On Sun, 12 Mar 2023 21:25:46 GMT, Eirik Bjorsnos <[email protected]> wrote:
>> Please review this PR which speeds up TestTooManyEntries and clarifies its
>> purpose:
>>
>> - The name 'TestTooManyEntries' does not clearly convey the purpose of the
>> test. What is tested is the validation that the total CEN size fits in a
>> Java byte array. Suggested rename: CenSizeTooLarge
>> - The test creates DEFLATED entries which incurs zlib costs and File Data /
>> Data Descriptors for no additional benefit. We can use STORED instead.
>> - By creating a single LocalDateTime and setting it with
>> `ZipEntry.setTimeLocal`, we can avoid repeated time zone calculations.
>> - The name of entries is generated by calling UUID.randomUUID, we could use
>> simple counter instead.
>> - The produced file is unnecessarily large. We know how large a CEN entry
>> is, let's take advantage of that to create a file with the minimal size.
>> - By adding a maximally large extra field to the CEN entries, we get away
>> with fewer CEN records and save memory
>> - The summary and comments of the test can be improved to help explain the
>> purpose of the test and how we reach the limit being tested.
>>
>> These speedups reduced the runtime from 4 min 17 sec to 4 seconds on my
>> Macbook Pro. The produced ZIP size was reduced from 5.7 GB to 2 GB. Memory
>> consumption is down from 8GB to something like 12MB.
>
> Eirik Bjorsnos has updated the pull request incrementally with two additional
> commits since the last revision:
>
> - MAX_EXTRA_FIELD_SIZE can be better expressed as 0xFFFF
> - Bring back '@requires sun.arch.data.model == 64' for now
test/jdk/java/util/zip/ZipFile/CenSizeTooLarge.java line 53:
> 51:
> 52: // Maximum size (unsigned short) of an extra field allowed by the
> standard
> 53: static final int MAX_EXTRA_FIELD_SIZE = 0XFFFF;
4.4.10 file name length: (2 bytes)
4.4.11 extra field length: (2 bytes)
4.4.12 file comment length: (2 bytes)
The length of the file name, extra field, and comment
fields respectively. The combined length of any
directory record and these three fields SHOULD NOT
generally exceed 65,535 bytes.
-------------
PR: https://git.openjdk.org/jdk/pull/12991
