RFR: 8281384: Random chars on paste from Windows clipboard [v7]

[Lukasz Kostyra]

On Wed, 26 Mar 2025 20:20:36 GMT, Oliver Schmidtmer <oschmidtmer at openjdk.org> wrote:

>> Windows programs may reuse a clipboard buffer that is larger than the new content. In this case de NUL terminator is not at the end of the buffer, but within it. 
>> The current implementation copys the whole buffer into a text field, including the NUL terminator and the remaining chars.
>> 
>> The JIRA ticket contains a JNA based sample program, which prefills the buffer for demonstrating this issue.
>> If this should be added as a unit test, I'm open for advice how to do that.
>
> Oliver Schmidtmer has updated the pull request incrementally with one additional commit since the last revision:
> 
>   readding flavors with changed mapping

Changes requested by lkostyra (Reviewer).

modules/javafx.graphics/src/main/native-glass/win/GlassClipboard.cpp line 207:

> 205: {
> 206:     addPair(GLASS_TEXT_PLAIN, CF_UNICODETEXT);
> 207:     addPair(GLASS_TEXT_PLAIN_LOCALE, CF_UNICODETEXT);

Seems like those changes made JFX unaware of text data ready to be pasted from "outside" - running your test program and trying to paste something to a TextBox (ex. in `HelloTextBoxClipboard`) doesn't work anymore (Paste popup menu option is disabled, Ctrl+V does nothing, whereas both were possible to do on master). I checked that these mime stuff changes are at fault.

My guess now would be that these mime_stuff changes have to be reverted and the actual change should happen as we request Clipboard data - probably a condition changing clipboard format `cf` from `CF_TEXT` and `CF_OEMTEXT` to `CF_UNICODETEXT` right before we call `me.Load()` in `PopMemory()`. Please check if that is in fact the case before committing though, I'm not 100% sure if that would work.

If that works, a comment explaining why we do this clipboard format swap would also come in handy for future generations.

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PR Review: https://git.openjdk.org/jfx/pull/1724#pullrequestreview-2720659536
PR Review Comment: https://git.openjdk.org/jfx/pull/1724#discussion_r2016138135