[RFC][Icedtea-web]: Changed how cache works.

[Andrew Su]

----- Original Message -----
> On 12:12 Mon 04 Apr , Andrew Su wrote:
> > Hi,
> >
> >  I have attached a patch for changing how cache stores its entries
> >  to fix some problems that existed in the current cache system.
> >
> > Right now the jar files may be overwritten by another plugin/javaws
> > when a new version is pushed while the user is using an old version
> > (prior update) then open another instance of the applet/javaws. With
> > the patch this gets fixed by creating a new location for the update
> > to be downloaded to instead of overwriting the current file.
> >
> > [I'm going to use applet, but assume I mean applet+javaws]
> > Another issue with the current one is.. When loading the same applet
> > twice (or more), it could detect that it's not current and both
> > applet would download to the same place. In the patch, we will wait
> > for the download to finish first then check if we have already
> > downloaded it. If so just proceed without re-downloading.
> >
> > This patch makes the cache keep track of the most recently used
> > items and remove items until we hit the cache limit if set.
> >
> > Changelog:
> >
> > 2011-04-04 Andrew Su <asu at redhat.com>
> >
> >         * netx/net/sourceforge/jnlp/cache/CacheEntry.java:
> >         (markForDelete, lock, unlock): New methods.
> >         * netx/net/sourceforge/jnlp/cache/CacheUtil.java:
> >         (getCacheFile): Changed to look for most recently used item,
> >         and when
> >         not found create a new entry.
> >         (makeNewCacheFile, cleanCache, lockFile, unlockFile,
> >         lockRecentlyUsedFile, unlockRecentlyUsedFile): New methods.
> >         * netx/net/sourceforge/jnlp/cache/ResourceTracker.java:
> >         (downloadResource): Changed to wait if we are already
> >         downloading the
> >         file. If file downloaded is compressed, mark compressed and
> >         extracted
> >         files for delete at shutdown.
> >         (initializeResource): Added checks for when the cache needs
> >         updating
> >         to create new folder entry.
> >         * netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java:
> >         (JNLPClassLoader): Change order so that we get resources
> >         first then
> >         check permissions for the jars.
> >         * netx/net/sourceforge/jnlp/runtime/JNLPRuntime.java:
> >         (markNetxRunning): Add call to clean up cache directory.
> >         * netx/net/sourceforge/jnlp/util/FileUtils.java:
> >         (getFileLock): New method.
> >
> > Any questions or comments welcome.
> >
> > Cheers,
> >  Andrew
> 
> I haven't looked over the whole patch, but I was disturbed by the use
> of 'RecentlyUsed'
> as the filename. Do we have other instances of mixed case in NetX? I
> would have
> thought something like 'recently_used' would be more appropriate.

Not a problem to change.

Cheers,
  Andrew