RFR: 8281384: Random chars on paste from Windows clipboard

[Kevin Rushforth]

On Tue, 25 Feb 2025 13:25:07 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.

I left a couple comments. As for an automated test, maybe there is something we could do with FFM, but it might be a bit of a project to figure out how to incorporate it into our test framework.

modules/javafx.graphics/src/main/java/com/sun/glass/ui/win/WinSystemClipboard.java line 255:

> 253:                 try {
> 254:                     // JDK-8118474 - internal Windows data null terminated
> 255:                     // JDK-8281384 - buffer might be larger than data and null terminator not at the end

Minor: We generally don't include the bug ID of the bug we are fixing in a comment (and I see no need here).

modules/javafx.graphics/src/main/java/com/sun/glass/ui/win/WinSystemClipboard.java line 258:

> 256:                     int nullTerm = data.length - 2;
> 257:                     for (int i = 0; i < data.length; i += 2) {
> 258:                         if (data[i] == 0) {

Since this is UTF-16, don't you need to check that both the even and odd bytes are 0?


                        if (data[i] == 0 && data[i+1] == 0) {


If you do this, you will want to validate that the length is even (if it isn't already ensured by `popBytes`).

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PR Review: https://git.openjdk.org/jfx/pull/1724#pullrequestreview-2641322865
PR Review Comment: https://git.openjdk.org/jfx/pull/1724#discussion_r1969912664
PR Review Comment: https://git.openjdk.org/jfx/pull/1724#discussion_r1969913328