RFR: 8015666: test/tools/pack200/TimeStamp.java failing

Xueming Shen xueming.shen at oracle.com
Tue Jul 2 18:29:08 UTC 2013

On 06/28/2013 07:47 AM, Kumar Srinivasan wrote:
> Some nits while reading the changes:
> 1. ZipEntry.java
>    a. typo:
> +     * Sets the laste access time of the entry.
>    b. extra space
> +                case EXTID_ZIP64 :
> 2. ZipOutputStream.java
> I think it would be nice to have the flags 0x1, 0x2 and 0x4 defined
> as constants, this will also help a casual reader as to what this means.
> Besides my previous concern with finish(), everything else appears to be ok.


I have the dostime "cached" in XEntry, so the writeCEN() and writeLOC() will
always write out the same local msdos time. The cache should help the perf
a little, as the javaToDosTime() now only invoked once for the same entry.

Nothing needs to be updated in unpack side now. (I took a look at the API,
it appears there is no way to do anything on unpack side to workaround
this issue, without the possibility of breaking someone's code)



> Kumar
>> On 06/27/2013 10:04 AM, Kumar Srinivasan wrote:
>>> Hi Sherman,
>>> I started looking at this, my initial comment, the Unpacker.unpack
>>> does not close its output and  we allow multiple pack  files to be concatenated,
>>> I am assuming out.finish() will allow further jar files to be appended ?
>>> or would this cause a problem ?
>> No, out.finish() will not allow further entry appending.  Then, it appears
>> we need to have a different approach to "finish" the Jar/ZipOutputStream.
>> What need to be done here is that either out.close/finish() need to be
>> invoked under the UTC locale as well (to output the time stamps in cen
>> table correctly).  This is another "incompatible" change of the previous
>> change, in which the msdosTime<->javaTime conversion no longer
>> occurs during the ZipEntry.set/getTime(), but during the read and write
>> the ZipEntry from/to the zip file.
>> -Sherman
>>> Kumar
>>>> Hi,
>>>> The zip time related changes[1] I pushed back last month appears
>>>> to have the compatibility risk of breaking existing code. The main
>>>> idea in that changeset is to use the more accurate and timezone
>>>> insensitive utc time stored in the extra field for the ZipEntry.set/getTime()
>>>> if possible. However it turns out the reality is that the code out there
>>>> might have already had some interesting workaround/hack solution
>>>> to workaround the problem that the time stamp stored in the "standard'
>>>> zip entry header is a MS-DOS standard date/time, which is a "local
>>>> date/time" and sensitive to timezone, in which, if the zip is archived
>>>> in time zone A (our implementation converts the "java" time to dos
>>>> time by using the default tz A) and then transferred/un-archived in
>>>> a different zone B (use default tz B to convert back to java time), we
>>>> have a time stamp mess up. The "workaround" from pack200 for this
>>>> issue when pack/unpacking a jar file is to "specify/recommend/suggest"
>>>> in its spec that the "time zone" in a jar file entry is assumed to be "UTC",
>>>> so the pack/unpack200 implementation set the "default time" to utc
>>>> before the pack/unpack and set it back to the original after that. It worked
>>>> "perfectly" for a roundtrip pack/unpacking, until the changeset [2], in
>>>> which ZipEntry.getTime() (packing) returns a real utc time and the following
>>>> ZipEntry.setTime() (unpacking), then mess up the MS-DOS date/time
>>>> entry, this is the root cause of this regression.
>>>> Given the facts that
>>>> (1) there are actually two real physical time stamps in a zip file header,
>>>> one is in the date/time fields, which is MS-DOS-local-date/time-with-2-
>>>> seconds-granularity , one is in the extra data field, which is UTC-1-second
>>>> -granularity
>>>> (2) and there are applications over there that have dependency on the
>>>> MS-DOS date/time stamp.
>>>> I'm proposing the following approach to add the functionality of supporting
>>>> the "utc-date/time-with-1-second granularity" and keep the old behavior
>>>> of the get/setTime() of the ZipEntry.
>>>> (1) keep the time/setTime()/getTime() for the MS-DOS standard date/time.
>>>>      To set via the old setTime() will only store the time into zip's standard
>>>>      date/time field, which is in MS-DOS date/time. And getTime() only returns
>>>>      the date/time from that field, when read from the zip file/stream.
>>>> (2) add mtime/set/getLastModifiedTime() to work on the UTC time fields,
>>>>      and the last modified time set via the new method will also set the "time",
>>>>      and the getLastModifiedTime() also returns the "time", if the UTC time
>>>>      stamp fields are not set in the zip file header. The idea is that for the new
>>>>      application, the recommendation is to use ZipEntry.set/getLastModifiedTime()
>>>>      for better/correct time stamp, but the existing apps keep the same behavior.
>>>> (3) jar and ZipOutputStream are updated to use the set/getLastModifiedTime().
>>>> (4) Pack/unpack continues to use the set/getTime(), so the current workaround
>>>>      continues work. I will leave this to Kuma to decide how it should be handled
>>>>      going forward. (there are two facts need to be considered here, a) the
>>>>      existing jar file might not have the utc time instored, and b) all "extra" data
>>>>      are wiped out during the pack/unpacking process)
>>>> (5) additionally add another pair of atime/get/setLastAccessTime and
>>>>      ctime/get/setCreationTime().
>>>> (6) The newly added 3 pairs of the m/a/ctime get/set methods use the "new"
>>>>      nio FileTime, instead of the "long". This may add some additional cost of
>>>>      conversion when working with them, but may also help improve the
>>>>      performance if the time stamps are directly from nio file system when
>>>>      get/set XYZTime. Good/bad?
>>>> http://cr.openjdk.java.net/~sherman/8015666/webrev/
>>>> Comment, option and suggestion are appreciated.
>>>> -Sherman
>>>> [1] http://hg.openjdk.java.net/jdk8/tl/jdk/rev/90df6756406f

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