Clean up .dll files on Windows #493
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bretambrose
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May 28, 2022
| // for old instances of the .dll and try to delete them. If another | ||
| // process is still using the .dll, the delete will fail, which is fine. | ||
| String os = getOSIdentifier(); | ||
| if (os == "windows") { |
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Feel like platform id shouldn't be a string, but that's a larger change.
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Another great reason to make it not-a-string!
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I started making it not-a-string but it was turning into a big refactor so going with .equals() as suggested by Dombo
sbSteveK
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May 31, 2022
graebm
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May 31, 2022
Update to latest aws-crt. Contains [fix](awslabs/aws-crt-java#493) that, on startup, deletes any .dll files it finds from previous runs of the library.
graebm
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May 31, 2022
Update to latest aws-crt. Contains [fix](awslabs/aws-crt-java#493) that, on startup, deletes any .dll files it finds from previous runs of the library.
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ISSUE: On Windows, the .dll file extracted to the temp directory was never being deleted. And repeated runs of the program were filling the disk with old .dll files.
DIAGNOSIS: We were using File.deleteOnExit() to clean up the shared lib, which is working OK on other platforms, but not on Windows. On Windows, files cannot be deleted while they're in use, and it appears that Java doesn't try to "unload" the .dll, so it's apparently impossible for a Java process to delete a .dll that it's using.
I did an experiment with a dead-simple JNI library. I simply loaded it, and called
File.deleteOnExit(). That .dll didn't get deleted either. So it's not just a problem with our .dll being very complex.DESCRIPTION OF CHANGES: On Windows only, during startup, scan the temp dir for old instances of
AWSCRT_*aws-crt-jni.dlland try to delete them.SIDE-NOTE:
I realized that on non-Windows platforms, the shared-lib won't be deleted on exit if Java dies suddenly (crash in C, OS terminated process, etc). But on non-Windows platforms you can delete the shared-lib from disk immediately after loading it, you don't need to wait until the process exits. I did experiments on Mac and this works. But I left it out of this PR because this is an emergency fix for windows and I don't want to introduce non-necessary changes.
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.