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List:       poi-user
Subject:    Re: getStorageClsid()
From:       "Andrew C. Oliver" <acoliver () apache ! org>
Date:       2006-03-21 22:12:25
Message-ID: 44207A49.7080502 () apache ! org
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Marc (who wrote most of POIFS) said he didn't know what the clsid was so 
he just set it to 0.

jwang@dicarta.com wrote:
> The sequence, as far as I can tell, is:
> 
> 1) POIFSFileSystem(stream) is called
> 
> 2) POIFSFileSystem() is the first call, which sets the property table to
> be new PropertyTable() and root to be null.
> Nothing else of relevance to the current issue, until processProperties,
> with the directory as null
> 
> 3)Inside processProperties, the first check for the parent, results it
> being set as getRoot().
> 
> 4)In getRoot(), since root is still null, it creates a root from the
> property table, so we can translate how _root got instantiated to:
> 
> new DirectoryNode(new PropertyTable().getRoot(), this, null)
> 
> in EntryNode (super of Directory Node) the property is assigned, which
> means it is equivalent to new PropertyTable().getRoot()
> 
> 5) getStorageClsid() is equivalent to getProperty().getStorageClsid(),
> which means that it is equivalent to (new
> PropertyTable()).getRoot().getStorageClsid()
> 
> 6) This can be substituted with (new RootProperty()).getStorageClsid()
> because root property is only ever assigned once in PropertyTable().
> 
> 7) in RootProperty, nothing overrides the determination of cls id, so,
> going through a bunch of supers, we get Property() as the one
> responsible for creating it.
> 
> 8) since _raw_data is of type new byte[], the assignment to
> _storage_clsid is new ClassID(new byte[], some default offset).  Since
> the byte array is empty, the stored class id is therefore all 0s.
> 
> In other words, 
> new POIFSFileSystem(stream).getRoot().getStorageClsid().toString()
> should always return a bunch of 0s.
> 
> Note that there is a PropertyTable(start, blockList) that appears to
> generate better stuff, but that is a local variable in
> POIFSFileSystem(InputStream) perhaps the bug is that it should be
> assigned to the class variable instead?
> 
> Jeff Wang
> diCarta, Inc.
> 
> 
> -----Original Message-----
> From: Daniel Noll [mailto:daniel@nuix.com.au] 
> Sent: Monday, March 20, 2006 7:46 PM
> To: POI Users List
> Subject: Re: getStorageClsid()
> 
> Daniel Noll wrote:
> 
>>I'm fairly certain this is a bug because I've traced the creation of
> 
> the 
> 
>>properties in a debugger, and the root property does have the correct 
>>ClassID.  At some point in the POIFSFileSystem constructor, it is then
> 
> 
>>throwing away the class ID, but I can't see exactly where it's being 
>>thrown to.
> 
> 
> A reasonable workaround seems to be adding this at the bottom of the 
> (second) POIFSFileSystem constructor:
> 
>      getRoot().setStorageClsid(properties.getRoot().getStorageClsid());
> 
> This doesn't fix the underlying problem which is that the entire root is
> 
> somehow being clobbered somewhere, but it does at least make the one 
> method I do need to call work as expected.
> 
> Daniel
> 


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