[icedtea-web] RFC: find jars based on Class-Path entry in manifest
Dr Andrew John Hughes
ahughes at redhat.com
Thu Apr 14 15:38:20 PDT 2011
On 16:34 Thu 14 Apr , Omair Majid wrote:
> Hi,
>
> The attached patch adds support in icedtea-web for finding other jars
> using the Class-Path entry in a jar's manifest file.
>
> An applet the demonstrates the bug is located at
> http://jung.sourceforge.net/applet/showlayouts2.html
>
> The logic of the patch is quite similar to the already-implemented case
> for jar indices: when a class cannot be found, we will download jars
> specified in the Class-Path and search there too.
>
> ChangeLog:
> 2011-04-14 Omair Majid <omajid at redhat.com>
>
> * netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java: Add new
> private variable classpathsInManifest.
> (activateJars): When adding jar index, also add Class-Path entries
> from the Manifest.mf file in the jar.
> (loadClass): Search for jars specified in classpaths before looking
> for entries in jar index.
> (addNewJar): New method refactored from loadClass.
>
> Any thoughts or comments?
>
> Cheers,
> Omair
Inline.
> diff -r 24f034f372e4 netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java
> --- a/netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java Wed Apr 06 10:02:46 2011 -0400
> +++ b/netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java Thu Apr 14 16:21:27 2011 -0400
> @@ -36,13 +36,16 @@
> import java.util.Collections;
> import java.util.Enumeration;
> import java.util.HashMap;
> +import java.util.HashSet;
> import java.util.LinkedList;
> import java.util.List;
> import java.util.Map;
> +import java.util.Set;
> import java.util.TreeSet;
> import java.util.Vector;
> import java.util.jar.JarEntry;
> import java.util.jar.JarFile;
> +import java.util.jar.Manifest;
>
> import net.sourceforge.jnlp.DownloadOptions;
> import net.sourceforge.jnlp.ExtensionDesc;
> @@ -138,6 +141,9 @@
> /** ArrayList containing jar indexes for various jars available to this classloader */
> private ArrayList<JarIndex> jarIndexes = new ArrayList<JarIndex>();
>
> + /** Set of classpath strings declared in the manifest.mf files */
> + private Set<String> classpathsInManfest = new HashSet<String>();
> +
> /** File entries in the jar files available to this classloader */
> private TreeSet<String> jarEntries = new TreeSet<String>();
>
> @@ -765,8 +771,28 @@
> // there is currently no mechanism to cache files per
> // instance.. so only index cached files
> if (localFile != null) {
> - JarIndex index = JarIndex.getJarIndex(new JarFile(localFile.getAbsolutePath()),
> - null);
> + JarFile jarFile = new JarFile(localFile.getAbsolutePath());
> + Manifest mf = jarFile.getManifest();
> + if (mf != null) {
> + String classpath = mf.getMainAttributes().getValue("Class-Path");
> + String[] paths = classpath.split(" +");
> + for (String path : paths) {
> + if (path.trim().length() == 0) {
> + continue;
> + }
> + // we want to search for jars in the same subdir on the server
> + // as this jar, so find out that subdirectory
> + String dir = jar.getLocation().getPath();
> + int lastSlash = dir.lastIndexOf("/");
> + if (lastSlash != -1) {
> + dir = dir.substring(0, lastSlash+1);
> + } else {
> + dir = "";
> + }
> + classpathsInManfest.add(dir + path);
> + }
> + }
> + JarIndex index = JarIndex.getJarIndex(jarFile, null);
Classpaths are joined by '+'?
> if (index != null)
> jarIndexes.add(index);
> }
> @@ -1007,8 +1033,32 @@
> try {
> result = loadClassExt(name);
> } catch (ClassNotFoundException cnfe) {
> + // Not found in external loader either
>
> - // Not found in external loader either. As a last resort, look in any available indexes
> + // Look in 'Class-Path' as specified in the manifest file
> + try {
> + for (String classpath: classpathsInManfest) {
> + JARDesc desc;
> + try {
> + URL jarUrl = new URL(file.getCodeBase(), classpath);
> + desc = new JARDesc(jarUrl, null, null, false, true, false, true);
> + } catch (MalformedURLException mfe) {
> + throw new ClassNotFoundException(name);
> + }
> + try {
> + addNewJar(desc);
> + } catch (Exception e) {
> + throw new ClassNotFoundException(name);
> + }
> + }
> +
> + result = loadClassExt(name);
> + return result;
> + } catch (ClassNotFoundException cnfe1) {
> + // continue below
> + }
> +
> + // As a last resort, look in any available indexes
Exceptions are getting eaten. The CNFE should use the thrown exceptions as the initCause. I'm especially
worried about just catching Exception; can we not be more specific?
>
> // Currently this loads jars directly from the site. We cannot cache it because this
> // call is initiated from within the applet, which does not have disk read/write permissions
> @@ -1026,33 +1076,11 @@
> } catch (MalformedURLException mfe) {
> throw new ClassNotFoundException(name);
> }
> -
> - available.add(desc);
> -
> - tracker.addResource(desc.getLocation(),
> - desc.getVersion(),
> - null,
> - JNLPRuntime.getDefaultUpdatePolicy()
> - );
> -
> - URL remoteURL;
> try {
> - remoteURL = new URL(file.getCodeBase() + jarName);
> - } catch (MalformedURLException mfe) {
> - throw new ClassNotFoundException(name);
> - }
> -
> - URL u;
> -
> - try {
> - u = tracker.getCacheURL(remoteURL);
> + addNewJar(desc);
> } catch (Exception e) {
> throw new ClassNotFoundException(name);
> }
> -
> - if (u != null)
> - addURL(u);
> -
What's happening here?
> }
>
> // If it still fails, let it error out
> @@ -1069,6 +1097,30 @@
> }
>
> /**
> + * Adds a new JARDesc into this classloader.
> + * <p>
> + * This will add the JARDesc into the resourceTracker and block until it
> + * is downloaded.
> + * @param desc the JARDesc for the new jar
> + */
> + private void addNewJar(JARDesc desc) {
> +
> + available.add(desc);
> +
> + tracker.addResource(desc.getLocation(),
> + desc.getVersion(),
> + null,
> + JNLPRuntime.getDefaultUpdatePolicy()
> + );
> +
> + URL remoteURL = desc.getLocation();
> +
> + URL u = tracker.getCacheURL(remoteURL);
> + if (u != null)
> + addURL(u);
> + }
> +
> + /**
> * Find the class in this loader or any of its extension loaders.
> */
> protected Class findClass(String name) throws ClassNotFoundException {
--
Andrew :)
Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)
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