[haiku-bugs] Re: [Haiku] #11306: "package add" no longer works
- From: "mmlr" <trac@xxxxxxxxxxxx>
- Date: Wed, 08 Oct 2014 21:57:41 -0000
#11306: "package add" no longer works
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Reporter: ttcoder | Owner: bonefish
Type: bug | Status: new
Priority: normal | Milestone: R1
Component: Kits/Package Kit | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking:
Has a Patch: 0 | Platform: All
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Comment (by mmlr):
I've investigated this and my conclusion is as follows:
When PackageFileHeapWriter tries to unwrite the last partial chunk in
PackageFileHeapWriter::_UnwriteLastPartialChunk() it uses ReadData() which
in turn calls into PackageFileHeapWriter::ReadAndDecompressChunk() with
the index argument set to the last, partial, chunk (0 in case of the
provided test case). Since it is the last chunk, it is assumed to be
pending (as it would be once the last partial chunk was unwritten), so the
pending buffer (which is yet to be filled) is copied to the uncompressed
buffer instead of decompressing the actual last chunk. The pending buffer
ends up containing nulls instead of the data of the last partial chunk.
Since the .PackageInfo is the only content of the package at this point,
it fully resides in the last partial chunk and is therefore completely
lost. Since the last chunk is lost in any case, using {{{package add}}}
should always be corrupting the package, even when not failing to read the
.PackageInfo (i.e. when there's enough additional data so that
.PackageInfo doesn't reside in the last partial chunk).
I'm attaching a workaround that uses a flag to signify whether we are
unwriting the last partial chunk so that
PackageFileHeapWriter::ReadAndDecompressChunk() uncompresses the last
chunk instead of returning the (yet unfilled) pending buffer. I can't
really tell how to fix this properly.
--
Ticket URL: <https://dev.haiku-os.org/ticket/11306#comment:8>
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