RFR: 8264774: Implementation of Foreign Function and Memory API (Incubator) [v2]

[Daniel Fuchs]

On Wed, 28 Apr 2021 10:42:54 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

>> This PR contains the API and implementation changes for JEP-412 [1]. A more detailed description of such changes, to avoid repetitions during the review process, is included as a separate comment.
>> 
>> [1] - https://openjdk.java.net/jeps/412
>
> Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address first batch of review comments

src/java.base/share/classes/jdk/internal/module/IllegalNativeAccessChecker.java line 40:

> 38: 
> 39:     private IllegalNativeAccessChecker(Set<String> allowedModuleNames, boolean allowAllUnnamedModules) {
> 40:         this.allowedModuleNames = Collections.unmodifiableSet(allowedModuleNames);

Should that be Set.copyOf() to take advantage of the immutability of `SetN` (but at the expense of additional copying)...

src/java.base/share/classes/jdk/internal/module/IllegalNativeAccessChecker.java line 78:

> 76:         int index = 0;
> 77:         // the system property is removed after decoding
> 78:         String value = getAndRemoveProperty(prefix + index);

I am not sure what is going on with the removal of the properties, but if I'm not mistaken this is racy: from the implementation of the checker() method above, it looks as if two different threads could trigger a call to the decode() function concurrently, which can result in a random partitioning of the properties against the two checkers being instantiated, with one of them being eventually set as the system-wide checker.

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PR: https://git.openjdk.java.net/jdk/pull/3699