(s2))) + return false; + s1 = url1.getHost(); + s2 = url2.getHost(); + if (s1 != s2 && (s1 == null || ! s1.equals(s2))) + return false; + s1 = canonicalizeFilename(url1.getFile()); + s2 = canonicalizeFilename(url2.getFile()); + if (s1 != s2 && (s1 == null || ! s1.equals(s2))) + return false; + return true; + } + + /** + * This methods sets the instance variables representing the various fields + * of the URL to the values passed in. + * + * @param u The URL to modify + * @param protocol The protocol to set + * @param host The host name to et + * @param port The port number to set + * @param file The filename to set + * @param ref The reference + * + * @exception SecurityException If the protocol handler of the URL is + * different from this one + * + * @deprecated 1.2 Please use + * #setURL(URL,String,String,int,String,String,String,String); + */ + protected void setURL(URL u, String protocol, String host, int port, + String file, String ref) + { + u.set(protocol, host, port, file, ref); + } + + /** + * Sets the fields of the URL argument to the indicated values + * + * @param u The URL to modify + * @param protocol The protocol to set + * @param host The host name to set + * @param port The port number to set + * @param authority The authority to set + * @param userInfo The user information to set + * @param path The path/filename to set + * @param query The query part to set + * @param ref The reference + * + * @exception SecurityException If the protocol handler of the URL is + * different from this one + */ + protected void setURL(URL u, String protocol, String host, int port, + String authority, String userInfo, String path, + String query, String ref) + { + u.set(protocol, host, port, authority, userInfo, path, query, ref); + } + + /** + * 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 url1 An URL object + * @param url2 An URL object + * + * @return True if both given URLs are equal, false otherwise. + */ + protected boolean equals(URL url1, URL url2) + { + // This comparison is very conservative. It assumes that any + // field can be null. + return (url1.getPort() == url2.getPort() + && ((url1.getProtocol() == null && url2.getProtocol() == null) + || (url1.getProtocol() != null + && url1.getProtocol().equals(url2.getProtocol()))) + && ((url1.getUserInfo() == null && url2.getUserInfo() == null) + || (url1.getUserInfo() != null + && url1.getUserInfo().equals(url2.getUserInfo()))) + && ((url1.getAuthority() == null && url2.getAuthority() == null) + || (url1.getAuthority() != null + && url1.getAuthority().equals(url2.getAuthority()))) + && ((url1.getHost() == null && url2.getHost() == null) + || (url1.getHost() != null && url1.getHost().equals(url2.getHost()))) + && ((url1.getPath() == null && url2.getPath() == null) + || (url1.getPath() != null && url1.getPath().equals(url2.getPath()))) + && ((url1.getQuery() == null && url2.getQuery() == null) + || (url1.getQuery() != null + && url1.getQuery().equals(url2.getQuery()))) + && ((url1.getRef() == null && url2.getRef() == null) + || (url1.getRef() != null && url1.getRef().equals(url2.getRef())))); + } + + /** + * Compares the host components of two URLs. + * + * @param url1 The first URL. + * @param url2 The second URL. + * + * @return True if both URLs contain the same host. + * + * @exception UnknownHostException If an unknown host is found + */ + protected boolean hostsEqual(URL url1, URL url2) + { + InetAddress addr1 = getHostAddress(url1); + InetAddress addr2 = getHostAddress(url2); + + if (addr1 != null && addr2 != null) + return addr1.equals(addr2); + + String host1 = url1.getHost(); + String host2 = url2.getHost(); + + if (host1 != null && host2 != null) + return host1.equalsIgnoreCase(host2); + + return host1 == null && host2 == null; + } + + /** + * Get the IP address of our host. An empty host field or a DNS failure will + * result in a null return. + * + * @param url The URL to return the host address for. + * + * @return The address of the hostname in url. + */ + protected InetAddress getHostAddress(URL url) + { + String hostname = url.getHost(); + + if (hostname.equals("")) + return null; + + try + { + return InetAddress.getByName(hostname); + } + catch (UnknownHostException e) + { + return null; + } + } + + /** + * 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 number. + */ + protected int getDefaultPort() + { + return -1; + } + + /** + * Provides the default hash calculation. May be overidden by handlers for + * other protocols that have different requirements for hashCode calculation. + * + * @param url The URL to calc the hashcode for. + * + * @return The hashcode for the given URL. + */ + protected int hashCode(URL url) + { + return url.getProtocol().hashCode() + + ((url.getHost() == null) ? 0 : url.getHost().hashCode()) + + url.getFile().hashCode() + url.getPort(); + } + + /** + * This method converts a URL object into a String. This method creates + * Strings in the mold of http URL's, so protocol handlers which use URL's + * that have a different syntax should override this method + * + * @param url The URL object to convert + * + * @return A string representation of the url + */ + protected String toExternalForm(URL url) + { + String protocol; + String file; + String ref; + String authority; + + protocol = url.getProtocol(); + authority = url.getAuthority(); + if (authority == null) + authority = ""; + + file = url.getFile(); + ref = url.getRef(); + + // Guess a reasonable size for the string buffer so we have to resize + // at most once. + int size = protocol.length() + authority.length() + file.length() + 24; + StringBuffer sb = new StringBuffer(size); + + if (protocol != null && protocol.length() > 0) + { + sb.append(protocol); + sb.append(":"); + } + + if (authority.length() != 0) + { + sb.append("//").append(authority); + } + + sb.append(file); + + if (ref != null) + sb.append('#').append(ref); + + return sb.toString(); + } +} |