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https://issues.apache.org/jira/browse/HDFS-573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14081665#comment-14081665
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Chris Nauroth commented on HDFS-573:
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I guess I misread something on HADOOP-10388. I thought I saw a nice clean init
function in the jni_helper.c over there. I may have incorrectly assumed that
this cascaded all the way out to the client-facing API. :-)
Thanks for sharing your experiences, Stephen. Unfortunately, I think we'd have
a hard time incorporating those changes right now, given the compatibility
concerns.
I suppose backwards-incompatible changes like this could be considered on the
3.x release boundary.
BTW Colin, thanks for the code review. The work so far has been aimed at a
straight port, warts and all, but I'm happy to roll in a few more small fixes
for existing problems while I'm in here. I'll work on a v2 of the patch.
I have just one question though. My initial inclination was to put
{{TYPE_CHECKED_PRINTF_FORMAT}} in platform.h as well. However, I then backed
that out and put the ifdef in exception.h, because it has never been clear to
me if exception.h is part of the public API. Most of the functions can't
reasonably be considered public, because of the dependence on passing a
{{JNIEnv}}. However, then there is {{getExceptionInfo}}. As long as we agree
that only hdfs.h is the public API, and not exception.h, then I'll move
{{TYPE_CHECKED_PRINTF_FORMAT}} back to platform.h. If client applications ever
{{#include <exception.h>}}, then they'd also have the complexity of selecting
the correct platform.h, which would be undesirable.
> Porting libhdfs to Windows
> --------------------------
>
> Key: HDFS-573
> URL: https://issues.apache.org/jira/browse/HDFS-573
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: libhdfs
> Environment: Windows, Visual Studio 2008
> Reporter: Ziliang Guo
> Assignee: Chris Nauroth
> Attachments: HDFS-573.1.patch
>
> Original Estimate: 336h
> Remaining Estimate: 336h
>
> The current C code in libhdfs is written using C99 conventions and also uses
> a few POSIX specific functions such as hcreate, hsearch, and pthread mutex
> locks. To compile it using Visual Studio would require a conversion of the
> code in hdfsJniHelper.c and hdfs.c to C89 and replacement/reimplementation of
> the POSIX functions. The code also uses the stdint.h header, which is not
> part of the original C89, but there exists what appears to be a BSD licensed
> reimplementation written to be compatible with MSVC floating around. I have
> already done the other necessary conversions, as well as created a simplistic
> hash bucket for use with hcreate and hsearch and successfully built a DLL of
> libhdfs. Further testing is needed to see if it is usable by other programs
> to actually access hdfs, which will likely happen in the next few weeks as
> the Condor Project continues with its file transfer work.
> In the process, I've removed a few what I believe are extraneous consts and
> also fixed an incorrect array initialization where someone was attempting to
> initialize with something like this: JavaVMOption options[noArgs]; where
> noArgs was being incremented in the code above. This was in the
> hdfsJniHelper.c file, in the getJNIEnv function.
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