urlimagesource.java

来自「This is a resource based on j2me embedde」· Java 代码 · 共 164 行

/*
 * @(#)URLImageSource.java	1.24 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program 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. 
 * 
 * This program 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 at /legal/license.txt). 
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA 
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions. 
 *
 */

package sun.awt.image;

import java.io.InputStream;
import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.net.MalformedURLException;

public class URLImageSource extends InputStreamImageSource {
    URL url;
    URLConnection conn;
    String actualHost;
    int actualPort;

    public URLImageSource(URL u) {
	SecurityManager sm = System.getSecurityManager();
	if (sm != null) {
	    try {
		java.security.Permission perm = 
		    u.openConnection().getPermission();
		if (perm != null) {
		    try {
			sm.checkPermission(perm);
		    } catch (SecurityException se) {
			// fallback to checkRead/checkConnect for pre 1.2
			// security managers
			if ((perm instanceof java.io.FilePermission) &&
				perm.getActions().indexOf("read") != -1) {
			    sm.checkRead(perm.getName());
			} else if ((perm instanceof 
				java.net.SocketPermission) &&
				perm.getActions().indexOf("connect") != -1) {
			    sm.checkConnect(u.getHost(), u.getPort());
			} else {
			    throw se;
			}
		    }
		}
	    } catch (java.io.IOException ioe) {
		    sm.checkConnect(u.getHost(), u.getPort());
	    }
	}
	this.url = u;

    }

    public URLImageSource(String href) throws MalformedURLException {
	this(new URL(null, href));
    }

    public URLImageSource(URL u, URLConnection uc) {
	this(u);
	conn = uc;
    }

    public URLImageSource(URLConnection uc) {
	this(uc.getURL(), uc);
    }

    final boolean checkSecurity(Object context, boolean quiet) {
	// If actualHost is not null, then the host/port parameters that
	// the image was actually fetched from were different than the
	// host/port parameters the original URL specified for at least
	// one of the download attempts.  The original URL security was
	// checked when the applet got a handle to the image, so we only
	// need to check for the real host/port.
	if (actualHost != null) {
	    try {
                SecurityManager security = System.getSecurityManager();
                if (security != null) {
                    if (context != null)
                        security.checkConnect(actualHost, actualPort, context);
                    else
                        security.checkConnect(actualHost, actualPort);                        
                }
	    } catch (SecurityException e) {
		if (!quiet) {
		    throw e;
		}
		return false;
	    }
	}
	return true;
    }

    private synchronized URLConnection getConnection() throws IOException {
	URLConnection c;
	if (conn != null) {
	    c = conn;
	    conn = null;
	} else {
	    c = url.openConnection();
	}
	return c;
    }

    protected ImageDecoder getDecoder() {
	InputStream is = null;
	String type = null;
	try {
	    URLConnection c = getConnection();
	    is = c.getInputStream();
	    type = c.getContentType();
	    URL u = c.getURL();
	    if (u != url && (!u.getHost().equals(url.getHost()) ||
			     u.getPort() != url.getPort()))
	    {
		// The image is allowed to come from either the host/port
		// listed in the original URL, or it can come from one other
		// host/port that the URL is redirected to.  More than that
		// and we give up and just throw a SecurityException.
		if (actualHost != null && (!actualHost.equals(u.getHost()) ||
					   actualPort != u.getPort()))
		{
		    throw new SecurityException("image moved!");
		}
		actualHost = u.getHost();
		actualPort = u.getPort();
	    }
	} catch (IOException e) {
	    if (is != null) {
		try {
		    is.close();
		} catch (IOException e2) {
		}
	    }
	    return null;
	}

	ImageDecoder id = decoderForType(is, type);
	if (id == null) {
	    id = getDecoder(is);
	}
	return id;
    }
}