RFR: 8299518: HotSpotVirtualMachine shared code across different platforms [v2]

[David Holmes]

On Wed, 4 Jan 2023 09:22:40 GMT, Yi Yang <yyang at openjdk.org> wrote:

>> harmless refactor to share code across different platforms of VirtualMachineImpl:
>> 1. Shared code to process command response after requesting a command execution
>> 2. Read functionality in SocketInputStream can be reused
>
> Yi Yang has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains two new commits since the last revision:
> 
>  - separate renaming
>  - 8299518: HotSpotVirtualMachine shared code across different platforms

src/jdk.attach/linux/classes/sun/tools/attach/VirtualMachineImpl.java line 195:

> 193:      * InputStream for the socket connection to get target VM
> 194:      */
> 195:     private static class SocketInputStreamImpl extends SocketInputStream {

Can this class definition also be shared by making it a protected nested class in the superclass?

src/jdk.attach/share/classes/sun/tools/attach/HotSpotVirtualMachine.java line 188:

> 186: 
> 187:     // known error
> 188:     private static final int ATTACH_ERROR_BADVERSION = 101;

It doesn't look right that this has the same value as ATTACH_ERROR_NOTONCP

src/jdk.attach/share/classes/sun/tools/attach/HotSpotVirtualMachine.java line 372:

> 370:     }
> 371: 
> 372:     void processCompletionStatus(IOException ioe, String cmd, InputStream sis) throws AgentLoadException, IOException {

Some doc comments for this method would be good.

src/jdk.attach/share/classes/sun/tools/attach/HotSpotVirtualMachine.java line 425:

> 423: 
> 424:         protected abstract int readImpl(long fd, byte[] bs, int off, int len) throws IOException;
> 425:         protected abstract void closeImpl(long fd) throws IOException;

If the subclasses all override these in exactly the same way then these do not need to be abstract and can simply delegate to VirtualMachineImpl.xxx

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PR: https://git.openjdk.org/jdk/pull/11823